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Robotic Spacecraft (Astronomy, Planetary, Earth, Solar/Heliophysics) => Space Science Coverage => Topic started by: Blackstar on 01/27/2012 05:30 pm

Title: Proposed Europa Missions
Post by: Blackstar on 01/27/2012 05:30 pm
Europa orbiter study.

See also
https://forum.nasaspaceflight.com/index.php?topic=47579 for additional discussion
Title: Re: Proposed Europa Missions
Post by: Blackstar on 01/27/2012 05:31 pm
Europa flyby study.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 01/27/2012 05:38 pm
Lander study.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 01/27/2012 07:01 pm
This is the Jupiter Europa Orbiter Component of the Europa Jupiter System Mission, dated March 2010.

This was the Europa mission as of a couple of years ago. This was a big, expensive spacecraft. It was too big to afford. The decadal survey recommended that this mission be de-scoped (i.e. reduced), but the committee was unwilling to do that de-scoping itself because there was no obvious way to do it.

As a result of the decadal survey, NASA told JPL to go back to the drawing board and try to come up with a cheaper Europa mission. The three concept presentations that I posted earlier summarize JPL's current effort to de-scope the Europa mission. Those proposals are a smaller orbiter, a flyby mission (Jupiter orbit, but not Europa orbit) and a Europa lander.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 05/09/2012 02:20 pm
I missed this when it came out, but this is from the March OPAG meeting. It shows more work on the Europa lander study.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 05/09/2012 02:26 pm
Here are summaries of the Europa studies.

Yesterday I heard that the studies were delivered to NASA last week. NASA and OMB/OSTP will review the studies before they are officially released. My guess is that will happen in a month or two.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 05/09/2012 02:27 pm
Another summary.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 05/09/2012 02:27 pm
The rest of the summaries.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 08/11/2012 06:46 pm
Heard some interesting stuff about this last week. Cannot discuss it, but it'll probably be public soon. When it does become public, I'll have to eat some crow. (But that's okay, I've got a recipe for eating crow.)
Title: Re: Proposed Europa Missions
Post by: ugordan on 08/11/2012 06:57 pm
Can you at least drop some hints?
Title: Re: Proposed Europa Missions
Post by: spectre9 on 08/11/2012 07:41 pm
I'm still trying to pick myself up after the hint hit me on the head  :P

Thanks Blackstar. Really excited by that news  8)
Title: Re: Proposed Europa Missions
Post by: jnc on 08/11/2012 09:34 pm
I'm still trying to pick myself up after the hint hit me on the head

So what do you think the announcement will be?

Quote
Thanks Blackstar.

Yes, those are very cool. Thanks very much for posting them. I had missed them previously (not much chatter about them).

Still processing them (will probably need to re-read them, there's an enormous amount of into there), but one thing caught my eye:tThe 'Wrapup' lists the flyby costs at $1.9B (pg. 5), but the 'Flyby Element' presentation gives it as $1.5B (pg. 24). Admittedly, the 'Wrapup' presentation is from ~5 months later, and also I haven't looked to see if there were major changes to the science packages/mission capabilites to see if that could have (reasonably) driven the costs, but an increase of $.4B in estimated cost in that time period is somewhat curious.

Noel
Title: Re: Proposed Europa Missions
Post by: robertross on 08/12/2012 12:49 am
Here are summaries of the Europa studies.

Yesterday I heard that the studies were delivered to NASA last week. NASA and OMB/OSTP will review the studies before they are officially released. My guess is that will happen in a month or two.

Thanks for these!
Title: Re: Proposed Europa Missions
Post by: spectre9 on 08/12/2012 01:26 am
I like the fly by concepts.

You will get the up close science on Europa without staying too close to Jupiter and getting cooked by radiation.

Gives you better instruments like IPR and allows you to do fly bys of other targets.

Any idea if an Io fly by is at all possible?
Title: Re: Proposed Europa Missions
Post by: Blackstar on 08/12/2012 05:08 pm
I have to be careful. I can say what it isn't: a Europa mission is not going to get funded anytime soon.

What it is: JPL has continued to iterate the "clipper" (flyby) mission and the results have been positive, and surprising (to me). The iteration should lower the costs even further.

So the cost of a Europa mission may now be even lower than the previous studies show.

Title: Re: Proposed Europa Missions
Post by: Blackstar on 08/12/2012 05:17 pm
1-Yes, those are very cool. Thanks very much for posting them. I had missed them previously (not much chatter about them).

2-Still processing them (will probably need to re-read them, there's an enormous amount of into there), but one thing caught my eye:tThe 'Wrapup' lists the flyby costs at $1.9B (pg. 5), but the 'Flyby Element' presentation gives it as $1.5B (pg. 24). Admittedly, the 'Wrapup' presentation is from ~5 months later, and also I haven't looked to see if there were major changes to the science packages/mission capabilites to see if that could have (reasonably) driven the costs, but an increase of $.4B in estimated cost in that time period is somewhat curious.

1-Here's a tip: you should regularly go to the websites for VEXAG, OPAG, MEPAG, LEAG, and SBAG. They have now started webcasting some of their meetings. And they usually put their presentations online soon after their meetings.

There is a LOT of stuff that happens in the planetary program that never gets covered in the popular media or on websites. There's a lot of fascinating stuff that you can tap into if you know where to look. So the assessment groups are a good place to start.

2-I don't know about the differences in cost estimates. I could find out. However, it is possible that these were preliminary and/or internal estimates versus final/independent cost estimates.

[more in a second post]
Title: Re: Proposed Europa Missions
Post by: Blackstar on 08/12/2012 05:21 pm
[Sorry to split this up, but my software is acting up and would not let me post longer.]

When we worked on the decadal survey we used a cost estimating process that was different than what NASA and JPL commonly used. They normally did a straight up cost estimate, and those estimates are actually pretty accurate if you assume no external impacts on the program. The problem is that lots of things happen to programs in development that are outside of their control. For example, launch costs can increase during development, and no matter how good and dilligent the spacecraft designers are, they cannot control that increase. So the process we used included "threats" to development, like what happens if NASA/OMB cuts the budget for your project, forcing a stretchout? Or what if launch costs go up?

When you add in the threats, it increased the costs of the projects on average of (I think) about 40% (could have been 60%--it's in the decadal survey and you can look it up because I'm too lazy at the moment). That naturally made the advocates of various missions angry, because they argued that their projects were not that expensive, and we were saying they would be (but not their fault).

So maybe the increase that you found is due to JPL going to Aerospace Corp and getting their independent estimate, which included program threats.
Title: Re: Proposed Europa Missions
Post by: jnc on 08/12/2012 06:30 pm
JPL has continued to iterate the "clipper" (flyby) mission and the results have been positive, and surprising (to me).

Can't wait to hear the latest+greatest! I have to say that of the three, that mission was the one I would have picked in today's budget environment. Yes, the lander would be 'way cool', and does some interesting science neither other mission can do, but with i) the much larger price-tag for the lander (almost 2x), and bigger risk, and ii) getting basically as much science out of the fly-by, it's (to me) a no-brainer.

Sigh, maybe we'll be able to afford the lander some day!

Here's a tip: you should regularly go to the websites ... They have now started webcasting some of their meetings. ... There is a LOT of stuff that happens in the planetary program that never gets covered in the popular media or on websites. ... So the assessment groups are a good place to start.

In my copious free time! :) (Seriously; space is my #2 hobby, see here (http://www.yoshitoshi.net/) for example about #1, at which I'm semi-professional, so after my real life (http://tools.ietf.org/html/draft-chiappa-lisp-introduction-01), I'm kind of short on time!)

So if you don't mind I'll continue to rely on you to keep us posted on all this cool stuff happening quietly in the corners!

[Sorry to split this up, but my software is acting up and would not let me post longer.]

No problem!

Quote
When we worked on the decadal survey we used a cost estimating process that was different ... When you add in the threats, it increased the costs of the projects on average of (I think) about 40% ... So maybe the increase that you found is due to JPL going to Aerospace Corp and getting their independent estimate, which included program threats.

Hmm. That's about the right magnitude, but... I went back and looked, and the orbiter didn't show a similar increase. (Couldn't find a number for the lander in the November presentations.)

The increase may well be as a result of the Aerospace review, but my guess would be that's it's not too likely that JPL added the 'threat' factor to one, and not the other. So perhaps the Aerospace review found something else?

Probably an interesting question to ask them, though.. :)

Noel
Title: Re: Proposed Europa Missions
Post by: Blackstar on 08/12/2012 09:42 pm
Yes, the lander would be 'way cool', and does some interesting science neither other mission can do, but with i) the much larger price-tag for the lander (almost 2x), and bigger risk, and ii) getting basically as much science out of the fly-by, it's (to me) a no-brainer.

Risk totally rules out the lander for now. It was included simply for completeness, and (I think) because by defining a lander, you could also identify any precursor requirements that would need to be incorporated into an orbiter or flyby mission. The lander mission study made it clear that high resolution imaging of the surface is required before you can fly a lander.
Title: Re: Proposed Europa Missions
Post by: jnc on 08/12/2012 09:55 pm
high resolution imaging of the surface is required before you can fly a lander.

Would they get enough from a fly-by, or would it require an orbiter?

(Although now that I think about it, the lander mission defined in the presentations had an orbital phase where they did a lot of imaging for selecting a landing spot - would that have been enough on its own, or would they have needed a separate imaging mission as well?)

Noel
Title: Re: Proposed Europa Missions
Post by: spectre9 on 08/12/2012 11:27 pm
Fly by doesn't mean that the distance for observations is longer.

It just means the probe doesn't stay at the one moon.

It flies in takes the readings and flys away. Obviously doing it like this takes a lot longer to image the full surface but I do think it's worth it.

It's like Cassini how it does a fly by of Titan or Enceladus every now and then.

The orbiter/lander mission can come later.

Thanks for clarification about what the hints you were dropping were about Blackstar.

I'm guessing that a cut down fly by mission from the ones in the already posted presentations are what is being considered?

C'mon outer planets!!!  8)
Title: Re: Proposed Europa Missions
Post by: Blackstar on 08/13/2012 12:18 am
I'm guessing that a cut down fly by mission from the ones in the already posted presentations are what is being considered?

I didn't say "cut down."

I said cheaper...

(and, surprisingly, better too--put another way, more capability at less money)
Title: Re: Proposed Europa Missions
Post by: spectre9 on 08/13/2012 12:24 am
Ok thanks for the added clarification.

Now I'm excited again but I still realise that outer planets has a fight ahead of them to get anything approved in the current environment.
Title: Re: Proposed Europa Missions
Post by: jnc on 08/13/2012 02:34 am
It just means the probe doesn't stay at the one moon.

Got that, thanks.

Quote
Obviously doing it like this takes a lot longer to image the full surface

They might get full surface imagery, but not at the level of detail the orbiter would give them. If you look at pg. 12 of the "Mission Studies" presentation, you'll see that the orbiter gives pretty good coverage at 100 m/pixel.

The multiple passes of the flyby won't give anything like as good coverage at high resolutions; check out the ground tracks (pg. 17 of the "Mission Studies") and the Topographic Imager coverage chart (next page).

Of course, 100 m/pixel is not enough resolution to really check out for landing spots, a point made on pp. 17-18 of the "Pappalardo Lander Forum" presentation. And while looking for the cite on that, I noticed that the "Lander Technical" presentation says, on pg. 10, that they need .5 m/pixel for a reasonably safe landing. (Which I guess kind of answers the question in my previous post...)

I see on pg. 11 that they're going to do hi-res imaging, and site selection from that imaging, as phases 1 and 2 of the landing process, but it's not clear from any of this material if they do that from the initial orbit (parameters not given), or the 200x5 km 'pre-landing' orbit; the timeline on pg. 9 makes it sound like it's from the inital orbit.

Noel
Title: Re: Proposed Europa Missions
Post by: spectre9 on 08/13/2012 03:05 am
For a nominal mission length yes I would agree that the orbiter is going to get the better mapping but consider this.

Cassini was a 4 year mission.

It's been going for 8 and doesn't look like the probe will die any time soon.

The flyby can also get closer to the surface. Some of those tracks are <25km. If it's just the type of camera stopping the detail from being better possibly the instrumentation could be altered?

It seems to me like these 2 separate spacecraft are designed to be the one mission so if one is flown and the other is not that would be a different mission design.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 08/13/2012 04:10 am
The multiple passes of the flyby won't give anything like as good coverage at high resolutions; check out the ground tracks (pg. 17 of the "Mission Studies") and the Topographic Imager coverage chart (next page).

Hmmm...

I'm not sure when the next OPAG meeting is, but you might check on that.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 09/24/2012 11:42 pm
Okay, I'll post the slides later, but here's the deal:

JPL has been studying the Europa Clipper mission since around May and now thinks that it is possible that they could do the mission with solar. That would reduce the cost of the mission, and possibly also decrease risk, since the ASRGs are considered risky. (So, while I previously posted that solar won't work for Europa missions, I may eventually have to eat my hat, with a heaping of crow.)

That's not a done deal, however. One of the big problems is that the Clipper would go into shadow for a long time (I think I heard them say around six hours) and that requires batteries and batteries are heavy. There are also other problems, such as the radiation damage to the solar panels and the issue of cold--a Clipper mission would get more radiation and more cold than Juno.

Another potential problem is jitter. The panels could introduce vibration. Now why is that important?

Well, it turns out that one of the other big things they have been looking at is adding a high-resolution camera to the Clipper to take photos of potential landing sites for a future mission. Apparently the lander mission that they studied got people sufficiently excited that they think that the lander is feasible, provided that you could get good landing site data.

I didn't hear the presentations that well, but the camera adds something like $200 million to the mission, pushing it over a cost cap (of, I think, $2 billion). Using solar instead of ASRGs then brings the cost down. Not sure if it brings it back into the cost cap, but it helps a lot.

Now let me be clear on this: THERE IS NO MONEY TO DO THIS MISSION. A senior planetary official made that clear at the end of the presentation--just because a study has reduced the cost doesn't mean that there is actual money to do a Europa flagship mission. But it does show that there is promise here.

I'll post the slides later.
Title: Re: Proposed Europa Missions
Post by: robertross on 09/25/2012 12:26 am
Thanks Blackstar!

They may not have the money, but perhaps it could generate enough interest outside the science community (and in the political arena) to find funding in a gov't/private partnership (doubt that would happen, but you never know).
Title: Re: Proposed Europa Missions
Post by: Blackstar on 09/25/2012 01:50 am
They may not have the money, but perhaps it could generate enough interest outside the science community (and in the political arena) to find funding in a gov't/private partnership (doubt that would happen, but you never know).

No. Impossible. Price tag is $2 billion. Nobody foots serious cash for stuff that they assume the government should fund. This is going to be the big problem for B612 and their asteroid search spacecraft.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 09/25/2012 04:28 am
Here's some of it.
Title: Re: Proposed Europa Missions
Post by: simonbp on 09/25/2012 02:53 pm
That is interesting.

The solution to the jitter may be a separate scan platform (like Voyager), which could both cancel out the jitter and allow more imaging during the pass. This would add to the cost, but solar+scan platform could still be cheaper than with an ASRG.
Title: Re: Proposed Europa Missions
Post by: robertross on 09/25/2012 03:21 pm
They may not have the money, but perhaps it could generate enough interest outside the science community (and in the political arena) to find funding in a gov't/private partnership (doubt that would happen, but you never know).

No. Impossible. Price tag is $2 billion. Nobody foots serious cash for stuff that they assume the government should fund. This is going to be the big problem for B612 and their asteroid search spacecraft.

aww shucks.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 09/25/2012 04:09 pm
Here is the first half of the presentation.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 09/25/2012 04:09 pm
Here is the rest of the presentation.
Title: Re: Proposed Europa Missions
Post by: Star One on 09/25/2012 09:34 pm
With that kind of price tag no one is going to fund this anytime soon are they?
Title: Re: Proposed Europa Missions
Post by: Blackstar on 09/25/2012 11:20 pm
With that kind of price tag no one is going to fund this anytime soon are they?

The quick answer is "no." The more complex answer is that OMB has apparently decided to not approve any flagships for planetary science, so it doesn't matter which ones get proposed, in what order, there is simply no support for doing it.

That said, the real action now is in the Mars area. Complex story, but you can find the threads.
Title: Re: Proposed Europa Missions
Post by: robertross on 09/25/2012 11:39 pm
Here is the rest of the presentation.

Hot off the presses! Thank you Sir.
Title: Re: Proposed Europa Missions
Post by: robertross on 09/26/2012 12:06 am
Very cool to see a 0.5m/pixel camera on the enhanced Clipper. That should be more than adequate. :)

Really like the margins.

I also like the Magnetometer boom addition.

Using SLS: 6 years to 2.8 years!! Wish it was affordable (but nowhere near holding my breathe...maybe pre-breathing) Really like the nanosat concept tied to it.

(smal spelling issue at bottom of Part 2, page 30)
Title: Re: Proposed Europa Missions
Post by: Solman on 09/26/2012 01:33 am
 Just want to suggest that a solar concentrator might have many advantages for a Europa mission. L'Garde has demonstrated one that focuses 17KW thermal roughly per KW thermal. Around 170W/kg at Saturn even. My mind wandered toward Enceladus and sampling of volcanic emissions by an orbiter ...
 A concentrator can double as a high baud antenna for such an outer planet mission due to its size.
 The solar cells that use concentrated sunlight have the highest efficiency - over 40% - and best specific power.
 The concentrator can power a solar thermal engine for LEO to escape saving much time over solar electric and power a solar electric engine after that.
 The concentrator can double as a radio telescope for some very long baseline interferometry and SAR at Europa.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 09/26/2012 01:56 am
Using SLS: 6 years to 2.8 years!! Wish it was affordable (but nowhere near holding my breathe...maybe pre-breathing) Really like the nanosat concept tied to it.

One of the people who worked on the study is really enthusiastic about SLS for this mission. My impression is that he's the only one.

It's simple: a really big rocket can give you really great margins for missions like this, and everybody would just love to have more mass and more delta-v to play with. And theoretically, you could possibly save money on your spacecraft design because you don't have to design anything to be extremely light weight, which always costs a lot.

The problem is programmatics--fitting a science spacecraft onto a non-existent rocket that actually belongs to another part of NASA, and which will be too expensive on a per-unit basis for the science part of NASA to afford. The science guys have said that they would only really consider this if the HEO part of NASA agreed to foot the bill for the launch, essentially providing the SLS launch for free for a science payload. Why would HEOMD agree to do that? They'd be giving away their money. And even if they agreed to it, there's no guarantee to the science guys that they would stick to that decision, and three years into the program the science program could find itself suddenly being stuck with the launch costs and having to cannibalize other parts of their portfolio.

So from a programmatic perspective, it is far safer for the science program to simply design for a rocket that already exists and that they already have some experience with. Now if you assume that SLS gets built, and flies successfully, and this Europa mission gets approved, then SLS might be an option. But it would be crazy to baseline it now.
Title: Re: Proposed Europa Missions
Post by: robertross on 09/26/2012 02:28 pm
and that is a 100% perfect assessment of the situation, and totally agree.

I might only add that they (HEOMD) might consider doing this if they could do a dual launch (launch of opportunity) for something else, like an empty depot, another spacecraft, or goodness knows what. But not likely.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 09/26/2012 02:34 pm
and that is a 100% perfect assessment of the situation, and totally agree.

I might only add that they (HEOMD) might consider doing this if they could do a dual launch (launch of opportunity) for something else, like an empty depot, another spacecraft, or goodness knows what. But not likely.

I do think it would be an interesting--possibly worthwhile--exercise to evaluate the benefits of heavy lift for planetary missions. I know of no detailed studies that have done it. When we did our assessment of Constellation for science, we didn't have any planetary missions to look at, so all we could really do was discuss the C3 and payload benefits without having anything more.

Dual manifesting has some potential in niche cases, but would require study. There was a ridiculous study about five years ago called CEMMENT (Worst. Name. Ever.) that looked at the possibility of doing an engineering test of a human lander at Mars that would be loaded up with science experiments. The basic idea was reasonable, but they went crazy with it, thinking that because they would have a lot of payload and volume, they should fill it all up with sciency stuff. The end result was a science fiction fantasy, because there was no way that, even if they got the launch vehicle and lander for free, the science program could afford to build all the science spacecraft.
Title: Re: Proposed Europa Missions
Post by: robertross on 09/26/2012 03:03 pm
and that is a 100% perfect assessment of the situation, and totally agree.

I might only add that they (HEOMD) might consider doing this if they could do a dual launch (launch of opportunity) for something else, like an empty depot, another spacecraft, or goodness knows what. But not likely.

I do think it would be an interesting--possibly worthwhile--exercise to evaluate the benefits of heavy lift for planetary missions. I know of no detailed studies that have done it. When we did our assessment of Constellation for science, we didn't have any planetary missions to look at, so all we could really do was discuss the C3 and payload benefits without having anything more.

Dual manifesting has some potential in niche cases, but would require study. There was a ridiculous study about five years ago called CEMMENT (Worst. Name. Ever.) that looked at the possibility of doing an engineering test of a human lander at Mars that would be loaded up with science experiments. The basic idea was reasonable, but they went crazy with it, thinking that because they would have a lot of payload and volume, they should fill it all up with sciency stuff. The end result was a science fiction fantasy, because there was no way that, even if they got the launch vehicle and lander for free, the science program could afford to build all the science spacecraft.

I don't know if a study was done per se, but using the Ares V (more like Ares VI...hehe) for science missions was definitely persued (more like flaunted) by NASA (obviously to gain support). Those docs are here on the public side or the L2 side.

Edit: here it is:
http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20070038373_2007037046.pdf
Title: Re: Proposed Europa Missions
Post by: vjkane on 09/26/2012 04:42 pm
With that kind of price tag no one is going to fund this anytime soon are they?

The quick answer is "no." The more complex answer is that OMB has apparently decided to not approve any flagships for planetary science, so it doesn't matter which ones get proposed, in what order, there is simply no support for doing it.

I think that you have to look at a Europa mission as a long game.  With JWST overruns and manned spaceflight budget challenges, this is not the time to ask for new Flagship missions in any of the science disciplines.  However, this is the first Europa mission proposal that comes in at $2B and doesn't require significant new technology development.  I believe that if the space community keeps Europa as a focus, then getting a new start after JWST flies later this decade would be a reasonable goal to work towards.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 09/26/2012 06:21 pm
I don't know if a study was done per se, but using the Ares V (more like Ares VI...hehe) for science missions was definitely persued (more like flaunted) by NASA (obviously to gain support). Those docs are here on the public side or the L2 side.

Edit: here it is:
http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20070038373_2007037046.pdf

You linked to a paper about using heavy lift for astronomy. That's an obvious option.

The NRC did a study around 2008 or so on using Constellation for science missions. When we did that study we had a lot of options for astronomy and other missions using heavy lift. We did not have any previous studies of using it for planetary missions. I was pointing out that there could be value at looking at this issue beyond simply additional mass and C3. It might allow you to do innovative orbits, or more complex mission architectures (not necessarily more complex spacecraft--for example, you could simply add fuel and do better things with your orbits). And the impact on spacecraft design could be significant, but so far all the discussions have been superficial.

What this really comes down to is a cost-benefit trade that nobody has really made. That could be summed up like this: "The HLV rocket costs you an extra $700 million for launch; can you save more than $700 million in spacecraft design using heavy lift?" Nobody has really looked at those trades.
Title: Re: Proposed Europa Missions
Post by: spectre9 on 09/26/2012 11:33 pm
Thanks very much for the information provided Blackstar.

Interesting that the mission can be traded to solar.

Asking for the money or not this is a mission that needs to be done.

The decadal survey says so. No MSR = Europa. That's the flagship priority. The MSR guys just can't let go yet.

The next survey might not be so sympathetic to their cause. Could awesome discoveries made by Curiosity push the priority for MSR back? I mean that's the whole reason for having something like SAM isn't it? So you can test the rocks at Mars without bringing them back.

I like the idea of using big rockets for exploring, the ice giants are so far away something like SLS really helps.

At $2 billion this is a cheap flagship for the science that can be had. These big questions about Europa have had planetary scientists giddy for years now, it's time to get some answers.  8)
Title: Re: Proposed Europa Missions
Post by: Blackstar on 09/27/2012 01:35 am
1-Interesting that the mission can be traded to solar.

2-The decadal survey says so. No MSR = Europa. That's the flagship priority. The MSR guys just can't let go yet.

3-I mean that's the whole reason for having something like SAM isn't it? So you can test the rocks at Mars without bringing them back.

1-It might be possible to do with solar. The studies are not done yet.

2-No, that's not really how it works. (Trust me, I was there.) The first choice in the decadal was MSR. The Office of Management and Budget decided to not do any flagships at all. It is not the case that because OMB said no to sample return that we now go on to Europa.

3-No. There are three, maybe four reasons to do sample return:

-the samples can be analyzed on Earth by hundreds of different research teams
-the samples can be analyzed for decades after they return (the best science done on Apollo samples is being done TODAY with modern instruments)
-you can use a far greater number of instruments to analyze samples on Earth than you can on a planetary body

One additional argument in favor of sample return is discovery--when you provide the samples to a broad group of people, rather than the narrow team that works on a single space mission, you can get discoveries that you never would have otherwise gotten.

The SAM instrument on Curiosity is an impressive piece of space hardware. It is very primitive and limited in capability compared to even a modest university chemistry lab on Earth. We have no way to squeeze all the incredibly sophisticated instruments that exist on Earth into a small package on a spacecraft. SAM is no substitute for bringing back the materials.
Title: Re: Proposed Europa Missions
Post by: baldusi on 09/27/2012 10:23 pm
I still think about the C3 benefits of a Heavy launcher (or a depot architecture). How do you trade the possibility of basing one mission on the results of previous one? If you have 6 to 8 years of travel, you can't get more than one mission per decade, if you are lucky, that need the previous one. On the other hand, at 2 to 3 years of transit, you can do twice the number. It get's interesting if you can use the previous missions assets. Say you want to send a lander to Europa. Communications with Earth is very difficult. May be, if it only has to wait for five years, there's a way to put it on hibernation and use the orbiters communication capabilities to support the lander. But if it took longer, the degradation would be too great, even in case of hibernation and protecting shrouds.
On hte other hand, a heavy launcher could send the communication orbiter AND the lander on the same mission. I'm just trying to get creative.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 09/28/2012 01:50 am
I still think about the C3 benefits of a Heavy launcher (or a depot architecture). How do you trade the possibility of basing one mission on the results of previous one? If you have 6 to 8 years of travel, you can't get more than one mission per decade, if you are lucky, that need the previous one. On the other hand, at 2 to 3 years of transit, you can do twice the number. It get's interesting if you can use the previous missions assets. Say you want to send a lander to Europa. Communications with Earth is very difficult. May be, if it only has to wait for five years, there's a way to put it on hibernation and use the orbiters communication capabilities to support the lander. But if it took longer, the degradation would be too great, even in case of hibernation and protecting shrouds.
On hte other hand, a heavy launcher could send the communication orbiter AND the lander on the same mission. I'm just trying to get creative.

I think that is the kind of trade it would be interesting to perform. But the key trade to explore would be cost reduction in missions. For instance, if you decrease the transit time and increase the mass margins and fuel margins and things like that, could you bring the cost of the mission down significantly? I've only seen very thin speculation about this, but nobody has actually gone into it in any depth.
Title: Re: Proposed Europa Missions
Post by: baldusi on 09/28/2012 08:11 pm
[...]

I think that is the kind of trade it would be interesting to perform. But the key trade to explore would be cost reduction in missions. For instance, if you decrease the transit time and increase the mass margins and fuel margins and things like that, could you bring the cost of the mission down significantly? I've only seen very thin speculation about this, but nobody has actually gone into it in any depth.

My intuition, is that any sort of increase in structural or payload mass due to lowering the cost, will be offset by the increased fuel and thrust increase needed. After all, the rocket formula is exponential on the pmf. Besides, AFAIK, the bulk of cost it on certification and testing, not on the materials themselves.
The other issue, and I think this is the core issue, is: how do you keep the scientists and engineers from adding features and science payload that actually increases the cost since they have weight and volume to spare? In other words, if the budget was made reasonably, the biggest danger is the project management's own desire for a better mission.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 09/28/2012 09:03 pm
1-My intuition, is that any sort of increase in structural or payload mass due to lowering the cost, will be offset by the increased fuel and thrust increase needed. After all, the rocket formula is exponential on the pmf. Besides, AFAIK, the bulk of cost it on certification and testing, not on the materials themselves.

2-The other issue, and I think this is the core issue, is: how do you keep the scientists and engineers from adding features and science payload that actually increases the cost since they have weight and volume to spare? In other words, if the budget was made reasonably, the biggest danger is the project management's own desire for a better mission.

1-I don't think that's an issue here because the initial margins are so huge. We're talking about throwing a relatively small spacecraft to the outer planets. With a heavy lift vehicle you can easily throw twice the mass. So if you give the designers 50% more margin to play with, the other penalties don't really bite.

2-Yes, that is an issue. But you're going to be cost constrained from the start. The way to do the initial trade is to take a spacecraft designed for a smaller vehicle and then tell the designers "You cannot add instruments, but you can add mass, fuel, operations, and other margins." I imagine that in some missions that would cause the scientists to hyperventilate and faint because they'd love to have those things even without more instruments. For example, the key limitation is radiation. If you told the scientists that instead of a 180 day mission they could have enough shielding for a five-year mission, they would be more than happy.
Title: Re: Proposed Europa Missions
Post by: baldusi on 09/29/2012 03:46 pm
1-My intuition, is that any sort of increase in structural or payload mass due to lowering the cost, will be offset by the increased fuel and thrust increase needed. After all, the rocket formula is exponential on the pmf. Besides, AFAIK, the bulk of cost it on certification and testing, not on the materials themselves.

2-The other issue, and I think this is the core issue, is: how do you keep the scientists and engineers from adding features and science payload that actually increases the cost since they have weight and volume to spare? In other words, if the budget was made reasonably, the biggest danger is the project management's own desire for a better mission.

1-I don't think that's an issue here because the initial margins are so huge. We're talking about throwing a relatively small spacecraft to the outer planets. With a heavy lift vehicle you can easily throw twice the mass. So if you give the designers 50% more margin to play with, the other penalties don't really bite.
But more mass means higher thrust engines. Higher mass means higher momentum of inertia, thus, bigger reaction wheels and thrusters, plus thruster fuel, etc. Bigger fuel tanks in relation to the payload also means a more over sized control authority when the tanks are near empty, thus requiring higher precision firings and more sophisticated control. Then you have to certify and test everything. I seriously doubt you would save much. The only way I see this saving money is if they can use a legacy platform and parts that are already designed and certified for the expected environment. If said parts and/or platform was too heavy for the "small" LV, then yes, using a more powerful rocket might actually lower the cost. But you won't save much, if anything, by doing it custom.
You know very well that planetary missions have very particular requirements that nobody else needs. You have to tolerate the environment from Venus to the outer planets (if you do a VVEGA maneuver), the radiation degradation environment is unique to deep space probes, and the thermal environment is very particular. You might save a bit if you can use a bigger LV to save the Venus Gravity assist, and thus you don't have to design for that thermal environment. Of course, we are talking about a mission already planned with a conservative estimation and good margins. If you want to put a 2.5tonnes mission on a 1.9tonnes LV, of course it's going to be cheaper to put it on a bigger LV than making enough technological advances to reduce the weight enough. But going from an EELV to SLS the jump in performance is so huge, that's not the case.

Quote
2-Yes, that is an issue. But you're going to be cost constrained from the start. The way to do the initial trade is to take a spacecraft designed for a smaller vehicle and then tell the designers "You cannot add instruments, but you can add mass, fuel, operations, and other margins." I imagine that in some missions that would cause the scientists to hyperventilate and faint because they'd love to have those things even without more instruments. For example, the key limitation is radiation. If you told the scientists that instead of a 180 day mission they could have enough shielding for a five-year mission, they would be more than happy.
I quite get how it would be ideally. But you have to plan the system for the "misbehaving". And in any case, more mass usually means more cost. You can add some layers of composite Ti/Br to protect the electronics. But then you have to actually certify that for a five year radiation and thermal environment. That means weeks, if not months on environmental testing chambers and more time in from of the accelerator. And then, how do you protect your sensors? You added protection to your electronics but now you have to develop hardened sensors, which you can't protect unless you don't want to get any reading. Might be an option if you want to take extended time domain samples. But then you have to design, certify, integrate and test a sensor protection system. More money and complexity.
And again, I think you can do that if you jump from an Atlas V531 to a 551. But even from a Falcon Heavy to SLS there's so much differential, that I can't think of any use save delta-v that will be "cheaper".
Title: Re: Proposed Europa Missions
Post by: Blackstar on 09/30/2012 01:56 pm
1-My intuition, is that any sort of increase in structural or payload mass due to lowering the cost, will be offset by the increased fuel and thrust increase needed. After all, the rocket formula is exponential on the pmf. Besides, AFAIK, the bulk of cost it on certification and testing, not on the materials themselves.

2-The other issue, and I think this is the core issue, is: how do you keep the scientists and engineers from adding features and science payload that actually increases the cost since they have weight and volume to spare? In other words, if the budget was made reasonably, the biggest danger is the project management's own desire for a better mission.

1-I don't think that's an issue here because the initial margins are so huge. We're talking about throwing a relatively small spacecraft to the outer planets. With a heavy lift vehicle you can easily throw twice the mass. So if you give the designers 50% more margin to play with, the other penalties don't really bite.
But more mass means higher thrust engines. Higher mass means higher momentum of inertia, thus, bigger reaction wheels and thrusters, plus thruster fuel, etc. Bigger fuel tanks in relation to the payload also means a more over sized control authority when the tanks are near empty, thus requiring higher precision firings and more sophisticated control. Then you have to certify and test everything. I seriously doubt you would save much. The only way I see this saving money is if they can use a legacy platform and parts that are already designed and certified for the expected environment. If said parts and/or platform was too heavy for the "small" LV, then yes, using a more powerful rocket might actually lower the cost. But you won't save much, if anything, by doing it custom.
You know very well that planetary missions have very particular requirements that nobody else needs. You have to tolerate the environment from Venus to the outer planets (if you do a VVEGA maneuver), the radiation degradation environment is unique to deep space probes, and the thermal environment is very particular. You might save a bit if you can use a bigger LV to save the Venus Gravity assist, and thus you don't have to design for that thermal environment. Of course, we are talking about a mission already planned with a conservative estimation and good margins. If you want to put a 2.5tonnes mission on a 1.9tonnes LV, of course it's going to be cheaper to put it on a bigger LV than making enough technological advances to reduce the weight enough. But going from an EELV to SLS the jump in performance is so huge, that's not the case.

Quote
2-Yes, that is an issue. But you're going to be cost constrained from the start. The way to do the initial trade is to take a spacecraft designed for a smaller vehicle and then tell the designers "You cannot add instruments, but you can add mass, fuel, operations, and other margins." I imagine that in some missions that would cause the scientists to hyperventilate and faint because they'd love to have those things even without more instruments. For example, the key limitation is radiation. If you told the scientists that instead of a 180 day mission they could have enough shielding for a five-year mission, they would be more than happy.
I quite get how it would be ideally. But you have to plan the system for the "misbehaving". And in any case, more mass usually means more cost. You can add some layers of composite Ti/Br to protect the electronics. But then you have to actually certify that for a five year radiation and thermal environment. That means weeks, if not months on environmental testing chambers and more time in from of the accelerator. And then, how do you protect your sensors? You added protection to your electronics but now you have to develop hardened sensors, which you can't protect unless you don't want to get any reading. Might be an option if you want to take extended time domain samples. But then you have to design, certify, integrate and test a sensor protection system. More money and complexity.
And again, I think you can do that if you jump from an Atlas V531 to a 551. But even from a Falcon Heavy to SLS there's so much differential, that I can't think of any use save delta-v that will be "cheaper".

You seem to be under the mistaken assumption that I'm an advocate for this. I was pointing out that I think it might be worthwhile to do a trade study. If you're looking to argue about this with somebody, you'll have to find somebody else.

And the actual advocates of this have claimed that more mass does not automatically mean more cost if you allocate that additional mass to "dumb" parts of the spacecraft, such as structure, fuel, shielding, etc. I just think it might be worth looking into that.
Title: Re: Proposed Europa Missions
Post by: baldusi on 10/01/2012 03:17 pm
Quite on the contrary. I have you in very high regard and really enjoy exchanging ideas with you. What I'm trying to say, and I apology if my term come sort of too candid, it's due to subtleties of the English language that I miss. What I do say is that for a certain "small" range, in some parts, you can trade cost for weight. But also, SLS is so out there in payload capabilities, that I find it extremely unlikely that it would offer any opportunity of lowering costs by adding that much weight. I also believe such trade studies are extremely hard to do in a general sense, because it depend both on unknown factor and the margins of the rest of the assemblies.
I would love a study on general patterns of weight trades that work. And an investigation on non weight savings that can be achieved if you have a significantly bigger LV (say optimizing trajectories for cost rather than delta-v, trading comm costs on the spacecraft with DSN time, etc.).
Title: Re: Proposed Europa Missions
Post by: Blackstar on 10/01/2012 03:31 pm
Don't get me wrong, I'm not offended. I'm just not advocating this as an idea, and I don't want words put in my mouth, because I need the room for inserting my foot in there.

I do think that it MIGHT be possible to lower the cost of an outer planets spacecraft by taking the mass issue out of the equation. But I also think that the SLS vehicle cost is going to wipe that out. You would have to save a LOT of money on a spacecraft to justify the launch vehicle cost. Suppose that an Atlas is going to cost you $300 million and an SLS is going to cost you $1 billion. You would have to save more than $700 million on the spacecraft simply to justify the change in launchers.

I also think that you went off on a tangent there that does not really lead to anything. All of these spacecraft are custom designed. They don't use standard equipment. So, for instance, just because the spacecraft is bigger (with SLS) and this requires bigger control moment gyros, does not mean that the cost will go up because of that. In fact, the argument is that the cost should go down overall because all of these components can be built with bigger margins--no need to try innovative and risky design features just to squeeze half a kilogram of mass out of the system.

That said, there are other things that this could do that I think it might be worthwhile to explore. For instance, if you could double the amount of propellant on your spacecraft, you might be able to do more things with that spacecraft that you would never consider doing. It doesn't just extend the lifetime, it could mean that you could visit more moons at Jupiter, for instance. It could really open up the trade space.

But I also think that doing a study like this might be really premature now. It might only make sense to do this after there is an SLS flying, when you have a good idea about the capabilities and the costs of the rocket.
Title: Re: Proposed Europa Missions
Post by: Star One on 12/14/2012 02:11 pm
Another proposal the Europa Clipper has been outlined in an article on Space.com

Quote
But NASA is also thinking about ways to investigate the possible habitability of Europa, Jupiter's fourth-largest moon. One concept that may be gaining traction is a so-called "clipper" probe that would make multiple flybys of the moon, studying its icy shell and suspected subsurface ocean as it zooms past.

"We briefed [NASA] headquarters on Monday, and they responded very positively," mission proponent David Senske, of NASA's Jet Propulsion Laboratory in Pasadena, Calif., said here Dec. 7 at the annual fall meeting of the American Geophysical Union.

http://www.space.com/18901-nasa-mission-jupiter-moon-europa.html
Title: Re: Proposed Europa Missions
Post by: Blackstar on 12/20/2012 07:57 pm
The Europa de-scope final report studies have been finished. Unfortunately, the flyby and lander volumes are 23 megs apiece, which makes them too big to post here.

Here's the intro.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 12/20/2012 07:58 pm
Here's the orbiter study. Note that the orbiter is no longer the preferred option. You can get the best science-cost ratio out of the flyby mission.

None of the three studies mentions the SLS at all. It's not a preferred way to accomplish any of these missions.
Title: Re: Proposed Europa Missions
Post by: butters on 12/20/2012 08:05 pm
The chronic mechanical problems plaguing the scientists drilling that frozen lake in Antarctica don't bode well for the classical sci-fi notion of drilling the ice sheet on Europa. That kind of mission seems to be well beyond our near-term capabilities.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 12/20/2012 08:26 pm
The chronic mechanical problems plaguing the scientists drilling that frozen lake in Antarctica don't bode well for the classical sci-fi notion of drilling the ice sheet on Europa. That kind of mission seems to be well beyond our near-term capabilities.

This is from the lander study:

"Over time, the composition of the surface ice
is modified by fragmenting and sputtering
larger molecules, and by emplacement of ions
from space such as sulfur (Carlson et al. 2009).
Thus, samples acquired from the very surface
will not compositionally represent the ocean.
Depending on the type and geographic location,
this radiation damage is expected to reach
depths of several centimeters (Patterson et al.
2012), and obtaining samples from as deep as
10 cm becomes necessary. Additionally, obtaining
a near-surface sample (from 0.5–2 cm
depth) and a deeper sample (5–10 cm depth)
would provide an in situ assessment of the
effects of radiation on ice composition. Therefore,
the recommended strategy is to drill into
the surface up to a depth of 10 cm, obtaining
samples from at least two different depths."


So not a very deep drill.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 12/21/2012 06:00 pm
I was able to split the files up. Here is part 1 for the flyby study. This is actually the best option of the three in terms of cost-benefit.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 12/21/2012 06:01 pm
Flyby part 2.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 12/21/2012 06:02 pm
Europa lander study, part 1.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 12/21/2012 06:03 pm
Europa lander study, part 2.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 12/22/2012 12:31 am
Some images from the Europa Lander study report.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 12/22/2012 02:15 am
Europa Flyby spacecraft report images.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 12/22/2012 02:15 am
Europa Orbiter spacecraft report images.
Title: Re: Proposed Europa Missions
Post by: Star One on 12/23/2012 12:08 pm
@Blackstar

That article I posted from Space.com about the Europa Clipper how does that fit in with the materials you have just posted?
Title: Re: Proposed Europa Missions
Post by: Alpha_Centauri on 12/23/2012 01:01 pm
Europa Clipper was an early name for the Europa Flyby option above.
Title: Re: Proposed Europa Missions
Post by: Alpha_Centauri on 12/23/2012 01:11 pm
A question from me,

I'm not up to date with the specifics of American politics.  I know there were attempts to get NASA's budget settlement reviewed, what is the current status on this?  Given that the new MSL 2020 rover has been planned based on the current projected budget envelope, if there were a change in the settlement to restore some of the planetary budget would there be sufficient funds to start work on the Europa mission, given that the Mars mission is already selected?
Title: Re: Proposed Europa Missions
Post by: Blackstar on 12/23/2012 09:55 pm
A question from me,

I'm not up to date with the specifics of American politics.  I know there were attempts to get NASA's budget settlement reviewed, what is the current status on this?  Given that the new MSL 2020 rover has been planned based on the current projected budget envelope, if there were a change in the settlement to restore some of the planetary budget would there be sufficient funds to start work on the Europa mission, given that the Mars mission is already selected?

Normally, the President's proposed FY2014 budget would be released in early February. Right now it is on hold and probably will not be released until late February or even March. Until that is released, we will not know what the planetary budget looks like. For instance, did the administration choose to fund the Mars 2020 rover by putting back into the budget the money that it proposed removing last year? Or did it choose to fund the Mars 2020 rover by cutting money from elsewhere in the planetary budget, like New Frontiers and Discovery?

Assume that they restored the money that they cut and that planetary is at about the rate it was projected to be a couple of years ago. There will still not be enough money to fund both the Mars 2020 rover and a Europa mission. Too expensive. The proper thing to do would be to put the money back into the New Frontiers and Discovery program lines, because those were cut too, along with the Mars budget, in the President's proposed FY2013 budget.

Assuming a relatively flat planetary science budget, the earliest that a Europa mission could be funded is in the 2020s.
Title: Re: Proposed Europa Missions
Post by: spectre9 on 12/23/2012 10:23 pm
I think it's a rort.

Sample return can't be done.

A caching rover is not sample return.

This mission is being cheated away.

I'm sure it's worded in such a way that lets it swoop in a steal the money at such a low fidelity (MSL repeat capability) but that doesn't mean it's the right thing to do and everybody is going to agree with it.  >:(
Title: Re: Proposed Europa Missions
Post by: Blackstar on 12/24/2012 01:27 am
I think it's a rort.

Sample return can't be done.

A caching rover is not sample return.

This mission is being cheated away.

I'm sure it's worded in such a way that lets it swoop in a steal the money at such a low fidelity (MSL repeat capability) but that doesn't mean it's the right thing to do and everybody is going to agree with it.  >:(

Okay, first of all, I don't speak Australian, so I don't know what a "rort" is.

Second of all, I'm not sure if you're worth taking seriously or not. So instead of replying, I'll just observe and then make a decision.
Title: Re: Proposed Europa Missions
Post by: spectre9 on 12/24/2012 01:57 am
I found a word Americans don't use lol

Here's what wiki says
Quote
Rort is a term used in Australia and New Zealand to mean a scam or fraud.[1] It is commonly used in relation to politics or a financial impropriety, particularly relating to a government programme.

Build MSL copy, get samples. No it takes billions more dollars. The whole Europa mission can be done and out the way for the same price.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 12/24/2012 02:53 am
I'll just continue observing.

But please read the executive summary of the decadal survey as well as these new Europa documents that I posted.
Title: Re: Proposed Europa Missions
Post by: baldusi on 12/26/2012 12:01 am
I found a word Americans don't use lol

Here's what wiki says
Quote
Rort is a term used in Australia and New Zealand to mean a scam or fraud.[1] It is commonly used in relation to politics or a financial impropriety, particularly relating to a government programme.

Build MSL copy, get samples. No it takes billions more dollars. The whole Europa mission can be done and out the way for the same price.
Why don't you go and read the MSR discussion on the MSL forum? It has answers to what you think.
Title: Re: Proposed Europa Missions
Post by: Star One on 12/27/2012 05:35 pm
A question from me,

I'm not up to date with the specifics of American politics.  I know there were attempts to get NASA's budget settlement reviewed, what is the current status on this?  Given that the new MSL 2020 rover has been planned based on the current projected budget envelope, if there were a change in the settlement to restore some of the planetary budget would there be sufficient funds to start work on the Europa mission, given that the Mars mission is already selected?

Normally, the President's proposed FY2014 budget would be released in early February. Right now it is on hold and probably will not be released until late February or even March. Until that is released, we will not know what the planetary budget looks like. For instance, did the administration choose to fund the Mars 2020 rover by putting back into the budget the money that it proposed removing last year? Or did it choose to fund the Mars 2020 rover by cutting money from elsewhere in the planetary budget, like New Frontiers and Discovery?

Assume that they restored the money that they cut and that planetary is at about the rate it was projected to be a couple of years ago. There will still not be enough money to fund both the Mars 2020 rover and a Europa mission. Too expensive. The proper thing to do would be to put the money back into the New Frontiers and Discovery program lines, because those were cut too, along with the Mars budget, in the President's proposed FY2013 budget.

Assuming a relatively flat planetary science budget, the earliest that a Europa mission could be funded is in the 2020s.

I would favour taking all the money from the Discovery & New Frontiers budgets for however long it takes and putting it into this instead. As the second highest ranked priority after Mars sample return I regard the financing of this project as far more important than any project that either of these two programmes might be financed for at this time.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 12/27/2012 07:22 pm
I would favour taking all the money from the Discovery & New Frontiers budgets for however long it takes and putting it into this instead. As the second highest ranked priority after Mars sample return I regard the financing of this project as far more important than any project that either of these two programmes might be financed for at this time.

It's fun to have opinions, isn' it?
Title: Re: Proposed Europa Missions
Post by: Star One on 12/28/2012 06:55 pm
I would favour taking all the money from the Discovery & New Frontiers budgets for however long it takes and putting it into this instead. As the second highest ranked priority after Mars sample return I regard the financing of this project as far more important than any project that either of these two programmes might be financed for at this time.

It's fun to have opinions, isn' it?

Is there any good reason not to go this route when money is tight?
Title: Re: Proposed Europa Missions
Post by: Blackstar on 12/29/2012 12:53 am
I would favour taking all the money from the Discovery & New Frontiers budgets for however long it takes and putting it into this instead. As the second highest ranked priority after Mars sample return I regard the financing of this project as far more important than any project that either of these two programmes might be financed for at this time.

It's fun to have opinions, isn' it?

Is there any good reason not to go this route when money is tight?

Yes.

Have you read the decadal survey? Do you know what it says? Are you familiar with the history of American planetary science programs over the past thirty years?

I'm guessing that the answers to all my questions are "no."

But what the heck, here goes:

-the priorities for the American planetary science program are established in the planetary science decadal survey. That decadal survey states the EXACT OPPOSITE of what you just asked. It states that when money gets tight, the first thing to do is to scale back or delay flagship class programs like the Europa mission. Only after that is done should cuts be made in other areas, like New Frontiers and Discovery. You can find the decision rules in the decadal survey. At no point does it say that smaller missions should be sacrificed for larger missions.

-Europa is ranked second to the Mars caching rover in the decadal survey. Unfortunately, what this means is that it will not get funded in this decade. Even assuming a flat budget, or even one with a slight increase, the decadal survey does not say do both flagship missions. Now there are a lot of reasons why that happened (the big one being that the Europa mission that was presented to the decadal survey was a bellybuster and not affordable, and it took a blow to the head for the Europa community to actually come up with an affordable mission, which they have now apparently done), but them's the breaks.

-if you want a good example of why what you proposed is a stupid idea, take a look at the astronomy and astrophysics program at NASA. They have sacrificed all their small and medium missions in favor of JWST, which is now eating their lunch. Focusing on a single large mission puts you in a situation where you will have one or two missions per decade vs. half a dozen or more.

-if you want a good example of what could happen, look at NASA's planetary science program during the 1970s into the 1980s. They got into a vicious cycle of fewer and fewer larger and more expensive missions. The result was what many people call "the lost decade" in planetary science. You can see various effects of this, such as 17 years between Mars missions culminating in the very expensive Mars Observer failing on its way to Mars. It's a bad idea to fall into that circle again.
Title: Re: Proposed Europa Missions
Post by: Star One on 12/31/2012 05:08 pm
I would favour taking all the money from the Discovery & New Frontiers budgets for however long it takes and putting it into this instead. As the second highest ranked priority after Mars sample return I regard the financing of this project as far more important than any project that either of these two programmes might be financed for at this time.

It's fun to have opinions, isn' it?

Is there any good reason not to go this route when money is tight?

Yes.

Have you read the decadal survey? Do you know what it says? Are you familiar with the history of American planetary science programs over the past thirty years?

I'm guessing that the answers to all my questions are "no."

But what the heck, here goes:

-the priorities for the American planetary science program are established in the planetary science decadal survey. That decadal survey states the EXACT OPPOSITE of what you just asked. It states that when money gets tight, the first thing to do is to scale back or delay flagship class programs like the Europa mission. Only after that is done should cuts be made in other areas, like New Frontiers and Discovery. You can find the decision rules in the decadal survey. At no point does it say that smaller missions should be sacrificed for larger missions.

-Europa is ranked second to the Mars caching rover in the decadal survey. Unfortunately, what this means is that it will not get funded in this decade. Even assuming a flat budget, or even one with a slight increase, the decadal survey does not say do both flagship missions. Now there are a lot of reasons why that happened (the big one being that the Europa mission that was presented to the decadal survey was a bellybuster and not affordable, and it took a blow to the head for the Europa community to actually come up with an affordable mission, which they have now apparently done), but them's the breaks.

-if you want a good example of why what you proposed is a stupid idea, take a look at the astronomy and astrophysics program at NASA. They have sacrificed all their small and medium missions in favor of JWST, which is now eating their lunch. Focusing on a single large mission puts you in a situation where you will have one or two missions per decade vs. half a dozen or more.

-if you want a good example of what could happen, look at NASA's planetary science program during the 1970s into the 1980s. They got into a vicious cycle of fewer and fewer larger and more expensive missions. The result was what many people call "the lost decade" in planetary science. You can see various effects of this, such as 17 years between Mars missions culminating in the very expensive Mars Observer failing on its way to Mars. It's a bad idea to fall into that circle again.

1. I have made a start on the decadal survey but what with Christmas & the new year haven't got any further than that.

2. As to JWST one would hope that NASA would have learnt their lessons from the problems with the management of that project and would seek not to repeat them with any similar large-scale Mission. Also just because they have had issues with JWST I fail to see how that should mean that they will automatically have problems with the management of any future large scale projects.

3. If your logic is accepted then what the heck is NASA doing starting another major project like building a second flagship Martian rover. The re-use of spares aside your logic would dictate that the cost of its development is bound to lean in an upwards direction and impact on other smaller projects.

4. Some might argue that this current fixation on Mars represents a potential lost decade (or longer) of exploration of the rest of the Solar System.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 12/31/2012 06:05 pm
1. I have made a start on the decadal survey but what with Christmas & the new year haven't got any further than that.

2. As to JWST one would hope that NASA would have learnt their lessons from the problems with the management of that project and would seek not to repeat them with any similar large-scale Mission. Also just because they have had issues with JWST I fail to see how that should mean that they will automatically have problems with the management of any future large scale projects.

3. If your logic is accepted then what the heck is NASA doing starting another major project like building a second flagship Martian rover. The re-use of spares aside your logic would dictate that the cost of its development is bound to lean in an upwards direction and impact on other smaller projects.

1-Good for you. We need knowledgeable people.

2 and 3-Balance. Balance. Balance. Balance. Balance.

Maybe I should repeat that again: Balance.

The decadal survey says to pursue a "balanced" program of small, medium, and large missions. It says that if money gets tight, you do NOT cancel the small and medium missions only to pursue a single big mission. It says that if money gets tight, you delay or de-scope the flagship, and protect the smaller missions, existing missions, and research and analysis funding.

I agree that just because JWST went pear-shaped that this does not mean that other large spacecraft missions will also do so. But the danger is that a flagship class mission that goes over budget is so big that it squashes everything else. For instance, a 20% cost overrun on a $2 billion flagship mission is enough to wipe out an entire Discovery class mission. But I'd also note that this is irrelevant to what you were proposing--you were proposing wiping out all the smaller stuff to fund the big mission that you think is cool, and that's not the way that things work, or should work.
Title: Re: Proposed Europa Missions
Post by: simonbp on 01/01/2013 02:29 am
The decadal survey says to pursue a "balanced" program of small, medium, and large missions. It says that if money gets tight, you do NOT cancel the small and medium missions only to pursue a single big mission. It says that if money gets tight, you delay or de-scope the flagship, and protect the smaller missions, existing missions, and research and analysis funding.

Advice which they appear to have completely ignored. The mood at DPS NASA night was positively sour when Jim Green confirmed that there would be no new Discovery selection until 2017. But apparently we've got money for another giant Mars rover!

Those of us in the Not Mars (and Not Geology for that matter) planetary community cannot help but feel rather abused.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 01/01/2013 03:06 am
Advice which they appear to have completely ignored. The mood at DPS NASA night was positively sour when Jim Green confirmed that there would be no new Discovery selection until 2017. But apparently we've got money for another giant Mars rover!

Those of us in the Not Mars (and Not Geology for that matter) planetary community cannot help but feel rather abused.

The fact that OMB completely ignored the decadal survey was not lost on many people. The announcement of the Mars 2020 rover appears to be a reluctant acquiescence to do the decadal's top flagship recommendation--doing the right thing after exhausting the alternatives.

Title: Re: Proposed Europa Missions
Post by: Star One on 01/01/2013 04:10 pm
Advice which they appear to have completely ignored. The mood at DPS NASA night was positively sour when Jim Green confirmed that there would be no new Discovery selection until 2017. But apparently we've got money for another giant Mars rover!

Those of us in the Not Mars (and Not Geology for that matter) planetary community cannot help but feel rather abused.

The fact that OMB completely ignored the decadal survey was not lost on many people. The announcement of the Mars 2020 rover appears to be a reluctant acquiescence to do the decadal's top flagship recommendation--doing the right thing after exhausting the alternatives.



So much for your argument on balance when NASA themselves don't seem to be following that mantra?

In fact have they not just done to a degree what I was talking about which is to take money from other smaller projects to fund a larger project in the form of a second Martian rover?

As to reading the DS well the copy I have, unless, it's suddenly an extended version, is 410 pages long (as you no doubt already know) & having only recently got my hands on it I might be excused for not having read it all yet. :-\ 
Title: Re: Proposed Europa Missions
Post by: Blackstar on 01/01/2013 10:06 pm
1-So much for your argument on balance when NASA themselves don't seem to be following that mantra?

2-In fact have they not just done to a degree what I was talking about which is to take money from other smaller projects to fund a larger project in the form of a second Martian rover?

3-As to reading the DS well the copy I have, unless, it's suddenly an extended version, is 410 pages long (as you no doubt already know) & having only recently got my hands on it I might be excused for not having read it all yet. :-\ 

1-No. A bad idea is a bad idea no matter who comes up with it. But I'd note that your bad idea is different than what OMB has done. In the FY2013 proposed budget, the OMB essentially killed the Mars flagship and cut money across the board from everything else. That's not really what you were proposing, which was to kill all the small and medium stuff and pump it into the flagship mission that you think is cool.

2-No. The cuts to small and medium missions came before the most recent proposal to revive the Mars rover idea. See also #1 above.

3-You don't need to read the entire thing, although doing so would give you a leg up on everybody (assuming you understand it). The executive summary does a good job of explaining what and why. It also explains the decision rules.
Title: Re: Proposed Europa Missions
Post by: Star One on 02/17/2013 06:41 pm
New article on the proposed Europa Clipper.

Quote
"On Earth, everywhere where there's liquid water, we find life," said Robert Pappalardo, a senior research scientist at Nasa's jet propulsion laboratory in California, who led the design of the Europa Clipper.

"Mars exploration is part of the bigger picture of human exploration," said Pappalardo. "However, part of Nasa's mission is to go explore and that should include places that are an extremely high scientific priority. It really is one of the most profound questions we can ask: is there life elsewhere in the solar system?"

Whereas Mars might have been habitable billions of years ago, he said, Europa might be a habitable environment for life today. If it took 50 years before humans ended up sending probes and then landers to Europa, Pappalardo said, "we're going to look back and say we should have been doing this all along – and that would be tragic".

http://www.guardian.co.uk/science/2013/feb/15/nasa-europa-clipper-mission-jupiter-moon?INTCMP=SRCH
Title: Re: Proposed Europa Missions
Post by: Dalhousie on 02/17/2013 10:33 pm
The decadal survey says to pursue a "balanced" program of small, medium, and large missions. It says that if money gets tight, you do NOT cancel the small and medium missions only to pursue a single big mission. It says that if money gets tight, you delay or de-scope the flagship, and protect the smaller missions, existing missions, and research and analysis funding.

Advice which they appear to have completely ignored. The mood at DPS NASA night was positively sour when Jim Green confirmed that there would be no new Discovery selection until 2017. But apparently we've got money for another giant Mars rover!

Those of us in the Not Mars (and Not Geology for that matter) planetary community cannot help but feel rather abused.

Whatever "Not Mars" group you belong to, you are getting more than the Mars people were getting between 1976 and 1996.
Title: Re: Proposed Europa Missions
Post by: truth is life on 02/22/2013 02:18 am
Whatever "Not Mars" group you belong to, you are getting more than the Mars people were getting between 1976 and 1996.

Ice giants? There has, quite literally, not been an ice giants mission since before I was born (if only by a matter of days).
Title: Re: Proposed Europa Missions
Post by: Blackstar on 03/06/2013 09:37 pm
Had an interesting conversation with a NASA official today. Apparently the solar powered Europa mission is still considered rather dicey. Lifetime is low, and there is limited confidence in the solar option in terms of risk. As a result, NASA is going to keep open the option of using the MMRTG on a future Europa mission.
Title: Re: Proposed Europa Missions
Post by: spectre9 on 03/06/2013 10:07 pm
Thanks for that update Blackstar.

Hopefully this happens not long after the Mars 2020 rover.... and I'm still alive when it makes JOI.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 03/22/2013 08:10 pm
Well, uh oh...

http://www.bbc.co.uk/news/science-environment-21341176

Ice blades threaten Europa landing
By Paul Rincon Science editor, BBC News website, The Woodlands, Texas

Jupiter's icy moon Europa is a prime target for future space missions as it harbours a buried ocean that could have the right conditions for life.

But attempts to land may face a major hazard: jagged "blades" of ice up to 10m long.

A major US conference has heard the moon may have ideal conditions for icy spikes called "penitentes" to form.

Scientists would like to send a lander down to sample surface regions where water wells up through the icy crust.

These areas could allow a robotic probe to sample a proxy for ocean water that lies several kilometres deep.

Details of the penitentes theory were announced as scientists outlined another proposal to explore the jovian moon with robotic spacecraft.

On Earth, these features (so named because of their resemblance to the pointed caps worn by "penitents" in Easter processions around the Spanish-speaking world) form in high altitude regions such as the Andes.

Here, the air is both cold and dry, allowing ice to sublimate (turn from a solid into vapour without passing through a liquid phase).

Penitentes begin to form when irregularities in the surface of the snow are enhanced by the Sun's energy. These furrows then act as a trap for solar radiation, and, as they deepen, the tall peaks are left behind.
Sun overhead

Dr Daniel Hobley, from the University of Colorado, who presented his research at the 44th Lunar and Planetary Science Conference in Texas on Tuesday, said the formation of penitentes also required the Sun to be overhead as much as possible.

"Light coming in at a high angle will illuminate the sides of the blades, causing them to retreat away," he explained.

On Earth, this restricts them to between 30 degrees latitude from the equator.

"Europa is very strongly tidally locked to Jupiter and Jupiter is very strongly tidally locked to the plane of the Sun. So the Sun is always coming down straight from above on Europa," said Dr Hobley, so the moon fulfils this requirement nicely.

He added: "You need a strong thermal gradient between the spike at the top of the penitente and the pit at the bottom. So any mechanism that acts to suppress that, i.e. warm cloudy days - or hot air - will also kill them."

With its negligible atmosphere, this wouldn't be a problem on Europa, suggesting the moon could have more or less ideal conditions for the formation of these icy blades.

"From our point of view, if the surface of Europa is subliming - if it is being sculpted by the sunlight - it will form these features," Dr Hobley told BBC News.
Title: Re: Proposed Europa Missions
Post by: baldusi on 03/22/2013 08:23 pm
Ouch! What sort of instrument would they need to fly there to get that sort of resolution? Were they planning on a retroburn just before the land? That would melt almost anything. Would leave a big hole to land, too.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 03/22/2013 08:50 pm
Ouch! What sort of instrument would they need to fly there to get that sort of resolution? Were they planning on a retroburn just before the land? That would melt almost anything. Would leave a big hole to land, too.

If you read the article all the way through, you see that not everybody accepts this explanation.

Anyway, the plan is to map Europa first before any mission to send a lander, so that would answer the question. However, even if Europa does not have these ice spikes, it could still be very dangerous terrain. That said, NASA funded some neat technology work called ALHAT that allows a lander to detect the terrain and avoid dangerous obstacles. No landers have really done that before. If they continue work on ALHAT, it would be very useful for a lander mission.

I always sigh when people start talking about submarines on Europa. That is probably a century or more away. Just landing on Europa will be difficult.
Title: Re: Proposed Europa Missions
Post by: spectre9 on 03/22/2013 10:10 pm
Speculation is all we're left with.

Mars has been mapped in high resolution and is being bombarded by probes yet nobody has a clue what the surface of Europa really looks like.

I hope that all that is stopping a mapping mission being funded is the plutonium.
Title: Re: Proposed Europa Missions
Post by: baldusi on 03/22/2013 11:41 pm
Ouch! What sort of instrument would they need to fly there to get that sort of resolution? Were they planning on a retroburn just before the land? That would melt almost anything. Would leave a big hole to land, too.

If you read the article all the way through, you see that not everybody accepts this explanation.

Anyway, the plan is to map Europa first before any mission to send a lander, so that would answer the question. However, even if Europa does not have these ice spikes, it could still be very dangerous terrain. That said, NASA funded some neat technology work called ALHAT that allows a lander to detect the terrain and avoid dangerous obstacles. No landers have really done that before. If they continue work on ALHAT, it would be very useful for a lander mission.

I always sigh when people start talking about submarines on Europa. That is probably a century or more away. Just landing on Europa will be difficult.
I worked in the Andes and thus have seen the penitentes. I that does makes me assume they are there. But I've never talked about submarines. Rather that a lander would make a mess at retroburn, which probably would contaminate any samples.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 03/23/2013 01:02 am
I hope that all that is stopping a mapping mission being funded is the plutonium.

No. It's money.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 03/23/2013 01:04 am
I worked in the Andes and thus have seen the penitentes. I that does makes me assume they are there. But I've never talked about submarines. Rather that a lander would make a mess at retroburn, which probably would contaminate any samples.

I talked to a well-known Titan scientist who saw this guy's talk about the penitentes at LPSC. He called it "unconvincing."

You're right that there may be a problem with a lander contaminating the site. The solution would be some kind of sampling arm. Perhaps a small rover, although that would be really difficult. Any Europa lander mission would have to possess a lot of autonomous capability.
Title: Re: Proposed Europa Missions
Post by: spectre9 on 03/23/2013 02:46 am
I hope that all that is stopping a mapping mission being funded is the plutonium.

No. It's money.

A little politics but only for reference.

Quote
Provided, That $75,000,000  6
shall be for pre-formulation and/or formulation activities  7
for a mission that meets the science goals outlined for the  8
Jupiter Europa mission in the most recent planetary  9
science decadal survey

What about this? What's that for?

I thought Europa missions have already been studied over and over...  ???
Title: Re: Proposed Europa Missions
Post by: Blackstar on 03/23/2013 03:15 am
A little politics but only for reference.

Quote
Provided, That $75,000,000  6
shall be for pre-formulation and/or formulation activities  7
for a mission that meets the science goals outlined for the  8
Jupiter Europa mission in the most recent planetary  9
science decadal survey

What about this? What's that for?

I thought Europa missions have already been studied over and over...  ???

I don't know, but if I had to guess, that's an earmark for JPL. That's to throw them some more technology development money. They have already gotten a lot of money over the years (over $400 million starting around 2002 for JIMO tech development). Yes, Europa has been studied over and over. My guess is that the money will go for radiation hardened electronics research, and JPL overhead. JPL always has overhead.
Title: Re: Proposed Europa Missions
Post by: Galactic Penguin SST on 03/23/2013 04:10 am
A little politics but only for reference.

Quote
Provided, That $75,000,000  6
shall be for pre-formulation and/or formulation activities  7
for a mission that meets the science goals outlined for the  8
Jupiter Europa mission in the most recent planetary  9
science decadal survey

What about this? What's that for?

I thought Europa missions have already been studied over and over...  ???

I don't know, but if I had to guess, that's an earmark for JPL. That's to throw them some more technology development money. They have already gotten a lot of money over the years (over $400 million starting around 2002 for JIMO tech development). Yes, Europa has been studied over and over. My guess is that the money will go for radiation hardened electronics research, and JPL overhead. JPL always has overhead.

I wonder after all if flying to Ganymede would have been the better option - while not as "sexy" as Europa, it does have an ocean underneath after all. The radiation level is lower there - hence the ESA JUICE is now targeting there instead of Europa, and that the Russians are making noises for making a lander for this mission (which I took with a handful of salt  ::)). It would be the intermediate step towards an eventual Europa surface mission.
Title: Re: Proposed Europa Missions
Post by: spectre9 on 03/23/2013 04:40 am
Thanks for the reply Blackstar.

I guess it's just a risk reduction to get prepared for when the stars align and the mission is funded.

As for Ganymede JUICE will be orbiting it for years. NASA doesn't have to go there as they'll just be duplicating the science done by ESA.

NASA has access to RTGs and Europa is their 2nd highest priority planetary flagship. I would hope the mission launches sometime in before 2030 which is likely unless the next survey shafts it into 2nd place again after Mars 2020 is underway.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 03/23/2013 12:23 pm
I guess it's just a risk reduction to get prepared for when the stars align and the mission is funded.


I suspect nobody involved knows how they will spend that money now other than to keep paying salaries of people at JPL. Congress cannot really initiate a "new start" of a program; the president has to do that. One possible good way to spend that money would be to start buying another MMRTG for this mission. That's hardware that could probably be purchased now even if it is not incorporated into a spacecraft for another 20 years (RTGs are mostly structure).

I know that JPL management, and to a lesser extent the broader scientific community, is concerned about losing a valuable resource in the form of all the good people at JPL with unique skills. I suspect that this money is partly intended to keep them employed. But it's also a case that there is a member of Congress who has no political interest in JPL (he comes from another state) who has a lot of personal interest in a Europa mission. He thinks it is cool and wants it to happen. He may be partly responsible for this language in the bill.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 03/23/2013 12:31 pm
I wonder after all if flying to Ganymede would have been the better option - while not as "sexy" as Europa, it does have an ocean underneath after all. The radiation level is lower there - hence the ESA JUICE is now targeting there instead of Europa, and that the Russians are making noises for making a lander for this mission (which I took with a handful of salt  ::)). It would be the intermediate step towards an eventual Europa surface mission.

The U.S. scientific community has a different view. Without looking this up, I think that the issue is that Ganymede's ocean is not as thick and scientists do not believe that it touches the core. In other words, it is water sandwiched between two layers of ice, whereas Europa's ocean is believed to have rock on the bottom and ice on top. This is important because the possibility of life is believed to be greater if the water is enriched with minerals by touching the rock. (I would also guess that you'd get more circulation, but I don't know that.)

The American scientific community has more geologists and biologists, so they are more interested in the search for life. Plus rocks.

The European community has a different bias. They have more scientists interested in magnetosphere physics. Ganymede is therefore where they want to go.

At times, science can be somewhat like the drunk who looks for his car keys under the street lamp because that's where the light is. Scientists pick things to study because that is what interests them, not necessarily because they are what are most "important" in some objective sense. I haven't looked at the latest plans for JUICE, but in earlier iterations they were going to try to do at least a couple of flybys of Europa.
Title: Re: Proposed Europa Missions
Post by: Zed_Noir on 03/23/2013 10:23 pm
Well, uh oh...

http://www.bbc.co.uk/news/science-environment-21341176

Ice blades threaten Europa landing
;D
Well one simple solution is to clear a landing zone for the lander like they used to do in SE Asia for improvise jungle helo pads. Maybe with a cluster kinetic impacters that will take some close up images before impacting with a separate launch several weeks prior to the lander launch.

Of course this idea is wild & wacky. Probably not workable.
Title: Re: Proposed Europa Missions
Post by: Alpha_Centauri on 03/23/2013 11:26 pm
The American scientific community has more geologists and biologists, so they are more interested in the search for life. Plus rocks.

The European community has a different bias. They have more scientists interested in magnetosphere physics. Ganymede is therefore where they want to go.

It isn't that the European scientific community is any less interested in Europa (or for that matter geology or biology...) it's simply that the technical challenges would push a European Europa mission well over the L-class mission financial threshold and so could only ever be part of an international collaboration.  Remember JUICE is the phoenix from the ashes of ESA's contribution to EJSM, JGO.

Ganymede does however provide a useful test of the subsurface studies required on Europa and other icy moons, and on a budget more affordable in the economic times.
Title: Re: Proposed Europa Missions
Post by: plutogno on 03/24/2013 08:28 am
Without looking this up, I think that the issue is that Ganymede's ocean is not as thick and scientists do not believe that it touches the core. In other words, it is water sandwiched between two layers of ice, whereas Europa's ocean is believed to have rock on the bottom and ice on top.

I think that another important difference is that Europa's ocean is much closer to the surface than that of Ganymede (a few kilometers instead of tens of kilometers)
Title: Re: Proposed Europa Missions
Post by: Blackstar on 04/02/2013 09:40 pm
It isn't that the European scientific community is any less interested in Europa (or for that matter geology or biology...) it's simply that the technical challenges would push a European Europa mission well over the L-class mission financial threshold and so could only ever be part of an international collaboration.  Remember JUICE is the phoenix from the ashes of ESA's contribution to EJSM, JGO.

Sorry for the late reply. I don't read all the threads on this site regularly.

I'm going to disagree on the first point, with the proviso that I don't have direct experience with this, but am basing it upon what I've heard from people who do have direct experience (in other words, maybe I have no idea what I'm talking about). And what I've heard is that the European community is more biased toward magnetospheric physics than the American planetary science community (where magnetosphere physics is often ignored). Now that's a relative thing, so your mileage may vary. But the United States did build up a substantial astrobiology community over the past two decades, and that helps tilt the scales as well.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 04/02/2013 09:43 pm
Well one simple solution is to clear a landing zone for the lander like they used to do in SE Asia for improvise jungle helo pads. Maybe with a cluster kinetic impacters that will take some close up images before impacting with a separate launch several weeks prior to the lander launch.

Of course this idea is wild & wacky. Probably not workable.


It's not workable. What you want is a predictable landing site. One problem with trying to blast it flat is that you have no way of knowing if that is actually going to work. What happens if you try this and the spacecraft looks down and all it sees is more lousy terrain? Indeed, one of the problems with trying to blast landing zones in the jungle during Vietnam was that it created a lot of debris that then got in the way.

What you want is a mission that finds a flat spot.
Title: Re: Proposed Europa Missions
Post by: copernicus on 05/09/2013 02:55 am
   Here is a link to an update on the status of the Europa Clipper mission.  I wrote it as a guest on Van Kane's "Future Planetary Exploration" website. 

http://futureplanets.blogspot.com/2013/05/europa-clipper-update.html

I hope that it answers some questions about the mission. 



Title: Re: Proposed Europa Missions
Post by: Blackstar on 05/09/2013 01:37 pm
I'm not so sure about the $75 million earmarked for Europa. Is it really intended to fund Europa Clipper, or to send money to JPL? I'm not sure that there's an efficient way to spend that money on Europa studies. It is too little money to start development, and too much to perform studies. Now if it goes into something like the RTGs, that would be useful. You could build a new MMRTG for Europa Clipper and put it on the shelf and use it fifteen years from now.

Good reference to Solar Probe, however. I had forgotten about that. There's a good story behind the creation of Solar Probe Plus. My limited understanding/memory is that Congress kept putting money in the budget for that but NASA kept ignoring them. NASA just did not think that they could afford Solar Probe. Finally, Alan Stern said to that community (this is almost a direct quote from a talk he gave) "Do you want 100% of nothing or 80% of something?" And he forced them to redesign Solar Probe into a mission that NASA could afford and got a new start on it.
Title: Re: Proposed Europa Missions
Post by: JohnFornaro on 05/13/2013 01:39 pm
Quote
"On Earth, everywhere where there's liquid water, we find life," said Robert Pappalardo, a senior research scientist at Nasa's jet propulsion laboratory in California, who led the design of the Europa Clipper.

"Mars exploration is part of the bigger picture of human exploration," said Pappalardo. "However, part of Nasa's mission is to go explore and that should include places that are an extremely high scientific priority. It really is one of the most profound questions we can ask: is there life elsewhere in the solar system?"

Whereas Mars might have been habitable billions of years ago, he said, Europa might be a habitable environment for life today. If it took 50 years before humans ended up sending probes and then landers to Europa, Pappalardo said, "we're going to look back and say we should have been doing this all along – and that would be tragic".

That would be tragic.
Title: Re: Proposed Europa Missions
Post by: Star One on 05/13/2013 05:29 pm
   Here is a link to an update on the status of the Europa Clipper mission.  I wrote it as a guest on Van Kane's "Future Planetary Exploration" website. 

http://futureplanets.blogspot.com/2013/05/europa-clipper-update.html

I hope that it answers some questions about the mission.

Thanks for that link. Pretty sad state of affairs that Congress have to 'kick' NASA into putting some money into this program.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 05/13/2013 08:05 pm
Thanks for that link. Pretty sad state of affairs that Congress have to 'kick' NASA into putting some money into this program.

Not really.

You cannot do everything. You have to establish priorities and fund the things you can reasonably do. They've established the priorities. Read the decadal survey.

What may be happening (and I say "may" because I don't really know) is that Congress may be earmarking this money not because of the program, but because of where it is being done (JPL). In other words, it's pork. It is hypocritical to decry pork in general but say that it is acceptable as long as the money is being spent on the particular flavor of pork that you enjoy.



There is, of course, a lot more that could be said about the whole subject, but I'd have to start writing a textbook.
Title: Re: Proposed Europa Missions
Post by: ChileVerde on 05/14/2013 05:48 pm

There is, of course, a lot more that could be said about the whole subject, but I'd have to start writing a textbook.

You might want to start doing that, or at least a book of some sort on the subject. The world will thank you for it.

Actually, it probably won't, but it should. Such is the way of the world.

Title: Re: Proposed Europa Missions
Post by: Blackstar on 05/15/2013 01:21 pm

There is, of course, a lot more that could be said about the whole subject, but I'd have to start writing a textbook.

You might want to start doing that, or at least a book of some sort on the subject. The world will thank you for it.

Actually, it probably won't, but it should. Such is the way of the world.



Nobody cares.

As you may know, there's a whole process for developing priorities for space science missions in each of the disciplines. It is difficult for people who are not intimately involved in that process (and even difficult for some people who ARE involved in that process) to understand how it works. But it does work, and it actually works pretty darn well. We have been working on improving that process, and there is always room for making things better. But I think that the American taxpayers and the American scientific community are both served well by how it all works. It would take a lot of time and effort to explain all of that to outsiders.

Now how does that relate to Europa? Well, the process, as enshrined in the decadal survey, came up with a series of decision rules for how to plan the planetary science program over the next decade, and also a priority list for the flagship missions, with starting Mars sample return first, and Europa second. There was a lot of work and careful consideration that led to those recommendations, and as close to a consensus opinion as you could get out of the scientific community. Abandoning that approach, or shortcutting it, simply because you disagree with it, could cause a lot of damage to the overall health of the program.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 05/15/2013 03:10 pm
Dunno if this is accurate, but it does seem to be a case of what I mentioned in the previous post, where the decadal survey essentially said to protect Discovery and research budgets before giving money to flagships, but the administration is doing the opposite. Of course, this could also be interpreted as the administration saying to Congress: "Okay, if you want to earmark money for Europa, we'll cut it out of other things that you think are important too. You're welcome."


http://spaceref.com/news/viewsr.html?pid=44031

"After removing essentially all of funds added by Congress to Planetary Science, NASA and and others in the Administration have further chosen to reallocate significant funds from present planetary research and Discovery budgets to pay for new studies in support of a future Europa mission. The next Discovery call will certainly be delayed. The impact to research programs will be severe - further reduced selection rates can be anticipated. Might existing awards be retroactively reduced? Damage is made worse by the fact that these cuts are being implemented in the final months of the fiscal year."
Title: Re: Proposed Europa Missions
Post by: Star One on 05/15/2013 07:02 pm
Dunno if this is accurate, but it does seem to be a case of what I mentioned in the previous post, where the decadal survey essentially said to protect Discovery and research budgets before giving money to flagships, but the administration is doing the opposite. Of course, this could also be interpreted as the administration saying to Congress: "Okay, if you want to earmark money for Europa, we'll cut it out of other things that you think are important too. You're welcome."


http://spaceref.com/news/viewsr.html?pid=44031

"After removing essentially all of funds added by Congress to Planetary Science, NASA and and others in the Administration have further chosen to reallocate significant funds from present planetary research and Discovery budgets to pay for new studies in support of a future Europa mission. The next Discovery call will certainly be delayed. The impact to research programs will be severe - further reduced selection rates can be anticipated. Might existing awards be retroactively reduced? Damage is made worse by the fact that these cuts are being implemented in the final months of the fiscal year."

I imagine this will result in yet another tug of war between the various sides which will no doubt do no one any good in the end.

That said and I am aware of what the survey recommended but you have to admit we do seem to have a number of quite vocal scientific proponents in favour of the Europa mission so it is not like there isn't support for it out there.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 05/15/2013 07:35 pm
1-I imagine this will result in yet another tug of war between the various sides which will no doubt do no one any good in the end.

2-That said and I am aware of what the survey recommended but you have to admit we do seem to have a number of quite vocal scientific proponents in favour of the Europa mission so it is not like there isn't support for it out there.

1-Yes and no. Note that what is going on here is that JPL got itself an earmark. That's money that is specifically going to JPL because they have political clout. Now that's not a good thing. The planetary science community includes a lot of competition, which makes for better science and also better spending of money. Anything that shortcuts the competition is probably bad. So, just because this earmark happened, should everybody else who plays by the rules just roll over and give up? Should they let the process just fall apart?

2-So what? People who lost out complain. Yeah, that's happened. But should they tear everything apart because they didn't get what they wanted?

There's no good way to discuss this without sounding nastier than I want to be about it. There's a lot of nuance and complexity to the whole issue that I just could not write down, and I'm not anti-Europa. I am against bypassing procedures and processes that work pretty good at keeping politics out of the way we select planetary science missions.

But if you watched the whole thing play out over several years, you'd have a better understanding of what went on. In short: the Europa advocates walked into the decadal survey with a mission proposal that was fat and bloated and not able to be funded (it would have wiped out the entire planetary budget). It was cost estimated at $4.7 billion. There was no way to fund that mission. As a result, it was not placed at the top of the priority list and they were told to go back and redesign their mission so that it was affordable. Now they have done that. But that is no reason that this mission should then come back and stomp all over other priorities for planetary science, including ones that proposed realistic missions from the start. It's kinda like missing the medal in the Olympics because you're fat and out of shape, practicing a bit, and calling for another Olympics a year later so you can win a medal this time. It's unfair to the people who played by the rules.
Title: Re: Proposed Europa Missions
Post by: Star One on 05/15/2013 08:55 pm
Well if they have got themselves more into shape then maybe to be generous to them perhaps that's a basis for congress allocating money to the studies.

Also isn't Europa such a scientifically important mission that it automatically outranks virtually any other proposed mission, it certainly should be the top ranked mission at the next survey. You may not like their approach and from what you have said I can see why, but I do understand why they feel the need to make the noise they do about it.
Title: Re: Proposed Europa Missions
Post by: robertross on 05/16/2013 12:13 am
Dunno if this is accurate, but it does seem to be a case of what I mentioned in the previous post, where the decadal survey essentially said to protect Discovery and research budgets before giving money to flagships, but the administration is doing the opposite. Of course, this could also be interpreted as the administration saying to Congress: "Okay, if you want to earmark money for Europa, we'll cut it out of other things that you think are important too. You're welcome."


http://spaceref.com/news/viewsr.html?pid=44031

"After removing essentially all of funds added by Congress to Planetary Science, NASA and and others in the Administration have further chosen to reallocate significant funds from present planetary research and Discovery budgets to pay for new studies in support of a future Europa mission. The next Discovery call will certainly be delayed. The impact to research programs will be severe - further reduced selection rates can be anticipated. Might existing awards be retroactively reduced? Damage is made worse by the fact that these cuts are being implemented in the final months of the fiscal year."

Appreciate your commentary on all this. I've been sitting here catching up on the posts.

Going back to your previous comments on all this, and the pace of SLS and such, I'm now getting into a position where I am accepting of a slow down on these massive & costly missions to protect the overall Planetary Science community. JWST should have taught us all a valuable lesson: we can't afford it all (even being a Canadian looking at these massive American budgetary requests).

It's not as if Europa is going anyware. It's not as if we could do anything about finding life there even if we found it (just as in the case of Mars, if it were to be made true). We anough enough priorities closer to home to be happy with the New Frontiers & Discovery class missions. Such Flagship missions can wait for when the economy has light at the end of that tunnel so that money (hopefully) isn't as scarce.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 05/16/2013 03:33 am
It's not as if Europa is going anyware. It's not as if we could do anything about finding life there even if we found it (just as in the case of Mars, if it were to be made true). We anough enough priorities closer to home to be happy with the New Frontiers & Discovery class missions. Such Flagship missions can wait for when the economy has light at the end of that tunnel so that money (hopefully) isn't as scarce.

I'd point out that flagship missions are important. They, more than any other missions, fundamentally advance the science. A decade without New Frontiers and Discovery would be bad. But a decade without a flagship mission would be bad too. It's all about balance.

However, we are now at risk of having a decade with only a flagship and few or none of the smaller missions. That's not good.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 05/16/2013 03:34 am
http://www.planetary.org/blogs/casey-dreier/2013/20130515-nasa-steals-back-money-from-planetary-science.html

NASA Robs Planetary Science
Leaked document shows NASA funding other programs with planetary money


Posted By Casey Dreier

2013/05/15 05:04 CDT

Topics: NASA Budget

Despite Congress rejecting cuts to NASA's Planetary Science Division in March, NASA plans to raid the restored funds for use in other projects for the remainder of this year. This is a stunning rebuke to Congress and a very rare move by NASA that continues to undercut this popular and productive program.

Just to recap: the final budget for 2013 wasn't passed until late March of this year. It provided $1.42 billion for Planetary Science, over $200 million more than the President's original request. This extra money would support initial work on the 2020 Mars Rover, formulation activities on a mission to Europa, and increase the pace of small missions. Of course, the sequester reduced this total to approximately $1.3 billion if applied evenly, still much better than the original proposal.

But NASA is not applying the sequester evenly. Mark Sykes of the Planetary Science Institute obtained a leaked draft of NASA's operating plan, which details the the actual implementation of the approved budget. Operating plans are prepared only after budgets pass Congress and must be submitted to the relevant appropriations committee within 45 days for review. Federal agencies have leeway in how they spend their allocated money internally, and up to 5% of any program's budget can be used to buttress other accounts. This is called "reprogramming."

However, the sequester requires that NASA find hundreds of millions of dollars of savings within its science programs. This requirement, combined with the ability to reprogram money as needed, drove NASA to essentially offset sequester cuts in other areas at the expense of the Planetary Science Division. Planetary's entire increase has been reprogrammed away for this.

This is an entirely separate issue from the proposed 2014 budget, which continues cuts to this program next year.

Key people in Congress will be very upset about this, especially Adam Schiff, Dianne Feinstein, and John Culberson, who wrote an open letter to the NASA Administrator just last month warning them to not defy congressional will on the importance of planetary science.

This is a leaked draft of the document, and may not reflect the final version sent to Congress on Friday. Once the operating plan is submitted Congress can voice their objections to it, and historically the agency works with them to address these issues. It's hard to say if that's the case this time since NASA was so clearly warned not to do this.

Planetary Science cannot get a break. NASA and the White House seem determined to underfund and sacrifice the future of planetary exploration despite the efforts of Congress and the public. Congress is our greatest ally in this struggle, and we've spoken to them about this. More details to come as we know them.

Note: Tomorrow I'll start posting more details about the Society's visits and discussion with Congress this week. There is lots to talk about.
Title: Re: Proposed Europa Missions
Post by: robertross on 05/16/2013 11:50 am
http://www.planetary.org/blogs/casey-dreier/2013/20130515-nasa-steals-back-money-from-planetary-science.html

NASA Robs Planetary Science
Leaked document shows NASA funding other programs with planetary money

...

UNreal

Quote
Note: Tomorrow I'll start posting more details about the Society's visits and discussion with Congress this week. There is lots to talk about.

don't know how to take that (hopefully it isn't too bad), but looking forward to it!
Title: Re: Proposed Europa Missions
Post by: Star One on 05/16/2013 05:26 pm
That's pretty outrageous no doubt the fall out on it is going to be something to follow.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 07/05/2013 10:05 pm
July 15-16 is the meeting of the Outer Planets Assessment Group in Washington, DC. OPAG provides advice on outer planets missions to NASA. The Europa Clipper mission is going to be discussed. You should be able to listen in via the web:

http://www.lpi.usra.edu/opag/

http://www.lpi.usra.edu/opag/jul2013/agenda.pdf

OPAG Agenda
July 15-16
Monday theme: where are we today
9:00 am Intro, welcome and objectives (Candy Hansen)
9:15 NASA PSD report, incl. responses to OPAG findings
(Jim Green)
10:15 Outer planets report, incl. JUICE (Curt Niebur)
10:30 Break
10:45 PSS Report (Janet Luhmann)
11:00 Europa Clipper update–Instrument development funding (Curt Niebur)
–Other progress (Bob Pappalardo & Barry Goldstein)
12:15 Destination Europa (Brittney Schmidt)
Title: Re: Proposed Europa Missions
Post by: JohnFornaro on 07/06/2013 01:59 pm
Appreciate your commentary on all this. I've been sitting here catching up on the posts.

Going back to your previous comments on all this, and the pace of SLS and such, I'm now getting into a position where I am accepting of a slow down on these massive & costly missions to protect the overall Planetary Science community. JWST should have taught us all a valuable lesson: we can't afford it all (even being a Canadian looking at these massive American budgetary requests).

It's not as if Europa is going anywhere.

Ditto on the appreciation, JWST's not-lesson, and the stability of Europa's future orbit.

The prioritization of these proposed missions is flawed in that the question, "What's the rush?" is not satisfactorily addressed, at least by my take.

I keep beating the MSR drum as an example of the "hurried" approach:  What's the rush?  MSR has been seen as high priority for many years, but the knowledge learned in the meantime has fundamentally changed the thinking on where to look.

Here we are, still looking for life on Mars, with equipment that can still be perfected, and with several more locations yet to be searched.  Are there not lessons still to be learned on how to conduct the search for a second genesis of life?  How can it be that it is already known how to do this on Europa?

We should not have flagship missions if we are not prepared for them.
Title: Re: Proposed Europa Missions
Post by: ClaytonBirchenough on 07/06/2013 04:23 pm
Thanks Blackstar for the wealth of information! Makes for a good read...
Title: Re: Proposed Europa Missions
Post by: grondilu on 07/08/2013 07:11 pm
It seems that lake Vostok is indeed full of life.

http://io9.com/new-evidence-antarctica-s-ancient-ice-covered-lake-is-706010511

Hopefully this will encourage space agencies around the world to actually send a probe to Europa.
Title: Re: Proposed Europa Missions
Post by: baldusi on 07/08/2013 07:26 pm
It seems that lake Vostok is indeed full of life.

http://io9.com/new-evidence-antarctica-s-ancient-ice-covered-lake-is-706010511

Hopefully this will encourage space agencies around the world to actually send a probe to Europa.
It might. But please remember that Earth was completely covered by ice at least twice in history. Thus, terran life developed without ice but was selected to survive. The Europan case is completely different. But most important, to reach the actual Europan ocean is currently not feasible, much less affordable. Currently we'd be extremely happy with an orbiter, and periodic flybys would put a smile on every single related scientist.
Only then we can thing of landing, and only after landing a couple of times (successfully) can we think if it's even possible to drill deep enough. Regrettably, that's at least a century away.
Title: Re: Proposed Europa Missions
Post by: EE Scott on 07/08/2013 07:35 pm
July 15-16 is the meeting of the Outer Planets Assessment Group in Washington, DC. OPAG provides advice on outer planets missions to NASA. The Europa Clipper mission is going to be discussed. You should be able to listen in via the web:

http://www.lpi.usra.edu/opag/

http://www.lpi.usra.edu/opag/jul2013/agenda.pdf

OPAG Agenda
July 15-16
Monday theme: where are we today
9:00 am Intro, welcome and objectives (Candy Hansen)
9:15 NASA PSD report, incl. responses to OPAG findings
(Jim Green)
10:15 Outer planets report, incl. JUICE (Curt Niebur)
10:30 Break
10:45 PSS Report (Janet Luhmann)
11:00 Europa Clipper update–Instrument development funding (Curt Niebur)
–Other progress (Bob Pappalardo & Barry Goldstein)
12:15 Destination Europa (Brittney Schmidt)

Great stuff, I look forward to it. Thx for letting us know.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 07/08/2013 10:11 pm
July 15-16 is the meeting of the Outer Planets Assessment Group in Washington, DC. OPAG provides advice on outer planets missions to NASA. The Europa Clipper mission is going to be discussed. You should be able to listen in via the web:

http://www.lpi.usra.edu/opag/

http://www.lpi.usra.edu/opag/jul2013/agenda.pdf

OPAG Agenda
11:00 Europa Clipper update–Instrument development funding (Curt Niebur)

Great stuff, I look forward to it. Thx for letting us know.

All of this should be web broadcast, but I cannot find any evidence of that. They might not post the link until just before the meeting.

Funny note: if you watch the movie "Europa Report" you'll see that Curt Niebur was one of the consultants. However, they misspelled the poor guy's name!
Title: Re: Proposed Europa Missions
Post by: Blackstar on 07/08/2013 10:16 pm
But most important, to reach the actual Europan ocean is currently not feasible, much less affordable. Currently we'd be extremely happy with an orbiter, and periodic flybys would put a smile on every single related scientist.
Only then we can thing of landing, and only after landing a couple of times (successfully) can we think if it's even possible to drill deep enough. Regrettably, that's at least a century away.

Yeah. That's something that gets lost in just about every popular article about Europa spacecraft and particularly the submarines. They will discuss the oceans, the possibility of life, and then include an artist impression of the submarine. Members of the public see that and think "That would be REALLY COOL!" But nobody bothers to explain that the technology to do this is way way out there, not to mention the budget and policy concerns.

I imagine that somebody who works on this stuff has probably developed a crude roadmap for Europa exploration, listing the things that need to be done and a notional timeline. We know that a Europa flyby or orbiter mission will not happen for the next ten years, and even if it gets prioritized in the early 2020s it will not get built and launched until the late 2020s, meaning it won't reach Europa until the mid-2030s. You can work out things from there. We're 20 years away from at least getting a close-up look at Europa.

Well, except for JUICE.
Title: Re: Proposed Europa Missions
Post by: Star One on 07/09/2013 07:36 am
I am hoping that the Russian's can get things resolved in time & I know it is a big if, to get their Ganymede lander onto the JUICE mission.

It feels like at least ESA is showing some drive in outer planetary exploration which is more than it seems NASA can manage these days who instead are more than willing to go along with a cut in their planetary budget.

Sorry for the rant but I get rather steamed up by this whole situation on the planetary budget at the moment. :)
Title: Re: Proposed Europa Missions
Post by: grondilu on 07/10/2013 06:21 pm
http://www.scientificamerican.com/article.cfm?id=new-space-engines-interplanetary

« The scientists and engineers are developing a new plasma propulsion system designed for ultrasmall CubeSats. If all goes well, they say, it may be possible to launch a life-detection mission to Jupiter's ocean-harboring moon Europa or other intriguing worlds for as little as $1 million in the not-too-distant future. »
Title: Re: Proposed Europa Missions
Post by: Blackstar on 07/10/2013 07:16 pm
http://www.scientificamerican.com/article.cfm?id=new-space-engines-interplanetary

« The scientists and engineers are developing a new plasma propulsion system designed for ultrasmall CubeSats. If all goes well, they say, it may be possible to launch a life-detection mission to Jupiter's ocean-harboring moon Europa or other intriguing worlds for as little as $1 million in the not-too-distant future. »

I read an earlier version of this and to put it mildly it all seemed like total B S to me. They haven't even flown anything, and yet they're talking about super cheap spacecraft operating in one of the most difficult environments that exist? What's the power source at Europa? How do they deal with radiation? How can they afford any instruments at all and do all this for $1 million?
Title: Re: Proposed Europa Missions
Post by: Blackstar on 07/26/2013 12:31 am
The latest on Europa Clipper. Note the new spacecraft configuration on slide 12 (there is no slide 10).
Title: Re: Proposed Europa Missions
Post by: Blackstar on 07/26/2013 12:32 am
Here's the new configuration as two separate slides.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 07/26/2013 12:34 am
Here's some information on using SLS for the Europa Clipper mission.
Title: Re: Proposed Europa Missions
Post by: robertross on 07/26/2013 02:12 am
The latest on Europa Clipper. Note the new spacecraft configuration on slide 12 (there is no slide 10).

Thank you Sir!

15kg (at this stage of the game) isn't too bad a savings.
Title: Re: Proposed Europa Missions
Post by: spectre9 on 07/26/2013 02:46 am
Thanks Blackstar. You're a champion.

Cool new stacked design. Makes sense.

I'm excited about the close up shots with the recon camera.  :)

All this time being taken to refine the mission seems to be paying off. The science objectives, the mission con ops, the spacecraft design.

I like how the stacked design allows it to be built in segments and then plugged together. Hopefully this modular approach creates a better funding profile.

Which module first? The avionics module with the vault? I assume the lower propulsion module will be last as the ASRGs will not be available for a while.

Seems like the orbit has possible encounters for Callisto and Ganymede. Might be an option for an extended mission if there's extra power.
Title: Re: Proposed Europa Missions
Post by: EE Scott on 07/26/2013 03:28 am
So exciting the possibility, so remote the chance.  Still I'll allow myself to believe it could happen.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 07/26/2013 12:48 pm
I think that the likely power source would be an MMRTG. NASA is building another one for Mars 2020, which maintains the experience/production base.

NASA is building/has built (my guess is that they are majority complete) two ASRG units that will be placed in "bonded storage" (what the heck does "bonded" mean in this context?). The problem is that the ASRGs would not be flight proven before this mission would enter build phase--although who knows when that will be? So I think that NASA would take the most conservative option and go with the MMRTG for a multi-billion dollar mission.
Title: Re: Proposed Europa Missions
Post by: robertross on 07/26/2013 12:54 pm

NASA is building/has built (my guess is that they are majority complete) two ASRG units that will be placed in "bonded storage" (what the heck does "bonded" mean in this context?).


Just 'secure' I beleive, but perhaps even with armed security. We see a lot of that here in Halifax with all the container traffic.
Title: Re: Proposed Europa Missions
Post by: Zed_Noir on 07/26/2013 07:37 pm
NASA is building/has built (my guess is that they are majority complete) two ASRG units that will be placed in "bonded storage" (what the heck does "bonded" mean in this context?). The problem is that the ASRGs would not be flight proven before this mission would enter build phase--although who knows when that will be?


Maybe they can test fly the ASRG unit and recover it for refueling with a space capsule.
Title: Re: Proposed Europa Missions
Post by: EE Scott on 07/26/2013 07:44 pm
I think that the likely power source would be an MMRTG. NASA is building another one for Mars 2020, which maintains the experience/production base.

NASA is building/has built (my guess is that they are majority complete) two ASRG units that will be placed in "bonded storage" (what the heck does "bonded" mean in this context?). The problem is that the ASRGs would not be flight proven before this mission would enter build phase--although who knows when that will be? So I think that NASA would take the most conservative option and go with the MMRTG for a multi-billion dollar mission.


Any idea what (or when) the first ASRG-equipped mission might be? 

Someone's got to step up and just do it so we can get a better idea of its true performance potential.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 07/26/2013 08:44 pm
Maybe they can test fly the ASRG unit and recover it for refueling with a space capsule.


No.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 07/26/2013 08:47 pm
Any idea what (or when) the first ASRG-equipped mission might be? 

Someone's got to step up and just do it so we can get a better idea of its true performance potential.

The next real opportunity will be with the next Discovery or New Frontiers selection. I think that the next Discovery selection is not slated to happen before 2016 and the next New Frontiers before 2017 or so. But both are going to slip because of ongoing budget cuts. And even if such a mission was selected, it would take five or more years to build the spacecraft, so we won't see an ASRG mission fly in this decade.

The last Discovery selection included three potential missions. Two required ASRGs and the third was conventional. That one, InSight, was selected, probably because it was the least risky of the three missions.

There are people inside of NASA who were pushing for an ASRG mission, but they did not win out.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 07/26/2013 08:49 pm

NASA is building/has built (my guess is that they are majority complete) two ASRG units that will be placed in "bonded storage" (what the heck does "bonded" mean in this context?).


Just 'secure' I beleive, but perhaps even with armed security. We see a lot of that here in Halifax with all the container traffic.

I'm guessing that it means storage in clean-room/controlled conditions, as opposed to being stuck in a warehouse. NASA kept the DSCOVR spacecraft in a temp and humidity controlled container at Goddard for many years, I believe, before retrieving it for refurbishment.
Title: Re: Proposed Europa Missions
Post by: robertross on 07/27/2013 12:44 am

NASA is building/has built (my guess is that they are majority complete) two ASRG units that will be placed in "bonded storage" (what the heck does "bonded" mean in this context?).


Just 'secure' I beleive, but perhaps even with armed security. We see a lot of that here in Halifax with all the container traffic.

I'm guessing that it means storage in clean-room/controlled conditions, as opposed to being stuck in a warehouse. NASA kept the DSCOVR spacecraft in a temp and humidity controlled container at Goddard for many years, I believe, before retrieving it for refurbishment.

not the typical definition of bonded storage; it would need to state that explicitely (or be clean room/controlled by default with the added feature of being in bonded storage).

Bonded is essentially lock & key with tamperproof features to ensure no tampering is possible without someone knowing about it.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 07/27/2013 02:36 am
not the typical definition of bonded storage; it would need to state that explicitely (or be clean room/controlled by default with the added feature of being in bonded storage).

Bonded is essentially lock & key with tamperproof features to ensure no tampering is possible without someone knowing about it.

Well, I'm presuming that because it is nuclear-related materials that there are certain restrictions applied to it. So, yeah, locked up, but probably also environmentally controlled as well.

On a tangentially-related note, I heard a story several years ago from a now-former NASA official about the remaining supply of Neptunium that would be used to create Pu-238 fuel. Apparently this guy ordered a NASA official to go and slap NASA inventory numbers on the containers filled with this fuel. He didn't want some DoE person to come along and assume that it was just DoE material and discard it. I'm sure that he did something, but I found the story to be a little hard to compute, because I'm pretty sure that NASA does not own that material and in fact is probably not allowed under law to own it, so I don't know how NASA could label it. But it's in a secure DoE warehouse somewhere, probably next to the Ark of the Covenant and Jimmy Hoffa's frozen corpse.
Title: Re: Proposed Europa Missions
Post by: EE Scott on 07/27/2013 02:59 am
Any idea what (or when) the first ASRG-equipped mission might be? 

Someone's got to step up and just do it so we can get a better idea of its true performance potential.

The next real opportunity will be with the next Discovery or New Frontiers selection. I think that the next Discovery selection is not slated to happen before 2016 and the next New Frontiers before 2017 or so. But both are going to slip because of ongoing budget cuts. And even if such a mission was selected, it would take five or more years to build the spacecraft, so we won't see an ASRG mission fly in this decade.

The last Discovery selection included three potential missions. Two required ASRGs and the third was conventional. That one, InSight, was selected, probably because it was the least risky of the three missions.

There are people inside of NASA who were pushing for an ASRG mission, but they did not win out.

Thanks for your thoughts on this.  The pace of progress is maddening to me.  There are so many promising ways to stretch resources, like ASRG, or aero capture/braking, etc.  But if we don't fly the first mission to try out these new technologies and techniques, we are stuck with the same capabilities.  I guess we don't even have the budget to choose a decent amount of conventional mission profiles, let alone something that pushes the boundaries.

Title: Re: Proposed Europa Missions
Post by: Blackstar on 07/27/2013 02:01 pm
The pace of progress is maddening to me.  There are so many promising ways to stretch resources, like ASRG, or aero capture/braking, etc.  But if we don't fly the first mission to try out these new technologies and techniques, we are stuck with the same capabilities.  I guess we don't even have the budget to choose a decent amount of conventional mission profiles, let alone something that pushes the boundaries.



With the Discovery program NASA had three mission options:

-TiME (Titan lake lander), ASRG, probably the most expensive of the missions
-Comet Hopper, ASRG, probably medium expensive
-InSight, Mars lander, solar panels, proven hardware

When I say "expensive," you have to understand that Discovery is cost-capped. That means that technically, all three mission proposals cost the same (~$475 million, I think). But TiME and Comet Hopper were more likely to go over budget than InSight.

When we say that we want NASA to take more risk, we also need to understand that we (or Congress, people in general) are just as likely to criticize those decision-makers when things don't go perfectly. So when TiME went over budget, people would complain and call for the leadership to be punished/fired, etc.

In addition, NASA's planetary budget was going down. In that environment, the safest course of action is to pick the cheapest mission, or at least the one that is unlikely to bust its cost cap.
Title: Re: Proposed Europa Missions
Post by: EE Scott on 07/29/2013 01:49 am
The pace of progress is maddening to me.  There are so many promising ways to stretch resources, like ASRG, or aero capture/braking, etc.  But if we don't fly the first mission to try out these new technologies and techniques, we are stuck with the same capabilities.  I guess we don't even have the budget to choose a decent amount of conventional mission profiles, let alone something that pushes the boundaries.



With the Discovery program NASA had three mission options:

-TiME (Titan lake lander), ASRG, probably the most expensive of the missions
-Comet Hopper, ASRG, probably medium expensive
-InSight, Mars lander, solar panels, proven hardware

When I say "expensive," you have to understand that Discovery is cost-capped. That means that technically, all three mission proposals cost the same (~$475 million, I think). But TiME and Comet Hopper were more likely to go over budget than InSight.

When we say that we want NASA to take more risk, we also need to understand that we (or Congress, people in general) are just as likely to criticize those decision-makers when things don't go perfectly. So when TiME went over budget, people would complain and call for the leadership to be punished/fired, etc.

In addition, NASA's planetary budget was going down. In that environment, the safest course of action is to pick the cheapest mission, or at least the one that is unlikely to bust its cost cap.

Yes.  In this budget environment, I should just be happy if we can get conservative missions funded. Even though I would love to see TiME chosen as a bonus mission (Senate proposal), or this Europa mission become reality. Because if there is some strange way the SLS fiasco could somehow be of use, because they are desperate  for missions/payloads using SLS, that would be a consolation.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 07/29/2013 07:07 pm
http://thespacereview.com/article/2338/1



Talk of an icy moon at Vegas for Nerds
by Dwayne Day
Monday, July 29, 2013

Every July a hundred and thirty thousand people descend upon San Diego for Comic-Con, an event best described as “Las Vegas for nerds.” There are thousands of events that take place both inside and outside the San Diego Convention Center over four days, some exclusive, some open to anybody who walks in. One of the more difficult to reach venues is the convention center’s Hall H, which can seat more than 6,000 people, and is the stage for most of the biggest-hyped and popular panels at Comic-Con, such as the ones where major Hollywood movies are rolled out and big name movie stars and directors unveil their new productions. Getting into Hall H often requires standing in line for many hours starting out in the early morning, or even sleeping on the lawn outside the Convention Center overnight—something you can do in your teens and twenties, but can strain the backs of people older than that. In all my years of going to Comic-Con I’ve never tried to get into Hall H, but last week Thursday I gave it a shot and easily got into the panel for the new movie Europa Report. The movie premieres in theaters August 2, but is already available via download or on demand (see “Life and death and ice”, The Space Review, July 1, 2013).
Title: Re: Proposed Europa Missions
Post by: simonbp on 07/29/2013 08:29 pm
With the Discovery program NASA had three mission options:

-TiME (Titan lake lander), ASRG, probably the most expensive of the missions
-Comet Hopper, ASRG, probably medium expensive
-InSight, Mars lander, solar panels, proven hardware

From the scuttlebutt around the time of the decision, it sounded like the breakdown was more:

- TiME: Low technical risk (essentially a reflight of Huygens hardware with an added ASRG), high science risk (not much data returned, risk of landing somewhere where the terrain impedes downlink).

- Comet Hopper: High technical risk (no one has ever landed on an comet), low science risk (no one has ever landed on an comet, anything is new)

- Insight: Low technical risk (Phoenix reflight), low science risk (it will return data, just not necessarily high-priority data)

Based on that, Insight had the lowest technical and science risk, and therefore was least likely to go overbudget. Plus, it's not a confidence that they announced Insight shortly after MSL landed...

For Europa, IMHO that means that the solar option may come to the fore. Assuming the solar arrays on Juno work well (and keeping in mind its periapse is much closer to Jupiter than Io), the JPL margin on them may come down enough that they are similar mass to the RTGs (and still lowest cost).
Title: Re: Proposed Europa Missions
Post by: Blackstar on 07/29/2013 08:40 pm
- TiME: Low technical risk (essentially a reflight of Huygens hardware with an added ASRG)

I have a hard time believing that it was a reflight of Huygens hardware. For starters, this was a U.S. mission and Huygens was built by ESA. But I know somebody who was on TiME and Huygens and can ask him.
Title: Re: Proposed Europa Missions
Post by: arachnitect on 07/30/2013 01:22 am

Based on that, Insight had the lowest technical and science risk, and therefore was least likely to go overbudget. Plus, it's not a confidence that they announced Insight shortly after MSL landed...


IIRC, they had already made the decision before MSL reached mars and were sitting on it so that the Discovery announcement wouldn't get lost in the MSL excitement.

When they explained the selection, I got the impression that the science return from all 3 proposals was considered very good and technical maturity/low risk alone sealed the deal for InSight.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 07/30/2013 01:27 am
I got the impression that the science return from all 3 proposals was considered very good and technical maturity/low risk alone sealed the deal for InSight.

There's a challenge with that. How do we rate the science return? According to NASA, the science return for all three missions was rated as "high," and therefore they were equal in terms of science. I know a highly respected space scientist who thought that all three were high value science missions.

But the value of that science also depends upon who is doing the valuing. I think that seismology is not rated highly by many scientists because they consider it to be narrow. So even though InSight would be the first seismic data from Mars, I don't think many scientists care. The flip side is that although we've never actually sampled a comet's surface, the group of scientists interested in primitive bodies like comets is isolated from the group that is interested in things like Mars habitability.

So it's not easy to make these comparisons.
Title: Re: Proposed Europa Missions
Post by: neveroddoreven on 07/30/2013 03:49 pm
So, currently the notional launch vehicle for this clipper would be the Atlas V 551. Using this vehicle the thing would have to use a VEEGA trajectory and end up taking six and a half years to get to Europa. Then they are talking about SLS as an alternative which would enable a direct route that would take less than 2 years, but we all know that them using SLS on this mission is unlikely. Well, looking at Falcon Heavy's new payload to GTO of 21,200 kg (relative to 551's 8,700kg) and payload to Mars of 13,500 kg (not sure what 551's is here, but I'm assuming significantly lower) I was wondering if it would be a feasible option as well. Would it be capable of a direct route like SLS or would it not have the power? If direct isn't possible could you use a trajectory different than VEEGA like VEGA or VGA to cut down on time or would the position of the planets not allow for such a trajectory?

On top of a possibly shorter trip Falcon Heavy would be significantly cheaper as well. They are listing it as costing $133 million whereas wiki says the 541 (couldn't find a price for the 551) is $223 million.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 07/30/2013 04:24 pm
On top of a possibly shorter trip Falcon Heavy would be significantly cheaper as well. They are listing it as costing $133 million whereas wiki says the 541 (couldn't find a price for the 551) is $223 million.

I don't want to get into a tiresome discussion of launch vehicles and their costs, but I'd just caution that you cannot make these comparisons using that available data. There are several reasons:

--FH is not operational

--the publicly quoted SpaceX costs are not the actual costs to NASA because they leave stuff out*

--FH is not rated for carrying Pu-238**



These back of the envelope comparisons are not that precise.


*(Hey, look! A footnote!) There's an explanation for this that you might be able to find if you dig around on this site for hours. But it basically comes down to the fact that there are a lot of payload processing, vehicle-unique mods, and other things that are not included in the website costs of SpaceX's rockets. If you want a better idea of actual costs, you need to look at NASA's stated costs for their launch services contract, which puts everything on the same baseline. But the bottom line is that the numbers are closer than you've stated. Of course, assuming that FH works as advertised, you'd get a lot more payload capability probably at equal or lesser price to a big Atlas, so it might still be a deal.

**(Hey, look! Another footnote!) It costs a decent amount of money to do all the assessments to certify a vehicle to carry Pu-238. That cost is already sunk for Atlas. Falcon 9 or FH would have to undergo the same certification. There has been some talk of eventually doing that, but NASA's (eminently logical) position right now is that it's premature to think about this until the rocket has started flying and demonstrated some reliability and lots and lots of data.

Title: Re: Proposed Europa Missions
Post by: neveroddoreven on 07/30/2013 04:40 pm
Ah, okay. I wasn't aware that vehicles had to be rated to carry Pu 238.

Also, sorry if my comment was a bit too OT. I was just curious about the advantages that a different launch vehicle could bring to the mission.
Title: Re: Proposed Europa Missions
Post by: baldusi on 07/30/2013 08:08 pm
I think that the 2020 rover studies had pegged the Atlas 551 cost for nasa at 320M, if I recall correctly. I also think I heard that the marginal cost of an SLS launch would be around 400M or so. For this mission the marginal cost might be closer to 500M. But still not such a huge difference. I mean, that's 180M, but you save four years of operations, which might well be around 80M. 100M is a lot of dough for SMD, but if Congress would want to actually use the rocket, I think it's feasible, albeit rather improbable.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 07/30/2013 10:10 pm
1-Ah, okay. I wasn't aware that vehicles had to be rated to carry Pu 238.

2-Also, sorry if my comment was a bit too OT. I was just curious about the advantages that a different launch vehicle could bring to the mission.

1-They have to be certified as a vehicle. Then each launch has to be individually certified (because of specific configurations, trajectories, the payloads, etc.). I heard what this would cost, but have forgotten. I think that the overall vehicle certification is a few tens of millions of dollars and the individual launch certification is (maybe?) less than $10 million. It is surprisingly expensive, but it's an exhaustive engineering analysis.

2-Not completely off topic. It's just that too many people on NSF tend to treat every issue as if it's a rocket issue and they don't care about payloads, which is not how people in the space business look at stuff (it's not how you get there, it's what you're going to do there).
Title: Re: Proposed Europa Missions
Post by: Blackstar on 07/30/2013 10:16 pm
I think that the 2020 rover studies had pegged the Atlas 551 cost for nasa at 320M, if I recall correctly. I also think I heard that the marginal cost of an SLS launch would be around 400M or so. For this mission the marginal cost might be closer to 500M. But still not such a huge difference. I mean, that's 180M, but you save four years of operations, which might well be around 80M. 100M is a lot of dough for SMD, but if Congress would want to actually use the rocket, I think it's feasible, albeit rather improbable.

It's not going to trade off that easily. For starters, NASA and the science community have experience with the Atlas. They're used to it. How many unique issues will they have to address if they go to an entirely different booster? For instance, Atlas is certified to carry Pu-238 missions, SLS would have to be certified. That's money.

I know that I'm going to sound strident on this topic, but when I'm not working directly in this subject area I'm at least hovering around the edges and talking to people who work directly in it, and there's almost zero interest in the planetary science community in hitching a ride on an SLS. Yeah, it could offer all kinds of advantages, but there are a lot of hidden pitfalls that people are wary of as well (like will the rocket still exist by the time you expect the mission to require it?). There is really only one person I know who is pushing the idea, and although he's really well-qualified and knowledgeable, I don't know of anybody else who agrees with him. So I cringe whenever I see an article that doesn't provide all kinds of qualifiers about how an SLS is unlikely to ever be used for such a mission.

That said, the idea is probably worth studying at a very low level, although there's still a risk that people will take it seriously and start shoving the program in that direction. That would be non-good.
Title: Re: Proposed Europa Missions
Post by: baldusi on 07/30/2013 10:47 pm
I didn't state that the actual scientists were interested. I just stated that the price difference might not be that huge as we used to think. I started thinking the launch would be an additional 1B or so. And who know, may be after doing trades the exploration program considers that certifying SLS for PU-238 is worth it, so they wouldn't charge it to SMD. May be they need an instrument to be left on an asteroid, or something. Those engineering works at MFSC are very politically viable.
And, regrettably, you have to actually get your money appropriated by Congress. And may be, just may be, they might the authorization for this flagship mission on the condition that it flies on SLS. A purely political decision, but it wouldn't be the first time that Congress forces NASA to use a "flagship" LV to launch a flagship mission even if it would actually cost more. And of course they will still try to lower the overall budget.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 07/30/2013 11:26 pm
And who know, may be after doing trades the exploration program considers that certifying SLS for PU-238 is worth it, so they wouldn't charge it to SMD.

If NASA had a viable exploration program, they would certainly certify SLS for Pu-238 on their own at some point. Previous lunar exploration studies included RTGs for emergency backup power for the lunar outpost. I just cannot see them spending that money when they don't have a clear requirement.
Title: Re: Proposed Europa Missions
Post by: baldusi on 07/31/2013 02:41 am
What would be the timeframe for an actual decision on this? I certainly wouldn't expect the Clipper mission to be given a go ahead before 2018. So many thing will happen in this four years wrt SLS, the political landscape, the LV fleet, the ISS, etc. That, even though I'm not saying it will happen, I do say that not impossible, merely that it would be extremely unlikely. As stated before, assuming that the SMD gets to do a flagship after JWST and the 2020 Mars Rover, it would be the cheapest possible payload for SLS. Not cheaper exactly, but if you look at it from an SLS supporter, say a Congressman, you're already doing the flagship, so if you put as little as 200M estra, you'd get an extra SLS launch, and you can say that its even used for flagship missions. It's, from that point of view, even cheaper than an Orion. And they might even put the very budget for the mission as a condition on using SLS. Again, assuming that by the time this is decided the SLS is a reality and theres a clear path in exploration to assure it's existence going forward. If Europa gets authorized in 2018, it would be expected to launch by 2024/5? that might work well with current exploration proposals. USA will have to recuperate its economy, eventually.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 07/31/2013 05:05 pm
What would be the timeframe for an actual decision on this?

An honest answer, based upon my analysis skills and not any real information (because there is no real information--nobody knows what is going to happen in 2014, 15, 16, 17 or 18) is that there will be no new-start on a Europa mission until after the next planetary science decadal survey, which will probably start in 2018 and produce a report by 20 or 21.

That's based upon reading tea leaves. Right now there is actually insufficient money in the NASA budget to do the Mars 2020 rover on time. And the administration is continuing to cut money out of the planetary sciences budget. Given that reality, there is no way that another flagship-class planetary mission is going to be approved before the current one (Mars 2020) is essentially paid for and ready to launch.

There's also a nasty little dynamic that happens in these things, which is that Washington lives by the saying "Why put off today what you can put off tomorrow?" As we get farther from the 2011 decadal survey, and nearer to the start of the next decadal survey, the decision makers will decide to defer any decisions in order to wait and hear what the decadal survey will say. In other words, even if the next president puts a lot more money into planetary science in 2017 or 2018, people will say "We should not start a new big mission until we hear what the scientists say in 2021..." And so the decision could easily get delayed from 2018 until 2022.

Something similar happened during the last round. NASA could have started working on the Europa mission. But they ended up deferring that work to wait for the decadal survey. (Note: that probably was not a bad idea, because the Europa mission being discussed in 2008 was too expensive and really needed to be de-scoped.)

Title: Re: Proposed Europa Missions
Post by: Blackstar on 09/03/2013 03:55 pm
Some current papers on Europa Clipper and Europa Lander.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 09/03/2013 03:58 pm
http://www.jpl.nasa.gov/news/news.php?release=2013-243&cid=release_2013-243

If We Landed on Europa, What Would We Want to Know?
August 07, 2013

Most of what scientists know of Jupiter's moon Europa they have gleaned from a dozen or so close flybys from NASA's Voyager 2 spacecraft in 1979 and NASA's Galileo spacecraft in the mid-to-late 1990s. Even in these fleeting, paparazzi-like encounters, scientists have seen a fractured, ice-covered world with tantalizing signs of a liquid water ocean under its surface. Such an environment could potentially be a hospitable home for microbial life. But what if we got to land on Europa's surface and conduct something along the lines of a more in-depth interview? What would scientists ask? A new study in the journal Astrobiology authored by a NASA-appointed science definition team lays out their consensus on the most important questions to address.

"If one day humans send a robotic lander to the surface of Europa, we need to know what to look for and what tools it should carry," said Robert Pappalardo, the study's lead author, based at NASA's Jet Propulsion Laboratory, Pasadena, Calif. "There is still a lot of preparation that is needed before we could land on Europa, but studies like these will help us focus on the technologies required to get us there, and on the data needed to help us scout out possible landing locations. Europa is the most likely place in our solar system beyond Earth to have life today, and a landed mission would be the best way to search for signs of life."

The paper was authored by scientists from a number of other NASA centers and universities, including the Johns Hopkins University Applied Physics Laboratory, Laurel, Md.; University of Colorado, Boulder; University of Texas, Austin; and the NASA Goddard Space Flight Center, Greenbelt, Md. The team found the most important questions clustered around composition: what makes up the reddish "freckles" and reddish cracks that stain the icy surface? What kind of chemistry is occurring there? Are there organic molecules, which are among the building blocks of life?

Additional priorities involved improving our images of Europa - getting a look around at features on a human scale to provide context for the compositional measurements. Also among the top priorities were questions related to geological activity and the presence of liquid water: how active is the surface? How much rumbling is there from the periodic gravitational squeezes from its planetary host, the giant planet Jupiter? What do these detections tell us about the characteristics of liquid water below the icy surface?

"Landing on the surface of Europa would be a key step in the astrobiological investigation of that world," said Chris McKay, a senior editor of the journal Astrobiology, who is based at NASA Ames Research Center, Moffett Field, Calif. "This paper outlines the science that could be done on such a lander. The hope would be that surface materials, possibly near the linear crack features, include biomarkers carried up from the ocean."

This work was conducted with Europa study funds from NASA's Science Mission Directorate, Washington, D.C. JPL is a division of the California Institute of Technology, Pasadena.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 09/04/2013 07:13 pm
Ta da.
Title: Re: Proposed Europa Missions
Post by: Star One on 09/04/2013 07:43 pm
In your opinion which would be the best power source for it to use & does this differ from the power source it is most probable to end up with?
Title: Re: Proposed Europa Missions
Post by: baldusi on 09/04/2013 07:50 pm
Why was the ASRG taken out of the option space?
Title: Re: Proposed Europa Missions
Post by: Blackstar on 09/04/2013 09:27 pm
Why was the ASRG taken out of the option space?

Complexity. They needed to narrow down the options and could not keep studying three, so they went down to two and got rid of the most complex one.

Interesting trades with solar. It is heavier, but cheaper. Batteries drive the mass.
Title: Re: Proposed Europa Missions
Post by: baldusi on 09/04/2013 10:19 pm
Why was the ASRG taken out of the option space?

Complexity. They needed to narrow down the options and could not keep studying three, so they went down to two and got rid of the most complex one.

Interesting trades with solar. It is heavier, but cheaper. Batteries drive the mass.
Aren't solar cells more sensitivo to radiation? Is there a trade off in expected life? Or will they destructivelly end to avoid danger or contaminatin Europa?
Title: Re: Proposed Europa Missions
Post by: Blackstar on 09/05/2013 01:36 am
Aren't solar cells more sensitivo to radiation? Is there a trade off in expected life? Or will they destructivelly end to avoid danger or contaminatin Europa?

Yes. Yes. Yes.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 09/05/2013 06:05 pm
Some more.
Title: Re: Proposed Europa Missions
Post by: baldusi on 09/05/2013 06:14 pm
Now that they got me thinking. Couldn't this mission help a lot in the understanding of Earth's processes? Because you tend to do lineal models and/or taking first order processes, but when investigating other solar bodies you start to understand extremes and secondary and/or tertiary processes that can refine greatly your understanding of Earth.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 09/06/2013 05:25 pm
Some more.
Title: Re: Proposed Europa Missions
Post by: EE Scott on 09/06/2013 07:29 pm
Great stuff!  Europa is such an exciting target (as are the other Jovian moons); so much potential low hanging fruit here that could be just mind blowing.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 09/06/2013 08:40 pm
Title: Re: Proposed Europa Missions
Post by: baldusi on 09/06/2013 08:44 pm
Just for the sake of inquiring. Couldn't a Gainymede or Callisto probe be an exact replica? Yes, it would be overbuilt for the radiation environment. And it would overstep with JUICE. But may be doing a second copy from the beginning, specially a solar powered one, would be particularly cheap. And may be it wouldn't need all the instruments.
Title: Re: Proposed Europa Missions
Post by: vjkane on 09/07/2013 05:29 am
If we were to build a replica, I'd send it to Titan and Europa (with some different instruments).  Assuming sufficient plutonium, of course.
Title: Re: Proposed Europa Missions
Post by: baldusi on 09/07/2013 05:27 pm
If we were to build a replica, I'd send it to Titan and Europa (with some different instruments).  Assuming sufficient plutonium, of course.
Are you aware that Titan is in Saturn, right?
I was wondering basically because each time the experts like Blackstar tells me why not, I learn a lot.
Title: Re: Proposed Europa Missions
Post by: ugordan on 09/07/2013 05:30 pm
If we were to build a replica, I'd send it to Titan and Europa (with some different instruments).  Assuming sufficient plutonium, of course.
Are you aware that Titan is in Saturn, right?

I'm pretty sure (http://futureplanets.blogspot.com/) he is...
Title: Re: Proposed Europa Missions
Post by: Blackstar on 09/07/2013 08:56 pm
Just for the sake of inquiring. Couldn't a Gainymede or Callisto probe be an exact replica? Yes, it would be overbuilt for the radiation environment. And it would overstep with JUICE. But may be doing a second copy from the beginning, specially a solar powered one, would be particularly cheap. And may be it wouldn't need all the instruments.

I don't know. Europa Clipper is really tied to its orbit. It might be possible to fly a similar spacecraft to do different orbits at another body, but I'm not sure that the science return would be good. EC actually has to fly very low over Europa to do the radar science, and that's considered a risky move. There is the danger of hitting the moon. And they go into eclipse several times, unlike Juno, meaning that they need batteries during that time.

I think I have a JUICE presentation that I can post here. They are different missions.

Nobody cares much about Callisto. It doesn't rank high for science prioritization.

Title: Re: Proposed Europa Missions
Post by: hello2 on 09/08/2013 11:43 am
Hi, sorry to intrude on the topic, but I'm a software engineer and I've always been fascinated with robot missions to other planets/moons, especially those towards Mars and Europa. It would be wonderful if I could contribute to the spacecraft/lander software in any way (as a volunteer). Do you know who can I contact? Is there any way to do this? Unfortunately that NASA only hires US citizens, but maybe they don't have such restrictions for volunteers.
Title: Re: Proposed Europa Missions
Post by: spectre9 on 09/08/2013 12:13 pm
I'm starting to come around to the idea of solar panels.

The "toe dip" into the heaviest radiation should give the spacecraft some breathing room.

The only reason I don't like it is the potential to build a great spacecraft bus that could cover all future missions to all the gas giants. Standardize the power, propulsion and tanks and then just change the instrumentation on top.

Then maybe launch on cheap SpaceX rockets.

Outer planets exploration on a budget? Perhaps I'm being too optimistic.

Title: Re: Proposed Europa Missions
Post by: Blackstar on 09/08/2013 03:02 pm
Here's the rest.
Title: Re: Proposed Europa Missions
Post by: baldusi on 09/08/2013 08:44 pm
Now that I'm looking at this mission, it feels like Cassini. In the sense that there are quite a few instruments, that it could probably use some international coolaboration, and that they should apply the market based management system.
Ehat they did with Cassini was to assign three resources to each instrument: mass, power and bandwidth. And their assigned budget. They even put the assigned margins to each group to manage. And they developed a market where any group could trade against any other. So, if you had a mass problem but were under power budget, you could go and trade against somebody who had excess mass margin but needed some extra watts. And if you had none, you could apply your budget margin and go buy margin from some other group. And the master stroke: you could donate any of your margins to any other instrument that was above their budgets but you were interested in their data (probably because the data was complementary, like mass estimations and diameter estimation that allow for density estimation).
The way I'm looking at this if they don't apply it, it would be a shame.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 09/08/2013 09:41 pm
That could work. But it's really premature. You don't do something like that until you enter development. This project has not even been approved, and there might be better ways to manage it than what they did with Cassini.
Title: Re: Proposed Europa Missions
Post by: baldusi on 09/09/2013 01:15 am
I'm an economist and Cassini used a market based solution, I can't avoid rooting for it  ;)
The other part that surprises me is the price difference with the SLS launch. Just 150M for a flagship and getting your data back much sooner to feed the next proposal is very interesting. And, as I speculated before, Congress might be more than happy to use an additional SLS for relative little money and with a certain advantage, it could be politically viable. In particular, those congressmen might still be in office by the time it arrives if launched in SLS. I know, that number might be pure wishful thinking, and the science team themselves might not care, but, Congress has forced worse things due to political influence.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 09/09/2013 02:30 am
The other part that surprises me is the price difference with the SLS launch. Just 150M for a flagship and getting your data back much sooner to feed the next proposal is very interesting.

My impression is that most of the people involved in defining the Europa mission do not want anything to do with SLS. The reason is that Atlas (and Delta) is a known vehicle. It is something they are familiar with. There's a lot of data on how the rocket performs, what it costs, what it can do. If they were given a go-ahead to build Europa Clipper tomorrow (which is not going to happen) they can easily design to an Atlas V. They cannot do that for an SLS.

There are a lot of other issues too. For one thing, you can count on the Atlas V being around for at least another 10-20 years. So it is a guaranteed ride. That's not true for SLS, which could be canceled next year or in five years. Nobody in their right mind would want to bank on that.

And then there's the nasty issue of cost. Who is going to pay for the rocket? Right now, the planetary division has to pay for its own launch vehicles. So they want the least expensive one they can get that will do the job. If they have to pay an extra $150 million for a launch vehicle, they are going to ask what else they could do with that money. Could it go for better instruments? Or more science?

There's another tough thing to try and explain, but saving time getting to Jupiter doesn't necessarily benefit you in many ways, because there is no Jupiter program guaranteeing future missions, unlike Mars. For Mars, you fly a mission, get the data back, and then design a new mission. Mars is a campaign. It is budgeted that way and planned that way. But Jupiter is different, and flying Europa Clipper and getting the data back faster theoretically makes it possible to fly a follow-up mission faster, but there's no program that allows you to do that. And because Jupiter missions are all expensive (billion dollar plus), getting the data back faster and having more time to plan another mission does not mean that you can afford a follow-up mission sooner. So the benefit is really not all that great. Put another way, by using SLS and flying a mission to Europa faster, you may have only increased the waiting time between Europa Clipper and any follow-on mission.

That said, if Europa Clipper found something really interesting on Europa, such as a very active surface indicating thin ice and a lot of activity under the ice, then that could create an argument for flying another mission, such as a lander, as soon as possible. But those are some big what ifs, and that assumes that the science priorities would change. That may not happen at all.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 09/09/2013 01:56 pm
Here's a presentation on NASA participation in the JUICE mission.

There are some complicated and (I think) interesting aspects to NASA being involved. Part of the issue is that NASA has limited money to provide instruments. Then there's the standard issue that the U.S. may be good at some types of instrumentation, but the Europeans would rather do those things themselves (to build capabilities, help scientific teams, etc.). So there's a lot of back and forth negotiation.

My impression is that the American Europa science community would like to be much more involved in this than they are, but there just isn't the money to do it.
Title: Re: Proposed Europa Missions
Post by: baldusi on 09/09/2013 05:43 pm
I decided to compare the Europa Clipper and the JUICE instruments. Help me here because I'm just comparing the abstracts of each instrument. I've put them in order of how similar they are. Since they are examining the same bodies, I would expect them to have a lot of similar science. On the other hand, since JUICE will be visiting three moons (and barely overflying Europa two times) while EC will concentrate on just one, even if they were identical they'd get different data. And I would expect JUICE to have a couple more instruments, too.

Europa ClipperJUICE
Instrument NameScience TypeSciente TypeInstrument Name
Ice Penetrating Radar (IPR)RadarRadarRIME
Magnetometer (Mag)Magnetometer Magnetometer Magnetometer   Magnetometer   JMAG
Reconnaisance Camera (Recon)CameraCameraCamera   JANUS
Langmuir Probes (LP)PlasmaPlasma & FieldsRadio and Plasma Wave Investigation (RPWI)
Neutral Mass Spectometer (NMS)ParticlesParticlesParticle Environment Package (PEP)
Gravity Science Antenna (GS)GravityGravityRadio Science 3GM
Topographical Imager (TI)TopographyTopographyLaser altimeter   Ganymede Laser Altimeter (GALA)
Shortwave Infrared Spectometer (SWIRS)SW/FIR SpecHeterodyne receiverSubmillimeter Wave Instrument (SWI)
Thermal Imager (Thermal)IR ImageIR Imaging SpectometerMAJIS
UV SpectographUltraviolet Spectograph (UVS)
VLBIPRIDE
One thing that this makes me wonder, is that JUICE is an approved Large Mission. And they'll be there by 2030 (hopefully). I simply don't see Europa Clipper arriving earlier, save for some miracle in SLS use (which you have so clearly assigned an infinitesimal probability). I'm right that Europa clipper might well be a decision for the 2020 Decadal Survey? If so, and given that by that time JUICE is well on track, how do you feel the science community would react? Would they feel that having dual missions to Jupiter would give great synergies and could mean the next big (science) exploration frontier, or that given the data that ESA will bring, it would be better to get at least the info on the two flybys and decide if it's worth it or not?
Title: Re: Proposed Europa Missions
Post by: ugordan on 12/12/2013 04:24 pm
I might as well put this in here...

Via unmannedspaceflight.com comes (IMHO huge) news of the first observations of water plumes on Europa.

Articles:
http://www.nature.com/news/hubble-spots-water-spurting-from-europa-1.14357
http://www.newscientist.com/article/dn24743-first-water-plume-seen-firing-from-jupiter-moon-europa.html

Quote
Now images taken by the Hubble Space Telescope have revealed a large cloud of hydrogen and oxygen – most likely in the form of water vapour – extending from the moon's south pole. A model suggests that it is a plume 200 kilometres high that is spouting 3000 kilograms of water per second.

Paper: http://hubblesite.org/pubinfo/pdf/2013/55/pdf.pdf
Title: Re: Proposed Europa Missions
Post by: Blackstar on 12/12/2013 04:25 pm
http://io9.com/massive-plumes-of-water-are-erupting-from-europas-icy-1481376874
Title: Re: Proposed Europa Missions
Post by: Star One on 12/12/2013 07:47 pm
This article from the Washington Post seems to indicate that this discovery increases pressure on NASA to move forward on a Europa mission.

http://www.washingtonpost.com/national/health-science/hubble-space-telescope-sees-geysers-on-jupiters-moon-europa/2013/12/12/b6f780ac-62c8-11e3-a373-0f9f2d1c2b61_story.html?hpid=z5
Title: Re: Proposed Europa Missions
Post by: Danderman on 12/12/2013 08:06 pm
This article from the Washington Post seems to indicate that this discovery increases pressure on NASA to move forward on a Europa mission.

http://www.washingtonpost.com/national/health-science/hubble-space-telescope-sees-geysers-on-jupiters-moon-europa/2013/12/12/b6f780ac-62c8-11e3-a373-0f9f2d1c2b61_story.html?hpid=z5

The implication is that the requirement would be for a Europa Polar Orbiter.

Watch that turn into a 3 billion dollar project.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 12/12/2013 09:12 pm
This article from the Washington Post seems to indicate that this discovery increases pressure on NASA to move forward on a Europa mission.

http://www.washingtonpost.com/national/health-science/hubble-space-telescope-sees-geysers-on-jupiters-moon-europa/2013/12/12/b6f780ac-62c8-11e3-a373-0f9f2d1c2b61_story.html?hpid=z5

Except that it's not NASA's call. It's a White House decision, and OMB has been cutting the planetary budget. This will get some more attention, but unless OMB puts money back into the planetary budget, nothing is going to happen.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 12/12/2013 09:13 pm
The implication is that the requirement would be for a Europa Polar Orbiter.

Watch that turn into a 3 billion dollar project.

It refers to Europa Clipper, which is not a "Polar Orbiter."
Title: Re: Proposed Europa Missions
Post by: savuporo on 12/13/2013 12:37 am
Aaand Bill Nye is at it again
http://www.planetary.org/press-room/releases/2013/1212-the-planetary-society-calls-for-a-mission-to-explore-europa.html

The interesting sentences there say that .. Europa could be habitable now. But, if more money is not given, we wont be going to Europa. We are going to Mars in 2020 again - to really figure out if the environment on that planet, once in distant past, could in fact have supported life.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 12/13/2013 12:44 am
The interesting sentences there say that .. Europa could be habitable now. But, if more money is not given, we wont be going to Europa. We are going to Mars in 2020 again - to really figure out if the environment on that planet, once in distant past, could in fact have supported life.

Yeah, so?

Space policy, and space science policy, cannot be and should not be run like a bunch of five year olds playing soccer, running after the ball no matter where it goes. Take that approach and you never go anywhere, you never make any progress, because each new project continues for a short time and then gets canceled in favor of another new project that continues a short time and gets canceled too.

NASA's space science program succeeds at achieving its goals because it is not at all run like the human spaceflight program.
Title: Re: Proposed Europa Missions
Post by: vjkane on 12/13/2013 03:58 am
A couple of thoughts on this.  First, the discovery appears to be based on a single observation from the press accounts (I haven't had time to download and read the paper).  The plumes need to be observed several times before we can be confident that they are real and persistent.

If the plumes prove to be persistent, then I would be surprised if no one proposed a Discovery mission to follow up.  A spacecraft with an UV spectrometer and a near IR spectrometer (if a mapping spectrometer, then useful observations of the terrain could also be made) to characterize the plumes over time and a mass spectrometer for sampling during flyby(s) would be a nice focused mission.  The characterization could be done from outside Europa's orbit to lower radiation and one to a few flybys could sample the plume to determine its composition.
Title: Re: Proposed Europa Missions
Post by: Star One on 12/13/2013 07:14 am

The interesting sentences there say that .. Europa could be habitable now. But, if more money is not given, we wont be going to Europa. We are going to Mars in 2020 again - to really figure out if the environment on that planet, once in distant past, could in fact have supported life.

Yeah, so?

Space policy, and space science policy, cannot be and should not be run like a bunch of five year olds playing soccer, running after the ball no matter where it goes. Take that approach and you never go anywhere, you never make any progress, because each new project continues for a short time and then gets canceled in favor of another new project that continues a short time and gets canceled too.

NASA's space science program succeeds at achieving its goals because it is not at all run like the human spaceflight program.

The problem with relying on something that is only run every decade is it makes no allowances for discovers like this. How often has something in that survey been marked as important in the survey only to seem less important in the intervening period or for other items to come up that look more important but cannot be looked into because they are not in the survey or had less importance in it when it was drawn up.
Title: Re: Proposed Europa Missions
Post by: AJA on 12/13/2013 10:13 am
I'm amused by mentions in various places that it's somehow 'easier' to get to the sub-surface ocean now.

Yeah, you can sample the sub-surface ocean by sampling the plume, but getting to the sub-surface hasn't become any easier. Trying to get in through the geysers (as opposed to melting/drilling your way through) is going to be like throwing a paper clip into a garden hose which is spewing water.

Nonetheless, if some probe demonstrates that such a thing, is in fact, feasible, I propose we call it "Salmon".

Btw, here's Emily's repost of Leigh Fletcher's comprehensive post: http://www.planetary.org/blogs/guest-blogs/2013/1212-fletcher-the-plumes-of-europa.html
Title: Re: Proposed Europa Missions
Post by: darkbluenine on 12/13/2013 01:15 pm
The problem with relying on something that is only run every decade is it makes no allowances for discovers like this. How often has something in that survey been marked as important in the survey only to seem less important in the intervening period or for other items to come up that look more important but cannot be looked into because they are not in the survey or had less importance in it when it was drawn up.

That's what the Discovery Program is (or used to be) for.  Cost-constrained but responsive investigations.

I'd also note that if there are active plumes a couple decades from now, ESA's JUICE mission will image them in UV.

I dunno if NASA's Juno mission, due to arrive in 2016, can help prove out the plumes from its polar orbit, but it will be interesting to see if the team tries.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 12/13/2013 03:58 pm
The problem with relying on something that is only run every decade is it makes no allowances for discovers like this. How often has something in that survey been marked as important in the survey only to seem less important in the intervening period or for other items to come up that look more important but cannot be looked into because they are not in the survey or had less importance in it when it was drawn up.

The Discovery program makes allowances for discoveries. So does adjusting instrument selection on approved missions. So does observation times on telescopes. And just how quickly do you think missions actually happen?

You wouldn't really want to initiate a multi-billion dollar program based upon an announcement that was made one day ago, would you?
Title: Re: Proposed Europa Missions
Post by: savuporo on 12/13/2013 04:20 pm
You wouldn't really want to initiate a multi-billion dollar program based upon an announcement that was made one day ago, would you?
That is exactly what planetary society releases call for.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 12/13/2013 04:33 pm
You wouldn't really want to initiate a multi-billion dollar program based upon an announcement that was made one day ago, would you?
That is exactly what planetary society releases call for.

Interest groups don't run the program.
Title: Re: Proposed Europa Missions
Post by: Star One on 12/13/2013 06:54 pm

The problem with relying on something that is only run every decade is it makes no allowances for discovers like this. How often has something in that survey been marked as important in the survey only to seem less important in the intervening period or for other items to come up that look more important but cannot be looked into because they are not in the survey or had less importance in it when it was drawn up.

The Discovery program makes allowances for discoveries. So does adjusting instrument selection on approved missions. So does observation times on telescopes. And just how quickly do you think missions actually happen?

You wouldn't really want to initiate a multi-billion dollar program based upon an announcement that was made one day ago, would you?

But you couldn't expect a discovery class mission to investigate something like this I would have thought.

Hopefully there might be some adjustment within JUICE to allow it to look into this, I would imagine that mission is still early enough in its planning to incorporate developments such as this.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 12/13/2013 08:59 pm
1-But you couldn't expect a discovery class mission to investigate something like this I would have thought.

2-Hopefully there might be some adjustment within JUICE to allow it to look into this, I would imagine that mission is still early enough in its planning to incorporate developments such as this.

1-Probably not. It might be possible to do a single flyby on a Discovery budget, but I doubt it. However, there HAS been a proposal for an Earth-orbiting planetary observatory, particularly for looking at Jupiter.

2-And that's what you do: you use current and planned assets to look more closely at the phenomena. More Hubble observing time. Maybe point some big ground-based telescopes at it. Maybe get some observing from Juno if possible. JUICE as well.

What you don't do is completely shelve existing plans to go chasing after the Neat New Thing. This announcement was made at the American Geophysical Union meeting. AGU will happen again next year. Should we cancel whatever we do in 2014 to go after what new information gets revealed next December? Of course not.
Title: Re: Proposed Europa Missions
Post by: Star One on 12/13/2013 09:32 pm

1-But you couldn't expect a discovery class mission to investigate something like this I would have thought.

2-Hopefully there might be some adjustment within JUICE to allow it to look into this, I would imagine that mission is still early enough in its planning to incorporate developments such as this.

1-Probably not. It might be possible to do a single flyby on a Discovery budget, but I doubt it. However, there HAS been a proposal for an Earth-orbiting planetary observatory, particularly for looking at Jupiter.

2-And that's what you do: you use current and planned assets to look more closely at the phenomena. More Hubble observing time. Maybe point some big ground-based telescopes at it. Maybe get some observing from Juno if possible. JUICE as well.

What you don't do is completely shelve existing plans to go chasing after the Neat New Thing. This announcement was made at the American Geophysical Union meeting. AGU will happen again next year. Should we cancel whatever we do in 2014 to go after what new information gets revealed next December? Of course not.

Fair points. Can only hope that next time around in the survey the focus moves away from Mars towards Europa.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 12/13/2013 09:57 pm
Can only hope that next time around in the survey the focus moves away from Mars towards Europa.

Why don't you start working on a white paper to submit for the next survey?

And this has been said over and over again, but the last survey did not neglect Europa. In fact, a Europa mission was rated equal in science with the MAX-C mission. It was essentially a tie in terms of science.

The problem was that the Europa mission proposal that was submitted to the decadal survey cost $4.7 billion. That was not affordable. In fact, it was so big that it completely wrecked the rest of the planetary budget (and this was a year before the administration started cutting the planetary budget). Simply put, the planetary science community looked at the mission options, decided that they didn't want to follow the path of their astronomer colleagues who advocated a mission that destroyed their program, and so they did not advocate the REALLY EXPENSIVE EUROPA MISSION.

Now if JPL had proposed something like Europa Clipper instead, with a much lower cost estimate, then that mission probably would have been ranked first, if only to maintain consistency with the last decadal survey.

So, you may ask, why didn't JPL propose something like Europa Clipper? Because they couldn't comprehend something like that. Because they were thinking in terms of a Christmas Tree mission, putting everything they could on it. It was only when they got smacked in the head by not getting selected that they finally started to come to their senses. And even then it took them awhile. I've heard a JPLer who was involved in the Europa Clipper effort say exactly that--that it took them a long time (over a year) to come up with Europa Clipper because lots of people didn't want to give up their sacred science instrument in order to design a mission that could be affordable. They had to be confronted with cold harsh reality before they would change their views. That only came after the decadal survey. So one of the results of the survey was to force JPL to produce an affordable mission. But that was after, not before.
Title: Re: Proposed Europa Missions
Post by: baldusi on 12/13/2013 11:21 pm
More realistic. In the best missions I always get vulcan unicorns. :p
Title: Re: Proposed Europa Missions
Post by: vjkane on 12/14/2013 03:54 am
So, you may ask, why didn't JPL propose something like Europa Clipper? Because they couldn't comprehend something like that. Because they were thinking in terms of a Christmas Tree mission, putting everything they could on it.
To be fair to JPL, they initially looked at reduced capacity missions.  NASA headquarters instructed them to focus on the sweetspot that included a very robust set of capabilities.  JPL thought the mission they came up with was ~$2B.  The Decadal Survey concluded that the cost would be twice that.

What has always puzzled me, and perhaps Blackstar has some insight, is how the JPL and Decadal Survey cost models could differ by a factor of 2.
Title: Re: Proposed Europa Missions
Post by: darkbluenine on 12/14/2013 04:27 am
how the JPL and Decadal Survey cost models could differ by a factor of 2.

Advocate (JPL) versus independent (decadals use Aerospace Corp, IIRC) cost estimates.  Setting aside issues of potential bias, the former is grounds-up while the latter is a high-level parametric model that correlates the complexity of the spacecraft/mission to historical figures.  The decadals started using an independent cost estimator to: 1) ensure an apples-to-apples cost comparison when considering different proposals, and 2) produce conservative plans that will better stand the test of time.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 12/14/2013 03:02 pm
how the JPL and Decadal Survey cost models could differ by a factor of 2.

Advocate (JPL) versus independent (decadals use Aerospace Corp, IIRC) cost estimates.  Setting aside issues of potential bias, the former is grounds-up while the latter is a high-level parametric model that correlates the complexity of the spacecraft/mission to historical figures.  The decadals started using an independent cost estimator to: 1) ensure an apples-to-apples cost comparison when considering different proposals, and 2) produce conservative plans that will better stand the test of time.


I'd have to go check (and I'm too lazy to do that, so I'll let somebody who is less lazy than me), but I don't think that the difference was that big. I think that the JPL estimate was greater than $2 billion and the decadal was $4.7. (And I vaguely remember hearing that a late JPL cost estimate done just before the decadal did the CATE estimate was much higher, and closer to the CATE.)

However, the CATE process used by the decadal (Aerospace Corp did the CATE) is based upon the history of a broad range of programs. It includes factors that the program does not control, particularly funding shortages due to budgeting issues. So it essentially says to the program "If everything went perfectly for you, your estimate would probably be right. However, all kinds of things happen that you cannot control. For instance, you expect peak funding of $X, but it is more likely that you will get peak funding of $X-1, and that will end up costing you more money in the long run."

Once this is explained to the program (the advocates for a mission), they are generally less hostile, because they realize that the blame for many of the cost increases is put on external forces (like Congress and OMB) and not them.

Now JPL is convinced that they do great cost estimates, but there might be some people who dispute that...

I believe that Aerospace is constantly calibrating their CATE process and comparing its predictions to each new mission. And I believe that they have shown that many of the advocate estimates are NOT wrong, they just don't account for exterior factors. They often say to the program people "You did everything right, but you got screwed over by things outside of your control."

Steve Squyres tells a good story about MER. They were forced to do an independent cost estimate and it came in much higher than the MER program (at JPL) predicted. He said that they never believed it--until their costs started rising. He said that in the end the independent estimate was very close to the actual cost and it changed his opinion about independent estimates.

Title: Re: Proposed Europa Missions
Post by: Star One on 12/14/2013 03:15 pm
If that's going to be the price tag it seems like they may need to attract other agencies such as ESA in as partners to share the cost.
Title: Re: Proposed Europa Missions
Post by: AJA on 12/14/2013 06:45 pm
So it essentially says to the program "If everything went perfectly for you, your estimate would probably be right. However, all kinds of things happen that you cannot control. For instance, you expect peak funding of $X, but it is more likely that you will get peak funding of $X-1, and that will end up costing you more money in the long run."

1. How does that not become a self-fulfilling prophecy?

cf. The PI for OSIRIS-REx, Dante Lauretta - did an AMA on Reddit (http://www.reddit.com/r/IAmA/comments/1sif2f/i_am_the_principal_investigator_for_the_nasa/cdxvz9w)

2. Is it really heresy to talk about fixed-price contracts for robotic missions, a la new space launch services providers? Yes, I know that exploration missions de facto require development in knowledge, technology and maybe even capital infrastructures - on the part of the agency that wins the bid, and is tasked with discharging the mission. Yes, I concede that the frontier nature of these things would make a 'realistic' cost estimation hard, and if fixed-price contracts are artificially mandated, then these costs would inflate to become conservative, and make the whole exercise pointless. (Also, development costs for new space haven't entirely been borne by the fledgling companies. They've had substantial programmatic support.)

However, what if you de-linked technology development from missions? I'm not talking about technology development like "cheaper" this or "cheaper" that... but mission-enabling technologies that are still in low TRL, but whose qualification and availability in a proposed mission time-frame is assumed, and the costs of getting from TRL..say 3-9 is factored into mission costs. I confess I've never read a proposal yet, and I don't know if the proposal guidelines specify a certain minimum readiness for all proposed sub-systems - if the advocates want a program seriously considered.

Anyway, my question is - if you did that, and just allocated this 'uncertainty' money to technology development, would it allow for a greater rate of missions? If nothing else, the certainty would make a major difference to human resources - people will work at the same thing for longer, and develop competencies, slashing the time spent learning on the mission budget's dime.

</Greenhorn_Rant>
Title: Re: Proposed Europa Missions
Post by: darkbluenine on 12/14/2013 09:11 pm
... I don't know if the proposal guidelines specify a certain minimum readiness for all proposed sub-systems...

Yes, competed programs like Explorer, Discovery, New Frontiers, etc. require a high level of technology readiness.  They typically don't suffer schedule delays and cost growth from immature technologies.

It's the big, strategic missions (JWST, most of the Mars program, Solar Probe, etc.) assigned to field centers in the absence of competition that typically require a lot of technology development.  And they're the missions that most suffer delays and overruns from immature technologies.

My 2 cents is that this disparity between the competed and strategic missions in technology readiness should be rebalanced.  Any investor who understands portfolio theory or asset allocation would tell NASA/SMD that it's asinine to undertake nearly all of the agency's/directorate's technology risks on big expensive missions. 

The competed programs need to find a way to stop rejecting proposals with anything below a TRL9 or TRL7 out of hand and allow new technologies to finish development and get flight tested on their smaller missions.  There has to be a way to assess the likelihood of a successful technology development at lower mid- and high-TRLs, along with their mission criticality and alternatives.

And the strategic missions have to find a way to resist political pressure to go forward in the absence of adequate technology work just to maintain full employment.  The way ESA carries studies and technology development for two or three major candidate missions before downselecting to one may be the answer.

Of course, as pointed out upstream in the thread, technology development is not the only source of cost growth in either competed or strategic missions.

Quote
if you did that, and just allocated this 'uncertainty' money to technology development, would it allow for a greater rate of missions?

NASA has tried various schemes to separate technology development from mission development in the past with varying degrees of failure.  Herding inventors and technologists is harder than herding cats, and it gets worse when you erect a wall that separates technology work from the needs of mission management.   NASA's old New Millennium Program, for example, provided dedicated missions to flight test unproven technologies.  But it's record was mixed at best with about half the missions never getting to flight and not a lot of technology transfer from the demonstration missions into science missions.  NASA's old Aerospace Technology Enterprise was even less responsive to science mission needs when it had the technology portfolio.  NASA has gone back to that model with the current Space Technology Mission Directorate, but they're not even following their own priorities from the technology decadal, nevertheless science mission technology priorities.

The downside to putting technology development under mission management is that mission managers rarely take risks on anything new and the technology budget gets redirected to cover overruns on the missions.  The technology developed will be relevant to the missions, but there will be very little of it.

My 2 cents is that either scheme could work, and some of both (technology-push and mission-pull) are needed in the end.  But it takes honest brokers, intelligent risk-takers, and good relationships to make it work, commodities in short supply in almost any organization.

Title: Re: Proposed Europa Missions
Post by: Blackstar on 12/14/2013 10:45 pm
So it essentially says to the program "If everything went perfectly for you, your estimate would probably be right. However, all kinds of things happen that you cannot control. For instance, you expect peak funding of $X, but it is more likely that you will get peak funding of $X-1, and that will end up costing you more money in the long run."

1. How does that not become a self-fulfilling prophecy?


Huh? It's based upon historical data. It is already the reality. It's not an excuse for them to spend more money.
Title: Re: Proposed Europa Missions
Post by: Andrew_W on 12/14/2013 11:36 pm
So it essentially says to the program "If everything went perfectly for you, your estimate would probably be right. However, all kinds of things happen that you cannot control. For instance, you expect peak funding of $X, but it is more likely that you will get peak funding of $X-1, and that will end up costing you more money in the long run."

1. How does that not become a self-fulfilling prophecy?


This bit here: "all kinds of things happen that you cannot control."

"Self-fulfilling" means doing things you can control to bring about your own (in this context usually negative) expectations.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 12/16/2013 04:08 am
NASA's old New Millennium Program, for example, provided dedicated missions to flight test unproven technologies.  But it's record was mixed at best with about half the missions never getting to flight and not a lot of technology transfer from the demonstration missions into science missions.  NASA's old Aerospace Technology Enterprise was even less responsive to science mission needs when it had the technology portfolio.  NASA has gone back to that model with the current Space Technology Mission Directorate, but they're not even following their own priorities from the technology decadal, nevertheless science mission technology priorities.

The downside to putting technology development under mission management is that mission managers rarely take risks on anything new and the technology budget gets redirected to cover overruns on the missions.  The technology developed will be relevant to the missions, but there will be very little of it.


Well, yeah, you can create a separate program line for technology development and develop it there. That's what they did with New Millennium. There are two problems. One is the one you cite, which is that it is difficult to focus such a program on developing the most needed and useful technologies and getting those into flight and then making them ready for operational missions.

The other problem is that separate technology development budgets are nice big fat targets for raiding, first by NASA itself, then OMB and also Congress. I am sure that there have been lots of NASA officials over the years who sat in rooms with higher level people and sputtered when somebody said "We see you need more money for program X, which is supposed to launch in three years. Well, we're going to take it out of your R&D budget, because you say that those technologies will not be mature for another 5-10 years." Or they get the latest OMB passback, or the congressional language, that simply moves the money out of R&D and into an operational program without ever explaining it at all. Poof! It's gone!

Now I used to think that the reason that these programs got raided for cash was because they were poorly managed, which meant that they had a lot of fat and they became targets for raiding. There seemed like there were lots of examples of that, such as NASA developing several different in-space propulsion technologies simultaneously instead of focusing on a very few.

But I've heard from at least a few people who have been in positions of authority over this stuff that they think it's just sort of the natural order, that separate R&D accounts are going to get raided no matter what, because it is a hard argument to make that we have to develop technology for a mission that doesn't exist yet.

Title: Re: Proposed Europa Missions
Post by: cosmicvoid on 12/16/2013 04:51 am
... because it is a hard argument to make that we have to develop technology for a mission that doesn't exist yet.
Seems like a good way to ensure that those kinds of missions will never exist, I think. No budget for forward thinking.
Title: Re: Proposed Europa Missions
Post by: simonbp on 12/16/2013 04:58 am
It's not so much the project that makes it self fulfilling, but the funding agency. If there are no consequences for missions that abuse the system (JWST, MSL), then the abuse will continue.
Title: Re: Proposed Europa Missions
Post by: vjkane on 12/16/2013 05:44 am
If there are no consequences for missions that abuse the system (JWST, MSL), then the abuse will continue.
The consequences appear to be ones that everyone will suffer -- the end of Flagship missions for the foreseeable future.  I listened in as Bolden told the NAC Science Subcommittee that they needed to be thinking of smaller missions because Flagships just are affordable.  Grunsfeld seconded the message.  (Yeah, there was a politically correct clarification issued afterwards that basically said NASA fully supports Flagship missions when funding is available.  And, if it didn't rain so much in Seattle, we'd have a lot more sunshine.)

For Astronomy and Astrophysics, there are mission studies for ~$1B as alternatives to WFIRST.  Grunsfeld said he wanted to see how much science could be done with a New Frontiers plus mission for Europa and other Flagship destinations.

I think that the lesson that OMB and senior NASA management have taken away is that Flagships always go well over budget, so don't do Flagships.  The one exception appears to be the ~$1.5B 2020 rover, which is about as safe a Flagship mission as you can get.  Rebuild a rover and EDL system and fly less expensive instruments.

We may end up with a science program in which the most expensive missions allowed are $1.25B to $1.5B, which is similar in size to ESA's Large science missions.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 12/16/2013 01:38 pm
... because it is a hard argument to make that we have to develop technology for a mission that doesn't exist yet.
Seems like a good way to ensure that those kinds of missions will never exist, I think. No budget for forward thinking.


Well, I said it was hard, not impossible. It has been done in some cases. Dawn is using technology developed in New Millennium. And the technology directorate is currently working on new entry descent and landing technology that could have a range of uses. One inherent problem with this approach is that you develop a technology that could then sit on the shelf for a decade or more before a mission comes along to use it, and that is difficult to justify even in the best of cases.

And if you go back a few posts in the thread, you see that the other way to do it is to perform the technology development in the mission budget itself. That's what they did with JWST and with Curiosity. In JWST that approach really bit them in the ass.

(Curiosity less so, because I think that the cost overrun problems were not so much due to the new technology development but to problems that were encountered in things that were not pushing the technology. But I would like to see a "lessons learned from Curiosity" report. I think there is one in existence. I'll have to look for it.)
Title: Re: Proposed Europa Missions
Post by: Blackstar on 12/16/2013 01:54 pm
The consequences appear to be ones that everyone will suffer -- the end of Flagship missions for the foreseeable future.  I listened in as Bolden told the NAC Science Subcommittee that they needed to be thinking of smaller missions because Flagships just are affordable.  Grunsfeld seconded the message.  (Yeah, there was a politically correct clarification issued afterwards that basically said NASA fully supports Flagship missions when funding is available.  And, if it didn't rain so much in Seattle, we'd have a lot more sunshine.)

For Astronomy and Astrophysics, there are mission studies for ~$1B as alternatives to WFIRST.  Grunsfeld said he wanted to see how much science could be done with a New Frontiers plus mission for Europa and other Flagship destinations.

I think that the lesson that OMB and senior NASA management have taken away is that Flagships always go well over budget, so don't do Flagships.  The one exception appears to be the ~$1.5B 2020 rover, which is about as safe a Flagship mission as you can get.  Rebuild a rover and EDL system and fly less expensive instruments.

We may end up with a science program in which the most expensive missions allowed are $1.25B to $1.5B, which is similar in size to ESA's Large science missions.

I avoided commenting on all that in the other thread for a few reasons. For starters, I think that Bolden's comments were taken somewhat out of context. The science community is aware of those issues, so Bolden was not telling them something they didn't know.

Grunsfeld is interested in looking at the management of missions, so his comments might have been in that context. I don't know about $1 billion WFIRST missions, but WFIRST was intentionally designed to be much cheaper.

All that said, there's only so much you can do to squash these things down before they are not worth doing anymore. You end up with a spacecraft where you are spending a huge amount of money simply to get it somewhere, and then it does almost nothing while there. In some ways that is why there are different mission classes, to delineate levels of science as well as cost.
Title: Re: Proposed Europa Missions
Post by: savuporo on 12/16/2013 04:33 pm
It's the big, strategic missions (JWST, most of the Mars program, Solar Probe, etc.) assigned to field centers in the absence of competition that typically require a lot of technology development.  And they're the missions that most suffer delays and overruns from immature technologies.

My 2 cents is that this disparity between the competed and strategic missions in technology readiness should be rebalanced.  Any investor who understands portfolio theory or asset allocation would tell NASA/SMD that it's asinine to undertake nearly all of the agency's/directorate's technology risks on big expensive missions. 
From financial and also human resource management perspective you would want exactly the opposite of the current situation - take minimal risks with big budget items and take high risks with low budget items. A CubeSat mission can afford to test a claimed warp drive - when it predictably fails to work the absolute financial loss is going to be tiny and a bunch of young people that worked on it a lot more experienced and smarter.  No careers will be hurt and someone can get a "craziest space idea attempted" medal.

And thanks everyone for the very insightful comments in the latter part of this thread.
Title: Re: Proposed Europa Missions
Post by: Star One on 12/16/2013 05:06 pm

The consequences appear to be ones that everyone will suffer -- the end of Flagship missions for the foreseeable future.  I listened in as Bolden told the NAC Science Subcommittee that they needed to be thinking of smaller missions because Flagships just are affordable.  Grunsfeld seconded the message.  (Yeah, there was a politically correct clarification issued afterwards that basically said NASA fully supports Flagship missions when funding is available.  And, if it didn't rain so much in Seattle, we'd have a lot more sunshine.)

For Astronomy and Astrophysics, there are mission studies for ~$1B as alternatives to WFIRST.  Grunsfeld said he wanted to see how much science could be done with a New Frontiers plus mission for Europa and other Flagship destinations.

I think that the lesson that OMB and senior NASA management have taken away is that Flagships always go well over budget, so don't do Flagships.  The one exception appears to be the ~$1.5B 2020 rover, which is about as safe a Flagship mission as you can get.  Rebuild a rover and EDL system and fly less expensive instruments.

We may end up with a science program in which the most expensive missions allowed are $1.25B to $1.5B, which is similar in size to ESA's Large science missions.

I avoided commenting on all that in the other thread for a few reasons. For starters, I think that Bolden's comments were taken somewhat out of context. The science community is aware of those issues, so Bolden was not telling them something they didn't know.

Grunsfeld is interested in looking at the management of missions, so his comments might have been in that context. I don't know about $1 billion WFIRST missions, but WFIRST was intentionally designed to be much cheaper.

All that said, there's only so much you can do to squash these things down before they are not worth doing anymore. You end up with a spacecraft where you are spending a huge amount of money simply to get it somewhere, and then it does almost nothing while there. In some ways that is why there are different mission classes, to delineate levels of science as well as cost.

Is WFIRST still planning to use the gifted NRO telescope?
Title: Re: Proposed Europa Missions
Post by: baldusi on 12/16/2013 05:18 pm
It's the big, strategic missions (JWST, most of the Mars program, Solar Probe, etc.) assigned to field centers in the absence of competition that typically require a lot of technology development.  And they're the missions that most suffer delays and overruns from immature technologies.

My 2 cents is that this disparity between the competed and strategic missions in technology readiness should be rebalanced.  Any investor who understands portfolio theory or asset allocation would tell NASA/SMD that it's asinine to undertake nearly all of the agency's/directorate's technology risks on big expensive missions. 
From financial and also human resource management perspective you would want exactly the opposite of the current situation - take minimal risks with big budget items and take high risks with low budget items. A CubeSat mission can afford to test a claimed warp drive - when it predictably fails to work the absolute financial loss is going to be tiny and a bunch of young people that worked on it a lot more experienced and smarter.  No careers will be hurt and someone can get a "craziest space idea attempted" medal.

And thanks everyone for the very insightful comments in the latter part of this thread.
Think of JWST. They had to develop active optics that worked at 4K. They had to design a frame that tolerated that. They had to design a sunshield. They had to design the folding mechanism. They had to design some serious cryocooler. Then think of the scale we're talking about. I don't think they could have retired much risk in small missions.
What they could have done, is take a bit longer to develop, ONLY do the critical demonstrations of TRL<7 or 6. And only then do an independent cost estimate. That would have lowered the cost estimate variance. And only then give it the full authorization to proceed. I don't believe that if they had come with an 8B price tag when they had spent 400M, they would have gone ahead with it.
BTW, MSL did try to do dry lubricated actuators and/or axes. I think to remember that that part failed and had to go with more traditional technology. Plus, they developed that flashy EDL system. And the cost of missing a launch window was 2 years of R&D overhead. That's the sort of risk that has to be embedded on a mission budget. Think of New Horizon, for example, where you simply couldn't miss the launch window. It was no only the Earth-Pluto window, but the fact that they wanted to arrive before it freezes over.
Title: Re: Proposed Europa Missions
Post by: baldusi on 12/16/2013 05:32 pm
Now that I think of it, losing the competitions helps with budgeting. I believe that if they accepted risky missions only if they first do TRL reduction investment, and only then take a final decision, it would be a very interesting approach. You know, instead of doing it in five, say seven, and only invest very little the first two to get a good idea on the cost of getting the technology to whatever they need. It would have two "problems":
1) Risky missions would take longer. The problem is that if you don't know your budget environment in five year, seven is worse.
2) Selected missions might not be final. Say you do a NF mission, but after two years you find it will cost 2X to make it happen. The mission is given the axe. But can you call a new NF again?
Title: Re: Proposed Europa Missions
Post by: Blackstar on 12/16/2013 05:40 pm
Is WFIRST still planning to use the gifted NRO telescope?

My quick answer is "I don't know." I'm much more familiar with the planetary stuff than astro.

I think the more wavering answer is that I don't think they have "planned" do do anything with that mirror yet. They are merely studying it. That could simply be a lousy way to do anything. They have to fully explore the alternatives first.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 12/16/2013 05:44 pm
From financial and also human resource management perspective you would want exactly the opposite of the current situation - take minimal risks with big budget items and take high risks with low budget items. A CubeSat mission can afford to test a claimed warp drive - when it predictably fails to work the absolute financial loss is going to be tiny and a bunch of young people that worked on it a lot more experienced and smarter.  No careers will be hurt and someone can get a "craziest space idea attempted" medal.

1-Cubesats cannot do much of jack squat. They're too small. They lack power. You can do some tech development with them, but not much. They are not a good way to retire risk.

2-If you're talking about taking higher risk on cheaper missions, yeah, people talk about how the Discovery class missions should assume higher risk. But that idea runs smash dab into reality. If you are a principal investigator, you don't want to get risky. Why should you? Lose the mission and you are doomed. And you have a cost cap on your mission, so you cannot develop new technology.

There is a possible lower level of missions, Explorer class, where you could take higher risks and could possibly develop new technologies. But there's no funding for them.
Title: Re: Proposed Europa Missions
Post by: savuporo on 12/16/2013 06:46 pm
1-Cubesats cannot do much of jack squat. They're too small. They lack power. You can do some tech development with them, but not much. They are not a good way to retire risk.
I was trying illustrate my point, Cubesats being one extreme and multibillion dollars the other far extreme of the cost spectrum. There is a lot of middle ground.
Besides, planetary Cubesats are a serious topic now and potentially can actually enable completely new mission capabilities - and there is a lot of active tech development happening in the area for comparatively low budgets. But this belongs in another thread.

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If you're talking about taking higher risk on cheaper missions, yeah, people talk about how the Discovery class missions should assume higher risk. But that idea runs smash dab into reality.
That reality should hit much sooner and more acutely with flagships.
Title: Re: Proposed Europa Missions
Post by: Star One on 12/16/2013 09:24 pm
Recent article from the New Scientist on using cubesats for interplanetery missions. (This looks to be a cut down from the full magazine article I read.)

http://www.newscientist.com/article/dn24679-boxy-cubesats-get-a-propulsion-boost-in-new-space-race.html
Title: Re: Proposed Europa Missions
Post by: Blackstar on 12/16/2013 09:24 pm
That reality should hit much sooner and more acutely with flagships.

Yeah, and everybody should floss more.

The fact remains that flagships are still where the most science and technology development are accomplished. They advance the field the most.
Title: Re: Proposed Europa Missions
Post by: darkbluenine on 12/17/2013 02:00 am
1-Cubesats cannot do much of jack squat. They're too small. They lack power.

What an ignorant statement.

Landsat-class imagery with multiple revisits per day is not "jack squat".

http://www.planet-labs.com/

The cosmic x-ray background is not "jack squat".

http://www.kentuckyspace.com/?catid=45:kentuckyspaceblog&id=505:unbridled-spirit-cosmic-x-ray-background-nanosatellite&Itemid=194&option=com_content&view=article

Transit searches for super-Earths around nearby stars is not "jack squat".

http://space.skyrocket.de/doc_sdat/exoplanetsat.htm

Gene expression in microgravity is not "jack squat".

http://www.space.com/1495-genesat-1-small-satellite-tackles-big-biology-questions.html

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2-If you're talking about taking higher risk on cheaper missions, yeah, people talk about how the Discovery class missions should assume higher risk. But that idea runs smash dab into reality. If you are a principal investigator, you don't want to get risky.

Because the existing proposal and review process for Discovery (and all the other competed mission programs) doesn't reward it.  Change the criteria and PIs will propose differently.
Title: Re: Proposed Europa Missions
Post by: Danderman on 12/17/2013 05:47 am

1-Nope. Jack squat. They're still toys. They don't advance the field in any meaningful way. That's why nobody is using them for operational military, civilian, or NASA science missions.


The statement above is doomed to become obsolete, as systems become smaller and more efficient. There will be CubeSATs flying all sorts of significant missions, unless our technological base somehow freezes in the next few years.   CubeSATs may become useful for planetary missions as subsatellites, allow multiple sensors to be flown in differing orbits.

And in the present there is:

http://www.planet-labs.com/
Title: Re: Proposed Europa Missions
Post by: QuantumG on 12/17/2013 06:48 am
And the other thing to remember is that "cubesats" are getting bigger. There's also other standards for "smallsats" that give you the greatest advantage of a cubesat: minimal integration costs.
Title: Re: Proposed Europa Missions
Post by: darkbluenine on 12/17/2013 09:01 am
1-Nope. Jack squat. They're still toys. They don't advance the field in any meaningful way.

This statement is now ignorant in multiple fields.  "Toys" can't provide Landsat-class imagery, measure the cosmic x-ray background, observe exoplanet transits, or take data on gene expression in microgravity.

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That's why nobody is using them for operational military, civilian, or NASA science missions.

Wrong.  NSF employs cubesats in operational, civil science missions.

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2-Why? What's that going to buy you?

More science, better science, enabled science, lower cost for the science baseline, budget bonus for technology validation or ride-ons, backup/alternative subsystems, etc.  It depends on the mission and technologies in question and how the AO incentivizes the PI.
Title: Re: Proposed Europa Missions
Post by: darkbluenine on 12/17/2013 01:40 pm
I've met the NSF guy who started their cubesat program. That's not what they're doing. NSF doesn't do "operational civil science missions." It's not their mission, not in their charter.

This NSF presentation on their cubesat program states that the program's goal is to "advance research in many science areas" and that "space missions [are] within the scope of traditional NSF grants".  A table in the presentation lists five of 12 missions as "operational".  Science targets and instruments include:

Auroral turbulence
Bistatic UHF radar - ISR measured E-Field

Stormtime E-fields and Plasma Density
E-field, langmuir probe, magnetometer

Radiation Belt Structure & Dynamics
Geiger-Mueller Tube

Energetic Ion, e- & Neutral Drivers
Multi-particle telescope & magnetometer

Outer Belt & Solar Energetic e- & H+
Electron/proton telescope

Iono Structure, Comp/Fields/Winds
WINCS, GPS RO UV Photometery

Relativistic electron microbursts
Ion implanted solid-state detectors

Terrestrial gamma ray flashes
RF, gamma-ray, and optical detectors

Thermosphere Comp/Dynamics
Wind, temp & mass spectrometer (WINCS)

Exosphere Structure & Dynamics
WINCS tuned for light Ions and neutrals

http://mstl.atl.calpoly.edu/~bklofas/Presentations/DevelopersWorkshop2013/Jorgensen_NSF_CubeSat_keynote.pdf
Title: Re: Proposed Europa Missions
Post by: baldusi on 12/17/2013 02:05 pm
1-Nope. Jack squat. They're still toys. They don't advance the field in any meaningful way.

This statement is now ignorant in multiple fields.  "Toys" can't provide Landsat-class imagery, measure the cosmic x-ray background, observe exoplanet transits, or take data on gene expression in microgravity.
Now you're getting bad mannered.
The original point was cubesats to increase technology TRL. You can validate only small components, and only those that fit the energy/heat rejection/communication limitations of a cube sat. You can't do that for most technologies.
Cubesats are useful, but you can't compare Skybox, Satellogic and much less Planet-Lab with Landsat 8. You can do useful things with cubesats. You can even get very good science. But you can't really advance the technology that BEO missions need.
And please remember that instruments might be 70% or more of the mission cost. And you can't use a cube sat for all instruments. Specially for surface operations. Or many properties where is actually cheaper to test it on ground.
Title: Re: Proposed Europa Missions
Post by: darkbluenine on 12/17/2013 03:37 pm
The original point was cubesats to increase technology TRL. You can validate only small components

That's not the point of this discussion.  The other poster was claiming that cubesats can't do "jack squat".  I pointed out that cubesats are being used to do all kinds of remote sensing and space science, which surely counts as much more than "jack squat".

I wasn't arguing about how much technology validation can be done on cubesats.  I readily concede that cubesats will never replace certain satellites and technologies simply due to the laws of physics.  But there's a big gulf between that and "jack squat".

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Cubesats are useful, but you can't compare Skybox, Satellogic and much less Planet-Lab with Landsat 8.

PlanetLabs is already delivering Landsat-class imagery using 3U cubesats.  If they deploy their whole fleet, they'll provide Landsat-class imagery for the same location on Earth several times a day.

Skybox is promising imagery that's much better than Landsat-class resolution.  But they're not using cubesats.

I don't know Satellogic and can't speak to them.

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you can't really advance the technology that BEO missions need...  And you can't use a cube sat for all instruments... Specially for surface operations.

Some technologies and instruments but not all.  For example, here's a blurb on one JPL study to sample Phobos using interplanetary cubesats.

http://www.gizmag.com/cubesats-phobos-nasa/22037/

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Now you're getting bad mannered.

I'd argue that it's pretty "bad mannered" to use terms like "jack squat" in reference to the capabilities of an entire class of spacecraft.

The fact that they even had to state that should tell you how much they felt they had to justify it.

I'll take what's written in black-and-white in an NSF presentation over hearsay and innuendo.

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You're not going to find cubesats prioritized as scientific platforms in any decadal survey.

After completing the ongoing program, the top priority in the last solar and space physics decadal includes a doubling of NSF's cubesat program.

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They're used for minor things,

Demonstrably wrong from the links I provided earlier, but clearly you don't want your bubble burst.
Title: Re: Proposed Europa Missions
Post by: vjkane on 12/18/2013 04:15 am
Is WFIRST still planning to use the gifted NRO telescope?
According to the most recent updates from the Astronomy and Astrophysics program, the NRO telescope is one option.  I don't think that a firm cost has been assigned to that option, but I remember that it was ~$1.5B (any have a clearer recollection?).

In a parallel effort, the program is examining at least two and perhaps several ~$1B alternative missions that would not fulfill all the goals for WFRIST.  I believe they would be more focused on exoplanets (or at least some of them).
Title: Re: Proposed Europa Missions
Post by: vjkane on 12/18/2013 04:28 am
Without being an expert in this field, I did look at proposed planetary SmallSat and CubeSat missions based on what is being discussed by the engineering community.  My walkaway was that by the time you upgrade a CubeSat to be able to travel to an interplanetary target, communicate over long distances, and carry useful instruments, you are really in the SmallSat world.  I think that CubeSats will play a role, but as deployed auxiliary instruments carried to their destinations by larger craft.  (Note: I do think that someone will do a standalone Mars or asteroid CubeSat mission just to prove it can be done, but I think that will be the exception.)

Whether SmallSats in the end represent a good return for the investment scientifically is another question that is best left to a review panel. 

Anyway, you can read what I wrote at

SmallSats: http://futureplanets.blogspot.com/2013/08/small-could-be-beautiful-planetary.html (http://futureplanets.blogspot.com/2013/08/small-could-be-beautiful-planetary.html)

CubeSats: http://futureplanets.blogspot.com/2013/10/cubesats-to-planets-ive-seen-evolution.html (http://futureplanets.blogspot.com/2013/10/cubesats-to-planets-ive-seen-evolution.html)
Title: Re: Proposed Europa Missions
Post by: darkbluenine on 12/18/2013 02:41 pm
I think that CubeSats will play a role, but as deployed auxiliary instruments carried to their destinations by larger craft.

Cubesats will play that role, but they'll also provide powerful capabilities on their own.  Planet Labs attracted over $50 million of investment just today.  Their initial constellation of 32 Earth observing satellites consists entirely of cubesats.

https://www.newspacewatch.com/articles/72542-planet-labs-raises-52m-in-series-b-financing.html

FWIW...

Title: Re: Proposed Europa Missions
Post by: Jim on 12/18/2013 02:49 pm
"Toys" can't provide Landsat-class imagery,


Proof please and not based on advertisements.
Title: Re: Proposed Europa Missions
Post by: Jim on 12/18/2013 02:58 pm

I'll take what's written in black-and-white in an NSF presentation over hearsay and innuendo.


what hearsay and innuendo?
Title: Re: Proposed Europa Missions
Post by: Jim on 12/18/2013 03:01 pm

This statement is now ignorant in multiple fields.


And yours are also in overstating the role of cubesats.
Title: Re: Proposed Europa Missions
Post by: darkbluenine on 12/18/2013 03:42 pm
Proof please and not based on advertisements.

From the Financial Times:

Quote
The quality of the images is similar to a person peering out of the window of a commercial airline flight and the resolution is 10 times higher than pictures produced by NASA’s Landsat programme, first launched in 1972 and now widely used for earth imaging.

http://www.ft.com/cms/s/0/a8b611c0-5661-11e3-ab12-00144feabdc0.html#axzz2nqMsqlBt

Planet Labs four cubesats in orbit have already produced images with 3-5m resolution, some of which you can see in compressed form by opening the "Photo Gallery" here:

http://www.planet-labs.com/

If you don't know, Landsat 7/8 images are 15-100m resolution.

Quote
what hearsay and innuendo

The other poster claimed that he had talked to someone at NSF and they said that space research was not part of NSF's mission.  I quoted from and linked to an NSF presentation that stated the exact opposite.  With some tortured logic, the other poster then claimed that the fact the presenter had to put that mission down on paper is proof that the mission does not belong to NSF.

Again, I'll take what is written in black-and-white in an NSF presentation over the other poster's hearsay (his claim that he talked to NSF) and innuendo (the ridiculous implication that space research is not part of NSF's mission because they wrote it down).

Quote
And yours are also in overstating the role of cubesats.

I take offense at that statement.  In response to the other poster's claim that cubesats can't do "jack squat", I've provided multiple, factual examples of cubesats obtaining remote sensing and space science data on par with larger, modern spacecraft.  These examples have been backed up with links.  I've further stated that I don't think cubesats can do everything that other satellites can do.  The laws of physics tell us this.  But there is a huge gulf between the limits of physics and "jack squat".  Unlike the other poster, I've stuck to the facts and backed them up with references.  That's not overstating anything.

If you feel the need to upbraid someone with your morning coffee, please take the other poster to task for the false, ignorant, and understated claim that cubesats can't do "jack squat".

Title: Re: Proposed Europa Missions
Post by: savuporo on 12/18/2013 03:46 pm
Without being an expert in this field, I did look at proposed planetary SmallSat and CubeSat missions based on what is being discussed by the engineering community.  My walkaway was that by the time you upgrade a CubeSat to be able to travel to an interplanetary target, communicate over long distances, and carry useful instruments, you are really in the SmallSat world. 

If a 6U cubesat is called a SmallSat then yes ( that is, a 6kg sat ) . Previously i thought something SMART-1 scale would be called a smallsat ( a 300kg vehicle )

http://www.planetary.org/blogs/guest-blogs/van-kane/20130823-smallsats-small-could-be-beautiful.html

Quote
An emerging class of spacecraft – I’ll call them SmallSats – would fit between LargeSats and CubeSats.  These spacecraft make use of the design techniques of CubeSats but scale the form factor up to a meter or so and the mass up to 50 to 100 kg or so.
Title: Re: Proposed Europa Missions
Post by: Jim on 12/18/2013 03:49 pm

If you don't know, Landsat 7/8 images are 15-100m resolution.


Landsat's forte is not visual resolution but multi spectral imaging.  Unless cubesats can do the same bands, then the comparison is nonsense.  The proper comparison is to the other commercial imaging spacecraft.
Title: Re: Proposed Europa Missions
Post by: Jim on 12/18/2013 03:50 pm

 I've provided multiple, factual examples of cubesats obtaining remote sensing and space science data on par with larger, modern spacecraft.


Another overstatement.  far from "on par.  They have a niche role.
Title: Re: Proposed Europa Missions
Post by: darkbluenine on 12/18/2013 05:30 pm
Landsat's forte is not visual resolution but multi spectral imaging.  Unless cubesats can do the same bands, then the comparison is nonsense.

Planet Labs' wavelength coverage is approximately the same as Landsats 1-5 and the first four bands of Landsdats 6-8.  AFAIK, Planet Labs does not do IR bands.

With Planet Labs, you trade Landsat's IR bands against a much higher revisit rate (multiple times daily) and resolution.  Images are free to small users under either provider.

Unless your application is all about IR imagery, Planet Labs provides more and better data than Landsat.

The proper comparison is to the other commercial imaging spacecraft.

It's not for Planet Labs.  Skybox is the new remote sensing company aiming for ~1m resolution in DigitalGlobe's ballpark.  Skybox uses smallsats, not the cubesat standard.

Another overstatement.  far from "on par.  They have a niche role.

Sure, have it your way.  Landsat-class imagery, the cosmic x-ray background, nearby exoplanets, gene expression, a dozen space physics missions, and the top initiative in a decadal survey are all "niches".
Title: Re: Proposed Europa Missions
Post by: vjkane on 12/18/2013 06:12 pm
I think the Landsat versus Planet Lab comparisons are misleading.  Landsat produces highly geometrically precise and spectrally consistent images in a range of bands from the visual to mid-infrared (which is the equivalent of several instruments).  It really matters, for example, that the spectral measurement made this year can be compared to the one made a decade from now.  (There is drift, and it's carefully tracked, but minimized by design.)  Sensitivity of the instrument is essential and precisely calibrated.

Planet Lab plans to produce rapidly acquired images for visual interpretation.  There's no need for Landsat quality images or spectral range.

It's like comparing a phone camera to a top-of-the-line Nikon.  Both are very useful and both are used differently.  Neither is bad.


Title: Re: Proposed Europa Missions
Post by: darkbluenine on 12/18/2013 07:25 pm
I think the Landsat versus Planet Lab comparisons are misleading.  Landsat produces highly geometrically precise and spectrally consistent images

It would be misleading to imply that Planet Labs does not perform georectification, orthorectification, and color calibration.  They do.

Chill. You called me ignorant multiple times

I never called you "ignorant".  I wrote that two of your statements are "ignorant" and provided the facts that those statements were ignorant of. 

Quote
Don't give more people no reason to take you seriously.

Sage advice from someone who employs very serious terms like "jack squat".
Title: Re: Proposed Europa Missions
Post by: robertross on 12/18/2013 10:32 pm
Okay, enough.

This was a great thread.
Title: Re: Proposed Europa Missions
Post by: Star One on 12/25/2013 09:53 pm
Wouldn't one of the biggest challenges be dealing with the high speed of the return capsule for such a mission, aren't we talking about speeds higher than that of the Stardust mission?
Title: Re: Proposed Europa Missions
Post by: ugordan on 12/25/2013 09:58 pm
Wouldn't one of the biggest challenges be dealing with the high speed of the return capsule for such a mission, aren't we talking about speeds higher than that of the Stardust mission?

Reentry via a Hohmann-type trajectory from the Jupiter system would likely pale in comparison to what the Galileo entry probe had to endure.
Title: Re: Proposed Europa Missions
Post by: savuporo on 12/25/2013 10:35 pm
I wonder if it would be possible to use two spacecraft approach for in-situ science. Park the bigger one with most science instruments on a Juno-like polar orbit with a similar "Radiation vault", and then use separate smaller probe(s) to do the sampling and return to mothership.
Complicated, for sure, but any sort of back to earth sample return will be as complicated.
Title: Re: Proposed Europa Missions
Post by: a_langwich on 12/26/2013 01:24 am
The other challenge--really more of a drawback--is that you get essentially zero science return until the sample gets back to Earth. And it is a long mission. So do you fund a mission knowing that you will wait 18 years for ANY data, and that it could fail at any point during those 18 years? There are much less risky missions you could fund.

What about Curiosity-style spectrometry, mass spec and other instruments for sample analysis?   Hang around, collect some, analyze it, store that sample group if you like it for sample return, or perhaps adjust your fly-by patterns if you don't to get something better.


Quote
Fourth, how could SLS change this equation? I am an SLS agnostic. Although I think that HLV is necessary for many human missions, and it _can_ be enabling for some robotic missions, I'm skeptical of the cost in the current political environment. However, SLS might be the only viable way to do sample return at Europa, so I think that this would be worth studying.

Well, SLS isn't going to be doing much until well into the 2020s, given the first 2-3 missions are spoken for, right?  I think regarding cost, it will only happen if NASA provides the SLS at no cost to the science budget, and that still implies a commitment on the level of JWST and Hubble:  unsinkable flagship.  (Not sure whether Europa can inspire that much determination in HQ, or more importantly in the public imagination which is where Hubble and JWST have gathered strength.  But also in the science community:  is this so valuable to the planetary community they'd forego many, many other opportunities as astro has done since JWST?  I'm thinking Mars projects have more pull than that.) 

Even so, there would still be the question of launch slots.  Every SLS DRM seems to involve groups of SLS launches, which involves committing years of SLS production to a mission set.  While it might be handy to have a different mission to slide in if there were delays--even the asteroid mission is extremely schedule-risky--a Europa mission, with outer planet launch windows, isn't a good candidate for moving around to fill gaps.

Title: Re: Proposed Europa Missions
Post by: savuporo on 12/26/2013 02:58 am
What about Curiosity-style spectrometry, mass spec and other instruments for sample analysis?
In-situ science around jupiter will always be severely hindered by what kind of instruments and electronics you can subject to the radiation.
Title: Re: Proposed Europa Missions
Post by: darkbluenine on 12/26/2013 04:03 am
What I was referring to boils down to this: up until now, nobody has discussed Europa sample return missions. They have discussed Enceladus sample return missions. A-what would be the parameters of a Europa sample return mission?

ARC/JPL studied Europa sample return before under the Ice Clipper concept for a ~$250M Discovery proposal back in 1996/7.  The idea was to create an "ice geyser" with a 20kg copper impactor sent ahead of the spacecraft and then fly through the cloud with an aerogel screen (think Deep Impact crossed with Stardust).  The "ice geyser" would not get very high, and the risk of flying that close to Europa on first approach was deemed too high and the proposal was rejected.  But if confirmed, persistent, and of the right height, a naturally occurring Europa geyser may solve this problem.

APL revisited the concept a decade later with a bigger, 100kg impactor and spectroscopy instead of sample return (think Deep Impact on steroids).  But if applied to a sample return mission, the larger impactor had the twin benefits of allowing the capture spacecraft to fly higher and safer while also accessing deeper and more interesting ice layers from Europa.

Not much exists on the web, but here's an article on both studies:

http://www.marsdaily.com/reports/Go_Flagship_Class_By_Jove_999.html

And some random Ice Clipper abstracts:

http://trs-new.jpl.nasa.gov/dspace/handle/2014/27403

http://archive.is/BdqH

http://www.sciencedirect.com/science/article/pii/S0273117702004805

Quote
B-could SLS make any difference for that mission given its difficult parameters (like delta-vee)?

No, totally unnecessary.
Title: Re: Proposed Europa Missions
Post by: Star One on 12/26/2013 09:16 am
Could the JUICE mission be reconfigured to if not do sample return then to fly through these plumes & do in situ science on them?
Title: Re: Proposed Europa Missions
Post by: ugordan on 12/26/2013 03:16 pm
Could the JUICE mission be reconfigured to if not do sample return then to fly through these plumes & do in situ science on them?

Almost certainly not. It's an entirely different mission with entirely different goals. They might be able to shift their observation strategy a bit, but they couldn't really change the main parameters of the mission without it being an entirely different mission--and maybe not workable.

There ought to be some freedom in tweaking the sub s/c point to move it to higher southern latitudes, but I wonder if flying through the plumes would be considered too hazardous to the solar panels. Even if they wanted to rotate them to present the lowest cross-section to the plume flux, I'd imagine the uncertainty in the actual plume/particle velocities would make predicting the "ram" direction difficult.
Title: Re: Proposed Europa Missions
Post by: ugordan on 12/26/2013 05:37 pm
There's probably not real reason to go through the plumes. What you'd want is some kind of assessment, particularly looking for organics. Cassini has done that at Saturn with Enceladus.

Yes, I was too lazy to check if JUICE will be carrying something similar to Cassini's INMS - which apparently it won't. I agree there's little added value in flying through the plumes in this case.
Title: Re: Proposed Europa Missions
Post by: ugordan on 12/26/2013 06:11 pm
One thing that just occurred to me is that there might be a benefit to turning JUICE to look at Europa at a point where the plumes might be illuminated by the sun. They might not have considered that yet, and the new data might cause them to reevaluate.

I cannot imagine them *not* doing that or, for that matter, monitoring all other satellites once on the Jovian tour.

Regular distant monitoring was IIRC something the Galileo mission was also originally supposed to do. Imagine if the HGA hadn't failed and we saw glimpses of these plumes (in forward-scattered light, too!) 15 years sooner than we did...
Title: Proposed Europa Missions
Post by: Star One on 12/26/2013 09:47 pm
There ought to be some freedom in tweaking the sub s/c point to move it to higher southern latitudes, but I wonder if flying through the plumes would be considered too hazardous to the solar panels. Even if they wanted to rotate them to present the lowest cross-section to the plume flux, I'd imagine the uncertainty in the actual plume/particle velocities would make predicting the "ram" direction difficult.

There's probably not real reason to go through the plumes. What you'd want is some kind of assessment, particularly looking for organics. Cassini has done that at Saturn with Enceladus.

But JUICE is only supposed to have a few observations of Europa, so it simply may lack any flexibility to expand the Europa observations without substantially impacting the Ganymede science objectives.

Are they targeting Ganymede because it's the only moon with a magnetosphere?

Also will Juno be able to do any observations of Jupiter's moons?
Title: Re: Proposed Europa Missions
Post by: vjkane on 12/27/2013 12:37 am
One thing that just occurred to me is that there might be a benefit to turning JUICE to look at Europa at a point where the plumes might be illuminated by the sun. They might not have considered that yet, and the new data might cause them to reevaluate.
The JUICE mission was planning to search for plumes at Europa prior to the AGU announcement.  There's a paper or abstract that discussed the plans using the ultraviolet spectrometer in the ~1 year in Jupiter orbit prior to the Europa flybys.
Title: Re: Proposed Europa Missions
Post by: mdatb on 12/28/2013 07:53 pm
Could the JUICE mission be reconfigured to if not do sample return then to fly through these plumes & do in situ science on them?
So the U.S. has a lot of Mars scientists, and therefore generates a lot of interest in more Mars missions. There are positives to this and negatives. The positive is that it results in great expertise and focus on a subject. The negative is that it results in slower response to new discoveries, and even neglect of potentially great scientific subjects. For instance, the ice giants remain the last major unexplored objects in our solar system (after New Horizons flies by Pluto), but there is still limited interest in them, meaning that it will probably be 30-40 years before we mount a robotic mission to Uranus or Neptune.
I agree. Mars gets a lot of interest and focus due to the many scientists who focus on mars. Thus, we get a lot of information on the subject and focus on putting missions there, but other objects get exploration-starved and projects focusing on them get cut or canceled.

This comment somewhat helped me understand why we have a 2020 mars rover.
Title: Re: Proposed Europa Missions
Post by: Star One on 12/29/2013 12:34 pm

1-I agree. Mars gets a lot of interest and focus due to the many scientists who focus on mars. Thus, we get a lot of information on the subject and focus on putting missions there, but other objects get exploration-starved and projects focusing on them get cut or canceled.

2-This comment somewhat helped me understand why we have a 2020 mars rover.

1-But that is not the ONLY reason Mars gets a lot of attention. Mars is a high-value scientific target. There is no way to deny that. Mars is also easily accessible, with regular launch windows and relatively short transit times compared to just about every other target in the solar system. Finally, Mars has always occupied a greater public role than any other planet, a fact that goes back centuries.

2-It's not that easy. The Mars 2020 rover was the right decision. The decadal survey prioritized the MAX-C rover mission and the Mars 2020 rover is going to do what MAX-C laid out. That's the way it is supposed to happen. Any other decision would have been in defiance of the wishes of the scientific community. And the only reason that MAX-C came out ahead of a Europa mission was because the Europa mission presented to the decadal survey was both too expensive to recommend, and could not be downscoped by the decadal survey committee itself.

But now that the Mars rover has been commissioned there should be no further Mars projects initiated when Europa is clearly the next target to be investigated.
Title: Re: Proposed Europa Missions
Post by: vjkane on 12/29/2013 04:27 pm
Yes, I was too lazy to check if JUICE will be carrying something similar to Cassini's INMS - which apparently it won't. I agree there's little added value in flying through the plumes in this case.
JUICE will carry what appears to be a very good mass spectrometer as part of its PEP instrument, which is really six different particle instruments.  This is from an abstract on the NIM sensor presented at the last European Planetary Science Conference:

"NIM is a highly sensitive neutral gas and ion mass spectrometer designed to measure the exospheric neutral gas and thermal plasma at Jupiter’s moons with a very high mass resolution and unprecedented sensitivity. The detection level for neutral gas is 1 ·10−16 mbar for a 5-second accumulation time (Wurz
et al., 2012), which corresponds to a particle density of about 1 cm−3. The mass resolution is M/M >
1100 in the mass range 1–1000 amu and NIM’s energy range is  5e V for neutrals and <10 eV for ions."

I'm not a mass spectrometer guy (give me a LiDAR or multi-spectral instrument any day), but this looks to be a very respectable mass spectrometer.  I believe that the Rosetta ROSINA MS only goes to 300 amu.
Title: Proposed Europa Missions
Post by: Star One on 12/29/2013 09:58 pm
But now that the Mars rover has been commissioned there should be no further Mars projects initiated when Europa is clearly the next target to be investigated.

Where does it say that?

That's what I am saying.

Sample collection has effectively been agreed for Mars with MSL 2 so let's start looking down the list so to speak.
Title: Re: Proposed Europa Missions
Post by: savuporo on 12/30/2013 01:04 am
Sample collection has effectively been agreed for Mars with MSL 2 so let's start looking down the list so to speak.
Whoa, interesting. I just read the AO Q&A doc doc here (http://soma.larc.nasa.gov/mars2020/pdf_files/Mars2020AO_QAs_131224.pdf) and learned that an ISRU O2 experiment by HEOMD is one of highest prio payloads. The 2020 rover should probably get its own thread here, esp as preproposal materials (http://soma.larc.nasa.gov/mars2020/prepropwkshop.html) etc get posted now.
Title: Re: Proposed Europa Missions
Post by: vjkane on 12/30/2013 03:36 am
... then maybe NASA could get started on a Europa mission by 2020 or so. But that should only happen after the overall balance has been restored to the program.
I have followed the fate of the four Decadal Surveys for each of NASA's science programs.  In terms of being able to implement the proposed program, the Earth Sciences program is perhaps in the worst shape and the astrophysics program perhaps is in the best shape (but only because the expectations were set so low).

Given much smaller budgets than anticipated, the managers of each of the programs are doing their best to implement the science priorities of the Surveys as best their resources allow.  I don't think it will be a question of returning the Decadal implementation plans, but rather what new plans will emerge.  (The science priorities identified by each Survey continue to be relevant. however.)

Jim Green was pretty specific about why Mars received the priority it did.  OMB told NASA it could have X dollars for a Mars program, and if it didn't accept it, then there were other places to put the funding.  I think that we under estimate the influence of mid-level budget officials at OMB in how roadmap decisions are being made.

Perhaps Blackstar knows more and let us know if my reading of the situation differs from what he's hearing.

Title: Re: Proposed Europa Missions
Post by: savuporo on 12/30/2013 04:10 am
Mars sample return has been a high priority for decades and is only now being implemented.

Every document on 2020 rover goes out of it's way to explain that MSR is not being implemented. Sample caching is. But MSR is not, and 2020 rover's sample caching applicability to eventual MSR is not established, either.
Title: Re: Proposed Europa Missions
Post by: vjkane on 12/30/2013 04:48 am
I agree with everything that Blackstar says (which means I find sources of information that may give me a fraction of what he hears :> ).  Just a couple of observations: The focus on Mars was, I believe, OMB directed.  If left to its own devices and with the same budgets as have occurred, Jim Green's folks might be talking about how sorry they are that they couldn't do a Flagship mission this decade but look at all the Discovery and New Frontiers missions they will select.  Green et al.'s genius was in turning a dictate into a mission that fit the Decadal plan.

And as an example of putting together what I meant by a new program, NASA appears to have made the decision to do a New Frontiers selection instead of two Discovery selections on its own.  I'm confident that they have a good reason, and I'll nod when I hear it.  The pieces come from the Decadal Survey, but the final mix will of necessity be different.  Look at all the missions that have been dropped or severely descoped in the Earth Science program to see a more extreme case (including one I wanted very much, a vegetation-oriented LiDAR instrument).

As for the mid-term assessment, I'm clearly less knowledgeable than Blackstar.  However, a parallel 2008 review, Opening New Frontiers in Space: Choices for the Next New Frontiers Announcement of Opportunity, did review the list of New Frontiers missions and recommended expanding the list to include a larger set previously identified by the full Survey.

The 2011 Survey identified the top scientific missions doable within the scope of a New Frontiers mission for each of the major types of destinations in the solar system: Inner planets (Venus Atmospheric Probe and Lander, Lunar South Pole-Aitken Basin Sample Return, Lunar Geophysical Network), small bodies (Comet Surface Sample Return, Trojan Asteroid Tour and Rendezvous), outer planets (Saturn probe, Io observer).  I don't see this list being overturned by the mid-term review.

What may get interesting is how NASA interprets the priority of a Europa mission (close #2 Flagship choice to a Mars caching rover) vis-a-vis the New Frontiers program.  Does it start the Europa Clipper in 2020 (~3 years before the next Decadal Survey takes effect) in place of New Frontiers 5 & 6 (assuming New Frontiers 4 starts ~2017)?  If Grunsfeld follows through with his idea to look at a New Frontiers or New Frontiers+25% mission for Europa and it comes through with a credible proposal, how would that fall into the mix?  NASA may ask the mid-term assessment team for advice on questions such as this for this one destination. 

Otherwise, short of Dawn finding spots on Ceres to be covered in complex organics or something equally solar system-shattering, I think the 2011 Survey priorities will stand.  The question will be how much of it can be implemented given the budgets provided and any more mandates from OMB or Congress.
Title: Re: Proposed Europa Missions
Post by: vjkane on 12/30/2013 04:55 am
Every document on 2020 rover goes out of it's way to explain that MSR is not being implemented. Sample caching is. But MSR is not, and 2020 rover's sample caching applicability to eventual MSR is not established, either.
In one of the Decadal Survey meetings, Squyres said that this (the 2011) Survey doesn't have to decide on the full sample return mission since the latter missions would fall into the following decade.

We have a mission that will provide great science and enables MSR.  I'm happy to wait and see if the 2020 mission finds great samples to return or not, especially since pushing for approval of all of the MSR program is likely to get the OMB guys all excited.  The debates on this topic in the next Survey will make great reading, and they will know whether or not the rover is finding samples that are high priority to return.
Title: Proposed Europa Missions
Post by: Star One on 12/30/2013 09:20 am
I suppose the larger question is we cannot discount other nations carrying out missions to the outer planets next decade aside from JUICE. So if NASA cannot do it maybe somebody else will put a project on the table that if not doing as envisioned here does at least cover the Jupiter system.

As far as next decade is concerned I think we can mostly count NASA out from planetary exploration to any great extend and instead see what others do in this area. I agree with what someone I saw wrote in the comments on another site that if NASA are happy to continue investing money in a dead ball of rock then let them and let's see who else comes to the table.
Title: Re: Proposed Europa Missions
Post by: darkbluenine on 12/30/2013 12:07 pm
2-No. NASA doesn't really have the freedom to go off and do its own thing, ignoring the decadal. Congress doesn't let them do that, which is why the decadal surveys are required by law.

This is true in theory, but not always in practice.  For example, NASA ignored the prior to last solar and space physics decadal, and initiated Solar Probe Plus ahead of several smaller missions, violating that decadal's decision rules.  The follow-on solar and space physics mid-term assessment emphatically pointed out NASA's error, but the White House and Congress did nothing to correct it.

Quote
(If you ask me, this was just OMB wasting time.)

Or OMB forcing NASA to do its homework for once and get its arms around flagship options and costs before jumping into design decisions and development -- an understandable position for the budget agency given cost growth on Curiousity and other flagships.
Title: Re: Proposed Europa Missions
Post by: Star One on 12/30/2013 12:32 pm
Is such a focus on Mars scientifically being driven at a financial level by an expectation of manned missions as if it is this seems an unfortunate state of affairs as I have no confidence we will see any person on Mars any time soon?
Title: Re: Proposed Europa Missions
Post by: Star One on 12/30/2013 04:02 pm
Not seen this article before.

http://www.planetary.org/blogs/guest-blogs/van-kane/20131227-nasa-planetary-new-mission-woes.html
Title: Re: Proposed Europa Missions
Post by: savuporo on 12/30/2013 05:02 pm
Is such a focus on Mars scientifically being driven at a financial level by an expectation of manned missions as if it is this seems an unfortunate state of affairs as I have no confidence we will see any person on Mars any time soon?

No. It's driven by scientific questions. The scientists have very little expectation of human missions to Mars in the next decades. I'm sure that many would love to see it, but they don't expect it to happen, and they don't want any expectation for human missions to affect their scientific goals. (For instance, some Mars scientists are unhappy that an ISRU experiment is taking up real estate on the Mars 2020 rover that they would prefer be devoted to scientific instrumentation.)

This is a very simplistic view, seeing as MSL 2 has joint SMD and HEOMD sponsorship. I dont think it has been established that the MSL 2 selection was a result of scientific priorities, at all - and i know you are going to say "decadal survey" about two dozen times more. In addition to OMB and SMD, there are obviously other decision influencers here. The real question is who and where. Rep. Adam Schiff and Sen. Dianne Feinstein may have a little something to do with it, too.

At the time of announcement, sample caching was very much not decided upon, even though apparently now that decision has been made. What Emily Lakdawalla wrote at the time (http://www.planetary.org/blogs/emily-lakdawalla/2012/12051226-response-2020-rover.html):
Quote
The rover that NASA announced yesterday is absolutely not the mission described in the Decadal Survey. It is not a small one based on MER with a lower science value than Curiosity because the science will happen back on Earth with samples returned through two later missions. It may not even cache samples at all. We actually don't know what it's going to do, because no scientific goals for the mission were mentioned in the announcement. The reason they weren't mentioned is because NASA doesn't know what the scientific goals are yet; those are yet to be defined, by a Science Definition Team.
Title: Re: Proposed Europa Missions
Post by: savuporo on 12/30/2013 05:39 pm
And it's an SMD mission, not an HEOMD mission (look who is paying for it).
Its cosponsored. HEOMD is paying for things like MEDLI+, the ISRU experiment and a few other things. Like i said this probably warrants its own thread.

( i was off by at least 4x by guessing two dozen , you only said "decadal survey" 6 times in your post. Its not a bible you know )

Btw here was the news piece (http://www.spacenews.com/article/figueroa-rules-out-another-nasa-mars-rover-2020)
Quote
Figueroa reiterated previous statements that his team will consider only missions that contribute in some way to an eventual Mars sample-return mission, which is the U.S. planetary science community’s top priority for flagship-class Mars exploration endeavors.

The White House in February sent Congress a 2013 budget request that would reduce the Planetary Science division’s budget from $1.5 billion to $1.2 billion. An appropriations bill drafted in the House of Representatives recommended giving the division $1.4 billion for 2013 and would require that NASA either create a Mars Next Decade mission that works toward sample return or scrap it in favor of sending an orbiter to Jupiter’s moon Europa.

The White House on May 7 threatened to veto the House proposal, which funds NASA at $17.6 billion as part of a broader $51.1 billion appropriations bill that funds several agencies.

Jim Green, director of NASA’s Planetary Science Division, warned that the White House could pull the plug on Mars Next Decade if the agency cannot decide on a mission that fulfills science, human exploration and space technology objectives.

“We are given an opportunity by this administration to craft a new Mars program,” Green said at the May 8 meeting. “If we are not able to do that, or if we are not able to show the synergies and move this agency forward both in human exploration and science, we may not be able to retain that budget.”

And another earlier one here (http://www.spacenews.com/article/former-mars-czar-tapped-lead-nasas-mars-reboot)
Quote
“With sample return, they didn’t mince the words in the decadal survey,” Figueroa said, acknowledging that his group must design a mission that not only supports Mars sample return but also passes muster with the White House budget hawks who nixed NASA’s involvement in such a campaign because it would tie up too much funding for too long.
...
Some scientists here, however, raised doubts that NASA could afford a rover capable of contributing to an eventual sample-return mission for $700 million.
..
Delaying a Mars Next Generation launch until 2020 would give Grunsfeld two more years over which to spread the mission’s development cost, but it would also mean a loss of 150 kilograms of payload due to the less-favorable relative positions of the Earth and Mars as they orbit the sun.
..
The MPPG is setting the stage for meaningful collaborations in the exploration of the red planet. To that end we have representation from the Science Mission Directorate, Human Exploration and Operations Mission Directorate, Office of the Chief Technologist, and Office of the Chief Scientist in our endeavor.

Its pretty easy to see that this was not a decadal survey/SMD and OMB fight alone

And this from the MPPG final report (http://www.nasa.gov/pdf/691580main_MPPG-Integrated-v13i-Summary%20Report-9-25-12.pdf):
Quote
The MPPG finds that sample return architectures provide a promising intersection of objectives and integrated strategy for long term SMD/HEOMD/STP collaboration

Title: Re: Proposed Europa Missions
Post by: savuporo on 12/30/2013 06:59 pm
As for MEDLI, the ISRU thing, they're minimal. They don't cost much, and they aren't the focus of the mission. The Science Mission Directorate is paying the vast majority of the cost of the Mars 2020 mission. It's a science mission first and foremost, with science priorities.

So you keep saying, but these claims are not supported by MPPG stated charter and results. MPPG charter explicitly said that the strategy has to be integrated HEOMD/STP/SMD goals. The selected 2020 rover mission is effectively Figueroa's "Rover C" , with the stated advantage of "Substantial HEO/STP payload opportunity"
HEOMD/STP sponsored payload total is a significant percentage of the estimated budget here, im not sure if you have looked at the docs at all.
The O2 experiment is at $55M, MEDLI up to $30M, potential weather station another $20M.

SMD instrument budget total is not to exceed $100M !

Atlas 5 launch is pinned at $400M.

Science driven ? Hmmm ..

EDIT: just for reference the docs where the numbers came from
http://www.nasa.gov/pdf/691580main_MPPG-Integrated-v13i-Summary%20Report-9-25-12.pdf
http://mars.jpl.nasa.gov/mars2020/files/m2020/SDT_Appendices_Final_v6.pdf
And
http://www.thk.edu.tr/~nsengil/feb13.pdf - page 32
Title: Re: Proposed Europa Missions
Post by: Star One on 12/30/2013 07:01 pm
How much of this confusion is down to political meddling? Would things be a lot easier if politicians didn't keep requiring x,y & z of NASA where x & z contradict one another?

It would be nice maybe if the politicians kept out of things full stop & let NASA fully allocate its own budget to its requirements & needs.
Title: Re: Proposed Europa Missions
Post by: vjkane on 12/31/2013 12:04 am
In my opinion, I think we've mined the topic of how/why the 2020 rover mission (and I'm hearing 2022, too, as a possibility) as much as we can.  It's done.

I would still like to see a Europa mission.  In a few days, I'll post to my blog the results of a thought experiment I did to see if Grunsfeld's idea of a Europa New Frontiers mission seemed to make sense.  I took the instrument package from the Io Observer and asked whether a package of instruments from the Clipper within the same mass, power, and data requirements would fulfill one or more of the Europa science objectives.  From this simplistic analysis, there appears to be at least a few subsets.  So the Clipper may not be the final word in lower cost viable Europa missions.  However, if you read the post, you'll see why I concluded that the Clipper is the mission I think we should fly.  If we look at the total Decadal spending time frame (2013 through 2022 or 2023), then NASA will have the ability to build the Clipper (or a cheaper Europa mission if it decides that is viable).  (This gets harder if the 2020 Mars mission becomes the 2022 Mars mission.)

My only other big regret about Decadal priorities that don't look like they would be flown is an Ice Giants mission.  I wish the Decadal had specified an outer planets atmospheric mission rather than specifying Saturn.  The arguments in the Survey report for a Uranus probe were equally compelling (and the report did prioritize Uranus, but Flagships opportunities have gone away), and I'd like the scientific community to have an opportunity to propose for either one.  Oh well.




Title: Re: Proposed Europa Missions
Post by: Star One on 01/04/2014 04:23 pm
New article from the New Scientist about missions to Europa.

http://www.newscientist.com/article/mg22129502.700-water-plumes-spark-a-race-to-jupiter-moon-europa.html
Title: Re: Proposed Europa Missions
Post by: vjkane on 01/04/2014 05:22 pm
New article from the New Scientist about missions to Europa.

http://www.newscientist.com/article/mg22129502.700-water-plumes-spark-a-race-to-jupiter-moon-europa.html
Some of the CubeSat guys keep suggesting that they can return to Europa faster than any other option.  We have yet to have any interplanetary CubeSats, and so this represents planning to run ultramarathons before taking baby steps.

CubeSats will find a role in planetary missions, but Europa is about as hard a target as you can pick for your first one.  At the very basics, what instrument (~1 kg) are you going to fly that will tell us something interesting?  How are you going to implement a radiation vault? 

I love the idea of CubeSats, but for nearby targets (NEOs, lunar) or a auxiliary instrument platforms for larger missions.

The New Scientist article, by the way, ignored JUICE's (at least) two Europa flybys plus long term distant observation campaign.  Any mission proposed for Europa has to exceed what is already planned by ESA.
Title: Re: Proposed Europa Missions
Post by: savuporo on 01/04/2014 06:19 pm
Yep, a cubesat plan to anywhere further than a simple deep space test or a lunar orbit at this point is just not reasonable. There are many technical issues that have to be figured out and tested as of yet. Radiation issues and communication being the most critical.
Title: Proposed Europa Missions
Post by: Star One on 01/04/2014 06:55 pm
For a start how would you even effectively radiation shield a cubesat in that kind of environment.

Quote from: vjkane
The New Scientist article, by the way, ignored JUICE's (at least) two Europa flybys plus long term distant observation campaign.  Any mission proposed for Europa has to exceed what is already planned by ESA.

I wonder if there is any possibility for them to increase the number of Europa flybys it does?
Title: Re: Proposed Europa Missions
Post by: vjkane on 01/04/2014 07:31 pm
I wonder if there is any possibility for them to increase the number of Europa flybys it does?
It's likely a tradeoff of radiation hardening $s and risk assumed for later portions of the mission (radiation accumulated during the Europa flybys will be added to radiation accumulated later and could put later operations at risk).

The JUICE team is properly, a decade before launch, talking only about their committed Europa flyby number, 2.  I would not be surprised to see that increased closer to launch and the effectiveness of the radiation hardening is better understood.  I don't think that 5 flybys would surprise me.  10 would.  At 20, I'd be really worried about chemical stimulants during their analysis.  :>

One of the challenges to Grunsfeld suggestion of a New Frontiers[+] to Europa is that it has to add significantly to what some small number of JUICE flybys would.  More on my blog later this weekend.
Title: Re: Proposed Europa Missions
Post by: Star One on 01/04/2014 08:33 pm

I wonder if there is any possibility for them to increase the number of Europa flybys it does?
It's likely a tradeoff of radiation hardening $s and risk assumed for later portions of the mission (radiation accumulated during the Europa flybys will be added to radiation accumulated later and could put later operations at risk).

The JUICE team is properly, a decade before launch, talking only about their committed Europa flyby number, 2.  I would not be surprised to see that increased closer to launch and the effectiveness of the radiation hardening is better understood.  I don't think that 5 flybys would surprise me.  10 would.  At 20, I'd be really worried about chemical stimulants during their analysis.  :>

One of the challenges to Grunsfeld suggestion of a New Frontiers[+] to Europa is that it has to add significantly to what some small number of JUICE flybys would.  More on my blog later this weekend.

There must be a lot of competing pressures on the mission planning team of JUICE as at this time it's the only definite game in town as far as looking into such matters in situ.
Title: Re: Proposed Europa Missions
Post by: vjkane on 01/05/2014 06:10 pm
At the last NAC Planetary Sciences Subcommittee meeting, John Grunsfeld (NASA Associate Administrator for Science) discussed the possibility of looking at New Frontiers or New Frontiers +25% $s as an alternative to the Europa Clipper.  This got me curious as to whether this was a brain dead idea or not.

I took the Io Observer spacecraft study from the Decadal Survey as a credible spacecraft that could study a Jovian moon and looked at what some of the key questions would be for a similar spacecraft with equivalent instruments to study Europa.  I also look at the questions that this type of idea would raise given that JUICE will make at least two Europa flybys.  (I only raise questions because I'm not a mission architect, but there are some obvious questions a professional study team would look at; my post hopefully raises some of the major ones.  This is blog journalism, not mission design.)

This board has lots of informed readers.  I'd be interested in your thoughts on what a New Frontiers-class Europa mission might do and whether it might  be a credible alternative.

You can read the post at http://futureplanets.blogspot.com/2014/01/europa-new-frontiers-mission-or-why-i.html (http://futureplanets.blogspot.com/2014/01/europa-new-frontiers-mission-or-why-i.html)
Title: Re: Proposed Europa Missions
Post by: Zed_Noir on 01/05/2014 08:10 pm
For a start how would you even effectively radiation shield a cubesat in that kind of environment.


Maybe placing cubesat components inside a sphere of water. :) Of course that still leaves the sensors exposed to the harsh rad environment.
Title: Re: Proposed Europa Missions
Post by: savuporo on 01/05/2014 09:42 pm
For a start how would you even effectively radiation shield a cubesat in that kind of environment.


Maybe placing cubesat components inside a sphere of water. :) Of course that still leaves the sensors exposed to the harsh rad environment.
Do the math, it doesn't work. And i think thats off topic here.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 01/06/2014 03:56 pm
Europa Ice Clipper.
Title: Re: Proposed Europa Missions
Post by: Star One on 01/06/2014 08:36 pm

Europa Ice Clipper.

Thanks for that.
Title: Re: Proposed Europa Missions
Post by: jongoff on 01/06/2014 09:50 pm
CubeSats will find a role in planetary missions, but Europa is about as hard a target as you can pick for your first one.  At the very basics, what instrument (~1 kg) are you going to fly that will tell us something interesting?  How are you going to implement a radiation vault? 

I love the idea of CubeSats, but for nearby targets (NEOs, lunar) or a auxiliary instrument platforms for larger missions.

It'll be interesting to see where "interplanetary" cubesat missions go. If by "auxiliary instrument platforms" you mean having the cubesats as distributed sensor platform free-fliers supporting a more traditionally-sized "mothership" spacecraft, that's along the lines of what I've been thinking too.

~Jon
Title: Re: Proposed Europa Missions
Post by: jongoff on 01/06/2014 10:08 pm
Newbie question--the radiation we're talking about here is basically like Van Allen Belt radiation around earth (mostly high energy/fast electrons and protons/light nuclei), just more intense, correct?

~Jon
Title: Re: Proposed Europa Missions
Post by: vjkane on 01/06/2014 10:51 pm
Newbie question--the radiation we're talking about here is basically like Van Allen Belt radiation around earth (mostly high energy/fast electrons and protons/light nuclei), just more intense, correct?
Far more intense than the Van Allen belts and concentrated more in the ecliptic.  The ions come primarily, I believe, from Io's erruptions.

Intensity increases as you approach Jupiter until just a few 10Ks kilometers above the cloud tops where they drop in intensity.  (Juno will sneak through this gap during its closest to avoid the worst of the radiation.  Even so, the spacecraft has extensive shielding.) 

The radiation at Europa would be lethal to humans and will fry electronics without shielding or specialty high radiation electronics (the latter are expensive and in some cases not available).
Title: Re: Proposed Europa Missions
Post by: jongoff on 01/07/2014 02:07 pm
Newbie question--the radiation we're talking about here is basically like Van Allen Belt radiation around earth (mostly high energy/fast electrons and protons/light nuclei), just more intense, correct?
Far more intense than the Van Allen belts and concentrated more in the ecliptic.  The ions come primarily, I believe, from Io's erruptions.

Intensity increases as you approach Jupiter until just a few 10Ks kilometers above the cloud tops where they drop in intensity.  (Juno will sneak through this gap during its closest to avoid the worst of the radiation.  Even so, the spacecraft has extensive shielding.) 

The radiation at Europa would be lethal to humans and will fry electronics without shielding or specialty high radiation electronics (the latter are expensive and in some cases not available).

Interesting, thanks. Is the higher intensity due to higher energy levels of particles (relative to earth's Van Allen Belts), or higher particle density, or both? I've got an idea that *might* work for protecting a cubesat from the worst of it, but I'm trying to make sure I understand the problem first.

~Jon
Title: Re: Proposed Europa Missions
Post by: Robotbeat on 01/07/2014 04:06 pm
Cubesats can be ready faster only because they're smaller and cheaper. The whole process of building them and picking a flight is just WAY easier because of that. So I don't take the claim that they can be ready faster as too outrageous. Yeah, no one has demonstrated an interplanetary cubesat, but what fundamentally would be the reason it couldn't be done?

A big issue with cubesats is communication over interplanetary distances. Some sort of relay using a larger vehicle (like we do on Mars with landers and rovers) is a great way to overcome that.

Anyway, the cubesat people have a huge advantage in nimbleness that may off-set their equally huge disadvantage of not demonstrating an interplanetary mission, yet. But it wouldn't be as capable as a real spacecraft, that much is certain, and I don't think we need to kid ourselves about that, yet.
Title: Re: Proposed Europa Missions
Post by: Star One on 01/07/2014 05:23 pm

Cubesats can be ready faster only because they're smaller and cheaper. The whole process of building them and picking a flight is just WAY easier because of that. So I don't take the claim that they can be ready faster as too outrageous. Yeah, no one has demonstrated an interplanetary cubesat, but what fundamentally would be the reason it couldn't be done?

A big issue with cubesats is communication over interplanetary distances. Some sort of relay using a larger vehicle (like we do on Mars with landers and rovers) is a great way to overcome that.

Anyway, the cubesat people have a huge advantage in nimbleness that may off-set their equally huge disadvantage of not demonstrating an interplanetary mission, yet. But it wouldn't be as capable as a real spacecraft, that much is certain, and I don't think we need to kid ourselves about that, yet.

I would have thought the most effective way of achieving interplanetary missions with them would be by using a swarm of them combined together using collective intelligence. This would allow for redundancy. Also scientific payloads along with items such as long range communications could be distributed amongst them.
Title: Re: Proposed Europa Missions
Post by: vjkane on 01/07/2014 06:45 pm
Anyway, the cubesat people have a huge advantage in nimbleness that may off-set their equally huge disadvantage of not demonstrating an interplanetary mission, yet. But it wouldn't be as capable as a real spacecraft, that much is certain, and I don't think we need to kid ourselves about that, yet.
I think that the challenge of putting science quality instruments on a CubeSat, navigate it to fly past Europa, and return science is daunting.  If all we needed were a few snap shots of the surface to answer the compelling questions, Galileo already did that.  Just getting some piece of (in this case, really small) hardware to Europa doesn't address the science questions.

There is a serious concept to add CubeSats to a Europa multi-flyby mission to perform very high resolution imaging a la the lunar Rangers.  But the CubeSats don't have to propel themselves to Jupiter, navigate precisely, and return many megabytes of data to Earth (the mother craft serves as data storage and relay). 
Title: Re: Proposed Europa Missions
Post by: darkbluenine on 01/07/2014 08:14 pm
The 2012 JPL paper linked at the bottom of this post summarizes a study of interplanetary cubesat missions, including:

1. Mineral Mapping of Asteroids [Small Body Science]
2. Solar System Escape Technology Demonstration [Tech Demo]
3. Earth–Sun Sub-L1 Space Weather Monitor [Heliophysics and Terrestrial Applications]
4. Phobos Sample Return [Planetary Science]
5. Earth–Moon L2 Radio Quiet Observatory [Astrophysics]
6. Out-of-Ecliptic Missions [Heliophysics]

It probably represents the "state-of-the-art" in cubesat mission concepts beyond LEO.  None are outer planets missions, and Europa would be especially challenging given the low solar flux and extremely high radiation.  That said, if you look sideways and squint really hard at the Phobos sample return mission and assume a couple different or newer approaches than what JPL baselined here, then maybe a simple, independent Europa geyser sample return would be possible within 6U.

In terms of enabling technologies for interplanetary cubesat missions, here's JPL's list:

1. CubeSat electronics and subsystems extended and improved from their low Earth orbit implementations in order to operate in the interplanetary environment, with particular attention to surviving increased radiation and
duration of operation.
2. Optical telecommunications to enable very compact, low-power uplink/downlink over interplanetary distances.
3. Solar sail propulsion to enable major maneuvers and rendezvous with multiple targets using no propellant.
4. Navigation of the Interplanetary Superhighway to enable multiple destinations over reasonable mission durations with achievable dV.
5. Small, highly capable instrumentation (such as a miniature imaging spectrometer) enabling acquisition of high quality scientific and exploration information.
6. Onboard storage and processing of raw instrument data and navigation information to enable maximum utility
of uplink and downlink telecom capacity, and minimal operations staffing.

I'd add alpha and/or betavoltaic power sources, passive optical comm, metamaterial and/or genetically engineered antennas, and microfluidic electrospray propulsion to that list for more capable future missions and potentially enabling for the outer planets.

Here's the PDF paper and live presentation:

http://www.nasa.gov/pdf/716078main_Staehle_2011_PhI_CubeSat.pdf

http://www.youtube.com/watch?v=WMSxBuyGoO0

And here's a somewhat technical PowerPoint presentation on the various missions:

http://mstl.atl.calpoly.edu/~bklofas/Presentations/DevelopersWorkshop2012/Staehle_Interplanetary_CubeSat.pdf

And here's another paper that delves more deeply into the Phobos sample return and variations on it:

http://www.lpi.usra.edu/meetings/marsconcepts2012/pdf/4123.pdf

FWIW...

Title: Re: Proposed Europa Missions
Post by: savuporo on 01/08/2014 03:22 am
Great summary of technical issues. Deep space environmental issues are really quite different from LEO and before a single cubesat has been even to a lunar distance for an extended period, it's way too premature to talk about outer planets.
Would be awesome if there was a funded cubesat launch opportunities program to GEO altitudes first
Title: Re: Proposed Europa Missions
Post by: plutogno on 03/03/2014 07:48 pm
the next NASA budget may at last fund initial work on an Europa mission
http://www.aviationweek.com/Article.aspx?id=%2Farticle-xml%2Fawx_03_03_2014_p0-668360.xml
Title: Re: Proposed Europa Missions
Post by: EE Scott on 03/04/2014 02:49 am
Yes, but is NASA able to be that thoughtful?  That sounds like the best way to spend the resources, guaranteed to contribute to the Europa mission, or many others should Europa not come to be.
Title: Re: Proposed Europa Missions
Post by: baldusi on 03/04/2014 02:57 am
Don't they need like four MMRTG? Is there enough weaved fabric?
Title: Re: Proposed Europa Missions
Post by: redliox on 03/04/2014 07:33 am
Although it's doubtful the Europa Clipper will do anything too inventive (i.e. using what's available now like chemical engines, solar panels, RTGs, instrument rebuilds), I have had thoughts on what would assist a future Jupiter mission (or possibly a Saturn/Titan mission)....

Both Galileo's and Juno's missions were driven partly by their mass.  More specifically, JOI propellant.  Galileo weighed about 2.4 metric tons, of which 0.9 was fuel/oxidizer.  However during the 8 years it orbited Jupiter Galileo used scarcely a hundred pounds.  If JOI could be scratched, any Jupiter spacecraft would weigh no more than a Martian one, giving room for thicker rad shielding and instruments.

Since SEP is a bit of a stretch at Jupiter and nuclear , an idea Arthur C. Clarke implemented comes to mind...
(http://mossfilm.files.wordpress.com/2013/12/2010-leonov.jpg)

Aerocapture is no doubt a stretch, but the technology is maturing.  Titan is an easier target compared to Jupiter's turbulence and radiation, but it's also a heck of a lot farther.  Jupiter with 4 large moons has the greater science payout for operation time, its just getting around JOI.  Something akin to a shielded Mariner probe could be stuffed in a cylinder and a tough inflatable utilized to get it into an orbit spanning out to Callisto (or Ganymede or Europa itself depending on mission needs), and from there pops out of its can and gravity assists its way among the moons.

So how much of a pain would it be to aerocapture a probe at Jupiter?
Title: Re: Proposed Europa Missions
Post by: Drkskywxlt on 03/04/2014 10:50 pm
I take back what I just wrote. Wait until the budget comes out. You'll be surprised.

Do you think this ~$15M in FY15 is enough to count as a new start?  Sounds more like they're relenting to the fact that Rep. Culbertson is going to put money into the budget anyway (and likely more than this).
Title: Re: Proposed Europa Missions
Post by: redliox on 03/05/2014 02:40 am
Do you think this ~$15M in FY15 is enough to count as a new start?  Sounds more like they're relenting to the fact that Rep. Culbertson is going to put money into the budget anyway (and likely more than this).

It's enough to give inquires into.  It is already on a promising arc and just needs a boost of attention from Congress.

One way that might ensure it gets funded is flying it aboard SLS.  With complaints about it lacking a payload or purpose beyond Orion, advocate to Bolden "Here one!"  Some projects survived by pulling on strings of others, such as Cassini dodging an ax because of it's heavy international ties or Galileo onboard the shuttle (granted Challenger's mishap delayed it quite a bit).  Something you have to fight politics with politics, since science alone can't do much without a crowd behind it.
Title: Proposed Europa Missions
Post by: vjkane on 03/05/2014 05:28 am
I take back what I just wrote. Wait until the budget comes out. You'll be surprised.

Which post should we forget? The out year funding or the mmrtg post?
Title: Re: Proposed Europa Missions
Post by: darkbluenine on 03/05/2014 02:07 pm
Also heard some info about an "enhanced" MMRTG and a small nuclear reactor. The former is new to me and I don't know any details. The latter has been talked for awhile, but I did not realize that they had done some work on that (namely identifying a Nevada site where they could test a small reactor).

A couple papers/presentations on these "kilopower" uranium reactor concepts.  First addresses testing.  I've seen the cost estimates for the second.  They're in the $1-2B range.

http://local.ans.org/trinity/files/mcclure-130920.pdf

http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20120001793.pdf

FWIW...
Title: Re: Proposed Europa Missions
Post by: Blackstar on 03/06/2014 04:45 pm
Here you go.
Title: Re: Proposed Europa Missions
Post by: Star One on 03/06/2014 07:27 pm
Thanks for that. Be interesting to see which way they go on both the power supply and launcher.
Title: Re: Proposed Europa Missions
Post by: yg1968 on 03/06/2014 07:57 pm
SN is reporting that Bolden is looking for a Europa mission that would cost less than $1B:
http://www.spacenews.com/article/civil-space/39756nasa-to-seek-ideas-for-1-billion-mission-to-europa
Title: Re: Proposed Europa Missions
Post by: redliox on 03/06/2014 08:08 pm
SN is reporting that Bolden is looking for a Europa mission that would cost less than $1B:
http://www.spacenews.com/article/civil-space/39756nasa-to-seek-ideas-for-1-billion-mission-to-europa

Heard about that.  I think a New Frontiers-class probe would have some potential, but understandably it'd be limited compared to a flagship.  If it has to be prioritized and limited, giving it a goal of mapping the surface and finding the ocean should be it - i.e. visible cameras and the radar but no spectrometers.  If we can't do everything, at least ensuring we can put a lander down later isn't a bad goal to settle for.

Here you go.

Great find Blackstar!  It's good to see more details and plans for E.C. emerging.  I just hope sometime this year they finally commit to it or establish a solid "plan B", be it flagship or N.F.
Title: Re: Proposed Europa Missions
Post by: baldusi on 03/06/2014 08:24 pm
I do wonder, thou. What if the final budget looks to be something like 1.5B?
Title: Re: Proposed Europa Missions
Post by: Sesquipedalian on 03/06/2014 08:41 pm
So how much of a pain would it be to aerocapture a probe at Jupiter?

I'd like an answer to this too, especially considering the recent discussion (http://forum.nasaspaceflight.com/index.php?topic=34127.0). :)
Title: Re: Proposed Europa Missions
Post by: Star One on 03/06/2014 08:59 pm

I do wonder, thou. What if the final budget looks to be something like 1.5B?

I could put all of this into italics for emphasis, but instead, just consider this to be a helpful reminder:

Your best bet (for your own peace of mind) is to not speculate too much and just watch the process play itself out. There is a lot of stuff that is in play, and a lot of things that will have to work themselves out, but not all the details are public (nor should be). But there is some reason to be optimistic about the way things may turn out. No guarantees, but for the first time the trend arrows are pointing in the right direction.

I really hope it all goes positively.

I posted about this mission on a general forum and there was a high level of enthusiasm for it. I know that isn't a very scientific survey but Europa does seem to capture people's minds in the same way Mars appears too.
Title: Re: Proposed Europa Missions
Post by: yg1968 on 03/06/2014 09:07 pm
SN is reporting that Bolden is looking for a Europa mission that would cost less than $1B:
http://www.spacenews.com/article/civil-space/39756nasa-to-seek-ideas-for-1-billion-mission-to-europa

You can probably ignore Bolden's comments on these things.

Grunsfeld said the same thing.

Quote
John Grunsfeld, the former astronaut turned associate administrator for NASA’s Science Mission Directorate, said at the symposium. NASA will ask for Europa mission concepts that could be done “for around a billion dollars.”
Title: Re: Proposed Europa Missions
Post by: baldusi on 03/06/2014 10:16 pm
From what I get they have estimated that for 2B they'll get a good idea of the surface and the undelying structures (i.e. if there are oceans and what type). But if they have to do away with the deep radar, they might end with a 1B mission that only tells them about the surgace and the interior will be left as an excercise for the PI.
Title: Re: Proposed Europa Missions
Post by: baldusi on 03/07/2014 12:16 am
I
But can you do an assessment of the plumes? And can you do high-resolution imaging of the surface to enable an eventual lander?
I see the plumes as a bet. If it's a recurrent process, they can hit a jackpot. But if not a lot of expensive instrument will be wasted.
Regarding the resolution, I understand that it might require a level of resolution that's not possible ( like sub meter), and many flybys might not get a global coverage. But more importantly, we don't know how it changes or regenerate. That's my understanding. I might be widely wrong.
But given that a follow up missions might be 15 to 20 years after this one, I think it's better to get enough information to know if Europa should be the biggest priority (probably after Mars) or not.
Title: Re: Proposed Europa Missions
Post by: redliox on 03/07/2014 06:59 am
So how much of a pain would it be to aerocapture a probe at Jupiter?

I'd like an answer to this too, especially considering the recent discussion (http://forum.nasaspaceflight.com/index.php?topic=34127.0). :)

Right now the goal is to get the cost of such a mission lower, and adding new and untested technologies is not a good way to lower costs. So it is not going to happen.

Correct, which I admitted to when mentioning it.  Still, with aerocapture being considered for outer planet targets like Neptune and Titan, it would make sense to test it closer to home, making Jupiter the first atmosphere in the outer solar system.  I just know that radiation belt and (to a lesser extent) rings would be a heck of a landmine field.

Other than another orbiter, a more specific probe that would get the maximum benefit from Jovian aerocapture would be a future Europa lander.  Timed correctly, it could arc from Jupiter directly to Europa without a massive JOI or months of gravity assists to guide it down the gravity well.  Aerocapture is too big a leap for Europa Clipper, but whatever it's successor is, that craft could attempt it.

...I'm just curious what kind of hellish geometry is needed.  ;)
Title: Re: Proposed Europa Missions
Post by: vjkane on 03/07/2014 11:55 am

And part of the way that you have to look at that question is with regards to any follow-on missions. If you do the $1 billion mission, but in order to answer the key questions you still have to do another $1.5 billion mission (say, a Europa orbiter), then you haven't made a wise choice, because you've spent more money in the long run rather than doing the first mission right. Of course, there are all kinds of trades here, and it requires judgement calls. But it ultimately points to the fact that the goal should not be to do a Europa mission simply to do a Europa mission, the goal should be to do a Europa mission that answers the key questions that people want to answer.
In support of what Blackstar is saying, the science definition team has specified several science goals: icy she'll, surface composition, surface geology, ocean depth and composition, and landing site reconnaissance. The plumes, if confirmed, would be an additional goal.

Each goal has one or two instruments (with several instruments shared between goals). Each also needs a specific number and geometries of encounters.

To me, a credible mission needs to knock of the two highest priority goals, the ice shell characterization (ice penetrating radar and topographic imager) and surface composition (add short wave IR spectrometer with a mass spectrometer as a desired instrument). For plumes you'd want the MS spectrometer and some remote sensing instrument to locate the plumes and their sources, maybe a UV spectrometer.

The instrument list looks reasonable, but the real challenge is likely to be surviving the radiation the achieve a sufficient number of encounters.
Title: Re: Proposed Europa Missions
Post by: vjkane on 03/07/2014 12:51 pm


I see the plumes as a bet. If it's a recurrent process, they can hit a jackpot. But if not a lot of expensive instrument will be wasted.
The key instrument for the plumes would be a mass spectrometer. That instrument also would be highly desired for measuring surface composition.

For a uv spectrometer, perhaps NASA could collaborate with ESA. The JUICE mission is planning an extensive search with their uv instrument.
Title: Re: Proposed Europa Missions
Post by: Star One on 03/07/2014 01:46 pm


And part of the way that you have to look at that question is with regards to any follow-on missions. If you do the $1 billion mission, but in order to answer the key questions you still have to do another $1.5 billion mission (say, a Europa orbiter), then you haven't made a wise choice, because you've spent more money in the long run rather than doing the first mission right. Of course, there are all kinds of trades here, and it requires judgement calls. But it ultimately points to the fact that the goal should not be to do a Europa mission simply to do a Europa mission, the goal should be to do a Europa mission that answers the key questions that people want to answer.
In support of what Blackstar is saying, the science definition team has specified several science goals: icy she'll, surface composition, surface geology, ocean depth and composition, and landing site reconnaissance. The plumes, if confirmed, would be an additional goal.

Each goal has one or two instruments (with several instruments shared between goals). Each also needs a specific number and geometries of encounters.

To me, a credible mission needs to knock of the two highest priority goals, the ice shell characterization (ice penetrating radar and topographic imager) and surface composition (add short wave IR spectrometer with a mass spectrometer as a desired instrument). For plumes you'd want the MS spectrometer and some remote sensing instrument to locate the plumes and their sources, maybe a UV spectrometer.

The instrument list looks reasonable, but the real challenge is likely to be surviving the radiation the achieve a sufficient number of encounters.

How many encounters would it need to make with Europa at a minimum to get an effective set of science results?
Title: Re: Proposed Europa Missions
Post by: Blackstar on 03/07/2014 06:02 pm
Two papers from 2008 on exactly what their titles indicate.
Title: Re: Proposed Europa Missions
Post by: redliox on 03/07/2014 07:21 pm
Other than another orbiter, a more specific probe that would get the maximum benefit from Jovian aerocapture would be a future Europa lander.  Timed correctly, it could arc from Jupiter directly to Europa without a massive JOI or months of gravity assists to guide it down the gravity well.


You sure of that?

It would be possible, but a more conservative approach using aerocapture would do its best to just graze the Jovian atmosphere and enter ~100 day orbit.  Naturally the longer a craft aerobrakes, the more speed it burns off so long as the heatshield holds.  Something wanting an orbit whose apogee touches Europa's would be ~7 days or less, and that would be on the higher end of entry speeds.

We've had heat shields, landers, and sample-return capsules for decades now, the only new elements to apply are inflatables and composites.  The only issue I see is calculating a right angle and whether or not the vehicle needs more aggressive autonomous programming (Curiosity's descent at Mars might be good example of this).
Title: Re: Proposed Europa Missions
Post by: Star One on 03/07/2014 10:05 pm
Space Politics article.

http://www.spacepolitics.com/2014/03/07/europa-on-five-hundred-thousand-dollars-a-day/
Title: Re: Proposed Europa Missions
Post by: vjkane on 03/08/2014 07:37 am



Quote from: baldusi link=
[/quote


How many encounters would it need to make with Europa at a minimum to get an effective set of science results?

The number of encounters is a complex question. From the Clipper presentations, my reading of a complex slide suggests that some investigations might get by with as few as 20-30 flybys, others perhaps as many as 50.

However, the Clipper goals are for full global coverage, tries to replicate with flybys what an orbiter would do, and assumes a ~$2b budget. 

An alternative strategy might be to remotely study  a handful of interesting locations instead. (Each interesting region would have a dedicated fly over during one of the encounters,).

Imagine that a ~$1b mission could do 12 flybys. You might budget them this way:

3 plume encounters
6 interesting regions such as the maculas
3 average areas

I'm not saying I favor this strategy, but it is a valid option to consider.   The targets chosen could also be coordinated with the ones the Juice mission will target
Title: Re: Proposed Europa Missions
Post by: redliox on 03/08/2014 08:06 am
An alternative strategy might be to remotely study  a handful of interesting locations instead. (Each interesting region would have a dedicated fly over during one of the encounters,).

Imagine that a ~$1b mission could do 12 flybys. You might budget them this way:

3 plume encounters
6 interesting regions such as the maculas
3 average areas

I'm not saying I favor this strategy, but it is a valid option to consider.   The targets chosen could also be coordinated with the ones the Juice mission will target

That would sound like a still viable plan.  Naturally not as elaborate or in depth, but the point is to establish some answers.  Kepler, for example, couldn't scan the whole sky but from what it could see and record has now confirmed hundreds of planets, supplying information that can give solid numbers for the Drake equation.  For Europa the least we can do is answer "Is there a liquid ocean down there?"
Title: Re: Proposed Europa Missions
Post by: Star One on 03/08/2014 10:05 am




Quote from: baldusi link=
[/quote


How many encounters would it need to make with Europa at a minimum to get an effective set of science results?

The number of encounters is a complex question. From the Clipper presentations, my reading of a complex slide suggests that some investigations might get by with as few as 20-30 flybys, others perhaps as many as 50.

However, the Clipper goals are for full global coverage, tries to replicate with flybys what an orbiter would do, and assumes a ~$2b budget. 

An alternative strategy might be to remotely study  a handful of interesting locations instead. (Each interesting region would have a dedicated fly over during one of the encounters,).

Imagine that a ~$1b mission could do 12 flybys. You might budget them this way:

3 plume encounters
6 interesting regions such as the maculas
3 average areas

I'm not saying I favor this strategy, but it is a valid option to consider.   The targets chosen could also be coordinated with the ones the Juice mission will target

Thanks for that. I assume you would want these encounters at different altitudes, or would that make a more simple mission too complex. How difficult is it too vary a perimeter such as this.
Title: Re: Proposed Europa Missions
Post by: redliox on 03/08/2014 07:31 pm
For Europa the least we can do is answer "Is there a liquid ocean down there?"

Scientists are already 99% sure there is a liquid ocean down there. A Europa mission would have to do a lot more to be worthwhile.

Scientists were sure about a lot of things, from the Earth being flat to Venus being a tropical paradise...until they got direct data.  There is still speculation it might be all ice.  IPR is a must whatever gets sent to Europa for that reason.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 03/08/2014 07:58 pm
For Europa the least we can do is answer "Is there a liquid ocean down there?"

Scientists are already 99% sure there is a liquid ocean down there. A Europa mission would have to do a lot more to be worthwhile.

Scientists were sure about a lot of things, from the Earth being flat to Venus being a tropical paradise...until they got direct data.  There is still speculation it might be all ice.  IPR is a must whatever gets sent to Europa for that reason.

The issue is not the presence of water, it is how much of it there is (as opposed to ice).
Title: Re: Proposed Europa Missions
Post by: vjkane on 03/09/2014 05:39 am


That would sound like a still viable plan.  Naturally not as elaborate or in depth, but the point is to establish some answers.  Kepler, for example, couldn't scan the whole sky but from what it could see and record has now confirmed hundreds of planets, supplying information that can give solid numbers for the Drake equation.  For Europa the least we can do is answer "Is there a liquid ocean down there?"
The Kepler analogy doesn't quite work. There are billions of stars in our galaxy and so a sample from thousands of stars is statistically valid. 

There's only one Europa with heterogenously distributed features. Fortunately, we have Galileo data to give us some idea where to look. However, without global coverage, we would miss many potentially interesting spots. Imagine if we only had coarse resolution Viking images and the Mars Reconnaissance orbiter could look at only a dozen locations.  We would have missed most of the exciting story that has emerged.

Galileo all but confirmed the ocean. My understanding is that the megnetometer and gravity measurements that would further would require a large number of flybys.
Title: Re: Proposed Europa Missions
Post by: vjkane on 03/09/2014 05:45 am



[quote author=Star One link=topic=27871.msg1168993#msg1168993 date=

Thanks for that. I assume you would want these encounters at different altitudes, or would that make a more simple mission too complex. How difficult is it too vary a perimeter such as this.
I believe that the Clipper strategy is to keep the flyby altitudes similar.  What the make clear is that they would distribute to locations of the closest approach across the Europan globe
Title: Re: Proposed Europa Missions
Post by: vjkane on 03/09/2014 07:36 am
The issue is not the presence of water, it is how much of it there is (as opposed to ice).
And the salinity of the ocean, which gives a lot of clues about the composition and the nature of the water-rocky surface interface

Edit/Lar: Fix quotes
Title: Re: Proposed Europa Missions
Post by: Blackstar on 03/15/2014 03:02 am
Here you go.
Title: Re: Proposed Europa Missions
Post by: redliox on 03/15/2014 07:37 am
Interesting reading through the older EL specifications, but it felt like a mix of pie-in-sky, irritating, and yet a touch of intrigue all at once.

The 2 bits that caught my attention most were locations for a relay orbiter and their (brief) thoughts on aerocapture:

Relay): Although I doubt NASA would devote an orbiter purely for relay, it would be an obvious side-function for a long lived observer orbiter meant for medium-range observations or plume observations (of either Europa or Io).  A LaGrange position would be easier to settle into, although, aside from radiation at one at Europa, the gravity-play of 4 moons and a giant planet might make it tricky.  A relay at either Ganymede's or Callisto's L-points or a distant Jovian orbit might be the best compromise, if your priority is avoiding radiation at least.

Aerocapture: Not an enabling technology my *&@$$#!!!  was my instinctive reaction.  JOI is also NOT a small burn, ITS HUGE!  Both Galileo and Juno devoted easily half their weight for just those events, which says a lot for finding a way to get around the burden.  Aside from electric propulsion (both ION and VASMIR), which they did point out was too power-hungry to be practical at Jupiter, aerocapture is the best way to slow down without giant fuel loads.  This was, of course, all written before experiments like IRVEE began, so I read this with a grain of salt.  Still I felt very disappointed, as I consider myself an advocate of aerobraking/capture (you can blame 2010 and the Leonov for that  ;D :P ).
Title: Re: Proposed Europa Missions
Post by: Blackstar on 03/15/2014 03:50 pm
Here's another one. I have not checked to see if this differs from the others. I have a 150 meg movie animation of this design, but it's too big to load here.
Title: Re: Proposed Europa Missions
Post by: redliox on 03/15/2014 04:21 pm
Aerocapture: Not an enabling technology my *&@$$#!!!  was my instinctive reaction. 

SNIP

Still I felt very disappointed, as I consider myself an advocate of aerobraking/capture (you can blame 2010 and the Leonov for that  ;D :P ).

I've seen a bunch of Europa presentations and none of them ever talk about aerocapture with Jupiter.

And likewise none of us have seen a Europa spacecraft, discounting perhaps Galileo.

Specifically for aerocapture, I have read into it from the 1980s' Race to Mars and Mark Zubrin's The Case for Mars, and more recently the IRVEE tests.  So many sources are advocating it as a means for reducing mass on Martian missions; on top of that both Titan and Neptune are being cited as future targets.  If the technology expands into the outer solar system, Jupiter is the closet body where it could be used.

A handy link full of data from the University of Houston: http://www.uh.edu/sicsa/library/media/Student%20Projects/Deceleraters (http://www.uh.edu/sicsa/library/media/Student%20Projects/Deceleraters)

The technology just needs to be demonstrated, just as Pathfinder used airbags and Deep Space 1 used ion propulsion, each later used by MER and Dawn respectively in full-fledged science missions.

I'm just seeing a logical use for it at Jupiter and the Outer Solar System as a means for reducing weight and size.  When you need 1,000 pounds+ of fuel to slow down....is it any wonder nothing but flagships are insisted upon whereas smaller, Discovery-sized missions in the Inner Solar System have made significant discoveries?
Title: Re: Proposed Europa Missions
Post by: Spiff on 03/15/2014 06:42 pm
Nice article on SpaceflightNow

http://spaceflightnow.com/news/n1403/14europa/#.UySenYX3ip0

Title: Re: Proposed Europa Missions
Post by: redliox on 03/15/2014 08:20 pm
Nice article on SpaceflightNow

http://spaceflightnow.com/news/n1403/14europa/#.UySenYX3ip0

Not a bad find Spiff.  :)  It at least establishes what the overall 'mood' of the Europa situation is.

Quote
   
NASA Administrator Charlie Bolden said March 5 that officials envision a mission to Europa with about the same cost as the agency's New Frontiers line, which carries a cost cap of approximately $1 billion. NASA has launched two New Frontiers mission to date, with the New Horizons probe on the way to the first flyby of Pluto and the Juno spacecraft cruising to Jupiter.

Another New Frontiers mission, OSIRIS-REx, is due for launch in late 2016 to return samples from an asteroid.

Green said that while NASA aims to design a Europa probe in the mold of a New Frontiers mission, it will be a standalone project. The National Research Council's planetary science decadal survey, which sets NASA's strategy in robotic exploration of the solar system, outlined specific concepts the space agency will choose from when crafting the next New Frontiers program.

"Everyone has been saying New Frontiers-class, but what they really mean is at about a billion dollars," Green said. "Could we really do Europa science at about a billion dollars?"

Engineers could design the spacecraft to be solar-powered instead of putting plutonium power generators on the probe, a design change that would cut costs. International partnerships are also an option, officials said.

Sadly budgets will drive this mission, but I am optimistic regarding what an official study for a New Frontiers-Europa probe could say.  Mapping Europa will certainly be a priority, but the plume discovery will be the new wild card now:

Quote
The discovery of the plumes drove NASA to ask "what out of our concepts could take advantage of flying through the plumes," Green said. "Is the orbiter or the multiple-flyby option in a better position to be able to study the plumes, make measurements, actually get samples, analyze those and be able to tell us what's in those? Is it just water, are there organics, what is Europa processing and how is that ocean communicating with the surface?"

The Europa Clipper concept, which carries a cost of about $2 billion, was designed before the plume discovery.

"Clipper wasn't designed to fly through plumes with the right instruments," Green said. "We're in the process of validating that. We're in the process of asking what could have Clipper done, or do we need to follow up with Clipper to do that. That's one option, but we're also looking at what can we do of value with the plumes at an even lower cost. We don't know for a fact that we can, but that's what pre-formulation is all about. Let's study that."

Lets hope the new round of studies bring promise to Europa exploration.
Title: Re: Proposed Europa Missions
Post by: vjkane on 03/16/2014 04:38 am
If NASA decided to cancel New Frontiers and do a cheapish Europa mission instead, they would be explicitly going against the direction of the decadal sururovey and the scientists would make a lot of noise complaining. NASA knows this, Congress certainly knows this, and OMB, depending upon the time of day and the phase of the Moon, knows this.

The Decadal Survey said that *global* mapping of Europa is the goal.  A $1B mission certainly would build on our knowledge of Europa.  Consider, though, that our current knowledge about Europa probably falls somewhere between what we knew of Mars between Mariner 9 and the Viking orbiters.  Imagine if we studied only a few percent of Mars at high resolution based on what we knew from Viking.  We would have missed so much that turned out to be important.  We need a good analysis of Europa as a world. 

If you read the original paper on the moons or the better stories reporting on it, the signal for the plumes is just above the noise level.  They may be real or not.

I suspect that NASA is using the plumes and the hopes for a credible $1B mission to get a mission approved earlier than the current mid-2020s.  It might work.  It did for Mars.
Title: Re: Proposed Europa Missions
Post by: Star One on 03/16/2014 10:06 am
A question if Atlas isn't available to launch this mission should it go ahead, SLS is too expensive, would it have to be launched on a Delta 4H and if that was the case what would the cost implications be?
Title: Re: Proposed Europa Missions
Post by: Blackstar on 03/16/2014 11:26 am
The Decadal Survey said that *global* mapping of Europa is the goal.  A $1B mission certainly would build on our knowledge of Europa.  Consider, though, that our current knowledge about Europa probably falls somewhere between what we knew of Mars between Mariner 9 and the Viking orbiters.  Imagine if we studied only a few percent of Mars at high resolution based on what we knew from Viking.  We would have missed so much that turned out to be important.  We need a good analysis of Europa as a world. 


We should also keep in mind that there are science goals and also programmatic goals. The programmatic goals are longer term, but essentially boil down to: what can we do with this first mission that makes further missions easier/better?

For example, if a flyby mission does not gather enough data to go straight to a lander mission, then that means that NASA will have to fly an orbiter next before a lander. What that means is that if they do the flyby mission wrong (to save a few hundred million dollars), they may have to spend an extra $2.5+ billion for an orbiter mission before a lander, and delay flying a lander for many decades.

You could spin out two scenarios:

Scenario 1
$1 billion (cheap) flyby mission in the 2020s--->$2.5+ billion orbiter mission in the 2030s-->lander mission 2040s/50s

Scenario 2
$2.1 billion Europa Clipper mission in the 2020s-->lander mission in the 2030s

Title: Re: Proposed Europa Missions
Post by: Blackstar on 03/16/2014 11:27 am
A question if Atlas isn't available to launch this mission should it go ahead, SLS is too expensive, would it have to be launched on a Delta 4H and if that was the case what would the cost implications be?

Yeah, or maybe Falcon Heavy, if it is available.

But there's no reason to assume that Atlas V will not be available.
Title: Re: Proposed Europa Missions
Post by: Star One on 03/16/2014 12:09 pm

A question if Atlas isn't available to launch this mission should it go ahead, SLS is too expensive, would it have to be launched on a Delta 4H and if that was the case what would the cost implications be?

Yeah, or maybe Falcon Heavy, if it is available.

But there's no reason to assume that Atlas V will not be available.

Well there is the possible RD-180 supply issue with the Atlas V. I know we are talking a long way off but I am not convinced whether the relevant decisions to fix this will take place. But that's a whole other thread.
Title: Re: Proposed Europa Missions
Post by: vjkane on 03/16/2014 03:23 pm
We should also keep in mind that there are science goals and also programmatic goals. The programmatic goals are longer term, but essentially boil down to: what can we do with this first mission that makes further missions easier/better?

For example, if a flyby mission does not gather enough data to go straight to a lander mission, then that means that NASA will have to fly an orbiter next before a lander. What that means is that if they do the flyby mission wrong (to save a few hundred million dollars), they may have to spend an extra $2.5+ billion for an orbiter mission before a lander, and delay flying a lander for many decades.

You could spin out two scenarios:

Scenario 1
$1 billion (cheap) flyby mission in the 2020s--->$2.5+ billion orbiter mission in the 2030s-->lander mission 2040s/50s

Scenario 2
$2.1 billion Europa Clipper mission in the 2020s-->lander mission in the 2030s
I just finished posting my analysis of the FY15 budget proposal.  http://futureplanets.blogspot.com/2014/03/2015-planetary-science-proposed-budget.html (http://futureplanets.blogspot.com/2014/03/2015-planetary-science-proposed-budget.html)

At the end of FY19, NASA will be spending ~$740M a year on mission development/operations, split between the Discovery program and a ramping down Mars 2020 rover.  If that level of spending continues through the following decade, my back of the envelope calculation suggests that NASA could fly the ~$2B Europa Clipper, a New Frontiers mission, and five Discovery missions (assuming NASA's total mission costs are 33% higher than the PI mission costs).

Other than an aversion to Flagship missions, I don't see a good reason to push studying a cheaper New Frontiers class mission now.  A mid 2020's mission would begin development around 2020.  It would arrive after JUICE does, which would already fulfill many of the goals that a cut rate dedicated Europa mission might do.

Deciding to fly a mission now to scout out the system might make sense (but recall the plumes are not confirmed).  A Discovery-class mission could make remote observations from the relatively benign region of Ganymede's orbit to verify the plumes.  It might even be able to fly once or twice through the plumes (although I don't know if radiation hardened instruments are doable on a Discovery budget). 

BUT committing to a Discovery mission based on a single unconfirmed observation does not seem sensible to me. 
Title: Re: Proposed Europa Missions
Post by: grondilu on 03/22/2014 02:04 am

Not sure it's related, but this article about a new kind of radiation-proof transistor made me think of Europa:

http://phys.org/news/2014-03-tiny-transistors-extreme-environs-plasma.html#ms
Title: Re: Proposed Europa Missions
Post by: Blackstar on 04/04/2014 12:52 pm
Here is a 1997 proposal for a Europa orbiter. This may be the first Europa orbiter proposal. This was a Discovery proposal. Note that it would have used solar and not RTGs.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 04/07/2014 09:48 pm
Jeff Foust's new article on this subject. I haven't read it yet, but Jeff is pretty good at understanding these things:

http://www.thespacereview.com/article/2483/1

Europa on the cheap
by Jeff Foust
Monday, April 7, 2014

For decades, scientists have dreamed of sending a mission to Europa, one of Jupiter’s four large Galilean moons. The fleeting flybys of the moon by Voyagers 1 and 2 in 1979, and the more frequent flybys of Galileo in the 1990s, revealed a world with a icy crust, crisscrossed by fractures and other complex features. Those and other observations led scientists to conclude that Europa has, below that icy crust, a subterranean ocean of liquid water that, combined with the energy from tidal heating that keeps that ocean liquid and organic compounds, provide the basic requirements for life.

As compelling as the scientific case is for Europa, NASA has yet to send a dedicated mission there. Part of that is due to the technical challenges involved in launching a spacecraft to Jupiter and operating in the high radiation environment created by Jupiter’s powerful magnetic field. Those technical obstacles drive up the costs of those proposed, and reduce the chances they can be funded. NASA has studied Europa orbiter mission proposals since the late 1990s, but those efforts typically foundered on costs and shifting priorities.



Title: Re: Proposed Europa Missions
Post by: kris on 04/14/2014 09:12 am
Hello sorry to go off topic but this seemed like the best thread and if the information is already in it, I can't find it.

I've read that it's possible that their is oxygen in the oceans of Europa trough the interaction of sunlight hitting the icy surface changing H2O into H2O2 that can get recycled under the ice changing it into H2O and O2. This prediction are pretty vague altough optimist says it could be enough to support Multi cellular life forms. I wonder if there would be any instrument that could potentially measure the O2 concentration (from orbit or flyby).
also as a gues could their be enough dissolved O2 (on Europe) to add 210 milliebar of O2 to a place like mars



http://phys.org/news174918239.html (http://phys.org/news174918239.html)
Title: Re: Proposed Europa Missions
Post by: redliox on 04/26/2014 09:06 am
An interesting idea suggested by Andrew LePage involves a Europa-Io Sample Return by flying through the plumes of each respective moon: http://www.drewexmachina.com/2014/03/27/a-europa-io-sample-return-mission/ (http://www.drewexmachina.com/2014/03/27/a-europa-io-sample-return-mission/)

Quote
With the announcement in December of the possible detection of plume activity over the southern polar region of the Jovian moon, Europa [2, 3], the possibility exists of using a spacecraft essentially identical to that employed in the proposed LIFE mission to secure samples from the Europan plume(s).  And as an added bonus, it may prove possible during the same mission to sample one or more volcanic plumes of Io (the next moon in from Europa) which have been observed to reach as high as 500 km above this active moon’s surface – easily within the reach of a passing spacecraft.

-----

Once at Jupiter, the spacecraft would use its propulsion system to enter an elongated Jovian orbit to keep the spacecraft away from the worst of Jupiter’s radiation belt for most of the mission.  Using repeated gravity assists from Europa, Ganymede and Callisto, the spacecraft’s orbit would be gradually decreased in size to allow multiple, relatively low velocity encounters with Europa’s polar plumes so that samples could be gathered using an aerogel collector.  With a spacecraft perijove distance equal to Europa’s mean orbital distance from Jupiter, encounter speeds of 3.7 to 4.0 km/s (the Enceladus encounter speed in the LIFE mission scenarios) are possible if the apojove is ~2.0 to ~2.4 million km – just beyond the orbit of Callisto.  By coincidence, this potential Europa encounter orbit would be in a 3:1 resonance with Europa (i.e. Europa would orbit Jupiter three times for every orbit of the spacecraft allowing repeated encounters with minimal orbit adjustments) with a apojove of ~2.1 million km.  Such a resonance would facilitate repeated encounters with Europa if the orbit is properly phased.

After months of observation from a safe distance to spot the most promising target, one final close pass by Io located deep inside Jupiter’s radiation belt could be made to sample one of its volcanic plumes.  This encounter with Io and (probably) during insertion into Jovian orbit would be the only two times this spacecraft would be required to pass through the most intense portions of Jupiter’s radiation belts thus helping to minimize the spacecraft’s total radiation exposure.  Keeping the encounter velocity with Io down to ~4 km/s will be more difficult but perhaps a greater velocity would be acceptable since the mineral grains from Io’s plumes will be more robust than any icy particles from Europa’s plume.  Depending on any limitations on the spacecraft’s orbit around Jupiter, it might even prove possible to sample Jupiter’s outer Gossamer Rings associated with Jovian moons Amalthea and Thebe thus allowing indirect sampling of these bodies as well (since these rings are believed to originate from material that has escaped these small inner moons).

Outside of the miracle of Europa Clipper getting full funding, a Europan sample return might be a worthy silver prize.  Naturally there are numerous considerations....

Firstly, the possibility is based on the plumes Hubble seems to have spotted.  What's needed next is confirmation, follow-up observations to make sure these aren't flukes of course.  Considering how Europa is a prime target and the excitement generated by the initial discovery...I believe there will be confirmation before the end of the 2010s.  So before the first nut and bolt is twisted on any Jovian craft, we will know about the plumes.

Second, funding issues.  Bolden has already admitted he's bite at a billion dollar probe, so odds now favor a scheme that fits a New Frontier budget.  Obviously this isn't a good fit for 'Clipper.  However, a plume-catcher might be more straightforward; already we have OSIRIS-REX, a fairly complex asteroid SR in the NF bracket, and Stardust before excelled at Discovery levels.  Most of the billion give to a ESR would focus on the flyby hardware, with 2 supplemental instruments like a more robust mass spectrometer and a color camera for PR (heck this is the rationale for JunoCam's existence).  In short, I could see a compact can-like ESR fitting into New Frontiers better than the mega-Christmas-tree designs (both figuratively and schematically) of typical Jovian orbiters.

Third, engineering.  Stardust has pretty much demonstrated what's needed for plume-catching, and with those huge speeds comets sweep at it was no small challenge they faced to catch a handful of comet stuff.  A Giotto-like bus with thickened aluminum for shielding and a capsule behind it is the gist of a ESR.  It wouldn't need to linger for dozens of flybys to finish its job, and while at Jupiter fetching fire from Io or ring material may be further options.  No booms, no spanning antennas.

Four, science.  Of course we want more photos in better detail, and answers to the ocean and life enigmas.  But when you say you have a piece of that moon, you'll get an avalanche of eager scientists storming in.  A few samples of ocean salt won't answer everything, but it will definitely help answer some of the bigger questions around Europa.

If it becomes adamant that a Europa mission must be on the cheap, well this might be one of the answers the project teams come up with, and while not as photogenic as Europa Clipper (which I do root for) this concept may be just as exciting.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 04/28/2014 02:54 am
An interesting idea suggested by Andrew LePage involves a Europa-Io Sample Return by flying through the plumes of each respective moon:

I read that a couple of weeks ago and although it is an interesting idea, I think he misses a key point--the U.S. scientific community said to go to Europa and do specific kinds of science. The community did not say go to Europa and collect samples from the plumes. Now if somebody wants to propose doing that with a Discovery class mission they are free to do so (good luck at fitting that in the cost cap). But it is not a recommended New Frontiers mission, nor is it a recommended flagship mission and therefore should not, and will not get funded out of those budgets.

Put another way, that sample return mission has not been recommended or vetted by the U.S. scientific community. And the way things work in the U.S. is that only science missions that are vetted get the necessary money to proceed.

And once again this highlights the key fact: what is important is not where you go, but what you do when you get there. The recent discussion of a Europa mission has sometimes lost sight of the fact that the reason that scientists said to go to Europa in the first place is to do specific science there, not to simply say that "we've gone to Europa." It's about science, not planting a flag. There's no point in doing the mission at all unless it focuses on the important science.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 04/28/2014 03:02 am
1-Second, funding issues.  Bolden has already admitted he's bite at a billion dollar probe, so odds now favor a scheme that fits a New Frontier budget. 

2-Four, science.  Of course we want more photos in better detail, and answers to the ocean and life enigmas.  But when you say you have a piece of that moon, you'll get an avalanche of eager scientists storming in.  A few samples of ocean salt won't answer everything, but it will definitely help answer some of the bigger questions around Europa.

1-Bolden doesn't really matter in this (and in fact, his comments are somewhat out of tune with the comments made by Grunsfeld and others). It ultimately comes down to OMB, Congress, and the scientific community. All three matter in this issue, and I'd note that if a significant part of the scientific community comes out and says "a plume sampling mission is not worth the cost of doing it and is no substitute for flagship-class science," then the political support will evaporate. As I heard one senior person put it, it's better to wait an extra decade and do the mission right than to do a lousy mission now and then have to try again two decades after that.

2-That's really looking at the science issues in a weird way. A sample return mission would provide particles. That's not going to satisfy the people interested in the geology, the water circulation, the entire Europa system dynamics. That's like saying to a weatherman "We could not afford to give you a satellite that will show where the hurricanes and tornadoes are, but here are a few raindrops instead. I'm sure you'll be happy with these."

There's a framework that has been developed over many decades: flyby, orbit, land, rove. Skipping all those steps to go straight to sample return doesn't produce the scientific knowledge that justifies spending the money in the first place.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 04/29/2014 06:19 pm
http://www.spacepolicyonline.com/news/house-appropriators-propose-substantial-increase-for-nasa-including-europa

House Appropriators Propose Substantial Increase for NASA, Including Europa
Marcia S. Smith
Posted: 29-Apr-2014
Updated: 29-Apr-2014 02:08 PM

The House Appropriations Committee released a draft of the FY2015 Commerce-Justice-Science (CJS) bill that will be marked up by the CJS subcommittee tomorrow (April 30).   It proposes a substantial increase for NASA compared to the President's request and funding for a robotic mission to Jupiter's moon Europa would be one beneficiary of the increased spending.

SNIP

The funding figures in the House CJS subcommittee draft bill are as follows

    Science:   $5,193 million.  That is $221 million more than the President requested, and $42 million more than the FY2014 amount.  Of the $5,193 million, $100 million is for the Europa mission.  The President requested $15 million for FY2015.   The President requested zero for Europa in FY2013 and FY2014, but Congress appropriated $75 million in FY2013 (subject to rescissions and the sequester, which left about $69 million) and $80 million in FY2014.
Title: Re: Proposed Europa Missions
Post by: redliox on 04/29/2014 08:20 pm
It looks like NASA will be taking a look at cheaper missions soon: http://www.space.com/25672-jupiter-moon-europa-nasa-mission-ideas.html (http://www.space.com/25672-jupiter-moon-europa-nasa-mission-ideas.html)

Quote
NASA is asking the scientific community to help it devise a relatively low-budget mission to Jupiter's moon Europa, perhaps the solar system's best bet to host alien life.

The space agency announced Monday (April 28) that it has issued a Request for Information (RFI), officially seeking ideas from outside researchers for a mission to study Europa and its subsurface ocean for less than $1 billion (excluding the launch vehicle).

"This is an opportunity to hear from those creative teams that have ideas on how we can achieve the most science at minimum cost," John Grunsfeld, associate administrator for the NASA Science Mission Directorate at the agency's headquarters in Washington, said in a statement.

"Europa is one of the most interesting sites in our solar system in the search for life beyond Earth," Grunsfeld added. "The drive to explore Europa has stimulated not only scientific interest but also the ingenuity of engineers and scientists with innovative concepts."

The deadline to submit ideas under the RFI is May 30, officials said.

So come June there'll at least be a few ideas on the table in addition to Europa Clipper.  The increase in Planetary Science is excellent but without that full $2 billion for 'Clipper we need to find what other options are possible.  Whatever those options will be the Decadal Survey that recommended Europa to begin with may be the guide (although naturally a smaller mission might only sate a few goals):

Quote
The Decadal Survey deemed a mission to the Jupiter moon as among the highest priority scientific pursuits for NASA. It lists five key science objectives in priority order that are necessary to improve our understanding of this potentially habitable moon.

The mission will need to:

• Characterize the extent of the ocean and its relation to the deeper interior

• Characterize the ice shell and any subsurface water, including their heterogeneity, and the nature of surface-ice-ocean exchange

• Determine global surface, compositions and chemistry, especially as related to habitability

• Understand the formation of surface features, including sites of recent or current activity, identify and characterize candidate sites for future detailed exploration

• Understand Europa's space environment and interaction with the magnetosphere.

So, going by priority, finding the depth and extent of the subsurface ocean comes first followed by chemistry.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 04/29/2014 09:44 pm
So come June there'll at least be a few ideas on the table in addition to Europa Clipper.  The increase in Planetary Science is excellent but without that full $2 billion for 'Clipper we need to find what other options are possible.  Whatever those options will be the Decadal Survey that recommended Europa to begin with may be the guide (although naturally a smaller mission might only sate a few goals):


I thought that the explanation as to what is going on appeared earlier in the thread.

This is OMB pushing the issue. OMB wants NASA to see what is possible at the $1 billion level. I know a lot of people who think that the answer is that decadal level science cannot be accomplished at that lower level. (One former Voyager/Galileo scientist was recently asked at a conference what $1 billion could buy at Jupiter and he replied "A lot of radiation shielding.") Remember that the reason why Europa is on the table, and why people have been talking about it, is to do the science described in the decadal survey, not simply to go and plant a flag at Europa (flipping that on its head, there's no reason to do a Europa mission if it is not going to accomplish that level of science; might as well just wait another decade and try again).

Now I don't think this is necessarily a bad thing to do. After all, we might get some interesting mission proposals out of it, and there is value to doing mission proposals, because--as an example--the next time there is a decadal survey it helps to know some of the options ahead of time. But there is a risk to this. The risk is that the politicians will go off and approve a mission just so they can say "We are doing Europa!" when that mission doesn't accomplish interesting science. There is also a risk that this could kill the next New Frontiers opportunity, and that would annoy a lot of people with interests in the Moon, Venus, Saturn, comets, and other targets. It would also lead to a lot of programmatic chaos.

Title: Re: Proposed Europa Missions
Post by: Blackstar on 04/29/2014 11:46 pm
So, going by priority, finding the depth and extent of the subsurface ocean comes first followed by chemistry.

As a senior NASA planetary science official recently explained, in addition to the science goals, there are also programmatic goals for any Europa mission. The key programmatic goal is that the mission should minimize the amount of science/data that has to be collected for the next mission.

Put more succinctly, if you do a flyby mission, it should provide enough data so that you can go to a lander mission next and not have to repeat another flyby or orbiter mission. That means that the mission should gather high resolution imagery of the surface to enable a lander.
Title: Re: Proposed Europa Missions
Post by: redliox on 04/30/2014 12:32 am
This is OMB pushing the issue. OMB wants NASA to see what is possible at the $1 billion level. I know a lot of people who think that the answer is that decadal level science cannot be accomplished at that lower level. And the reason why Europa is on the table, and why people have been talking about it, is to do the science described in the decadal survey (flipping that on its head, there's no reason to do a Europa mission if it is not going to accomplish that level of science; might as well just wait another decade and try again).

Now I don't think this is necessarily a bad thing to do. After all, we might get some interesting mission proposals out of it, and there is value to doing mission proposals, because--as an example--the next time there is a decadal survey it helps to know some of the options ahead of time.

That's why I see this more as a positive.  It opens opportunities.  Everyone says it must be a flagship...but only because nobody seriously looked into what a smaller spacecraft might do.  That's not engineering, that's presumption.

We've had spacecraft with modest instrumentation that served well.  A great example would be Mars Odyssey: an 800kg orbiter with 3 instruments, only 2 of which remote sensing.  Its THERMIS instrument singled out the MER landing sites, including the hematite Opportunity found, not to mention mapped the whole of Mars at resolutions only MRO surpassed.  Never underestimate the small guys.

Quote
The risk is that the politicians will go off and approve a mission just so they can say "We are doing Europa!" when that mission doesn't accomplish interesting science. There is also a risk that this could kill the next New Frontiers opportunity, and that would annoy a lot of people with interests in the Moon, Venus, Saturn, comets, and other targets. It would also lead to a lot of programmatic chaos.

Err...that already happened when EJSM won over TSSM, only to get canceled (i.e. the annoying everyone part).  Frankly as much as I retroactively wish TSSM won instead of EJSM (presuming its budget could fit better), if any mission deserves the next New Frontiers slot it should be the Uranus Orbiter, which was 3rd on the Decadal-to-do-list.  Of course this thread is about Europa, not to mention wishful thinking should be kept to a minimum.

Quote
Put more succinctly, if you do a flyby mission, it should provide enough data so that you can go to a lander mission next and not have to repeat another flyby or orbiter mission. That means that the mission should gather high resolution imagery of the surface to enable a lander.

Definitely agreed there.  Whatever gets sent, large or small, must be able to find safe ground for landing.  At worst, an orbiter with a camera system ought to be sent; more so coupled with the ice radar; Van Kane mentioned that as a suggestion for a New Frontiers fitting.  If we end up flying New Frontiers-class, it should be functional yet conservative.

Europa needs options, least we all end up waiting forever.  'Clipper is an excellent option, but shouldn't be exclusive in case Congress' generosity runs low.  I'm eager to see what's suggested by June, that way we all can better judge the choice between flagships and 'frontiers.  I'm hoping to be pleasantly surprised either way!
Title: Re: Proposed Europa Missions
Post by: Blackstar on 04/30/2014 02:47 am
That's why I see this more as a positive.  It opens opportunities.  Everyone says it must be a flagship...but only because nobody seriously looked into what a smaller spacecraft might do.  That's not engineering, that's presumption.

No, that's not what happened.
Title: Re: Proposed Europa Missions
Post by: Star One on 07/28/2014 03:07 pm
Europa Clipper Would Wash Out Other Nuclear-powered Missions.

Quote
BETHESDA, Md. — If NASA sends a nuclear-powered probe to Jupiter’s moon Europa, it would launch no sooner than 2024, and effectively rule out other nuclear missions to the outer solar system before then by tying up the specialized infrastructure required to produce plutonium-powered spacecraft batteries, a senior NASA official said here.

“If the Europa mission goes nuclear, it needs four or five [Multi-Mission Radioisotope Thermoelectric Generators],” Curt Niebur, a program scientist at NASA headquarters in Washington, said in a July 23 interview here during a meeting of the NASA-chartered Outer Planets Assessment Group. “That’s quite a few. If Europa needs that many, that sucks up all the output for the production line between now and 2024. There’s no more left."

Clipper will likely need such a power source, but the U.S. Department of Energy, which owns and operates all the equipment needed to refine plutonium-238 and press it into pellets usable by an MMRTG, now plans to shut down its aging pellet-stamping hot press at the Los Alamos National Laboratory in Los Alamos, New Mexico, after 2015, when the department plans to produce one last batch of pellets for the single MMRTG needed for Mars 2020, a sample-caching rover based on Curiosity and slated to launch in 2020.

Len Dudzinski, program executive for radioisotope power systems at NASA headquarters, said in an interview here that the Department of Energy “won’t promise us to be able to support Europa without a new hot press.” NASA, not the Department of Energy, is on the hook to pay for the new equipment.


http://www.spacenews.com/article/civil-space/41399europa-clipper-would-wash-out-other-nuclear-powered-missions
Title: Re: Proposed Europa Missions
Post by: Alpha_Centauri on 07/28/2014 05:16 pm
What other realistic nuclear-powered outer solar system mission before 2024 is there to sacrifice?!
Title: Re: Proposed Europa Missions
Post by: GalacticIntruder on 07/28/2014 05:26 pm
Might need to add the last part of the SpaceNews article.

Quote
That process will likely start in 2015, Carroll said. When it is done, the press will be taken offline until a new one can be installed. The Department of Energy hopes the new machine will be online by 2017. After that, the department could press enough fuel to prepare one flight-ready MMRTG a year, Carroll said.

2017 is probably optimistic for these things, but nevertheless, it is not a permanent end of Pu pellet production.

Title: Proposed Europa Missions
Post by: Star One on 07/28/2014 06:34 pm
Might need to add the last part of the SpaceNews article.

Quote
That process will likely start in 2015, Carroll said. When it is done, the press will be taken offline until a new one can be installed. The Department of Energy hopes the new machine will be online by 2017. After that, the department could press enough fuel to prepare one flight-ready MMRTG a year, Carroll said.

2017 is probably optimistic for these things, but nevertheless, it is not a permanent end of Pu pellet production.

I wasn't sure if too add as it wasn't a definitive response on the issue.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 07/29/2014 02:04 pm
This is not a surprise to anybody who has been following either the Pu-238 subject or Europa mission plans closely. They've been saying things like this--although not loudly--for almost a year now. The context is that a lot of the Pu-238 production infrastructure is in poor shape and they need to replace equipment. I was talking to one person familiar with the whole issue. He said that NASA was initially concerned that they were getting stuck with too much cost, but after a group looked at the infrastructure, they said that if anything, NASA is getting off easy, because there are a lot of associated infrastructure costs that are hidden, and fortunately NASA is not being charged for them.
Title: Re: Proposed Europa Missions
Post by: Star One on 07/29/2014 03:02 pm

This is not a surprise to anybody who has been following either the Pu-238 subject or Europa mission plans closely. They've been saying things like this--although not loudly--for almost a year now. The context is that a lot of the Pu-238 production infrastructure is in poor shape and they need to replace equipment. I was talking to one person familiar with the whole issue. He said that NASA was initially concerned that they were getting stuck with too much cost, but after a group looked at the infrastructure, they said that if anything, NASA is getting off easy, because there are a lot of associated infrastructure costs that are hidden, and fortunately NASA is not being charged for them.

So it will be the DOE who picks up the majority of the cost of updating this equipment.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 07/29/2014 06:37 pm

This is not a surprise to anybody who has been following either the Pu-238 subject or Europa mission plans closely. They've been saying things like this--although not loudly--for almost a year now. The context is that a lot of the Pu-238 production infrastructure is in poor shape and they need to replace equipment. I was talking to one person familiar with the whole issue. He said that NASA was initially concerned that they were getting stuck with too much cost, but after a group looked at the infrastructure, they said that if anything, NASA is getting off easy, because there are a lot of associated infrastructure costs that are hidden, and fortunately NASA is not being charged for them.

So it will be the DOE who picks up the majority of the cost of updating this equipment.

I would not say that. For this specific equipment, NASA may get stuck with most of the bill. I was saying that for the overall cost of doing all of this stuff, NASA may be getting a deal. Now I don't know why that is. One possibility is that if you had to run all of this entirely separate from DoE, then NASA would have to duplicate security, handling, staff, etc. that is currently being covered by DoE overhead. It gets squiggly when you start trying to figure out cross-agency costs.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 07/29/2014 08:45 pm
I did not make it to OPAG last week, but a colleague did. I asked him about the "$1 billion Europa missions" in response to NASA's RFI. He said that there were 6 proposals. They are all being CATEd right now. NASA would not say anything more than that. Nothing about who proposed them or what they are about.
Title: Re: Proposed Europa Missions
Post by: sdsds on 07/29/2014 10:05 pm
Sorry for asking a rather basic question but: could the "$1 billion" Europa missions be designed (like Clipper) to take either a VEEGA trajectory after launch on Atlas or a direct trajectory after launch on SLS? Or is there something about $1b that makes that not possible?
Title: Re: Proposed Europa Missions
Post by: Jim on 07/30/2014 12:31 am
Sorry for asking a rather basic question but: could the "$1 billion" Europa missions be designed (like Clipper) to take either a VEEGA trajectory after launch on Atlas or a direct trajectory after launch on SLS? Or is there something about $1b that makes that not possible?

yes, that is why it could fly on SLS or Atlas V
Title: Re: Proposed Europa Missions
Post by: Blackstar on 07/30/2014 03:52 am
Sorry for asking a rather basic question but: could the "$1 billion" Europa missions be designed (like Clipper) to take either a VEEGA trajectory after launch on Atlas or a direct trajectory after launch on SLS? Or is there something about $1b that makes that not possible?

Er, this is a weird question. No matter what the cost of the mission, it still has to get to Europa. So it's either going to launch on an Atlas or an SLS. Now some people argue that taking a VEEGA trajectory is going to cost more in operations costs than a direct trajectory, because you have to spend $X per year and it is more years to go that way than directly. So maybe you save $80 million in operating costs with the direct trajectory vs. the VEEGA trajectory (but do you pay more for the launch vehicle?).

But that whole discussion is essentially irrelevant to the $1 billion mission issue. The $1 billion cost goal came from OMB, which is opposed to an expensive mission (which they define as "more than $1 billion") and so they told NASA to see what could be done for $1 billion. I suspect that the answer to that question is going to be "you cannot do much."

Title: Re: Proposed Europa Missions
Post by: vjkane on 07/30/2014 04:43 am
Europa Clipper Would Wash Out Other Nuclear-powered Missions.

SpaceNews generally writes does very good reporting, and this article is except for one omission.  The Clipper mission can also be done (based on current engineering assessments) with solar panels.  There are various engineering and budget trades (solar panels are heavier and must always point toward the sun; but the solar option is cheaper than the Pu-238 option). 

So far as I know, there's been no decision on which direction to go.

If the Clipper doesn't use Pu-238, then NASA could make MMRTGs available to Discovery and New Horizon missions.  There are a number of concepts that either depend on a plutonium power supply or would benefit from it.
Title: Re: Proposed Europa Missions
Post by: metaphor on 07/30/2014 03:18 pm
Sorry for asking a rather basic question but: could the "$1 billion" Europa missions be designed (like Clipper) to take either a VEEGA trajectory after launch on Atlas or a direct trajectory after launch on SLS? Or is there something about $1b that makes that not possible?

Er, this is a weird question. No matter what the cost of the mission, it still has to get to Europa. So it's either going to launch on an Atlas or an SLS. Now some people argue that taking a VEEGA trajectory is going to cost more in operations costs than a direct trajectory, because you have to spend $X per year and it is more years to go that way than directly. So maybe you save $80 million in operating costs with the direct trajectory vs. the VEEGA trajectory (but do you pay more for the launch vehicle?).


Is there also an additional cost due to the thermal insulation needed because of the higher temperatures at Venus?  I seem to remember that being an advantage of a straight-to-Jupiter trajectory.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 07/30/2014 04:44 pm
Sorry for asking a rather basic question but: could the "$1 billion" Europa missions be designed (like Clipper) to take either a VEEGA trajectory after launch on Atlas or a direct trajectory after launch on SLS? Or is there something about $1b that makes that not possible?

Er, this is a weird question. No matter what the cost of the mission, it still has to get to Europa. So it's either going to launch on an Atlas or an SLS. Now some people argue that taking a VEEGA trajectory is going to cost more in operations costs than a direct trajectory, because you have to spend $X per year and it is more years to go that way than directly. So maybe you save $80 million in operating costs with the direct trajectory vs. the VEEGA trajectory (but do you pay more for the launch vehicle?).


Is there also an additional cost due to the thermal insulation needed because of the higher temperatures at Venus?  I seem to remember that being an advantage of a straight-to-Jupiter trajectory.

I've heard something about that too, but I suspect that it's not a big cost. Really, it's just insulation (plus the engineering evaluation). Shouldn't cost much.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 07/30/2014 04:48 pm
Europa Clipper Would Wash Out Other Nuclear-powered Missions.

SpaceNews generally writes does very good reporting, and this article is except for one omission.  The Clipper mission can also be done (based on current engineering assessments) with solar panels.  There are various engineering and budget trades (solar panels are heavier and must always point toward the sun; but the solar option is cheaper than the Pu-238 option). 

So far as I know, there's been no decision on which direction to go.

If the Clipper doesn't use Pu-238, then NASA could make MMRTGs available to Discovery and New Horizon missions.  There are a number of concepts that either depend on a plutonium power supply or would benefit from it.


There's also a hybrid solar/RTG option that was going to be evaluated as of a few months ago. But RTGs are the lowest risk option. I suspect that for an expensive mission they will want the lowest risk option.
Title: Re: Proposed Europa Missions
Post by: baldusi on 07/30/2014 05:50 pm
Europa Clipper Would Wash Out Other Nuclear-powered Missions.

SpaceNews generally writes does very good reporting, and this article is except for one omission.  The Clipper mission can also be done (based on current engineering assessments) with solar panels.  There are various engineering and budget trades (solar panels are heavier and must always point toward the sun; but the solar option is cheaper than the Pu-238 option). 

So far as I know, there's been no decision on which direction to go.

If the Clipper doesn't use Pu-238, then NASA could make MMRTGs available to Discovery and New Horizon missions.  There are a number of concepts that either depend on a plutonium power supply or would benefit from it.


There's also a hybrid solar/RTG option that was going to be evaluated as of a few months ago. But RTGs are the lowest risk option. I suspect that for an expensive mission they will want the lowest risk option.
If they go with SLS, RTG also mean nuclear-rating it.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 07/30/2014 06:13 pm
If they go with SLS, RTG also mean nuclear-rating it.

Yes. But I think that's something that is going to have to happen eventually. If you assume that SLS will become operational and that it will be used for decades to launch human missions, then it will eventually carry RTGs for human missions.

So I think the most important/relevant question is who pays for that nuclear certification: the science community or the human spaceflight community?
Title: Re: Proposed Europa Missions
Post by: a_langwich on 07/30/2014 06:49 pm
Europa Clipper Would Wash Out Other Nuclear-powered Missions.

SpaceNews generally writes does very good reporting, and this article is except for one omission.  The Clipper mission can also be done (based on current engineering assessments) with solar panels.  There are various engineering and budget trades (solar panels are heavier and must always point toward the sun; but the solar option is cheaper than the Pu-238 option). 

So far as I know, there's been no decision on which direction to go.

If the Clipper doesn't use Pu-238, then NASA could make MMRTGs available to Discovery and New Horizon missions.  There are a number of concepts that either depend on a plutonium power supply or would benefit from it.


There's also a hybrid solar/RTG option that was going to be evaluated as of a few months ago. But RTGs are the lowest risk option. I suspect that for an expensive mission they will want the lowest risk option.

I would think the hybrid option would be pretty competitive on risk.  You can get just enough RTGs to support a baseline science level, so that even if the solar completely disappeared you could get most of the science done.  And, truth is, solar panels aren't too shabby in reliability themselves.  If solar panels are safe enough to risk for the $8 billion JWSC and Hubble, they are probably okay for a measly $1 - $2 billion mission.

But the hybrid option would carry all the complication, cost, size, and weight of both the RTGs and solar and then some.  Maybe not a problem if you are launching on SLS and you don't have the money to fill the size/weight envelope with instruments, but could be trouble for an Atlas.  Still, it might be worth it, IF it enables another small mission or two to take place (meaning there is some assurance the RTG capability wouldn't just sit unused for the entire time frame).

It will be interesting, once Falcon Heavy gets going, to see what its payload/C3 graph looks like. 
Title: Re: Proposed Europa Missions
Post by: Jim on 07/30/2014 07:02 pm
  If solar panels are safe enough to risk for the $8 billion JWSC and Hubble, they are probably okay for a measly $1 - $2 billion mission.


Not the same trade.  The issue is getting enough power which does not apply to JWST and HST and not reliability.
The risk for Europa is holding to a spacecraft power level and then having the mass for large enough panels with margin to supply the required levels.

Europa needs more power than other probes because of the radar mapper.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 07/30/2014 07:02 pm
I would think the hybrid option would be pretty competitive on risk.  You can get just enough RTGs to support a baseline science level, so that even if the solar completely disappeared you could get most of the science done.  And, truth is, solar panels aren't too shabby in reliability themselves.  If solar panels are safe enough to risk for the $8 billion JWSC and Hubble, they are probably okay for a measly $1 - $2 billion mission.

But the hybrid option would carry all the complication, cost, size, and weight of both the RTGs and solar and then some.  Maybe not a problem if you are launching on SLS and you don't have the money to fill the size/weight envelope with instruments, but could be trouble for an Atlas.  Still, it might be worth it, IF it enables another small mission or two to take place (meaning there is some assurance the RTG capability wouldn't just sit unused for the entire time frame).

It will be interesting, once Falcon Heavy gets going, to see what its payload/C3 graph looks like. 

I don't think they would count risk in this case as "solar plus RTG." Instead, the risk comes in integrating those two technologies. That might seem easy to us, who don't know anything about doing it, but I would note that it has not been done before. There could be all kinds of complications that come from running two different power supplies into the bus.

My impression, and I've said this before, is that if you put 100 Europa scientists into a room and told them they could vote for either Atlas or SLS, you would probably get 99 people voting for Atlas. SLS comes with all kinds of unknown and murky political and budgetary risks. Better to go with the known quantity, which is Atlas. So I think that the hybrid RTG/solar option is being evaluated for Atlas, because that's what most of the Europa scientists and engineers believe is the most likely launch vehicle.
Title: Re: Proposed Europa Missions
Post by: metaphor on 07/30/2014 08:28 pm

It will be interesting, once Falcon Heavy gets going, to see what its payload/C3 graph looks like.

Extrapolating from the 21.2 tons to GTO and 13.2 tons to Mars on the SpaceX website, and the second stage stats here (http://www.spacelaunchreport.com/falcon9v1-1.html), the Falcon Heavy would only be able to take about 1-2 tons on a trajectory straight to Jupiter.  Adding a solid upper booster stage like a Star 48 would increase the payload to about 3-4 tons.  The payload would go up to 13-14 tons using a VEEGA.
Title: Re: Proposed Europa Missions
Post by: denis on 07/30/2014 11:58 pm
Sorry for asking a rather basic question but: could the "$1 billion" Europa missions be designed (like Clipper) to take either a VEEGA trajectory after launch on Atlas or a direct trajectory after launch on SLS? Or is there something about $1b that makes that not possible?

Er, this is a weird question. No matter what the cost of the mission, it still has to get to Europa. So it's either going to launch on an Atlas or an SLS. Now some people argue that taking a VEEGA trajectory is going to cost more in operations costs than a direct trajectory, because you have to spend $X per year and it is more years to go that way than directly. So maybe you save $80 million in operating costs with the direct trajectory vs. the VEEGA trajectory (but do you pay more for the launch vehicle?).


Is there also an additional cost due to the thermal insulation needed because of the higher temperatures at Venus?  I seem to remember that being an advantage of a straight-to-Jupiter trajectory.

I've heard something about that too, but I suspect that it's not a big cost. Really, it's just insulation (plus the engineering evaluation). Shouldn't cost much.
That's a pretty wild statement. How do you know it would just need "extra insulation" ? It depends a lot on the spacecraft design. Maybe it's just insulation? Maybe it will need a new attitude "BBQ-like" mode? Maybe it will need active thermal control?

As for the cost of engineering evaluation, it is one of the main reason all these missions cost billions.

Title: Re: Proposed Europa Missions
Post by: denis on 07/31/2014 12:03 am

If they go with SLS, RTG also mean nuclear-rating it.

What does nuclear-rating a launcher mean ?

I thought the RTG were designed to survive intact even an explosion of the launcher.  Isn't it the case ?
Title: Re: Proposed Europa Missions
Post by: Blackstar on 07/31/2014 02:30 am
Sorry for asking a rather basic question but: could the "$1 billion" Europa missions be designed (like Clipper) to take either a VEEGA trajectory after launch on Atlas or a direct trajectory after launch on SLS? Or is there something about $1b that makes that not possible?

Er, this is a weird question. No matter what the cost of the mission, it still has to get to Europa. So it's either going to launch on an Atlas or an SLS. Now some people argue that taking a VEEGA trajectory is going to cost more in operations costs than a direct trajectory, because you have to spend $X per year and it is more years to go that way than directly. So maybe you save $80 million in operating costs with the direct trajectory vs. the VEEGA trajectory (but do you pay more for the launch vehicle?).


Is there also an additional cost due to the thermal insulation needed because of the higher temperatures at Venus?  I seem to remember that being an advantage of a straight-to-Jupiter trajectory.

I've heard something about that too, but I suspect that it's not a big cost. Really, it's just insulation (plus the engineering evaluation). Shouldn't cost much.
That's a pretty wild statement. How do you know it would just need "extra insulation" ? It depends a lot on the spacecraft design. Maybe it's just insulation? Maybe it will need a new attitude "BBQ-like" mode? Maybe it will need active thermal control?

As for the cost of engineering evaluation, it is one of the main reason all these missions cost billions.



Please, tell me some more. I don't know much about this subject.
Title: Re: Proposed Europa Missions
Post by: sdsds on 07/31/2014 03:22 am
if you put 100 Europa scientists into a room and told them they could vote for either Atlas or SLS, you would probably get 99 people voting for Atlas.

I understand why today's researchers are the population one would first think to poll. For them, now, arrival dates in 2025 and 2028 don't look that far apart. Nor do departure dates in 2022 and 2021. But as the departure dates get closer the calculus might change. Engineers might want those extra few months of time to assure the spacecraft is ready. And a student in 2021 is going to see a meaningful difference between a 2025 arrival and a 2028 arrival.

In any case, the notion that a mission in development can "maintain dual launch capability through CDR" seems in the current political reality to mandate that it do so.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 07/31/2014 01:23 pm
I understand why today's researchers are the population one would first think to poll.

Yeah, because they're the only ones that actually have the knowledge and expertise.
Title: Re: Proposed Europa Missions
Post by: a_langwich on 07/31/2014 07:38 pm
I would think the hybrid option would be pretty competitive on risk.  You can get just enough RTGs to support a baseline science level, so that even if the solar completely disappeared you could get most of the science done.  And, truth is, solar panels aren't too shabby in reliability themselves.  If solar panels are safe enough to risk for the $8 billion JWSC and Hubble, they are probably okay for a measly $1 - $2 billion mission.

But the hybrid option would carry all the complication, cost, size, and weight of both the RTGs and solar and then some.  Maybe not a problem if you are launching on SLS and you don't have the money to fill the size/weight envelope with instruments, but could be trouble for an Atlas.  Still, it might be worth it, IF it enables another small mission or two to take place (meaning there is some assurance the RTG capability wouldn't just sit unused for the entire time frame).

It will be interesting, once Falcon Heavy gets going, to see what its payload/C3 graph looks like. 

I don't think they would count risk in this case as "solar plus RTG." Instead, the risk comes in integrating those two technologies. That might seem easy to us, who don't know anything about doing it, but I would note that it has not been done before. There could be all kinds of complications that come from running two different power supplies into the bus.

My impression, and I've said this before, is that if you put 100 Europa scientists into a room and told them they could vote for either Atlas or SLS, you would probably get 99 people voting for Atlas. SLS comes with all kinds of unknown and murky political and budgetary risks. Better to go with the known quantity, which is Atlas. So I think that the hybrid RTG/solar option is being evaluated for Atlas, because that's what most of the Europa scientists and engineers believe is the most likely launch vehicle.


Re: Atlas vs SLS, seems pretty reasonable to me.  ANY never-flown rocket would of course be riskier, and the large size and development cost and schedule of SLS, and the fickleness of using a manned rocket for an unmanned mission and depending essentially on the manned program for that impetus--yes, it's more risky.

Re: combining solar and RTGs, having built voltage converters and power management buses, I think combining them would be fairly easy.  AFAIK there will still be a layer of voltage conversion to the bus voltage chosen for instruments; the input to that voltage conversion usually has a wide latitude/tolerance for different sources and voltages.  Especially for a solar panel system, the combination would be simple.  The RTG would just look like another battery, permanently charged.  It IS just another battery.

I don't know how feasible or practical solar power by itself is; I guess Juno will retire a lot of that risk when it starts returning science?  But Juno's panels were 340 kg...that's a pretty big chunk out of a probe's weight budget, isn't it?  That doesn't include the batteries.  340 kg for 420 W (EOM)...a little more than 2 MMRTGs, right?  To me, that's the trade, along with the difficulties of stowing/unfurling, figuring out how to point your probe at the target while your arrays point toward the sun and try to maximize insolation, arranging your instruments and comm to avoid being blocked by the panels, etc. 
Title: Re: Proposed Europa Missions
Post by: vjkane on 07/31/2014 08:17 pm
Another issue with solar is that much of the power goes to running heaters in the spacecraft (about 50% in the case of Juno if memory serves me right). Mmrtg's have heat to spare
Title: Re: Proposed Europa Missions
Post by: a_langwich on 07/31/2014 08:22 pm
But as the departure dates get closer the calculus might change.

Well, sure, because "future risk" is being retired.  By 2021, if all goes well, SLS will have flights under its belt.  There will presumably be much lower risk that it could get cancelled between mission selection and mission launch.  A lot more people would bet on the high-wire artist after, or even 2/3 of the way through, his walk over the {landmark of interest}.

At the same time, if we are prognosticating the future, I'd bet 99 out of 100 Europa scientists would pick Falcon Heavy in 2021 over SLS.  Possibly even if it still has crappy high-energy mission performance.

In any case, the notion that a mission in development can "maintain dual launch capability through CDR" seems in the current political reality to mandate that it do so.

This may not be so hard for the Clipper concepts, if the mass launched by SLS direct is similar to Atlas VEEGA mass.  The Venus environment should be trivially easy to handle with shading and minor thermal design, since the probe isn't trying to do any science there.

The problem with using SLS for a $1 billion probe is that to halve the price of the budget, you are going to have to throw out instruments, which will reduce both weight and power.  That won't make any significant difference in travel time, either direct or VEEGA, but it means you will be seriously underusing SLS.  And it won't help SLS for people to be talking about cutting half of a $2 billion probe's cost in tight budget times, while flying it on an LV which has cost tens of billions.

Title: Re: Proposed Europa Missions
Post by: Blackstar on 08/01/2014 04:02 pm
But as the departure dates get closer the calculus might change.

Well, sure, because "future risk" is being retired.  By 2021, if all goes well, SLS will have flights under its belt.


But that's not really it. It's not the danger that SLS will get canceled between now and then, it's all the programmatic instability that would come with using an SLS instead of an Atlas V. Simply put, if the Science Mission Directorate buys an Atlas V for a Europa mission, then they own it. It's theirs. Everybody knows that. But if they go with an SLS, the program managers are always going to be worried that they are at risk from larger political and bureaucratic forces. For instance, if HEOMD decides to change their bookkeeping for SLS and unexpectedly shifts more costs onto the payload side. If I was a Europa scientist, I would want the launch vehicle that is a 100% known variable and where I'm the full owner. There won't be any surprises.
Title: Re: Proposed Europa Missions
Post by: baldusi on 08/01/2014 04:07 pm
There's no internal equivalent to an insurance or warranty?
Title: Re: Proposed Europa Missions
Post by: Blackstar on 08/01/2014 06:11 pm
There's no internal equivalent to an insurance or warranty?

We're talking about a bureaucracy here. If somebody from the government promised you something would you believe them?

I will pose a theoretical example: suppose when HEOMD and the Science Mission Directorate (SMD) are negotiating over using SLS for the Europa mission HEOMD says that they (HEOMD) will pay the cost of nuclear rating the SLS. Suppose that they say this because they expect that in a few years they are going to have to nuclear rate the SLS for HEOMD missions. So SMD says yes. And then a few years later, HEOMD slips its plans and no longer plans to fly its own nuclear payloads on SLS in the next few years. And so, because they do not need to nuclear rate SLS for their own purposes, they say "SMD, you are the only user who needs the nuclear capability, so you should pay for nuclear rating the SLS." And then SMD gets stuck with an added cost that they were told that they would not have to pay. Surprise!

I am not saying that this is the kind of thing that will happen. What I am saying is that it is the kind of thing that can happen. And people know it.*

So when a program selects a launch vehicle, or anything else, they try to maximize the things that they can control within their own office, and minimize the things that other people control. If I was a Europa scientist, I would want to use the rocket that has a high flight rate, high reliability rate, and that my people have a lot of experience with.







*I am sure that if you talked to principal investigators who ran missions in the past you could get lots of similar horror stories. I remember New Horizons PI Alan Stern explaining once about how after his mission was selected his team wanted to pick a launch vehicle and start designing their spacecraft for that vehicle. However, because of some contracting policy issue at NASA, NASA told New Horizons that they could not pick a single launch vehicle at that time. That forced New Horizons to design for both Atlas and Delta for much of their development, which Stern claimed cost them a lot of money in the design phase. Eventually, NASA picked an Atlas. My point is that these are the kinds of decisions that program managers like to nail down quickly, and they want to go with the safest and most well-known choice. They do not necessarily want the highest performance option. Thus, even when Falcon Heavy starts flying, I suspect it will take a long time before program managers will embrace it. They will all want to see a lot of successful flights before they agree to use it. "Cheap" is not really cheap if the launch vehicle fails.
Title: Re: Proposed Europa Missions
Post by: baldusi on 08/01/2014 07:43 pm
Thanks for your reply Blackstar. But I meant that if NASA signs a contract with some other entity, if they don't perform, they are in breach of contract and can be taken to court, if necessary. But was wondering if they could have legally binding contracts within divisions of the same entity (NASA). I understand from your answer that no.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 08/02/2014 12:04 pm
Thanks for your reply Blackstar. But I meant that if NASA signs a contract with some other entity, if they don't perform, they are in breach of contract and can be taken to court, if necessary. But was wondering if they could have legally binding contracts within divisions of the same entity (NASA). I understand from your answer that no.

I am no federal contracting expert (and despite what you see on this forum, I doubt that there is more than one person who _is_ a federal contracting expert here), but the government can write contracts that allow it to cancel them at any time. Usually there is a penalty clause of some kind in there, but it happens all the time.

My point is that the science side which runs the Europa mission would rather own their rocket, meaning that they control almost everything about it. With SLS that would not be the case, because primary authority for the SLS rests with the HEOMD.
Title: Re: Proposed Europa Missions
Post by: John-H on 08/02/2014 01:01 pm
If the contractor doesn't perform, you can take him to court. But you have missed the launch window. How often does a window to Jupiter occur?
Title: Re: Proposed Europa Missions
Post by: Jim on 08/02/2014 01:38 pm
If the contractor doesn't perform, you can take him to court. But you have missed the launch window. How often does a window to Jupiter occur?

The contractor is a NASA center
Title: Re: Proposed Europa Missions
Post by: ugordan on 08/02/2014 01:41 pm
How often does a window to Jupiter occur?

For a direct insertion to Jupiter, every 13 months or so. VEEGA-type trajectories are more complex so there's no single answer, the launch C3 cost can vary a lot between different opportunities.
Title: Re: Proposed Europa Missions
Post by: baldusi on 08/02/2014 02:48 pm

How often does a window to Jupiter occur?

For a direct insertion to Jupiter, every 13 months or so. VEEGA-type trajectories are more complex so there's no single answer, the launch C3 cost can vary a lot between different opportunities.
But now that we think of it, there might be some intermediate LV. Let's say a DIVH with a Star 48GXV. Or eventually a Falcon Heavy with a kick stage. What if the extra performance requires just a VEGA maneuver? It may cut a year from the trip and almost pay for itself. And whomever wins the Solar Probe Plus mission will have every certification save the nuclear rating.
Title: Re: Proposed Europa Missions
Post by: sdsds on 08/02/2014 10:58 pm
Starting this post with an observation: Europa is of high interest to people on the internet. See the attached "google fight" results below. "mars 64 100 000 résultats, europa 89 600 000 résultats." Europa is the "winner!" Of course that's not very scientific, but it gives a sense of the potential "popularity" of a Europa mission.

I think it's fair to contrast that popularity with the rather esoteric nature of the Europa science community. I was interested in the comment earlier that suggested putting 100 Europa scientists in a room and polling them on their preferences for a mission. My first reaction was, "Wait! Do that many dedicated Europa scientists really exist?"

Several times in the past when I have had some expertise in an esoteric topic that suddenly became popular I have been disappointed in how the unwashed masses "played with my toys." I'm sure others have experienced similar feelings. Maybe the coming years will be like that for Europa scientists. (Indeed, the threat of "cooperation" from NASA's HEOMD might have many in the SMD area feeling that way already!)

Going back some way in this thread:
ARC/JPL studied Europa sample return before under the Ice Clipper concept for a ~$250M Discovery proposal back in 1996/7.

With that as background, is there in principle a reason why two different Clipper missions, one in the ~$2B range and one in the ~$250M range, would be unable to share launch on an SLS?
Title: Re: Proposed Europa Missions
Post by: belegor on 08/03/2014 01:06 am
Starting this post with an observation: Europa is of high interest to people on the internet. See the attached "google fight" results below. "mars 64 100 000 résultats, europa 89 600 000 résultats." Europa is the "winner!" Of course that's not very scientific, but it gives a sense of the potential "popularity" of a Europa mission.

Have you considered that "Europa" is the way Europe (the continent) is written in German, Italian and Spanish? How do you know that you're not actually comparing Mars (the planet) with Europe (the planet + the continent)?
Title: Re: Proposed Europa Missions
Post by: sdsds on 08/03/2014 08:04 am
Have you considered that "Europa" is the way Europe (the continent) is written in German, Italian and Spanish? How do you know that you're not actually comparing Mars (the planet) with Europe (the planet + the continent)?

Oh, you're right: it probably isn't comparing references to the planet Mars and references to the moon Europa! To make the case I would need some other evidence that "Europa the moon of Jupiter" is a hot topic right now. Would a quotation from the movie 2010: Odyssey Two count? "All these worlds are yours, except Europa. Attempt no landing there!" ;)

Title: Re: Proposed Europa Missions
Post by: Oli on 08/03/2014 05:02 pm

Regarding the popularity of Mars vs Europa, I think this is more relevant:

http://www.google.com/trends/explore?hl=en-US#q=/m/0bv05,%20/m/09cws&cmpt=q
Title: Re: Proposed Europa Missions
Post by: vjkane on 08/04/2014 01:40 am
"With that as background, is there in principle a reason why two different Clipper missions, one in the ~$2B range and one in the ~$250M range, would be unable to share launch on an SLS?"

$250m is not credible. The most similar mission, Deep Impact, would cost in the neighborhood of $450m plus today. A mission to Europa would have substantially higher costs: longer flight, low light levels, etc.
Title: Re: Proposed Europa Missions
Post by: vjkane on 08/04/2014 02:23 am
Oops, actually the closest analogy is a mixture of Deep Impact and Stardust, driving the cost even higher
Title: Re: Proposed Europa Missions
Post by: Blackstar on 08/04/2014 03:34 am
This discussion of "the popularity" of a Europa vs. Mars mission is a whole lotta silliness. These missions are not selected via a popularity contest. The general public doesn't get to vote.

There is in fact a well-established process for prioritizing space science missions. It works. And in fact it is working at this very moment, which is why Europa is even being discussed as a possible future flagship class mission.

Title: Re: Proposed Europa Missions
Post by: sdsds on 08/04/2014 04:52 am
This discussion of "the popularity" of a Europa vs. Mars mission is a whole lotta silliness. These missions are not selected via a popularity contest. The general public doesn't get to vote.

No one but you has suggested that, Blackstar. You are fighting against a straw-man opponent!

What you don't seem able to accept is the true sentiment beneath, which your belittling mis-interpretation disregards. I do understand your defense of the way science missions have been selected in recent years; it has worked well! Do you understand that SMD is not an empire unto itself?
Title: Re: Proposed Europa Missions
Post by: TakeOff on 08/04/2014 11:38 am
The problem with using SLS for a $1 billion probe is that to halve the price of the budget, you are going to have to throw out instruments, which will reduce both weight and power.  That won't make any significant difference in travel time, either direct or VEEGA, but it means you will be seriously underusing SLS.
Couldn't the extra payload be used for cheap and heavy payloads, such as fuel and radiation shielding material? A probe actually orbiting Europa requires good shielding from Jupiter's radiation. And fuel to manage the unstable gravitational environment.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 08/04/2014 01:23 pm
This discussion of "the popularity" of a Europa vs. Mars mission is a whole lotta silliness. These missions are not selected via a popularity contest. The general public doesn't get to vote.

No one but you has suggested that, Blackstar. You are fighting against a straw-man opponent!

What you don't seem able to accept is the true sentiment beneath, which your belittling mis-interpretation disregards. I do understand your defense of the way science missions have been selected in recent years; it has worked well! Do you understand that SMD is not an empire unto itself?

Silliness.
Title: Re: Proposed Europa Missions
Post by: a_langwich on 08/07/2014 06:46 pm
My point is that these are the kinds of decisions that program managers like to nail down quickly, and they want to go with the safest and most well-known choice. They do not necessarily want the highest performance option. Thus, even when Falcon Heavy starts flying, I suspect it will take a long time before program managers will embrace it. They will all want to see a lot of successful flights before they agree to use it. "Cheap" is not really cheap if the launch vehicle fails.


Yes, I would expect they would wait at least 3 missions.  And something like Solar Probe Plus, where a mission gets bumped onto Falcon Heavy because there aren't any good alternatives, will probably be the first SMD payload.  But the enormous capability FH opens up, for a price that is cheaper than what they've been paying for Atlas 5's...that's going to drive proposals toward it.  At the end of the day, when the proposal is more likely to win because of the extra goodies it can achieve, than lose because it uses a Falcon Heavy LV, then it will go with FH.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 08/27/2014 05:07 pm
I just had an interesting discussion with somebody who has helped review the Europa Clipper study progress and he had some interesting things to say. I should add that he's an engineer, not a scientist, and not a Europa hugger or SLS hugger or anything like that. He's also highly credible (a well-respected guy, by me and others).

He said that the solar power case for Europa is looking really good. He said that current experience with Juno is already giving them a lot of confidence. He also added a really subtle point--if you consider the timeline for developing a Europa mission, they will not enter full-scale development until after Juno has flown its full mission. That will give them really good confidence in the engineering data. In other words, starting to design EC they will not have to guess about solar panels at Jupiter (cold and radiation) they will have real-world data to use.

There's a complicated issue that I don't totally understand concerning the RTG availability. I didn't catch all of it, but apparently the production rate for Pu-238 is so low that they'll be really pressed for power on the mission. I imagine that this has to do with both how old the Pu-238 is at launch and when the spacecraft eventually reaches Europa. He said that this is one of the things that is making solar look even better. He also said that they have looked at a hybrid solar/RTG mission, and it has some advantages, but the way he put it, if you're going to use solar anyway, why mess with RTGs at all? I think that's a valid point, because you can save money by not having to certify the rocket, etc.

He said that the SLS option looks pretty good. You can save a lot of money on the spacecraft because of both the shorter transit time and the fact that you don't have to deal with thermal issues flying past Venus. That's nothing new (reported numerous places before). However, he was pretty impressed with it. The problem, of course, is that it depends upon the mission essentially getting an SLS for free. He did say that using an Atlas V and a VEEGA trajectory provides more mass for the spacecraft than SLS, because the SLS is just shooting it out and has less C3.

He confirmed what I've believed and I've heard from numerous other people that the $1 billion Europa mission concept is not viable.

Of course, the politics on this has to play out, but I've been a skeptic on both solar power and SLS for Europa Clipper, and the fact that somebody I highly respect considers them both viable and positive is something that I'll accept.
Title: Re: Proposed Europa Missions
Post by: veblen on 08/27/2014 05:44 pm

He confirmed what I've believed and I've heard from numerous other people that the $1 billion Europa mission concept is not viable.

Of course, the politics on this has to play out, but I've been a skeptic on both solar power and SLS for Europa Clipper, and the fact that somebody I highly respect considers them both viable and positive is something that I'll accept.

Very interesting. However, to be clear, are you saying that there are multiple Europa mission concepts and the one that has the $1B price tag is not viable? And another (cheaper&solar?) one is?


The reg process for missions with RTG is lengthy = expensive. Correct?
Title: Re: Proposed Europa Missions
Post by: Star One on 08/27/2014 05:57 pm
Being solar powered of course also saves the time and expense of certifying the SLS for nuclear carriage.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 08/27/2014 06:11 pm
1-Very interesting. However, to be clear, are you saying that there are multiple Europa mission concepts and the one that has the $1B price tag is not viable? And another (cheaper&solar?) one is?

2-The reg process for missions with RTG is lengthy = expensive. Correct?

1-There is the Europa Clipper mission proposal, which currently runs in the $2.4 billion range. Earlier this year OMB directed NASA to see what could be possible to do at Europa for about $1 billion. NASA put out a request for information and apparently received back six proposals for ~$1 billion Europa missions. The question is if it is possible to do decadal survey level science for $1 billion. I don't know anybody who thinks it is (although whoever proposed those six missions may believe it is possible).

2-Yes. There's really two aspects to this, as I understand. The first is an engineering assessment of the specific payload and specific vehicle to determine what would happen in various launch accident scenarios. The second is a legal certification, essentially somebody going through all the paperwork and assessing that all the procedures are done properly. Neither one is cheap. Now Atlas V is already nuclear certified. My guess is that this means that both the engineering assessment and the legal certification are easier. SLS is not nuclear certified, so there would have to be an initial major engineering assessment of the overall vehicle, then the other two steps that I mentioned above.

My colleague mentioned something that I had not thought of--the SLS's solid boosters are more dangerous to a payload than the Atlas. They can produce a more energetic explosion (and presumably more debris, because you could get pieces of rocket casing blasted at the payload). So SLS is a trickier vehicle to certify for nuclear payloads.

However, as I have mentioned before in this thread, if SLS is eventually going to carry humans into deep space, they're going to have to get a nuclear certification of some kind, because those missions will eventually carry RTGs. So I think the question becomes whether you do the certification five years from now or 15 years from now. You don't do it until you need to do it.
Title: Re: Proposed Europa Missions
Post by: simonbp on 08/28/2014 02:56 pm
He said that the solar power case for Europa is looking really good. He said that current experience with Juno is already giving them a lot of confidence. He also added a really subtle point--if you consider the timeline for developing a Europa mission, they will not enter full-scale development until after Juno has flown its full mission. That will give them really good confidence in the engineering data. In other words, starting to design EC they will not have to guess about solar panels at Jupiter (cold and radiation) they will have real-world data to use.

I heard something similar from someone who should know recently. Though, you have to remember that Juno's primary mission is pretty short (14 months), and terminates with Juno impacting Jupiter, which obviously limits the amount of engineering data we'll get on how solar works at Jupiter.

That said, RTGs are such a production to pull off that if there is any chance to make a solar Europa mission work, they will try. Especially with all the Pu238 production issues, even a nominal-RTG mission proposal needs a solar backup option in their back pocket.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 09/02/2014 07:24 pm
These are not strictly Europa presentations, but they're close. They were made at the July meeting of the Outer Planets Assessment Group (OPAG).

They can also be found at the OPAG site.
Title: Re: Proposed Europa Missions
Post by: vjkane on 09/03/2014 08:15 pm
I think that opag's plan to pre-prioritize New Frontiers missions well ahead of the next Decadal Survey will help them out especially if they can get some money to flesh out the details.

Any news from today's pas meeting on Europa planning? I had to drop off the call
Title: Re: Proposed Europa Missions
Post by: Blackstar on 09/03/2014 09:32 pm
I think that opag's plan to pre-prioritize New Frontiers missions well ahead of the next Decadal Survey will help them out especially if they can get some money to flesh out the details.


Huh?

That's actually not up to OPAG. According to NASA, it is the NRC's CAPS committee that is "the keeper of the decadal survey." OPAG can provide input to CAPS, and they could voice their opinion to NASA on this subject, but NASA would not be inclined to listen to them on that, and it would create problems (for instance, all the other AGs would complain).
Title: Re: Proposed Europa Missions
Post by: Zed_Noir on 09/03/2014 11:42 pm
Why is the SLS being push as a launch vehicle?
Title: Re: Proposed Europa Missions
Post by: Kryten on 09/03/2014 11:57 pm
Why is the SLS being push as a launch vehicle?
Because it needs payloads. There's not much else to it.
Title: Re: Proposed Europa Missions
Post by: veblen on 09/04/2014 12:10 am
Why is the SLS being push as a launch vehicle?
Be cause it needs payloads. There's not much else to it.

To make up for the cratering of Planetary science over several years, resulting in a paucity of science missions in particular to the outer solar system, by JWST budget balloon.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 09/04/2014 01:22 am
Why is the SLS being push as a launch vehicle?
Be cause it needs payloads. There's not much else to it.

To make up for the cratering of Planetary science over several years, resulting in a paucity of science missions in particular to the outer solar system, by JWST budget balloon.

That's not really it. Planetary has ultimately done better than people expected a few years ago (you can thank Congress for that). There are currently three outer planets missions underway: Cassini, New Horizons, and Juno. And Europa is under study. The outer planets community likes to cry into its milk a lot, but the reality was that their missions are inherently expensive and Cassini ballooned in costs, and so it was not realistic for them to expect to get everything they wanted.
Title: Re: Proposed Europa Missions
Post by: vjkane on 09/04/2014 01:42 am
But they can prepare their input for the *next* Decadal Survey. Starting now is smart.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 09/04/2014 02:42 am
But they can prepare their input for the *next* Decadal Survey. Starting now is smart.

I don't think that's what they're doing. It wouldn't make sense to start preparing their input for a decadal survey that is not going to happen for another 7 years. Think about the science changes that will happen in that time.

What will happen in the interim is the mid-term assessment of the planetary program. That will probably kick off sometime later next year. There are some people who naively think that the mid-term can be used to change the New Frontiers list. That won't happen. There is a long and healthy list of New Frontiers candidates and it won't be reevaluated just because some people don't like the options.
Title: Re: Proposed Europa Missions
Post by: redliox on 09/04/2014 03:19 am
These are not strictly Europa presentations, but they're close. They were made at the July meeting of the Outer Planets Assessment Group (OPAG).

They can also be found at the OPAG site.

Excellent find Blackstar.  A lot of the OPAG's site material is dated, but quite relevant.

I heartily support a Europa mission, but they should refocus on Uranus/Neptune (most likely Uranus) next presuming their priority is on new science.  Lord knows outside of Hubble observations they've been left out colder than Pluto.  One would think the Uranus Orbiter would be the cheapest option between it, MSR, and Europa...but I'm guessing it's study hasn't been as involved as either Mars or Europa, that a good assumption Blackstar?
Title: Re: Proposed Europa Missions
Post by: Blackstar on 09/04/2014 04:08 am
1-Excellent find Blackstar.  A lot of the OPAG's site material is dated, but quite relevant.

2-I heartily support a Europa mission, but they should refocus on Uranus/Neptune (most likely Uranus) next presuming their priority is on new science.  Lord knows outside of Hubble observations they've been left out colder than Pluto.  One would think the Uranus Orbiter would be the cheapest option between it, MSR, and Europa...but I'm guessing it's study hasn't been as involved as either Mars or Europa, that a good assumption Blackstar?

1-Just look up all the AGs: LEAG, VEXAG, OPAG, MEPAG, SBAG. Go find their presentations. Usually they have a separate presentation link, but sometimes you can also look via their agenda. They hold two meetings a year, and the most recent stuff was July, so it should be quite current. I think the next meeting is LEAG in October. I'm hoping to go myself (not that far from me). VEXAG should have an upcoming meeting too.

Keep in mind that the slides are just that, slides. You really need to hear the talks, but they don't record these meetings (nor should they). You can listen in live if you want.

2-Well, I sorta cringe when I see people post on boards saying what "should" happen. Really, these decisions are made through a process, i.e. meetings and rules and lots and lots of deliberation. We can all have our own opinions, but it is really best if the community makes those decisions based upon their understanding of the science.

Now I actually agree that an ice giant mission is a logical next high priority. But it's going to take awhile for that to really happen. The decision on what to do next--for big missions--is not going to happen until after the next decadal survey, which will probably kick off around 2019 or so. (I was one of the people who ran the last one and it was one of the most fun and inspiring studies I've ever run. Really smart people working hard to come up with a good plan.)

Now an ice giants mission came in third on the last list (technically, the Mars rover and Europa tied for second place, so the ice giants mission really came in second). Such a mission will be a good contender next time. Certainly the science return on the dollar will be high because we've never studied either planet in detail, so everything will be new and revelatory.

But, the next step for Mars after a caching rover is bringing the cache back. So the Mars community is going to push hard for a return vehicle and a Mars Ascent Vehicle to be in first place. That will be an expensive mission. And if a Europa mission gets underway, the next logical step at Europa is a lander. And by then Cassini will be dead, so the people who study Titan will clamor for a Titan mission (and maybe they'll wise up and not ask for such a flipping big mission next time). So an ice giants mission might still get stuck in the number 3 priority list next time.

There was an ice giants workshop held in late July in Laurel, Maryland at APL. Unfortunately, it required paid registration and I didn't have the money to attend. They'll be producing some kind of proceedings, of course. So we'll learn what their science priorities are for such a mission. That workshop was in some ways a direct result of the decadal survey ranking an ice giants mission so high. But you can look at any large planetary science mission and you can trace back its origins 2-3 decades at least. These things take a long time to go from initial idea to flight.

Personally, I want to see a Neptune mission happen, but I expect that will not happen for many decades.
Title: Re: Proposed Europa Missions
Post by: redliox on 09/04/2014 04:44 am
-Well, I sorta cringe when I see people post on boards saying what "should" happen. Really, these decisions are made through a process, i.e. meetings and rules and lots and lots of deliberation. We can all have our own opinions, but it is really best if the community makes those decisions based upon their understanding of the science.

Correct; wasn't trying to be presumptuous.  If anything, the Decadal Study suggestion that if neither MSR or a EO were affordable, that UO was 'plan C'.  Otherwise, just logical option.

Now I actually agree that an ice giant mission is a logical next high priority. But it's going to take awhile for that to really happen. The decision on what to do next--for big missions--is not going to happen until after the next decadal survey, which will probably kick off around 2019 or so. (I was one of the people who ran the last one and it was one of the most fun and inspiring studies I've ever run. Really smart people working hard to come up with a good plan.)

Now an ice giants mission came in third on the last list (technically, the Mars rover and Europa tied for second place, so the ice giants mission really came in second). Such a mission will be a good contender next time. Certainly the science return on the dollar will be high because we've never studied either planet in detail, so everything will be new and revelatory.

But, the next step for Mars after a caching rover is bringing the cache back. So the Mars community is going to push hard for a return vehicle and a Mars Ascent Vehicle to be in first place. That will be an expensive mission. And if a Europa mission gets underway, the next logical step at Europa is a lander. And by then Cassini will be dead, so the people who study Titan will clamor for a Titan mission (and maybe they'll wise up and not ask for such a flipping big mission next time). So an ice giants mission might still get stuck in the number 3 priority list next time.

Everyone wants a piece of the pie...  ;)

Frankly Mars has been hogging the frickn' pie long enough, and if humans are coming well it's time to shift the Martian paradigm to serve man, literally for the crewed missions.  Once (or if) MSR is accomplished, leave the fossil hunting to the humans.

In fairness, I know there will always be high-priority targets like Europa and Titan (in their cases for exobiology), but every planet deserves a turn.  Aside from the Ice Giants, Venus is another prime example.  Whereas Uranus and Neptune are just hard to reach, Venus is literally Hellish to endure.  In their case I'd rank Uranus, Neptune, and Venus in order of the technology to study (good luck landing on Venus long enough for seismology, a much-needed science for Earth's sister).

Personally, I want to see a Neptune mission happen, but I expect that will not happen for many decades.
Outside of aerocapture (and lord knows we've both exchanged remarks on that technology), my bet would be a fly-by/probe mission using available technology. 

This post probably flew well beyond the topic...but still strengthens importance of the Outer Planets with Europa included.
Title: Re: Proposed Europa Missions
Post by: Zed_Noir on 09/04/2014 04:51 am
Why is the SLS being push as a launch vehicle?
Be cause it needs payloads. There's not much else to it.

To make up for the cratering of Planetary science over several years, resulting in a paucity of science missions in particular to the outer solar system, by JWST budget balloon.

That's not really it. Planetary has ultimately done better than people expected a few years ago (you can thank Congress for that). There are currently three outer planets missions underway: Cassini, New Horizons, and Juno. And Europa is under study. The outer planets community likes to cry into its milk a lot, but the reality was that their missions are inherently expensive and Cassini ballooned in costs, and so it was not realistic for them to expect to get everything they wanted.
But using the SLS and certifying it to carry nukes for outer system missions will balloon the budget astronomically. Wouldn't that make the mission less likely to be selected?
Title: Re: Proposed Europa Missions
Post by: redliox on 09/04/2014 05:20 am
But using the SLS and certifying it to carry nukes for outer system missions will balloon the budget astronomically. Wouldn't that make the mission less likely to be selected?

If so, they technically still list the Atlas as their primary choice.  However, if the solar option is used worrying about certifying the SLS for carrying plutonium becomes irrelevant.  It becomes more like a technological chicken-and-the-egg game: if we so solar we get there faster for a shorter study; if we go nuclear we have to so slow for a longer study...

I hate the unnecessary wait times cruises impose, not to mention the need to accommodate a Venus fry-by is counterproductive for an Outer Solar System expedition.  Short and sweet is better; Juno's Earth fly-by should be the most at least a Jupiter-bound probe should ensure - the whole Galileo VEEGA bit was just an improvised scheme thanks to space shuttle nonsense.

They'll figure out something; regarding "nukes" it will just depend on RTG availability and the power needs of the spacecraft.
Title: Re: Proposed Europa Missions
Post by: Zed_Noir on 09/04/2014 05:31 am
But using the SLS and certifying it to carry nukes for outer system missions will balloon the budget astronomically. Wouldn't that make the mission less likely to be selected?

If so, they technically still list the Atlas as their primary choice.  However, if the solar option is used worrying about certifying the SLS for carrying plutonium becomes irrelevant.  It becomes more like a technological chicken-and-the-egg game: if we so solar we get there faster for a shorter study; if we go nuclear we have to so slow for a longer study...

I hate the unnecessary wait times cruises impose, not to mention the need to accommodate a Venus fry-by is counterproductive for an Outer Solar System expedition.  Short and sweet is better; Juno's Earth fly-by should be the most at least a Jupiter-bound probe should ensure - the whole Galileo VEEGA bit was just an improvised scheme thanks to space shuttle nonsense.

They'll figure out something; regarding "nukes" it will just depend on RTG availability and the power needs of the spacecraft.
Hmm. Don't think solar power is variable beyond the orbit of Jupiter.
Title: Re: Proposed Europa Missions
Post by: redliox on 09/04/2014 09:54 am
But using the SLS and certifying it to carry nukes for outer system missions will balloon the budget astronomically. Wouldn't that make the mission less likely to be selected?

If so, they technically still list the Atlas as their primary choice.  However, if the solar option is used worrying about certifying the SLS for carrying plutonium becomes irrelevant.  It becomes more like a technological chicken-and-the-egg game: if we so solar we get there faster for a shorter study; if we go nuclear we have to so slow for a longer study...

I hate the unnecessary wait times cruises impose, not to mention the need to accommodate a Venus fry-by is counterproductive for an Outer Solar System expedition.  Short and sweet is better; Juno's Earth fly-by should be the most at least a Jupiter-bound probe should ensure - the whole Galileo VEEGA bit was just an improvised scheme thanks to space shuttle nonsense.

They'll figure out something; regarding "nukes" it will just depend on RTG availability and the power needs of the spacecraft.
Hmm. Don't think solar power is variable beyond the orbit of Jupiter.

Tell that to the CURRENTLY FLYING Juno mission...
Title: Re: Proposed Europa Missions
Post by: redliox on 09/04/2014 09:55 am
Finally found a link to the Europa workshop:

http://soma.larc.nasa.gov/europa/conf_wkshop.html (http://soma.larc.nasa.gov/europa/conf_wkshop.html)

From one of the PEA slides comes a breakdown of the immediate schedule:
Title: Re: Proposed Europa Missions
Post by: Zed_Noir on 09/04/2014 10:14 am
...
Hmm. Don't think solar power is variable beyond the orbit of Jupiter.

Tell that to the CURRENTLY FLYING Juno mission...

The Juno mission is not flying beyond the orbit of Jupiter.
Title: Re: Proposed Europa Missions
Post by: redliox on 09/04/2014 10:24 am
...
Hmm. Don't think solar power is variable beyond the orbit of Jupiter.

Tell that to the CURRENTLY FLYING Juno mission...

The Juno mission is not flying beyond the orbit of Jupiter.

Correct, but there have been proposals to the Trojans, Saturn (with Titan), and even Uranus using large and advanced solar arrays.  It depends on the mission needs, and especially for Uranus much of the solar power goes toward ion propulsion.  With the 2020 Rover in the works and a Europa mission in consideration, even with the restarted enrichment program the cupboards are going to be thin for some time...and even weak solar power is going to be considered.  It's an option and it tends to be cheaper at the expense of mass.

p.s.
I believe you meant viable beyond the orbit of Jupiter.
Title: Re: Proposed Europa Missions
Post by: Dalhousie on 09/04/2014 11:56 am

Regarding the popularity of Mars vs Europa, I think this is more relevant:

http://www.google.com/trends/explore?hl=en-US#q=/m/0bv05,%20/m/09cws&cmpt=q

Running the cursor over it shows that this is still picking up Europa the continent hits.

A simple Mars + planet Google search yields 53,900,000 hits

A simple Europa + moon Google search yields 23,900,000 hits
Title: Re: Proposed Europa Missions
Post by: Blackstar on 09/04/2014 12:52 pm
But using the SLS and certifying it to carry nukes for outer system missions will balloon the budget astronomically. Wouldn't that make the mission less likely to be selected?

It depends upon what part of NASA pays for the SLS. I've said this before, but it's worth repeating: there's no great enthusiasm within the planetary community for using SLS for Europa. They would all be perfectly happy with Atlas or whatever rocket is available. SLS is an expensive rocket, but if the human side pays for it, it could actually lower the cost of a Europa mission for the science side.
Title: Re: Proposed Europa Missions
Post by: redliox on 09/04/2014 08:09 pm
It depends upon what part of NASA pays for the SLS. I've said this before, but it's worth repeating: there's no great enthusiasm within the planetary community for using SLS for Europa. They would all be perfectly happy with Atlas or whatever rocket is available. SLS is an expensive rocket, but if the human side pays for it, it could actually lower the cost of a Europa mission for the science side.

If it weren't for a fear of a new rocket blowing up it's be an excellent match for the Outer Solar System.  The Voyagers and Cassini both needed the heft of a Titan rocket to do their jobs, and ULA/Boeing/Lockheed have yet to speak of successors to either Delta 4 or Atlas 5...so beyond Falcon 9 Heavy SLS is the most obvious heavy-duty rocket coming to market.

i.e. if push comes to shove and if NASA seriously wants a new probe to show off it's new rocket, in the end the science community will be the fussy baby getting the spoon shoved in it's mouth.
Title: Re: Proposed Europa Missions
Post by: Jim on 09/04/2014 08:18 pm

If it weren't for a fear of a new rocket blowing up it's be an excellent match for the Outer Solar System.  The Voyagers and Cassini both needed the heft of a Titan rocket to do their jobs, and ULA/Boeing/Lockheed have yet to speak of successors to either Delta 4 or Atlas 5......so beyond Falcon 9 Heavy SLS is the most obvious heavy-duty rocket coming to market.


Not so.   

NASA is not lacking for performance from launch vehicles for unmanned mission.  There has been no need for successors to either Delta 4 or Atlas 5, there hasn't been a science payload that needs a Delta IV Heavy (which has more capability than any Titan configuration and Atlas V 551 has more than any Titan III configuration).   And Falcon Heavy can't do some of the high energy missions.

i.e. if push comes to shove and if NASA seriously wants a new probe to show off it's new rocket, in the end the science community will be the fussy baby getting the spoon shoved in it's mouth.


Not so again.  NASA isn't going to build a probe just for SLS.  Europa can fly without it.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 09/04/2014 08:46 pm
See one of my earlier posts. One of the ironic things is that for this mission, Atlas V can actually carry a little more payload than the SLS. That's because the SLS spends all its energy shooting the thing there directly, whereas the Atlas V gets a gravity assist. So if they need to add a little mass, the Atlas V offers more margin.
Title: Re: Proposed Europa Missions
Post by: Star One on 09/04/2014 09:23 pm

See one of my earlier posts. One of the ironic things is that for this mission, Atlas V can actually carry a little more payload than the SLS. That's because the SLS spends all its energy shooting the thing there directly, whereas the Atlas V gets a gravity assist. So if they need to add a little mass, the Atlas V offers more margin.

But don't you to loose some payload because of the additional shielding needed for a Venus flyby?
Title: Re: Proposed Europa Missions
Post by: veblen on 09/04/2014 09:25 pm
Yeah AtlasV is great hopefully it will remain available for science missions, probably will but who knows? FH can't do a Europa mission? Disappointing non-option. Interesting to read, from wiki, that Magellan and Galileo s/c were basically spin-offs of the Voyager missions, plus other parts of other s/c programs. Why weren't they launched on Delta or some other medium lift (?) rocket? Why did they get launched on STS?
Title: Re: Proposed Europa Missions
Post by: Jim on 09/05/2014 12:51 am
Why weren't they launched on Delta or some other medium lift (?) rocket? Why did they get launched on STS?

Because the shuttle was to be the only launch vehicle.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 09/05/2014 01:29 am
Yeah AtlasV is great hopefully it will remain available for science missions, probably will but who knows? FH can't do a Europa mission? Disappointing non-option. Interesting to read, from wiki, that Magellan and Galileo s/c were basically spin-offs of the Voyager missions, plus other parts of other s/c programs. Why weren't they launched on Delta or some other medium lift (?) rocket? Why did they get launched on STS?

There are some good books you can read that discuss this.
Title: Re: Proposed Europa Missions
Post by: Zed_Noir on 09/05/2014 03:00 am
...

Correct, but there have been proposals to the Trojans, Saturn (with Titan), and even Uranus using large and advanced solar arrays.  It depends on the mission needs, and especially for Uranus much of the solar power goes toward ion propulsion.  With the 2020 Rover in the works and a Europa mission in consideration, even with the restarted enrichment program the cupboards are going to be thin for some time...and even weak solar power is going to be considered.  It's an option and it tends to be cheaper at the expense of mass.

p.s.
I believe you meant viable beyond the orbit of Jupiter.
It is highly unlikely such solar powered missions can done for New Frontier level budgets, IMO. However a flagship program might be possible, if NASA approve one in the mid term.

p.s.
I meant viable beyond the orbit of Jupiter. Auto-correct strikes again.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 09/05/2014 03:05 am
There was actually some brief discussion about that during the OPAG presentation to PSS/CAPS this morning. I don't think it is reflected in the slides, but they did say that they are interested in exploring if solar is viable beyond Jupiter and also what can be done on a New Frontiers budget at the outer planets. They said that they were inspired by the TiME mission, which implied that Saturn distance science could be done even on a Discovery budget. (I think the key term is "implied.")

That was just the OPAG chair expressing an opinion, but the opinion is held by somebody who knows their stuff.
Title: Re: Proposed Europa Missions
Post by: vjkane on 09/05/2014 05:02 am
Regarding solar power missions to the outer planets, I've chatted with a JPL architect on this subject.  His take is that solar power at Jupiter's distance from the sun is a proven technology.  There are some challenges.  Extensive testing of the candidate lots of solar panels must be done to find those that can operate at the low temperatures.  Significant amounts of power has to be diverted to run heaters of for the spacecraft.  (Almost half of Juno's power at Jupiter goes to the heaters.)  And the panels are heavy and bulky.  (And while we didn't discuss this, the bulk is the likely reason for the fine stability problems if the Europa Clipper goes solar.  During the encounters, the spacecraft has to torque rapidly to point its instruments, and the panels likely express Newton's first law by vibrating.  I just saw a Cirque de Soleil show, and the high wire artists' poles were vibrating rapidly at their ends in response to each movement.)

Given this, solar power missions can be done for Jupiter and the Trojan asteroids.  Flying even one MMRTG to provide heat would dramatically lower the size of the panels, but would also incur all the costs of using radioactive material on the mission.

His take was that for Saturn, solar cells that would operate at Jupiter would probably also operate there.  But the bulk and weight problem would be four times greater than at Jupiter to make up for the lower sunlight.

At Uranus and beyond, current solar panel technology is simply impractical.  There are groups working on really advanced cells that may solve this problem, but my impression is that they aren't very far along.
Title: Re: Proposed Europa Missions
Post by: robertross on 09/05/2014 01:17 pm
Regarding solar power missions to the outer planets, I've chatted with a JPL architect on this subject.  His take is that solar power at Jupiter's distance from the sun is a proven technology.  There are some challenges.  Extensive testing of the candidate lots of solar panels must be done to find those that can operate at the low temperatures.  Significant amounts of power has to be diverted to run heaters of for the spacecraft.  (Almost half of Juno's power at Jupiter goes to the heaters.)  And the panels are heavy and bulky.  (And while we didn't discuss this, the bulk is the likely reason for the fine stability problems if the Europa Clipper goes solar.  During the encounters, the spacecraft has to torque rapidly to point its instruments, and the panels likely express Newton's first law by vibrating.  I just saw a Cirque de Soleil show, and the high wire artists' poles were vibrating rapidly at their ends in response to each movement.)

Given this, solar power missions can be done for Jupiter and the Trojan asteroids.  Flying even one MMRTG to provide heat would dramatically lower the size of the panels, but would also incur all the costs of using radioactive material on the mission.

His take was that for Saturn, solar cells that would operate at Jupiter would probably also operate there.  But the bulk and weight problem would be four times greater than at Jupiter to make up for the lower sunlight.

At Uranus and beyond, current solar panel technology is simply impractical.  There are groups working on really advanced cells that may solve this problem, but my impression is that they aren't very far along.


Thanks for that detailed explanation.

I know it has commented that running solar + RTG makes little sense, and going with strictly one or the other just makes sense, but I wonder if there truly is something to be gained by having RTGs employed strictly for thermal issues, leaving Solar for the instruments/spacecraft ops.

Of course in my little world, I would also have a cross-connect feature in case one had an issue (to add redundancy), but I know that introduces a whole complex set of issues, not least of which is additional mass & failure points.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 09/05/2014 05:16 pm
I know it has commented that running solar + RTG makes little sense, and going with strictly one or the other just makes sense, but I wonder if there truly is something to be gained by having RTGs employed strictly for thermal issues, leaving Solar for the instruments/spacecraft ops.

If all they need is heat they would not use an RTG. They would use RHUs, or radioisotope heating units. Less Pu-238 required.
Title: Re: Proposed Europa Missions
Post by: robertross on 09/06/2014 12:02 am
I know it has commented that running solar + RTG makes little sense, and going with strictly one or the other just makes sense, but I wonder if there truly is something to be gained by having RTGs employed strictly for thermal issues, leaving Solar for the instruments/spacecraft ops.

If all they need is heat they would not use an RTG. They would use RHUs, or radioisotope heating units. Less Pu-238 required.

You learn something new every day, thanks.
I would say this could be a consideration?

http://en.wikipedia.org/wiki/Radioisotope_heater_unit

"Radioisotope heater units (RHU) are small devices that provide heat through radioactive decay. They are similar to tiny radioisotope thermoelectric generators (RTG) and normally provide about one watt of heat each, derived from the decay of a few grams of plutonium-238—although other radioactive isotopes could be used."

So another isotope can be used (and that makes sense). It notes less Pu-238 is required, so that may make it a desirable approach due to the shortage. I wonder if it has been considered?
Title: Re: Proposed Europa Missions
Post by: Blackstar on 09/06/2014 01:30 am
"Radioisotope heater units (RHU) are small devices that provide heat through radioactive decay. They are similar to tiny radioisotope thermoelectric generators (RTG) and normally provide about one watt of heat each, derived from the decay of a few grams of plutonium-238—although other radioactive isotopes could be used."

So another isotope can be used (and that makes sense). It notes less Pu-238 is required, so that may make it a desirable approach due to the shortage. I wonder if it has been considered?

Yeah, there are other options. They're just not good. Some are gamma emitters, which is yucky. Some have short half-lives, which is icky. And some dissolve in water, which is not good if you need to launch them from a planet that is 70% covered with water.

There's another thing that I didn't really appreciate until I hung around Ralph McNutt for a long time (he will talk your ear off about this stuff): we have a LOT of experience with Pu-238. Decades. That means that just about every possible question has been answered. Somebody can go look it up in their big 3-ringed binder at the lab. They know all the procedures and all of the behaviors of the material. That's not true for any of the other isotopes. So if somebody asks something like "How will material X react when it is heated and shocked by a rocket explosion at 30,000 feet?" they won't have an answer and they'll have to go model it. That's expensive and time consuming. Better the devil you know...
Title: Re: Proposed Europa Missions
Post by: robertross on 09/06/2014 02:00 am
"Radioisotope heater units (RHU) are small devices that provide heat through radioactive decay. They are similar to tiny radioisotope thermoelectric generators (RTG) and normally provide about one watt of heat each, derived from the decay of a few grams of plutonium-238—although other radioactive isotopes could be used."

So another isotope can be used (and that makes sense). It notes less Pu-238 is required, so that may make it a desirable approach due to the shortage. I wonder if it has been considered?

Yeah, there are other options. They're just not good. Some are gamma emitters, which is yucky. Some have short half-lives, which is icky. And some dissolve in water, which is not good if you need to launch them from a planet that is 70% covered with water.

There's another thing that I didn't really appreciate until I hung around Ralph McNutt for a long time (he will talk your ear off about this stuff): we have a LOT of experience with Pu-238. Decades. That means that just about every possible question has been answered. Somebody can go look it up in their big 3-ringed binder at the lab. They know all the procedures and all of the behaviors of the material. That's not true for any of the other isotopes. So if somebody asks something like "How will material X react when it is heated and shocked by a rocket explosion at 30,000 feet?" they won't have an answer and they'll have to go model it. That's expensive and time consuming. Better the devil you know...

Yes, the devil you know, but not as readily available as one would hope (not that we haven't seen this coming for years). I do agree Pu-238 is the right material for the job. At least they're working on harnessing more.

Well, I still think a lot of 'alignments' need to happen to pull off this Europa mission.
It's a super cool destination however.
Title: Re: Proposed Europa Missions
Post by: sdsds on 09/06/2014 02:18 am
Americium 241 (Am-241) is apparently a fairly virtuous RHU option.
Quote
Am-241 is available at around 1 kg/yr commercially, [...] produces 59 kev gammas which are stopped readily by tungsten so the radiation field is very low, [and] has a half-life that is approximately five times greater than that of Pu-238.
Preliminary Analysis: Am-241 RHU/TEG Electric Power Source for Nanosatellites. Glen A. Robertson et al.
http://hdl.handle.net/2060/20140008746



Title: Re: Proposed Europa Missions
Post by: baldusi on 09/06/2014 03:59 am
AM-241 need heavier insulation, and itself weight like four times more for the same heat output. And the extra life would be unnecessary given the solar panels natural degradation in space?
Title: Proposed Europa Missions
Post by: Star One on 09/08/2014 05:21 pm
Plate Tectonics May Increase Chances for Life on Europa.

Quote
Jupiter’s moon Europa is a fascinating little world, but particularly so for one reason: water. It’s deep alien ocean underneath the surface ice is reminiscent of our own planet, and since our oceans and seas are teeming with life, even beneath the ice at the poles, could Europa’s ocean also harbor life of some kind? Now, another discovery shows that Europa may be similar to Earth in yet another way, and one that could bolster the chances of life even more: plate tectonics. The new results were just published in Nature Geoscience on Sep. 7, 2014.

Why is this significant? It means that the icy surface may be connected to the ocean below; plate tectonics can provide a way for nutrients to be carried from the surface down into the waters below, just as they do on Earth. Even microbes themselves might be able to make that journey.

Learning more about Europa’s tectonics and the ocean below will require follow-up missions such as the proposed Europa Clipper, which would make repeated flybys of the moon while studying its surface and interior. Other missions have also been proposed, although it is likely that costs may be a limiting factor. There is, however, a big push happening now for a return mission to Europa that could help answer some of the long-standing questions—primarily, is or was there ever life there?



http://www.americaspace.com/?p=67147
Title: Re: Proposed Europa Missions
Post by: jongoff on 09/08/2014 11:10 pm
...
Hmm. Don't think solar power is variable beyond the orbit of Jupiter.

Tell that to the CURRENTLY FLYING Juno mission...

The Juno mission is not flying beyond the orbit of Jupiter.

Correct, but there have been proposals to the Trojans, Saturn (with Titan), and even Uranus using large and advanced solar arrays.  It depends on the mission needs, and especially for Uranus much of the solar power goes toward ion propulsion.  With the 2020 Rover in the works and a Europa mission in consideration, even with the restarted enrichment program the cupboards are going to be thin for some time...and even weak solar power is going to be considered.  It's an option and it tends to be cheaper at the expense of mass.

p.s.
I believe you meant viable beyond the orbit of Jupiter.

Under our MIDAS SBIR at Altius we're looking at a system for enabling a 6U cubesat mission to Titan using solar power (with ~2U worth of useable payload space). We're about 1/3 of the way through the Phase 1 study, and while things don't close yet, we're making progress. Won't be a lot of power available, but our aerocapture system requires huge batteries, so we may be able to make it close by doing some things in pulsed-mode (ie where you trickle charge the batteries over the course of a few days and then do something power intensive for a few hours using battery power to augment the solar power).

Obviously we'll be limited in how far we can analyze this in a Phase 1/Phase 2 SBIR, but we're hoping to retire some of the key risks. Figured it might be relevant.

~Jon
Title: Re: Proposed Europa Missions
Post by: truth is life on 09/09/2014 08:43 pm
Yeah, there are other options. They're just not good. Some are gamma emitters, which is yucky. Some have short half-lives, which is icky. And some dissolve in water, which is not good if you need to launch them from a planet that is 70% covered with water.

There's another thing that I didn't really appreciate until I hung around Ralph McNutt for a long time (he will talk your ear off about this stuff): we have a LOT of experience with Pu-238. Decades. That means that just about every possible question has been answered. Somebody can go look it up in their big 3-ringed binder at the lab. They know all the procedures and all of the behaviors of the material. That's not true for any of the other isotopes. So if somebody asks something like "How will material X react when it is heated and shocked by a rocket explosion at 30,000 feet?" they won't have an answer and they'll have to go model it. That's expensive and time consuming. Better the devil you know...
I thought we had a pretty good handle on americium? I mean, they use the stuff in smoke detectors, so they've got to have a huge amount of information about how it behaves under different circumstances (not least HOT circumstances, for obvious reasons).
Title: Re: Proposed Europa Missions
Post by: a_langwich on 09/09/2014 10:06 pm
Americium 241 (Am-241) is apparently a fairly virtuous RHU option.
Quote
Am-241 is available at around 1 kg/yr commercially, [...] produces 59 kev gammas which are stopped readily by tungsten so the radiation field is very low, [and] has a half-life that is approximately five times greater than that of Pu-238.
Preliminary Analysis: Am-241 RHU/TEG Electric Power Source for Nanosatellites. Glen A. Robertson et al.
http://hdl.handle.net/2060/20140008746



"Stopped readily by tungsten" -- ie, a very dense, heavy material
vs
"stopped by a thin sheet of paper"  for alpha particles

That is, the current power supply does not need to waste much mass on radiation shielding.  Very important because W/kg is the key metric.  Given the longer half-life, just the americium already will weigh much more than plutonium, and now you are looking at heavy shielding, which means an even heavier structure.  The larger size (required by the lower decay rate) will mean less heat density.

Still, given the huge costs of producing plutonium 238, there is probably a lot of leeway for much less ideal (but also possibly much less expensive) alternatives.  Solar arrays are increasingly viable, but for landers/rovers/floaters/subs (beyond Mars) an RTG option still seems needed.

Aren't the Europeans pursuing Americium?  That's a good thing, because the options right now are clearly too limited, and NASA SMD is stretched out just trying to recreate the Pu238 production.

Who knows?  It may be the much heavier structure (sturdier in overpressure), plus the disappearance of the name "plutonium", and the whole concept of "nuclear rating" a rocket might quietly be ditched.  Similar to the calmness with which people face MRIs vs the dreaded Nuclear Magnetic Resonance imaging (as the chemistry community still calls it).  Or there may be other silver linings to choosing a second-best RTG material.  Maybe it will force the development of much higher efficiency electrical conversion systems.  I hear there's a Stirling engine option out there somewhere... ::)

For me, that's the fantastic thing about having the Europeans, Japanese, Chinese, Indians, and Russians all capable of tackling scientific missions:  there's a wonderful diversity of approaches, which together accomplish much more than a single mindset.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 09/18/2014 03:28 pm
I thought I had posted these here. They are from the recent OPAG meeting.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 09/18/2014 03:29 pm
Ah, yes, I did previously post those. But here they are again so you can enjoy them all the more...
Title: Re: Proposed Europa Missions
Post by: baldusi on 10/02/2014 07:44 pm
From Stephen Clark Tweeter at IAC2014

Quote
Stephen Clark @StephenClark1 (https://twitter.com/StephenClark1/status/517754605619253248)
APL's Thomas Magner: We've selected solar power for the Europa Clipper mission, baselined for launch on SLS in June 2022. #IAC2014
Might the LV have determined the power source? Could it have been that with extra throw weight they could add solar panels without much penalty?
Title: Re: Proposed Europa Missions
Post by: Blackstar on 10/02/2014 08:38 pm
From Stephen Clark Tweeter at IAC2014

Quote
Stephen Clark @StephenClark1 (https://twitter.com/StephenClark1/status/517754605619253248)
APL's Thomas Magner: We've selected solar power for the Europa Clipper mission, baselined for launch on SLS in June 2022. #IAC2014
Might the LV have determined the power source? Could it have been that with extra throw weight they could add solar panels without much penalty?

I am skeptical of this comment. There's no approved Europa Clipper program right now, let alone one scheduled for a 2022 launch (where's the money going to come from?).

And as I mentioned earlier, SLS has lower throw weight than Atlas V for this mission.
Title: Re: Proposed Europa Missions
Post by: Jim on 10/02/2014 09:01 pm
They just held a mission concept review.
Title: Re: Proposed Europa Missions
Post by: redliox on 10/02/2014 09:02 pm
From Stephen Clark Tweeter at IAC2014

Quote
Stephen Clark @StephenClark1 (https://twitter.com/StephenClark1/status/517754605619253248)
APL's Thomas Magner: We've selected solar power for the Europa Clipper mission, baselined for launch on SLS in June 2022. #IAC2014
Might the LV have determined the power source? Could it have been that with extra throw weight they could add solar panels without much penalty?

I am skeptical of this comment. There's no approved Europa Clipper program right now, let alone one scheduled for a 2022 launch (where's the money going to come from?).

And as I mentioned earlier, SLS has lower throw weight than Atlas V for this mission.

I'm likewise skeptical about this comment and the source, who appears to be another random space enthusiast.  I'm emailing one of the outer planet managers to verify this; based on what I heard they are still reviewing missions concepts, although this month they might unveil what instruments will be used.
Title: Re: Proposed Europa Missions
Post by: veblen on 10/02/2014 09:13 pm
Stephen Clark of SFN? I don't know if I would describe him as "another random space enthusiast", that would be me!
Title: Re: Proposed Europa Missions
Post by: Jim on 10/02/2014 11:42 pm
I'm likewise skeptical about this comment and the source, who appears to be another random space enthusiast.  I'm emailing one of the outer planet managers to verify this; based on what I heard they are still reviewing missions concepts, although this month they might unveil what instruments will be used.

Like I said they held a mission concept review.  SLS is prime and EELV is backup.  The basic instruments included in the review.
Title: Re: Proposed Europa Missions
Post by: sdsds on 10/03/2014 01:32 am
SLS has lower throw weight than Atlas V for this mission.

Disingenuous. To the same sub-optimal trajectory an Atlas V mission would use, SLS has a better throw weight. Atlas V cannot launch the mission on the better trajectory SLS would use.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 10/03/2014 02:17 am
SLS has lower throw weight than Atlas V for this mission.

Disingenuous. To the same sub-optimal trajectory an Atlas V mission would use, SLS has a better throw weight. Atlas V cannot launch the mission on the better trajectory SLS would use.

I'm disingenuous?
Title: Re: Proposed Europa Missions
Post by: sdsds on 10/03/2014 03:45 am
I'm disingenuous?

We're in agreement?
Title: Re: Proposed Europa Missions
Post by: ncb1397 on 10/03/2014 04:22 pm

I am skeptical of this comment. There's no approved Europa Clipper program right now, let alone one scheduled for a 2022 launch (where's the money going to come from?).

The planetary science mission slots in 2022+ are basically to be decided. The internet meme that NASA no longer has money to do anything is rather annoying. The budget is bigger than ISRO, JAXA, Roscosmos, ESA and CNSA combined. The last manifested and defined planetary science mission is Mars 2020. Everything past that in the NASA FY2014 AMPM are placeholders for Mars, Discovery and New Frontier class missions. The house budget is 100 million, 80 million was the budget in 2014 and 75 million was the budget for Europa in 2013. It has congressional support if not presidential support and congressmen don't have term limits.
Title: Re: Proposed Europa Missions
Post by: GClark on 10/03/2014 05:32 pm
It's good that Congress is giving NASA money for this.  Polite applause.

Someone better convince OMB to authorize a new start for it, otherwise it's going nowhere fast.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 10/03/2014 08:36 pm

I am skeptical of this comment. There's no approved Europa Clipper program right now, let alone one scheduled for a 2022 launch (where's the money going to come from?).

The planetary science mission slots in 2022+ are basically to be decided. The internet meme that NASA no longer has money to do anything is rather annoying. The budget is bigger than ISRO, JAXA, Roscosmos, ESA and CNSA combined. The last manifested and defined planetary science mission is Mars 2020. Everything past that in the NASA FY2014 AMPM are placeholders for Mars, Discovery and New Frontier class missions. The house budget is 100 million, 80 million was the budget in 2014 and 75 million was the budget for Europa in 2013. It has congressional support if not presidential support and congressmen don't have term limits.

That's not how the budgeting system works at all. Congress cannot make a space mission happen without the executive branch's cooperation (beginning with a formal new program start). Congress, for example, cannot write contracts to build hardware. So they can stuff all the money they want into a bill, but that doesn't write the contracts to build stuff.

Write a letter to NASA and ask them if they are planning on launching a Europa mission in 2022. They're not. The funding profiles don't support it and the administration has not approved any such mission.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 10/03/2014 09:07 pm
I'm disingenuous?

We're in agreement?

Was it really necessary to just pop in here and be all grumpy? Have some coffee, you'll feel better.

NASA has two basic Europa Clipper missions under study. The SLS one doesn't use gravity assist. It has slightly lower throw weight to Jupiter.


Title: Re: Proposed Europa Missions
Post by: ncb1397 on 10/04/2014 08:18 am

I am skeptical of this comment. There's no approved Europa Clipper program right now, let alone one scheduled for a 2022 launch (where's the money going to come from?).

The planetary science mission slots in 2022+ are basically to be decided. The internet meme that NASA no longer has money to do anything is rather annoying. The budget is bigger than ISRO, JAXA, Roscosmos, ESA and CNSA combined. The last manifested and defined planetary science mission is Mars 2020. Everything past that in the NASA FY2014 AMPM are placeholders for Mars, Discovery and New Frontier class missions. The house budget is 100 million, 80 million was the budget in 2014 and 75 million was the budget for Europa in 2013. It has congressional support if not presidential support and congressmen don't have term limits.

That's not how the budgeting system works at all. Congress cannot make a space mission happen without the executive branch's cooperation (beginning with a formal new program start). Congress, for example, cannot write contracts to build hardware. So they can stuff all the money they want into a bill, but that doesn't write the contracts to build stuff.

Write a letter to NASA and ask them if they are planning on launching a Europa mission in 2022. They're not. The funding profiles don't support it and the administration has not approved any such mission.

Quote
Impoundment is an act by a President of the United States of not spending money that has been appropriated by the U.S. Congress. Thomas Jefferson was the first president to exercise the power of impoundment in 1801. The power was available to all presidents up to and including Richard Nixon, and was regarded as a power inherent to the office. The Congressional Budget and Impoundment Control Act of 1974 was passed in response to perceived abuse of the power under President Nixon. Title X of the act, and its interpretation under Train v. City of New York, essentially removed the power. The president's ability to reject congressionally approved spending thus became severely inhibited.[1]

The Impoundment Control Act of 1974 provides that the president may propose rescission of specific funds, but that rescission must be approved by both the House of Representatives and Senate within 45 days. In effect, the requirement removed the impoundment power, since Congress is not required to vote on the rescission and, in fact, has ignored the vast majority of presidential requests
http://en.wikipedia.org/wiki/Impoundment_of_appropriated_funds


Title: Re: Proposed Europa Missions
Post by: ncb1397 on 10/04/2014 09:07 pm
Er, yeah, still doesn't work like that when it comes to creating new programs (as opposed to stuffing money into an ongoing project).

Look, I know the guy who is in charge of the planetary program. He has said in public on several occasions that he cannot pursue a new program without a formal new program start from OMB. Just cannot do it. For starters, the money provided by Congress is only there for one year (technically, they usually have two years to spend it), without any promise of further money. Thus, NASA cannot sign contracts for programs that would require many years to pay for them. Go ask him.

All NASA programs are part of the discretionary budget, which is funded on an annual basis. Are you suggesting that NASA can't sign contracts for long term projects because the funds for a year out are not there? How did NASA sign a contract with Boeing and SpaceX for crew access to ISS when no funds have been appropriated? I presume contracts have the ability to be cancelled. If funds are zeroed out in the future, as so often occurs for NASA programs, the contract is cancelled.

In fact, there is actually still money left over in the Europa account from when Congress first appropriated it. That's because it was a huge chunk of money for "studies" and there's only so much that you can spend on studies without actually bending metal. It's a rather sloppy and inefficient way to run a program (in part because that money is not free, but is being taken from other things that NASA has on its plate, like another New Frontiers mission). What it does do, however, is send a message to the OMB that if OMB doesn't get in front of the horse on a Europa mission, it will continue to be behind the horse on a Europa mission, and nobody really wants to be behind the horse.

The joint Omnibus spending bill in 2013 had Planetary Science funded at 127 million over the administration's request. Of that 127 million, 80 million was set aside for Europa "formulation" work. I don't see how this could be seen as taking away funds from other programs when not even counting this money, it was above the administration's request. Stretching the defination of "formulation" to include detailed design, build and test activities is more consistent with the law than effectively impounding the funds which can't be reconciled at all.

Quote
When NASA has a real program for building a Europa Clipper you will know it because they will talk about it as a development program. They don't have it now, and Congress cannot make it happen on its own.

Perhaps taking the example that caused Congress and the Supreme Court to strip the President of the impounding power could be illustrative.

Quote
And overridden it was. On October 18, 1972, first the Senate, then the House overrode Nixon's veto and the bill became law. After the veto override, Nixon refused to spend the money appropriated by Congress, using his presidential powers to impound half of the money. For a time, members of the House considered impeachment proceedings against Nixon and his actions were eventually challenged in the Supreme Court. In Train v. City of New York (1975), the court ruled "that the president had no authority to withhold funds provided by Congress in the Clean Water Act of 1972," stating essentially, "The president cannot frustrate the will of Congress by killing a program through impoundment." In addition, the Impoundment Control Act of 1974 provided a means of controlling the President's ability to impound funds for programs that they don't support.
http://www.huffingtonpost.com/robin-madel/nixons-clean-water-act-im_b_1372740.html

You suggest that Congress doesn't have the power to create a program. The example with the Clean Water Act strongly suggests that the President doesn't have the power not to implement programs funded by Congress.
Title: Re: Proposed Europa Missions
Post by: Jim on 10/05/2014 05:09 pm

 How did NASA sign a contract with Boeing and SpaceX for crew access to ISS when no funds have been appropriated?


Because of the contract structure, they have not obligated the gov't for any real money.
Title: Re: Proposed Europa Missions
Post by: redliox on 10/05/2014 08:30 pm
From Stephen Clark Tweeter at IAC2014

Quote
Stephen Clark @StephenClark1 (https://twitter.com/StephenClark1/status/517754605619253248)
APL's Thomas Magner: We've selected solar power for the Europa Clipper mission, baselined for launch on SLS in June 2022. #IAC2014

Let's presume what Thomas Magner divulged from the concept review is true or at least heavily favored.  Would going solar benefit a Europa spacecraft enough to out-weigh nuclear?  Is SLS wiser to use than Atlas V?  Both are options I could get behind personally, but I know there's always a downside to everything.  Let's debate...

Title: Re: Proposed Europa Missions
Post by: baldusi on 10/05/2014 11:13 pm
Since I didn't new this was so preliminary, I assumed that solar would have been chose, in part to avoid nuclear rating the SLS. Also, since they don't have to go through Venus orbit, they don't have to rate the panels and heat rejection system for anything hotter than Earth. And since they are leaving fast, they could tolerate some degradation at Earth orbit.
The only issue is that Atlas V as backup means a lot of adaptation on those systems.
Title: Re: Proposed Europa Missions
Post by: vjkane on 10/07/2014 05:42 am

The SLS thing is not at all assured. They have studied it because they were _told_ to study it. But I know a lot of people in the planetary program who just roll their eyes whenever it comes up. That's not because it is a bad engineering choice, but because they think the politics is very sketchy. Nobody wants to go down that road and get burned.


We've been down the road where planetary missions were tied to a new launch system.  NASA didn't pursue a Voyager Uranus probe mission because they were phasing out the Titan launch system and the shuttle wouldn't be ready in time.  We all know the story of how Galileo was repeatedly delayed because of its dependence on the shuttle.
Title: Re: Proposed Europa Missions
Post by: baldusi on 10/07/2014 02:34 pm
Blackstar, when would you expect an Europa Clipper Authorization to Start? I'm guessing "not with this OMB". But that's gonna change soon enough.
Title: Re: Proposed Europa Missions
Post by: arachnitect on 10/08/2014 05:05 pm
Jeff Foust reports from IAC in Toronto:

http://www.spacenews.com/article/civil-space/42121europa-clipper-opts-for-solar-power-over-nuclear

Quote
In an Oct. 3 presentation at the 65th International Astronautical Congress here, Europa Clipper deputy project manager Thomas Magner of the Johns Hopkins University Applied Physics Laboratory in Laurel, Maryland, said that using large solar panels for the mission was both technically viable and less expensive than a radioisotope thermoelectric generator (RTG).

EC is an APL project?
Title: Re: Proposed Europa Missions
Post by: redliox on 10/08/2014 10:03 pm
http://www.spacenews.com/article/civil-space/42121europa-clipper-opts-for-solar-power-over-nuclear

Quote
In an Oct. 3 presentation at the 65th International Astronautical Congress here, Europa Clipper deputy project manager Thomas Magner of the Johns Hopkins University Applied Physics Laboratory in Laurel, Maryland, said that using large solar panels for the mission was both technically viable and less expensive than a radioisotope thermoelectric generator (RTG).

Saw that article too, and it's great to see a news update that confirms what Stephen Clark heard about earlier (my apologies to him if I came off a bit harsh).

So whatever degradation the panels may endure, apparently they decided it's easier to handle versus acquiring plutonium, the paperwork to utilize it, and the environmental risks to both Europa and Earth.  At least there won't be any no-nuke-protestors like there were for Galileo and Cassini.  I've never been fond of nuclear power, but it is steadfast and necessary in the deeper parts of the solar system; on that note I'd hope whatever plutonium that isn't used for Mars 2020 can be applied to a new outer planet mission (my guess would be to either Saturn's moons or Uranus).

So that leaves two further factors for a new Europa mission: official funding (and between the forthcoming Congressional elections and the next Presidential one this is definitely a wild card not to underestimate) and choice of launch vehicle. 

Going by what Magner stated from APL, the SLS is recognized as an option but, as Blackstar elucidated upon, scientists likely find it more a political ploy than an vehicle at this point.  Still, it wouldn't be the first time politics came into play; recall Galileo and Magellan and their ties to the shuttle.  As complicated as that relationship was, it simultaneously preserved them (they were the only major planetary missions launched in the '80s after all).  The SLS, more so under a new administration, will need to justify its development and utility.  Considering EC was examined alongside ARM, that implies there already are political currents that will nudge spacecraft towards SLS.  Ultimately however, I would call it a 50/50 chance with Atlas V as well (then again, with politics in play, there could be frowns regarding 'relying on Russian technology'). 

It is still too soon to be certain.  With the OPAG having a meeting next February, I believe that is when we'll get firmer answers on the nature of a Europa mission.
Title: Re: Proposed Europa Missions
Post by: redliox on 10/08/2014 10:18 pm

The SLS thing is not at all assured. They have studied it because they were _told_ to study it. But I know a lot of people in the planetary program who just roll their eyes whenever it comes up. That's not because it is a bad engineering choice, but because they think the politics is very sketchy. Nobody wants to go down that road and get burned.


We've been down the road where planetary missions were tied to a new launch system.  NASA didn't pursue a Voyager Uranus probe mission because they were phasing out the Titan launch system and the shuttle wouldn't be ready in time.  We all know the story of how Galileo was repeatedly delayed because of its dependence on the shuttle.

The death of the Titan definitely put limits on probes, with the multiple fly-bys that keep the spacecraft away from their targets nearly as long as issues (technical and political) on the ground.  The shuttle, at least for anything beyond LEO, was a half-assed launcher because of design.  The SLS at least is a vehicle that combines the strengths of both; just shove the Orion out of the way and you have a big rocket with some of the most thoroughly tested parts (since mere humans are so squishy).

I don't recall probes in the '60s and '70s opting for numerous out-of-the-way gravity assists, so I see them for what they are: improvising.  And you only improvise when you don't have the best tools for the job.  It is wise to keep both an EELV and a HLV open, but if the HLV is ready by the launch date don't hesitate to use it.
Title: Re: Proposed Europa Missions
Post by: Jim on 10/08/2014 10:46 pm

The death of the Titan definitely put limits on probes,

Huh?  Delta IV has more capability than Titan IV and cheaper.
Title: Re: Proposed Europa Missions
Post by: ncb1397 on 10/09/2014 03:10 am
I don't recall probes in the '60s and '70s opting for numerous out-of-the-way gravity assists, so I see them for what they are: improvising. 
You cannot simply throw a large launch vehicle at every mission. That's expensive. That is money better spent on instruments.

Has anyone proposed doing something like using an HLV for every mission?

Instruments are usually a small portion of a mission's budget. For instance, from memory, I think MSL was 2.5 billion total cost and the instruments were ~100 million total. Not sure how you would spend the money on an HLV on instruments. Most of the money goes to the logistics of getting the instruments where they need to go with the resources available to them to get the job done. The reason space science is so much more expensive than earth science is the logistics, not the lab equipment. Instruments could probably use a few extra kgs of mass budget, a few more watts in the power budget rather than a few million in the dollar budget.
Title: Re: Proposed Europa Missions
Post by: Star One on 10/09/2014 06:27 am
If the mission was solar powered rather than nuclear would there be any advantage to using a Delta IVH for it rather than the Atlas 551?
Title: Re: Proposed Europa Missions
Post by: Blackstar on 10/09/2014 01:49 pm
I don't recall probes in the '60s and '70s opting for numerous out-of-the-way gravity assists, so I see them for what they are: improvising. 
You cannot simply throw a large launch vehicle at every mission. That's expensive. That is money better spent on instruments.

Has anyone proposed doing something like using an HLV for every mission?

Instruments are usually a small portion of a mission's budget.


Launch vehicle size, and cost, has been a factor in the selection and non-selection of many planetary missions over the years. Look at Voyager-Mars as the classic example. Of course, size of the spacecraft (and cost) usually tracks with size of the rocket, but as a general rule, planetary missions have sought to keep the launch vehicle size as small as possible and mission designers are not automatically given the option of the largest rocket (there's a reason why Curiosity and Juno did not launch on Delta IVs, for instance).

There are lots of examples, but I'll mention just one: In the 1970s NASA considered a Mercury orbiting mission. But the mission would have required a large launch vehicle, and that (among other things) made it more expensive than people were willing to spend on such a mission. It wasn't until somebody was able to successfully propose a Mercury orbiter mission that could fly on a Delta II that the mission became viable and affordable.

The elimination of the Delta II and the increase in launch costs has materially hit the planetary program. It is one of the major factors in the reduction in Discovery missions.
Title: Re: Proposed Europa Missions
Post by: Jim on 10/09/2014 01:51 pm

Has anyone proposed doing something like using an HLV for every mission?


Too expensive.  You can fund a whole Discovery class mission for the cost of just the SLS.
Title: Re: Proposed Europa Missions
Post by: Jim on 10/09/2014 01:56 pm

Instruments are usually a small portion of a mission's budget. For instance, from memory, I think MSL was 2.5 billion total cost and the instruments were ~100 million total.

Wrong.  They are not a small portion.  A lander is the wrong example.  MSL had 3 additional pieces of hardware that other spacecraft don't have: aeroshell, descent stage, and rover.



Title: Re: Proposed Europa Missions
Post by: Blackstar on 10/09/2014 02:19 pm

Instruments are usually a small portion of a mission's budget. For instance, from memory, I think MSL was 2.5 billion total cost and the instruments were ~100 million total.

Wrong.  They are not a small portion.  A lander is the wrong example.  MSL had 3 additional pieces of hardware that other spacecraft don't have: aeroshell, descent stage, and rover.

Also, the Curiosity instrument suite cost more than that. I think the cost was more like $170-$190 million. After all, the cost of the instrument suite for Mars 2020--not including the sample cacher--is over $130 million.
Title: Re: Proposed Europa Missions
Post by: baldusi on 10/09/2014 03:04 pm

Instruments are usually a small portion of a mission's budget. For instance, from memory, I think MSL was 2.5 billion total cost and the instruments were ~100 million total.

Wrong.  They are not a small portion.  A lander is the wrong example.  MSL had 3 additional pieces of hardware that other spacecraft don't have: aeroshell, descent stage, and rover.

Also, the Curiosity instrument suite cost more than that. I think the cost was more like $170-$190 million. After all, the cost of the instrument suite for Mars 2020--not including the sample cacher--is over $130 million.
And that's for a rover, for telescopes is much more (like 200M per instrument for a big one). And I wonder about something like Cassini which should be the closest match for this mission.
Title: Re: Proposed Europa Missions
Post by: vjkane on 10/09/2014 03:13 pm
The direct costs of instruments often runs 10-15% of the total cost of a mission. Accommodations on the spacecraft to provide power, stable pointing, space, data return, mission operations, etc can be much more. 

I've heard that if one wanted to just have a spacecraft flyby Europa many times with no instruments, the cost would be about $1B.   If you want to do great science, too, about double that price
Title: Re: Proposed Europa Missions
Post by: Blackstar on 10/09/2014 04:39 pm
And that's for a rover, for telescopes is much more (like 200M per instrument for a big one). And I wonder about something like Cassini which should be the closest match for this mission.

I'd quibble with counting a telescope that way. When it comes to a telescope, I don't think it is totally fair to divide it in terms of "instruments" and everything else. The telescope itself should in some way be considered a scientific instrument. It's not just support equipment.

Title: Re: Proposed Europa Missions
Post by: baldusi on 10/09/2014 04:50 pm
And that's for a rover, for telescopes is much more (like 200M per instrument for a big one). And I wonder about something like Cassini which should be the closest match for this mission.

I'd quibble with counting a telescope that way. When it comes to a telescope, I don't think it is totally fair to divide it in terms of "instruments" and everything else. The telescope itself should in some way be considered a scientific instrument. It's not just support equipment.
They include a deep radar. The whole craft has to act as an instrument. Similar concept can be made for the rest of the instruments. A craft with no instruments would have minimum power and heat rejection, basic comm, no pointing and stability needs, etc. So, I concur with vjkane that the instrument cost is the instrument itself plus the incremental cost to the craft.
But I concede that the telescope case is pretty particular.
Title: Re: Proposed Europa Missions
Post by: metaphor on 10/09/2014 04:55 pm
I've heard that if one wanted to just have a spacecraft flyby Europa many times with no instruments, the cost would be about $1B.   If you want to do great science, too, about double that price

If you add instruments, you're adding mass to the payload, plus additional power/thermal/communications requirements, so that makes the rest of the spacecraft cost more.  So the cost of the instruments themselves would not be equal to the difference in cost between a full-science Europa flyby mission and a Europa flyby mission with no instruments.  (edit--misread that post, I agree with your point)

According to this source (http://"http://orion.asu.edu/Additional%20Reading/Cassini_resource-margin_trade.pdf")(pdf), Cassini's scientific instrument cost was $200 million out of a $1.4 billion total spacecraft development budget.
Title: Re: Proposed Europa Missions
Post by: Jim on 10/09/2014 05:22 pm


According to this source (http://"http://orion.asu.edu/Additional%20Reading/Cassini_resource-margin_trade.pdf")(pdf), Cassini's scientific instrument cost was $200 million out of a $1.4 billion total spacecraft development budget.

$400M for the TIV, so 1/5 of the spacecraft cost.
Title: Re: Proposed Europa Missions
Post by: ncb1397 on 10/09/2014 05:30 pm
I don't recall probes in the '60s and '70s opting for numerous out-of-the-way gravity assists, so I see them for what they are: improvising. 
You cannot simply throw a large launch vehicle at every mission. That's expensive. That is money better spent on instruments.

Has anyone proposed doing something like using an HLV for every mission?

Instruments are usually a small portion of a mission's budget.


Launch vehicle size, and cost, has been a factor in the selection and non-selection of many planetary missions over the years. Look at Voyager-Mars as the classic example. Of course, size of the spacecraft (and cost) usually tracks with size of the rocket, but as a general rule, planetary missions have sought to keep the launch vehicle size as small as possible and mission designers are not automatically given the option of the largest rocket (there's a reason why Curiosity and Juno did not launch on Delta IVs, for instance).

I've heard it argued here that Curiosity maxes out NASA's EDL technology for downmass(i.e. they can't make the parachutes any bigger). If this is the case, more upmass wouldn't enable much more rover. This doesn't apply to Europa Clipper. Delta IVs are generally never used for NASA missions, partly due to not being a NASA certified launch vehicle. For whatever reason, ULA/Boeing/Lockheed generally push Atlas over Delta for NASA/commercial.


Instruments are usually a small portion of a mission's budget. For instance, from memory, I think MSL was 2.5 billion total cost and the instruments were ~100 million total.

Wrong.  They are not a small portion.  A lander is the wrong example.  MSL had 3 additional pieces of hardware that other spacecraft don't have: aeroshell, descent stage, and rover.


Also, the Curiosity instrument suite cost more than that. I think the cost was more like $170-$190 million. After all, the cost of the instrument suite for Mars 2020--not including the sample cacher--is over $130 million.

If a lander is a wrong example, maybe JIMO would be a better example given that it was also a Jupiter moon mission. It includes multiple mission elements assembled in orbit via multiple launches, a nuclear reactor, electric drive, massive radiators, etc. All of that is logistics and is just as complicated as MSL if not more so.

Anyways, the constraint for a Jupiter moon mission needs to be the ability to equip a full power, full scale ground penetrating radar. I'm not sure it would be hugely expensive, but it will be power hungry and heavy. What is going on below the surface is the whole point after all.

As far as budget for Mars 2020:
Quote
The 19-member SDT, headed by Brown University geologist Jack Mustard, has been told NASA will have about $80 million for rover science instruments, Meyer said, adding that at least one and possibly two more instruments, with a total value of about $20 million, also should be coming from participating international or other partners.
http://www.spacenews.com/article/civil-space/34035nasa-outlines-budget-scope-for-next-mars-rover-in-2020

MSL budget was about what I said, but ended up significantly over budget resulting in the ~170 million.

Quote
Although Curiosity’s initial budget for science instruments was $85 million in 2004 dollars, the agency ended up spending roughly twice that amount.
http://www.spacenews.com/article/civil-space/34035nasa-outlines-budget-scope-for-next-mars-rover-in-2020

Still, we are talking about 7% of the mission cost even after going over-budget(more so than the mission overall) which some people here have pointed out might be on the low end of the spectrum given it is a lander. I'm having a bit of trouble finding cost figures for the instruments on Cassini, but the linked page below says the UVIS instrument cost 12.5 million and is one of 12 while the whole mission cost 3.3 billion. Extrapolating this towards all twelve would yield 150 million out of 3.3 billion or 4.5%. I would characterize this as a small portion. Anyone with better numbers and more expert google-fu, feel free to post.

http://lasp.colorado.edu/cassini/education/faqs.htm

p.s. Yes, I see someone posted numbers above me. I am just going to push the button anyways.

Title: Re: Proposed Europa Missions
Post by: ncb1397 on 10/09/2014 05:44 pm


According to this source (http://"http://orion.asu.edu/Additional%20Reading/Cassini_resource-margin_trade.pdf")(pdf), Cassini's scientific instrument cost was $200 million out of a $1.4 billion total spacecraft development budget.

$400M for the TIV, so 1/5 of the spacecraft cost.

You don't just look at spacecraft cost, you look at mission cost. This properly accounts for shorter missions on SLS vs Atlas. You don't count the Huygen's probe as an instrument(I assume this is what you mean by "TIV"). It is an instrumented lander. If the 200 million is right, it is 200 million out of 3.3 billion or 6%.
Title: Re: Proposed Europa Missions
Post by: Jim on 10/09/2014 05:51 pm


According to this source (http://"http://orion.asu.edu/Additional%20Reading/Cassini_resource-margin_trade.pdf")(pdf), Cassini's scientific instrument cost was $200 million out of a $1.4 billion total spacecraft development budget.

$400M for the TIV, so 1/5 of the spacecraft cost.

You don't just look at spacecraft cost, you look at mission cost. This properly accounts for shorter missions on SLS vs Atlas. You don't count the Huygen's probe as an instrument(I assume this is what you mean by "TIV"). It is an instrumented lander. If the 200 million is right, it is 200 million out of 3.3 billion or 6%.

TIV is Titan IV.  $1.4B total mission cost - $400M LV = $1B spacecraft.  Instruments are 1/5 of it.
Title: Re: Proposed Europa Missions
Post by: ncb1397 on 10/09/2014 06:13 pm


According to this source (http://"http://orion.asu.edu/Additional%20Reading/Cassini_resource-margin_trade.pdf")(pdf), Cassini's scientific instrument cost was $200 million out of a $1.4 billion total spacecraft development budget.

$400M for the TIV, so 1/5 of the spacecraft cost.

You don't just look at spacecraft cost, you look at mission cost. This properly accounts for shorter missions on SLS vs Atlas. You don't count the Huygen's probe as an instrument(I assume this is what you mean by "TIV"). It is an instrumented lander. If the 200 million is right, it is 200 million out of 3.3 billion or 6%.

TIV is Titan IV.  $1.4B total mission cost - $400M LV = $1B spacecraft.  Instruments are 1/5 of it.

Cassini-Huygens was a lot more expensive than that:

Quote
The total cost of this scientific exploration mission is about US$3.26 billion, including $1.4 billion for pre-launch development, $704 million for mission operations, $54 million for tracking and $422 million for the launch vehicle. The United States contributed $2.6 billion (80%), the ESA $500 million (15%), and the ASI $160 million (5%).
http://en.wikipedia.org/wiki/Cassini%E2%80%93Huygens

Your 1.4 Billion is only "pre-launch development".
Title: Re: Proposed Europa Missions
Post by: Jim on 10/09/2014 06:23 pm


Your 1.4 Billion is only "pre-launch development".

So 1/7 of the spacecraft, which is still a sizable portion.
Title: Re: Proposed Europa Missions
Post by: ncb1397 on 10/09/2014 06:40 pm


Your 1.4 Billion is only "pre-launch development".

So 1/7 of the spacecraft, which is still a sizable portion.


Instruments are usually a small portion of a mission's budget. For instance, from memory, I think MSL was 2.5 billion total cost and the instruments were ~100 million total.

Wrong.  They are not a small portion.  A lander is the wrong example.  MSL had 3 additional pieces of hardware that other spacecraft don't have: aeroshell, descent stage, and rover.

Now calculating the "portion" to be the percentage of the spacecraft vs the percentage of the mission is moving the goal post. 200 million is ~1/16th of 3.3 billion. Still, let's say a big LV costs 1 billion(no idea how much SLS costs). I still haven't heard what the instrument developers would spend 1 billion on in the same mass and power constraints(R&D for science instrument optimization?). No other probes have ever spent this amount of money on instrumentation.
Title: Re: Proposed Europa Missions
Post by: veblen on 10/09/2014 07:54 pm
$422M in 1997 for Cassini TitanIV-Centaur launch vehicle. $625M today with inflation factored in. How much more expensive for SLS, add another $375M =$1B? AtlasV 541 $226M, good price but availability?
Title: Re: Proposed Europa Missions
Post by: Jim on 10/09/2014 08:10 pm

Now calculating the "portion" to be the percentage of the spacecraft vs the percentage of the mission is moving the goal post.

Yes, it is.  That is why is it part of the spacecraft.  Mission operations costs are mainly driven by time on station and not during cruise.  Mission extensions increase mission costs.  Cassini operations are around $80m per year. 
Title: Re: Proposed Europa Missions
Post by: Jim on 10/09/2014 08:13 pm

You don't just look at spacecraft cost, you look at mission cost. This properly accounts for shorter missions on SLS vs Atlas. You don't count the Huygen's probe as an instrument(I assume this is what you mean by "TIV"). It is an instrumented lander.

yes, Huygen's probe would be counted as an instrument/payload of the spacecraft.
Title: Re: Proposed Europa Missions
Post by: redliox on 10/09/2014 08:31 pm
$422M in 1997 for Cassini TitanIV-Centaur launch vehicle. $625M today with inflation factored in. How much more expensive for SLS, add another $375M =$1B? AtlasV 541 $226M, good price but availability?

Good point.  The Atlas V is supposed to have enough spare Russian engines to last a few years, but I would presume by the early 2020s that supply would be at an end.  It's a good rocket but they will eventually need to upgrade or replace it.

I wonder how a Falcon Heavy compares; if SLS is "too fantastic" and the Atlas too underpowered for a direct flight, could an FH deliver something to Jupiter with a single Earth fly-by? 
Title: Re: Proposed Europa Missions
Post by: redliox on 10/09/2014 08:59 pm
Another update for Europa: Cubesat proposals!
http://www.astrowatch.net/2014/10/jet-propulsion-laboratory-selects.html (http://www.astrowatch.net/2014/10/jet-propulsion-laboratory-selects.html)

If they can get those things into Europa orbit, they could be a boost for gravity and magnetic mapping, but aside from what instruments could get crammed in, the question I ponder is how they'd be placed in orbit while, presumably, the long-lived mothership (Europa Clipper or otherwise) continues circling Jupiter.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 10/10/2014 12:44 am
Another update for Europa: Cubesat proposals!
http://www.astrowatch.net/2014/10/jet-propulsion-laboratory-selects.html (http://www.astrowatch.net/2014/10/jet-propulsion-laboratory-selects.html)

If they can get those things into Europa orbit, they could be a boost for gravity and magnetic mapping, but aside from what instruments could get crammed in, the question I ponder is how they'd be placed in orbit while, presumably, the long-lived mothership (Europa Clipper or otherwise) continues circling Jupiter.

This stuff is tossed around as an idea, but I have real doubts about its practicality. Small spacecraft don't have any shielding. How long are they going to last in that radiation hell? And is that the best use of that limited mass?
Title: Re: Proposed Europa Missions
Post by: vjkane on 10/10/2014 01:06 am


This stuff is tossed around as an idea, but I have real doubts about its practicality. Small spacecraft don't have any shielding. How long are they going to last in that radiation hell? And is that the best use of that limited mass?

Hey, if you think cubesats lack shielding, how about Draper Labs Europa chipsets?

I suspect that most of the cubesats are for short life, deploy from a shielded canister, missions.   The might be deployed for imaging specific areas a la Ranger or for gravity tracking a la Grail.  They are also likely to be battery powered. I suspect that any solar panels would have more volume than the cubesat

I think of these as short-lived deployed instruments.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 10/10/2014 02:09 am
Yeah, that is how they would have to be used--short life. But that itself is an issue. If you are a mission designer and somebody says "I want 10 kg of payload to operate some cubesats for about 1 hour of data and there is high risk that they will fail immediately," will you sit there and say "Go on..." or will you kick that person out of your office?

Put more diplomatically, are short-lived cubesats the proper way to spend mass? Is it a good idea to spend many years to send an instrument to Europa that is only going to last a very short time?

I have a friend who is currently a PI for a NASA-led planetary cubesat mission and they have noted that many of the things that keep cubesat costs down--short lives, high risk, limited testing--are things that you don't want on an expensive planetary mission.

So if you're going to use them, they better be really really worth it. Otherwise, that mass could probably be put to better use as shielding.
Title: Re: Proposed Europa Missions
Post by: metaphor on 10/10/2014 05:23 am
I'm guessing with the cubesats they're just exploring all the options right now.  There's only so much you can spend $100 million dollars on for "studies".


I wonder how a Falcon Heavy compares; if SLS is "too fantastic" and the Atlas too underpowered for a direct flight, could an FH deliver something to Jupiter with a single Earth fly-by? 

The FH might be able to get about 6 tons to a 2-year solar orbit so the spacecraft could do an Earth flyby to Jupiter, like Juno.  But in that case you would need more fuel on the spacecraft itself for the needed deep-space maneuver of about 600 m/s delta-v.  Also, it wouldn't save much time compared to a VVE/VEE gravity assist transfer (about 5 years instead of 6).
Title: Re: Proposed Europa Missions
Post by: baldusi on 10/10/2014 11:29 am

I'm guessing with the cubesats they're just exploring all the options right now.  There's only so much you can spend $100 million dollars on for "studies".


I wonder how a Falcon Heavy compares; if SLS is "too fantastic" and the Atlas too underpowered for a direct flight, could an FH deliver something to Jupiter with a single Earth fly-by? 

The FH might be able to get about 6 tons to a 2-year solar orbit so the spacecraft could do an Earth flyby to Jupiter, like Juno.  But in that case you would need more fuel on the spacecraft itself for the needed deep-space maneuver of about 600 m/s delta-v.  Also, it wouldn't save much time compared to a VVE/VEE gravity assist transfer (about 5 years instead of 6).
Adding fuel is cheap, and 1 year of operations might cost 80M (like Cassini). Which is about same the difference from F9 to FH. But this would need an Atlas V 551 otherwise, so if FH actually pans out, it could mean a cheaper and faster mission. Less than 3% overall i. The whole mission cost, but good enough none the less.
If FH does launches by 2015, it should be able to be certified by PDR, at least. If this delays a bit more, it might be certifiable by SDR, in fact.
Title: Re: Proposed Europa Missions
Post by: robertross on 10/10/2014 01:17 pm
Yeah, that is how they would have to be used--short life. But that itself is an issue. If you are a mission designer and somebody says "I want 10 kg of payload to operate some cubesats for about 1 hour of data and there is high risk that they will fail immediately," will you sit there and say "Go on..." or will you kick that person out of your office?

Put more diplomatically, are short-lived cubesats the proper way to spend mass? Is it a good idea to spend many years to send an instrument to Europa that is only going to last a very short time?

I have a friend who is currently a PI for a NASA-led planetary cubesat mission and they have noted that many of the things that keep cubesat costs down--short lives, high risk, limited testing--are things that you don't want on an expensive planetary mission.

So if you're going to use them, they better be really really worth it. Otherwise, that mass could probably be put to better use as shielding.

In retrospect to my original 'like' for this concept, I have to agree with your assessment. I could envision the mass being better spent on additional instruments on the spacecraft, or more fuel, than to have to give up mass & space for the Cubesats, deployment mechanism, and possibly the coms requirement.

My original 'like' was to help out the universities & students for these types of cutting edge missions.
Title: Re: Proposed Europa Missions
Post by: metaphor on 10/10/2014 07:04 pm
If the Europa Clipper does launch on the SLS, which version would it use?  Block 1 with the ICPS or Block 1B with the exploration upper stage?  Which version did the mission concept study consider?  By 2022 I'm guessing both would be available.

From my calculations the ICPS could get about 5 tons to Jupiter, and the exploration upper stage could get about 7-8 tons to Jupiter.  If using a third stage such as a solid kick stage, the payload for the EUS to Jupiter could be improved to about 12-15 tons.  I'm not sure if that much mass is really needed, but it's possible.

Atlas V payload to Venus is about 5 tons.
Title: Re: Proposed Europa Missions
Post by: baldusi on 10/11/2014 12:09 am
The faster it reaches Jupiter, the more braking propellant it will need. There's not such a thing as too much performance.
Title: Re: Proposed Europa Missions
Post by: ugordan on 10/17/2014 08:37 am
There is an interesting drawback to the RTG design (I'm guessing that this is peculiar to the MMRTG design that we now have). It loses power at a greater rate, so long flight times (or mission times) are greater problems.

Interesting. One could naively expect that, once in the Jovian radiation environment, solar arrays would degrade much faster than an MMRTG, although the latter would have a big head start right from launch. Kind of a rabbit and turtle story situation. Modern solar arrays must be more resilient than I expected.
Title: Re: Proposed Europa Missions
Post by: redliox on 10/17/2014 08:55 am
He explained the trades over solar and RTGs. Ultimately, the decision on power is going to be a headquarters decision, although the project can recommend one over the other. Solar is cheaper, although solar is also a problem for the VEEGA trajectory because near Venus it is awfully hot and this presents thermal design problems. There is an interesting drawback to the RTG design (I'm guessing that this is peculiar to the MMRTG design that we now have). It loses power at a greater rate, so long flight times (or mission times) are greater problems. That is one of the things that made solar more appealing. But he also emphasized that solar is particular to this mission design and that if you wanted to do other things out at Jupiter solar may not be an option at all. So don't think that "we now can do solar at Jupiter." No, we can do it in some specific mission implementations.

I wager the power needs of the IPR will drive the minimum size of the arrays in addition to 'life support' functions like communication and heating.  If a smaller payload is used it might get by, but naturally that's why they're debating this: quality versus cost issues.  However, I distinctly feel they won't let the probe launch without the radar; did your source say much on payload considerations?

Venus...ugh.  With those thermal issues it'd make more sense just to use exclusively Earth fly-bys instead.  Useful gravity well, hellish location (in just about every sense) especially for an outer planet probe.
Title: Re: Proposed Europa Missions
Post by: kevin-rf on 10/17/2014 12:20 pm
Venus...ugh.  With those thermal issues it'd make more sense just to use exclusively Earth fly-bys instead.  Useful gravity well, hellish location (in just about every sense) especially for an outer planet probe.
Or use a bigger rocket...
Title: Re: Proposed Europa Missions
Post by: simonbp on 10/17/2014 07:56 pm
So don't think that "we now can do solar at Jupiter." No, we can do it in some specific mission implementations.

Well, ever since we launched a solar-powered mission to Jupiter (that will arrive less than two years), the question will always be raised. ;)

IIRC, the missions that solar really fails on right now involve lots of time in the radiation belt (i.e. Io Observer-style mission) and/or high-power ground-penetrating radar. Either of those is an expensive proposition in and of itself, which is exactly why Clipper came to be...
Title: Re: Proposed Europa Missions
Post by: Blackstar on 10/18/2014 05:38 am
IIRC, the missions that solar really fails on right now involve lots of time in the radiation belt (i.e. Io Observer-style mission) and/or high-power ground-penetrating radar. Either of those is an expensive proposition in and of itself, which is exactly why Clipper came to be...

It's not just that. It is overall mission design. If you need to operate multiple instruments at once, or even some instruments for a long time, solar may not work very well.
Title: Re: Proposed Europa Missions
Post by: Nilof on 10/18/2014 10:35 pm
What about using an electrodynamic tether for power to complement solar? Could that be viable?
Title: Re: Proposed Europa Missions
Post by: Blackstar on 10/19/2014 12:30 am
There is a rule of space mission design (that seems to go out the window here on NSF): you are allowed only one miracle technology per mission.

Multiplying technologies that have not been proven by other technologies that have not been proven increases your chance of failure.
Title: Re: Proposed Europa Missions
Post by: redliox on 10/19/2014 02:42 am
There is a rule of space mission design (that seems to go out the window here on NSF): you are allowed only one miracle technology per mission.

Multiplying technologies that have not been proven by other technologies that have not been proven increases your chance of failure.

Agreed.  There are some technologies that are on the cusp, such as aerocapture that I'd love to see demonstrated, but the maturation of those technologies can eat up the budget.  Deep Space 1, which pioneered SEP, flew a slew of new mechanisms but only had 2 intruments: a hybrid spectrometer/camera and a plasma detector (a third instrument was improvised from a device meant to monitor the ions from the propulsion).

This is why both MAVEN and OSIRIS-REX both borrow the 'body' of MRO, to keep costs down, and likewise with InSight using Phoenix's setup.  If there's a design, and tech, that works, improvise with what you got.  The JIMO concept from the early 2000s fell flat on its face because they thought they could shove nuclear reactor technology into space with a high-powered NEP at a warp-speed-pace.  Baby steps are best taken; even in the Apollo era there was Mercury and Gemini beforehand along with missions set to test incrementally.

For Europa, there could be a lot of heritage drawn upon from Cassini, Juno, and New Horizons that would serve very well.  The only 'experimental' tech that could be utilized would be solar arrays and cubesats.  Both are being considered and have been utilized before; the real trick to both is adapting them to the extreme radiation at Jupiter.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 10/19/2014 08:25 pm
Agreed.  There are some technologies that are on the cusp, such as aerocapture that I'd love to see demonstrated, but the maturation of those technologies can eat up the budget.  Deep Space 1, which pioneered SEP, flew a slew of new mechanisms but only had 2 intruments: a hybrid spectrometer/camera and a plasma detector (a third instrument was improvised from a device meant to monitor the ions from the propulsion).

This is why both MAVEN and OSIRIS-REX both borrow the 'body' of MRO, to keep costs down, and likewise with InSight using Phoenix's setup.  If there's a design, and tech, that works, improvise with what you got.  The JIMO concept from the early 2000s fell flat on its face because they thought they could shove nuclear reactor technology into space with a high-powered NEP at a warp-speed-pace.  Baby steps are best taken; even in the Apollo era there was Mercury and Gemini beforehand along with missions set to test incrementally.

For Europa, there could be a lot of heritage drawn upon from Cassini, Juno, and New Horizons that would serve very well.  The only 'experimental' tech that could be utilized would be solar arrays and cubesats.  Both are being considered and have been utilized before; the real trick to both is adapting them to the extreme radiation at Jupiter.

I would make an important distinction here: DS1 was a technology demonstration spacecraft. NASA doesn't really do that anymore. There's a long story behind that, but the quick version is that there has always been a tendency at NASA to raid the R&D budget to feed the flight programs, and so dedicated R&D/tech demo spacecraft like DS1 are really hard to fund. So they don't happen.

On the other things, there's a constant desire to minimize risk in order to make the mission successful, but also to increase the chance that it will not go over budget or get canceled. MAVEN is an example of a mission that took no risks and the PI for that mission has been totally open about that. Last year I saw him give a talk where he was asked about it and he was pretty blunt: "I wanted to get funded." And advancing technology decreased his chances of that.

With big flagship class missions you can develop some new technology if it is necessary for the mission, but program managers always want to reduce that. If you look at JWST, one of the big reasons that JWST went so obscenely over budget is that it needed all new technology in several key areas such as very low temperature electronics, a folding mirror, and the sunshade. They may not qualify as "miracles," but each of them is relatively immature. That creates problems--which drive up costs--and it also requires more simulation and testing--which drive up costs.

(more later)
Title: Re: Proposed Europa Missions
Post by: Blackstar on 10/19/2014 08:28 pm
So for Europa Clipper, what mission designers want to do is to reduce the new technologies that they need to carry with them. In fact, that is why solar power is now seriously being considered, because it is no longer considered "new" after Juno flies.

But keep in mind the timeline--Juno has not reached Jupiter yet, and has not operated at Jupiter yet. There are going to be senior people (at NASA HQ, OMB, elsewhere) who are going to be nervous about entrusting a $2.5 billion mission to solar panels. So they will not get comfortable with it until after Juno operates and collects a lot of data.

In fact, if Juno's solar panels are still working great at the end of the mission, solar panels for Europa Clipper will probably be an easy sell, assuming that the mission designers are able to convince the powers that be that there is not a big difference between the two missions.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 10/28/2014 08:58 pm
The Wernher von Braun Symposium is going on in Huntsville right now. This afternoon featured a panel on SLS (not only the rocket, but ground systems, Orion, etc.). One thing that has changed with SLS is that they are now talking about mass and volume available below the Orion that could carry other payloads. I saw a presentation about that last week at a workshop, but I don't remember seeing anybody discuss is very publicly before now. (See attached image for some examples.)

No, you cannot stick a Europa Clipper underneath an Orion.

There was one question (from somebody from the Planetary Society) about putting Europa Clipper on an SLS. The SLS guy's response was actually quite reasonable. He said that this was a planetary decision, of course, but he also thought that the smart thing for the EC program to do was to not make a decision until just before their preliminary design review. Instead, they should be studying their trades, trying to figure out what all their options are. For example, if they see themselves running into a mass/cost issue (with Atlas) they might be able to solve it by switching vehicles and using SLS instead and throwing mass at the problem. (I'd note that this is the kind of problem that might only show up long after PDR, but he made a reasonable point.)

If the sessions end up on the internet, you might want to watch that one.

Title: Re: Proposed Europa Missions
Post by: baldusi on 10/28/2014 10:47 pm
Very interesting opportunity for validating any Moon technology (like landers, LCT sats and such). I also wonder about some habitat module. It appears to rest against Orion's main engines, so it might have to do a maneuver (like Apollo) to retrieve the module. But for the rest it seems like a very real possibility.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 10/28/2014 11:10 pm
I don't want to derail this thread to discuss payloads that can fly below Orion. I have some better slides about that, but won't post them. I assume that Chris will do some SLS update article eventually and will mention this.
Title: Re: Proposed Europa Missions
Post by: jongoff on 10/29/2014 03:42 am
I would make an important distinction here: DS1 was a technology demonstration spacecraft. NASA doesn't really do that anymore. There's a long story behind that, but the quick version is that there has always been a tendency at NASA to raid the R&D budget to feed the flight programs, and so dedicated R&D/tech demo spacecraft like DS1 are really hard to fund. So they don't happen.

On the other things, there's a constant desire to minimize risk in order to make the mission successful, but also to increase the chance that it will not go over budget or get canceled. MAVEN is an example of a mission that took no risks and the PI for that mission has been totally open about that. Last year I saw him give a talk where he was asked about it and he was pretty blunt: "I wanted to get funded." And advancing technology decreased his chances of that.

With big flagship class missions you can develop some new technology if it is necessary for the mission, but program managers always want to reduce that. If you look at JWST, one of the big reasons that JWST went so obscenely over budget is that it needed all new technology in several key areas such as very low temperature electronics, a folding mirror, and the sunshade. They may not qualify as "miracles," but each of them is relatively immature. That creates problems--which drive up costs--and it also requires more simulation and testing--which drive up costs.

(more later)

It's kind of frustrating to have a big budget space science program like what NASA has that is so scared of putting money into new technologies and technology demonstrations. That should be one of the points of having a national space program--to make the far-sighted technology investments that are too risky for industry to invest in. Have you seen any good suggestions for how to solve this problem? Because a failure to properly invest in  up-front new technology maturation and demonstration is basically a tax on future programs. By not investing now, you guarantee future programs will deliver less for a given amount of money. Unmanned space science seems less neurotic than HSF at NASA, but this is still a pretty serious neuroses that's going to keep cutting into what we can do in the future if we don't find a way of solving it.

May not be the best specific thread for this discussion, but I wanted to get your take on it, since you're more up-to-the-elbows in this sort of space policy issue.

~Jon
Title: Re: Proposed Europa Missions
Post by: Oli on 10/29/2014 11:47 am
It's kind of frustrating to have a big budget space science program like what NASA has that is so scared of putting money into new technologies and technology demonstrations. That should be one of the points of having a national space program--to make the far-sighted technology investments that are too risky for industry to invest in. Have you seen any good suggestions for how to solve this problem? Because a failure to properly invest in  up-front new technology maturation and demonstration is basically a tax on future programs. By not investing now, you guarantee future programs will deliver less for a given amount of money. Unmanned space science seems less neurotic than HSF at NASA, but this is still a pretty serious neuroses that's going to keep cutting into what we can do in the future if we don't find a way of solving it.

May not be the best specific thread for this discussion, but I wanted to get your take on it, since you're more up-to-the-elbows in this sort of space policy issue.

~Jon

I think the goal of the space science program should be to maximize the scientific return. Technology is secondary. Maybe the fact that unmanned space science has a more or less clearly defined goal makes it less 'neurotic' than HSF?
Title: Re: Proposed Europa Missions
Post by: Blackstar on 10/29/2014 01:13 pm
It's kind of frustrating to have a big budget space science program like what NASA has that is so scared of putting money into new technologies and technology demonstrations. That should be one of the points of having a national space program--to make the far-sighted technology investments that are too risky for industry to invest in. Have you seen any good suggestions for how to solve this problem? Because a failure to properly invest in  up-front new technology maturation and demonstration is basically a tax on future programs. By not investing now, you guarantee future programs will deliver less for a given amount of money. Unmanned space science seems less neurotic than HSF at NASA, but this is still a pretty serious neuroses that's going to keep cutting into what we can do in the future if we don't find a way of solving it.

May not be the best specific thread for this discussion, but I wanted to get your take on it, since you're more up-to-the-elbows in this sort of space policy issue.

~Jon

I've got no good answer. If you look at the planetary decadal survey, they made a recommendation for devoting a percentage of the budget for technology. PSD wanted to do that. They recognize how important it is. But they got their budget whacked, and all the budget categories are tight. No matter what you cut somebody gets hurt. And even cutting things like flight programs now can have long-term down the road impacts. For instance, reducing the number of Discovery missions drives people out of the program and scares away young and innovative people. That's a long term hit as a result of a near-term cut. The same is true for the research and analysis (R&A) funding, which keeps alive many scientists. Cut R&A and you lose a lot of graduate students and your future people base.

Now there are different ways to approach the problem. I'm no expert on it, but on one extreme you have the approach typified by DS-1 (I forget the name of the overall program it was part of). That approach is a separate R&D budget and demo missions. Although that seems like the ideal, it is just too vulnerable to getting cut. So it doesn't work. Another method is to offer incentives to mission PIs. For example, in the previous Discovery call, NASA actually offered the ASRG (replacement for the RTG) "free" to the mission so that they might use it and therefore demonstrate it in space. That allowed PIs to propose new and exciting missions and not have to pay for their power source. (I think I heard that the PIs were less than thrilled about this in the end, because they got stuck with unexpected ASRG integration costs, so it was not really "free" to them. But I don't know about the details.)

But yeah, it's a perpetual struggle, and nobody thinks that R&D is winning.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 10/29/2014 01:19 pm
1-I think the goal of the space science program should be to maximize the scientific return. Technology is secondary.

2-Maybe the fact that unmanned space science has a more or less clearly defined goal makes it less 'neurotic' than HSF?


1-Except that, as Jon noted, if you rob the tech base, over time you can produce less and less science. If nobody invests in the things you need for future missions, then those missions won't happen.

2-Robotic space science does a really good job of defining its goals and eventually achieving them. The space geeks who populate this board generally don't care about the robotic stuff, but I think that if you looked at the space science priority lists for the 1970s, 80s, 90s and 00s, you would see that the science community did a remarkably good job of achieving the goals they established for themselves. Accomplishment rates above 80-90% by some measures.
Title: Re: Proposed Europa Missions
Post by: jongoff on 10/29/2014 02:24 pm
It's kind of frustrating to have a big budget space science program like what NASA has that is so scared of putting money into new technologies and technology demonstrations. That should be one of the points of having a national space program--to make the far-sighted technology investments that are too risky for industry to invest in. Have you seen any good suggestions for how to solve this problem? Because a failure to properly invest in  up-front new technology maturation and demonstration is basically a tax on future programs. By not investing now, you guarantee future programs will deliver less for a given amount of money. Unmanned space science seems less neurotic than HSF at NASA, but this is still a pretty serious neuroses that's going to keep cutting into what we can do in the future if we don't find a way of solving it.

May not be the best specific thread for this discussion, but I wanted to get your take on it, since you're more up-to-the-elbows in this sort of space policy issue.

~Jon

I think the goal of the space science program should be to maximize the scientific return. Technology is secondary. Maybe the fact that unmanned space science has a more or less clearly defined goal makes it less 'neurotic' than HSF?

I think the problem that I was highlighting was that avoiding technology maturation/demonstration doesn't maximize long-term scientific return. So long as the technologies are legitimately enabling, it's a standard consumption (flying missions using existing technology) vs. investment (developing and demonstrating new technologies) economics story. You might be able to consumer more today by not investing, but in the long run you can't consume as much as you could if you had sacrificed a little today for more consumption in the future.

Basically, I'm saying that the approach we're taking appears to be myopic, sacrificing long-term benefits for near-term gratification... Which ironically is the kind of "market failure" a government program is supposed to avoid.

~Jon
Title: Re: Proposed Europa Missions
Post by: jongoff on 10/29/2014 02:27 pm
But yeah, it's a perpetual struggle, and nobody thinks that R&D is winning.

Thanks Blackstar. I have noticed several recent solicitations where they do incentivize optional, non-mission critical, bonus tech maturation/demos on solicitations. But yeah, this is a fundamental challenge. The good news is that if we can ever find a way to make this work (ie find a way to increase R&D and tech demo spending), we'll likely be able to get a lot more out of SMD in the future.

~Jon
Title: Re: Proposed Europa Missions
Post by: Blackstar on 10/29/2014 02:43 pm
But yeah, it's a perpetual struggle, and nobody thinks that R&D is winning.

Thanks Blackstar. I have noticed several recent solicitations where they do incentivize optional, non-mission critical, bonus tech maturation/demos on solicitations. But yeah, this is a fundamental challenge.

Tech demo happens on flagship missions which usually are ambitious and have money so they can spend money on it. So Curiosity developed the skycrane, and JWST is developing lots of things like low-temperature sensors and the foldable mirrors which may eventually get used on future telescopes.

However, those missions develop the technologies that they specifically need and not broader technologies that can be used for other things, like in-space propulsion. So the goal for R&D has been to fund tech that can be used by several different future missions. Either create a program that does that, or encourage it to happen on smaller missions. That's the problem.

Now it is not all bad news. Skycrane is getting re-used for Mars 2020. Juno is demonstrating low temperature solar cells that may get used for Europa Clipper as well as rad-hardened systems. The thermal management techniques developed for MESSENGER are being applied to Solar Probe Plus (and the MESSENGER team has aided the Europeans with Bepi-Columbo). So new tech does get developed and re-used.
Title: Re: Proposed Europa Missions
Post by: GClark on 10/29/2014 06:09 pm
...you have the approach typified by DS-1 (I forget the name of the overall program it was part of).

New Millennium program
Title: Re: Proposed Europa Missions
Post by: redliox on 11/21/2014 08:42 pm
I emailed Curt Niebur, whose in charge of both Cassini and the efforts tied to Europa.  I asked the following regarding solar power to get a straight answer:

Quote
I wrote to you previously regarding the schedule for a Europa mission's planning.  This time I write because a surprising rumor has popped up on twitter, stating that solar power has been chosen for the mission.  I thought it prudent to get straight answers from a legitimate source rather than rumor.
 
 This is what was stated via twitter: APL's Thomas Magner: We've selected solar power for the Europa Clipper mission, baselined for launch on SLS in June 2022. #IAC2014
 
 I find it doubtful this could be true, mainly because mission concepts are still being viewed.  I believe solar power could be both useful and practical, so long as radiation decay can be mitigated.  However I'm more concerned this is just a rumor and I don't like the idea of amateurs making assumptions while your colleagues are making though choices and evaluations.  Please look into this if you can.

Niebur replied:
Quote
Yes, this is true.  While we haven’t decided on a final concept, for the Clipper concept in particular we have baselined solar.  We did look at the radiation effect on the panels, which degrades their power output.  But testing shows that the panels are good for over 200 flybys, well beyond the 45 flybys in the Clipper concept.

Presuming the panels can retain the better part of their power production, this would be good news for mission extensions.  Considering Galileo held up reasonably well during its Jupiter cruise, sans the antenna and tape recorder issues (neither of which related to radiation), it should be safe to presume 'Clipper could live through it's primary mission and one mission extension; I don't go so far as to say two since even Galileo didn't as long as this potential successor will in the radiation belts.

Hopefully we'll hear good news for Europa.  Obviously much is still in the air but I'm feeling good vibes.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 11/21/2014 09:19 pm
Yeah, I got the same thing from a colleague who talked to another member of the EC team: they have baselined both solar and SLS.

That said, you have to ask what "baseline" actually means, because, a) this is not yet an approved mission, it's only a study, so no final decisions have been made, and b) those decisions ultimately are made at the HQ level, not by the study team, and they depend on lots of things such as funding.

So at some future point if EC gets approved as a mission, then somebody at NASA Headquarters has to approve both the choice of solar (which could still be rejected because of risk), and the use of SLS (which all depends upon who is paying the cost of the rocket--if the Science Mission Directorate has to shell out $1 billion, or even $500 million for an SLS launch they are not going to do it).

Title: Re: Proposed Europa Missions
Post by: rcoppola on 11/21/2014 09:37 pm
Has there been any discussions to include a small robotic lander to a Europa mission? If we're going to go into orbit, might as well land on it as well. We've proven damn capable of doing both. And if you're going to hitch a ride on a $500 Million HLV, may as well go all the way to bright.
Title: Re: Proposed Europa Missions
Post by: NovaSilisko on 11/21/2014 09:50 pm
Has there been any discussions to include a small robotic lander to a Europa mission? If we're going to go into orbit, might as well land on it as well. We've proven damn capable of doing both. And if you're going to hitch a ride on a $500 Million HLV, may as well go all the way to bright.

I do wonder what's the minimum mass you can get away with for a lander with decent payload. The proposed Mercury Surface Element of BepiColumbo was only 44 kg for the entire lander package, and used airbags for braking on the surface at ~30 m/s to reduce propulsion needs.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 11/21/2014 09:53 pm
Has there been any discussions to include a small robotic lander to a Europa mission? If we're going to go into orbit, might as well land on it as well. We've proven damn capable of doing both. And if you're going to hitch a ride on a $500 Million HLV, may as well go all the way to bright.

No. Keep in mind that the goal of EC has been to get the cost down to something that is affordable and doing that required keeping out of Europa orbit entirely. A lander would blow the cost sky high.

Plus, JPL did a Europa lander study in 2012 that indicated that a necessary precursor to a lander was high resolution photos of the potential landing sites. You cannot do that on the same mission with any degree of confidence.
Title: Re: Proposed Europa Missions
Post by: Star One on 11/21/2014 10:24 pm

Has there been any discussions to include a small robotic lander to a Europa mission? If we're going to go into orbit, might as well land on it as well. We've proven damn capable of doing both. And if you're going to hitch a ride on a $500 Million HLV, may as well go all the way to bright.

No. Keep in mind that the goal of EC has been to get the cost down to something that is affordable and doing that required keeping out of Europa orbit entirely. A lander would blow the cost sky high.

Plus, JPL did a Europa lander study in 2012 that indicated that a necessary precursor to a lander was high resolution photos of the potential landing sites. You cannot do that on the same mission with any degree of confidence.

Also if you're going to do a lander you might as well do it properly with a full up dedicated mission not something bolted onto a completely different one.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 11/21/2014 11:44 pm

Has there been any discussions to include a small robotic lander to a Europa mission? If we're going to go into orbit, might as well land on it as well. We've proven damn capable of doing both. And if you're going to hitch a ride on a $500 Million HLV, may as well go all the way to bright.

No. Keep in mind that the goal of EC has been to get the cost down to something that is affordable and doing that required keeping out of Europa orbit entirely. A lander would blow the cost sky high.

Plus, JPL did a Europa lander study in 2012 that indicated that a necessary precursor to a lander was high resolution photos of the potential landing sites. You cannot do that on the same mission with any degree of confidence.

Also if you're going to do a lander you might as well do it properly with a full up dedicated mission not something bolted onto a completely different one.

Well, it's not clear that you could do anything worthwhile with a small lander. What will it be able to take with it that can do anything useful?
Title: Re: Proposed Europa Missions
Post by: redliox on 11/22/2014 08:44 am
Also if you're going to do a lander you might as well do it properly with a full up dedicated mission not something bolted onto a completely different one.

Well, it's not clear that you could do anything worthwhile with a small lander. What will it be able to take with it that can do anything useful?

Lord knows we're having enough arguments on scaling a (flyby) orbiter down to fit into a smaller budget...

As ambitious the folks supporting the Antarctic drilling are, I don't think we're quite at the readiness to send a submersible down there - just enough to scratch the surface a bit.  I definitely would wait until we have at least global and regional maps of Europa; as is they're still spotty as heck and would make maps of Mars in the early '70s look more accurate.

A lander would be great to send down, but I'd expect something that'd be a mix of both the Martian missions, Phoenix and InSight, in terms of science and function: analyzing surface chemistry, drilling and probing the near-surface ice, seismology, and good-old-fashion pictures for PR.  A probe using an updated version of their experiments would serve well, not to mention fit into a budget better.
Title: Re: Proposed Europa Missions
Post by: Jim on 11/22/2014 12:59 pm
Has there been any discussions to include a small robotic lander to a Europa mission? If we're going to go into orbit, might as well land on it as well. We've proven damn capable of doing both. And if you're going to hitch a ride on a $500 Million HLV, may as well go all the way to bright.

 "might as well land on it as well" is out of the question."  It is not going into orbit around Europa.  It will be in orbit around Jupiter and then perform flyby's of Europa.  The delta V for orbit is too high and landing is a non starter.  Anyways, going into orbit does not mean landing is just a simple step.  That completely ignore the additional complexities.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 11/22/2014 03:50 pm
This is from JPL's 2012 Europa Lander study.
Title: Re: Proposed Europa Missions
Post by: Torbjorn Larsson, OM on 11/23/2014 02:04 pm
A lander would be great to send down, but I'd expect something that'd be a mix of both the Martian missions, Phoenix and InSight, in terms of science and function: analyzing surface chemistry, drilling and probing the near-surface ice, seismology, and good-old-fashion pictures for PR.  A probe using an updated version of their experiments would serve well, not to mention fit into a budget better.

That they have to include seismology, especially now that it seems Europa has an ice analog to plate tectonics going on (which would be only the second such known instance in the solar system), may mean that they would like to land a set of smaller probes sometime in the future. Say, with a follow up through-the-ice drill mission. But the first lander should be more generalist along the lines proposed here.

Speaking of future science, since ice moon oceans may be the largest type of biosphere out there (certainly by volume and perhaps by bioproductivity considering all the water), the end game would have us drilling most or all of found ones for habitability and habitation. That may include debris disk objects such as Ceres and Charon. (The latter has potentially a similar ocean kept open after its collisional formation with proto-Pluto.)

That may be the only way to get a firmer grip on the frequency of life in the universe, since we can mostly probe the surface habitable zone only from afar. Europa would be an important prerunner to that major task, and the better the initial science program the faster that goal could be realized. Reusing integration of experiments would be a robust way forward, even as drill and organics analysis subsystems presumably would  be advancing fast. (E.g. Rosetta looked for chirality, thus far lacking in martian missions.)
Title: Re: Proposed Europa Missions
Post by: vjkane on 11/23/2014 03:55 pm
There have been proposals for fairly simple hard Europa landers or penetrators (see for example, http://futureplanets.blogspot.com/2010/05/europaganymede-penetrator.html).  Even a simple lander could provide valuable data on seismology and composition.

HOWEVER, even these simple landers would be expensive (we learned from the Beagle 2 experience that short cuts don't work in designing landers) and would not fit within the budget of the Europa Clipper.  That said, if the Europa Clipper launches on the SLS (which I personally do not ever expect to see fly) there would be plenty of mass margin for a simple contributed lander.  But mission creep is a dangerous thing.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 11/25/2014 11:46 am
HOWEVER, even these simple landers would be expensive (we learned from the Beagle 2 experience that short cuts don't work in designing landers) and would not fit within the budget of the Europa Clipper.  That said, if the Europa Clipper launches on the SLS (which I personally do not ever expect to see fly) there would be plenty of mass margin for a simple contributed lander.  But mission creep is a dangerous thing.

Actually, I talked to one of the people involved in the SLS/EC evaluation and he said that the surprising thing is that there is less mass margin for the SLS version than one using an Atlas. The reason is that SLS puts all its energy into velocity, whereas the gravity assist version using Atlas trades speed for a bit more payload capability.

An interesting question, however, concerns the next steps after EC. I've heard that there is some grumbling over this among the outer planets community. They want Europa to be treated somewhat like Mars, with a "campaign" of missions to Europa--EC with its flybys followed by an orbiter followed by a lander. But the problem with that is that every mission to Europa is going to be expensive, in the multi-billions class. So they're making an argument that they should get a whole bunch of flagships. Meanwhile, there is an argument from elsewhere that they should do EC right so that it will enable a Europa lander as the follow-on mission. And considering the time between these missions, you gotta admit that it makes sense to go to a lander next, because going to an orbiter (unless you really really have to) means that the lander won't happen for another 30 years at least.
Title: Re: Proposed Europa Missions
Post by: baldusi on 11/25/2014 12:50 pm
So, the Atlas V551 v SLS is one of payload against mission time (and Venus thermal environment requirements?). It would still seems like the SLS will enable a faster turnaround for a lander. Any idea how much work can be advanced into a lander before we have the actual data from the flybys? BTW, has anybody actually got a planetary lander for a body without atmosphere? Philae is the closest I can think of.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 11/25/2014 03:45 pm
So, the Atlas V551 v SLS is one of payload against mission time (and Venus thermal environment requirements?). It would still seems like the SLS will enable a faster turnaround for a lander. Any idea how much work can be advanced into a lander before we have the actual data from the flybys? BTW, has anybody actually got a planetary lander for a body without atmosphere? Philae is the closest I can think of.

The only thing I can really speculate on is the first one, and it would be interesting to learn if eliminating the Venus flyby and thermal requirements actually saves any mass, or of it is just a complexity thing. More precisely: if SLS can throw less mass to Europa, how much mass are you saving by eliminating the Venus flyby and does that matter?

But these things might be in the margins, only a few kilos or tens of kilos.

Faster transit times and return of data are good things (although that has to be compared to cost). But I would add that a major pacing item between missions is funding. You might be able to throw EC at Europa faster, but that doesn't mean you can fund the follow-on mission any faster. You still have to pay for it. And presumably you have to let the Decadal Survey choose the priorities.
Title: Re: Proposed Europa Missions
Post by: baldusi on 11/25/2014 04:14 pm
Faster transit times and return of data are good things (although that has to be compared to cost). But I would add that a major pacing item between missions is funding. You might be able to throw EC at Europa faster, but that doesn't mean you can fund the follow-on mission any faster. You still have to pay for it. And presumably you have to let the Decadal Survey choose the priorities.
Well, but that might well mean that a faster mission might generate enough interest to accelerate funding for a follow up mission. It will clearly miss the 2023 Survey, but may be by a couple of years. If what they find is interesting enough, they might get their money faster (because of shorter transit times). I know that the SLS cost is quite a difficult matter. So I'm not speculating on the probabilities of each scenario, just on the consequences.
BTW, given that this mission isn't even approved, aren't they speculating on a FH service? It might save a gravity assist. Or be cheap enough to procure a Star 48GXV to add some extra delta-v margin. Again, this mission is so far in the future that even the next ULA's LV might well be an option.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 11/25/2014 05:53 pm
Faster transit times and return of data are good things (although that has to be compared to cost). But I would add that a major pacing item between missions is funding. You might be able to throw EC at Europa faster, but that doesn't mean you can fund the follow-on mission any faster. You still have to pay for it. And presumably you have to let the Decadal Survey choose the priorities.
Well, but that might well mean that a faster mission might generate enough interest to accelerate funding for a follow up mission. It will clearly miss the 2023 Survey, but may be by a couple of years. If what they find is interesting enough, they might get their money faster (because of shorter transit times). I know that the SLS cost is quite a difficult matter. So I'm not speculating on the probabilities of each scenario, just on the consequences.
BTW, given that this mission isn't even approved, aren't they speculating on a FH service? It might save a gravity assist. Or be cheap enough to procure a Star 48GXV to add some extra delta-v margin. Again, this mission is so far in the future that even the next ULA's LV might well be an option.

They are only evaluating SLS as an option because they were told to do that. Until other rockets fly, I don't think they will really consider them in their trade studies.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 11/25/2014 08:52 pm
JUICE
JUpiter ICy moons Explorer
Exploring the emergence of habitable worlds around gas giants
Definition Study Report
Title: Re: Proposed Europa Missions
Post by: baldusi on 11/25/2014 09:18 pm
So, when the FH gets in the NLS II contract, they will be able to study its use? That might be available by 2016. and the Delta IV Heavy is being used for EFT-1 and (probably) Solar Probe Plus. So it might be quite available, too. So it would seem like the SLS option is purely political. In your experience, would this mission receive an ATP before 2017? And could it be politically married to the SLS?
Title: Re: Proposed Europa Missions
Post by: Blackstar on 11/26/2014 12:29 am
1-So, when the FH gets in the NLS II contract, they will be able to study its use?

2-and the Delta IV Heavy is being used for EFT-1 and (probably) Solar Probe Plus. So it might be quite available, too.

3-So it would seem like the SLS option is purely political.

4-In your experience, would this mission receive an ATP before 2017?

5-And could it be politically married to the SLS?

1-They could probably study it before then. However, I believe that FH lacks an upper stage required for planetary missions. In fact, a few weeks ago I met some guy from some company that I forget (Aerojet-Rocketdyne?) that is currently studying an upper stage for Falcon Heavy so that it can be offered for Solar Probe Plus. Maybe there is more information about that elsewhere on this site. However, keep in mind that SpaceX's cost savings are exaggerated, and the fainting phanboys on this site don't understand the actual costs. The best comparison is what NASA pays for a Falcon 9 and what it pays for an Atlas V of similar capability under the launch services contract. Falcon is cheaper, but not THAT much cheaper. The same will be true comparing a Falcon Heavy to a Delta IV Heavy, especially if that Falcon Heavy is equipped with a new upper stage.

2-Yeah, but it's expensive. When we did the DS, the Aerospace Corp guys who were doing the CATE for Europa Orbiter warned us that it was at risk of moving from an Atlas V to a Delta IV, which would substantially increase launch costs. Nobody wants a big expensive rocket if they can avoid it.

3-I would not say "purely political." I would say "mostly" political. But yes.

4-What do you mean "ATP"? Is that a new start? I think that it is possible. But there's a window--It is possible it can get a new start during the next few years, but I think that the likelihood drops later in the decade when people start saying "Let's wait and see if the new decadal survey says that we should do a Europa mission." There is still a large uncertainty factor, however. Culberson is a new important ally for the Europa mission. But how powerful is he? Also, it would be VERY BAD if we got a Europa Clipper mission at the expense of New Frontiers and Discovery. New Frontiers is already unfunded. There are important missions in New Frontiers and they are competed. They deserve a chance.

5-Yes.

Title: Re: Proposed Europa Missions
Post by: HIP2BSQRE on 11/26/2014 12:53 am
How much does NASA pay for a Falcon 9 and a comparable Atlas?
Title: Re: Proposed Europa Missions
Post by: baldusi on 11/26/2014 02:26 am
ATP: Authorization To Proceed, that was what I understand was a new start.
Regarding the numbers, I believe that a F9 is about 160M for a NASA mission and an Atlas V 551 was expected to be 320M. Or those are the numbers from the MSR missin trades I remember. If I'm not mistaken those numbers include everything, from LV to integration, certification and mission specific mods. I expected a FH to cost 250M with better than 551 performance. But the FH high C3 curve will probably fall a lot faster than a Delta IV Heavy/ AV551. The question is where does it crosses. FH is expected to throw more than 10tonnes to a 13km2/s2 C3, which I believes trumps both ULA LV. But I have no comparison for the DIVH nor the Europa C3 requirement.
Title: Re: Proposed Europa Missions
Post by: rcoppola on 11/26/2014 02:41 am
ATP: Authorization To Proceed, that was what I understand was a new start.
Regarding the numbers, I believe that a F9 is about 160M for a NASA mission and an Atlas V 551 was expected to be 320M. Or those are the numbers from the MSR missin trades I remember. If I'm not mistaken those numbers include everything, from LV to integration, certification and mission specific mods. I expected a FH to cost 250M with better than 551 performance. But the FH high C3 curve will probably fall a lot faster than a Delta IV Heavy/ AV551. The question is where does it crosses. FH is expected to throw more than 10tonnes to a 13km2/s2 C3, which I believes trumps both ULA LV. But I have no comparison for the DIVH nor the Europa C3 requirement.
Doesn't the F9 160M number for NASA you mentioned include Dragon? 
Title: Re: Proposed Europa Missions
Post by: ncb1397 on 11/26/2014 08:41 am
How much does NASA pay for a Falcon 9 and a comparable Atlas?

Quote
CAPE CANAVERAL, Fla. -- NASA has selected Space Exploration Technologies (SpaceX) of Hawthorne, Calif., to launch the National Oceanic and Atmospheric Administration's (NOAA) Jason-3 spacecraft in December 2014 aboard a Falcon 9 v1.0 rocket from Complex 4 at Vandenberg Air Force Base in California.

The total value of the Jason-3 launch service is approximately $82 million. This estimated cost includes the task ordered launch service for the Falcon 9 v1.0, plus additional services under other contracts for payload processing, launch vehicle integration, mission-unique launch site ground support and tracking, data and telemetry services. NASA is the procurement agent for NOAA.
http://www.nasa.gov/home/hqnews/2012/jul/HQ_C12-029_RSLP-20_Launch_Services.html

Quote
CAPE CANAVERAL, Fla. -- NASA has selected United Launch Services, LLC of Littleton, Colo., to launch the Mars Atmosphere and Volatile Evolution spacecraft known as MAVEN. MAVEN will launch in November 2013 aboard an Atlas V 401 rocket from Complex 41 at Cape Canaveral Air Force Station, Fla.

The total cost value for the MAVEN launch service is approximately $187 million. This estimated cost includes the task ordered launch service for the Atlas plus additional services under other contracts for payload processing; launch vehicle integration; mission unique launch site ground support; and tracking, data and telemetry services.
http://www.nasa.gov/home/hqnews/2010/oct/HQ_C10-065_Maven_Services.html

82 million vs 187 million...(counting other launch related costs not part of the launch contract)

edit: more recent data points

Quote
InSight will launch in March 2016 aboard an Atlas V 401 rocket from Space Launch Complex 3E at Vandenberg Air Force Base in California.
The total cost for NASA to launch InSight is approximately $160 million, including spacecraft processing, payload integration, tracking, data and telemetry and other launch support requirements.
http://www.nasa.gov/press/2013/december/nasa-awards-launch-services-contract-for-insight-mission/#.VHWzINLF_X4

Quote
NASA has selected United Launch Services LLC of Centennial, Colo., to launch the Solar Orbiter Collaboration mission to study the sun in July 2017. The Solar Orbiter will launch on an Atlas V 411 rocket from Space Launch Complex 41 at Cape Canaveral Air Force Station, Florida.
The total cost for NASA to launch the Solar Orbiter is approximately $172.7 million, which includes the launch service, spacecraft processing, payload integration, tracking, data and telemetry and other launch support requirements.
http://www.nasa.gov/press/2014/march/nasa-awards-launch-services-contract-for-solar-orbiter-mission/#.VHWzW9LF_X4
Title: Re: Proposed Europa Missions
Post by: Proponent on 11/26/2014 09:40 am
Is it possible to estimate the marginal cost of each additional year of interplanetary cruise?
Title: Re: Proposed Europa Missions
Post by: Blackstar on 11/26/2014 02:09 pm
Is it possible to estimate the marginal cost of each additional year of interplanetary cruise?

The place to start would be with the cost for New Horizons.
Title: Re: Proposed Europa Missions
Post by: vjkane on 11/26/2014 04:20 pm
Is it possible to estimate the marginal cost of each additional year of interplanetary cruise?

In various OPAG meetings, a cost of $7-10M a year has been quoted in the context of the penalty that outer planet (and any mission with a long cruise) faces in Discovery mission proposals.  (The newest Discovery Announcement of Opportunity has NASA picking up the cost of "reasonable" cruise costs to level the playing field.)
Title: Re: Proposed Europa Missions
Post by: vjkane on 11/26/2014 08:21 pm
Is it possible to estimate the marginal cost of each additional year of interplanetary cruise?

In various OPAG meetings, a cost of $7-10M a year has been quoted in the context of the penalty that outer planet (and any mission with a long cruise) faces in Discovery mission proposals.  (The newest Discovery Announcement of Opportunity has NASA picking up the cost of "reasonable" cruise costs to level the playing field.)
Title: Re: Proposed Europa Missions
Post by: Vultur on 11/27/2014 01:30 am
HOWEVER, even these simple landers would be expensive (we learned from the Beagle 2 experience that short cuts don't work in designing landers) and would not fit within the budget of the Europa Clipper.  That said, if the Europa Clipper launches on the SLS (which I personally do not ever expect to see fly) there would be plenty of mass margin for a simple contributed lander.  But mission creep is a dangerous thing.

Actually, I talked to one of the people involved in the SLS/EC evaluation and he said that the surprising thing is that there is less mass margin for the SLS version than one using an Atlas. The reason is that SLS puts all its energy into velocity, whereas the gravity assist version using Atlas trades speed for a bit more payload capability.

An interesting question, however, concerns the next steps after EC. I've heard that there is some grumbling over this among the outer planets community. They want Europa to be treated somewhat like Mars, with a "campaign" of missions to Europa--EC with its flybys followed by an orbiter followed by a lander. But the problem with that is that every mission to Europa is going to be expensive, in the multi-billions class. So they're making an argument that they should get a whole bunch of flagships. Meanwhile, there is an argument from elsewhere that they should do EC right so that it will enable a Europa lander as the follow-on mission. And considering the time between these missions, you gotta admit that it makes sense to go to a lander next, because going to an orbiter (unless you really really have to) means that the lander won't happen for another 30 years at least.

That would make sense. I think there's a very good argument for Europa being the top priority of planetary science (or Enceladus, but Juno is demonstrating solar at Jupiter's distance so no RTGs needed, and it's much closer/quicker).
Title: Re: Proposed Europa Missions
Post by: redliox on 11/29/2014 08:53 am
While Europa Clipper's under debate, it now looks like ESA's JUICE may soon be under construction (quoted from ESA's webpage):

Quote
The European Space Agency's JUICE (JUpiter ICy moons Explorer) mission has been given the green light to proceed to the next stage of development. This approval is a milestone for the mission, which aims to launch in 2022 to explore Jupiter and its potentially habitable icy moons.

JUICE gained approval for its implementation phase from ESA’s Science Programme Committee during a meeting at the European Space Astronomy Centre near Madrid, Spain, on 19 and 20 November 2014.

---------

At the November 2014 meeting of the SPC, the multilateral agreement for JUICE was also approved. This agreement provides the legal framework for provision of payload equipment and ongoing mission support between funding agencies. The parties to the agreement are the European Space Agency and the funding agencies of the European countries leading the instrument developments in the JUICE mission: the Agenzia Spaziale Italiana (Italy); the Centre National d’Etudes Spatiales (France); the Deutsches Zentrum für Luft- und Raumfahrt e.V. (Germany); the Swedish National Space Board, and the United Kingdom Space Agency. Austria, Belgium, the Czech Republic, Greece, Poland, and Switzerland participate via the PRODEX programme.
Title: Re: Proposed Europa Missions
Post by: Targeteer on 11/30/2014 07:01 am
A really good article on how Pu-238 production is restarting, slowly

http://www.nature.com/news/nuclear-power-desperately-seeking-plutonium-1.16411

"NASA has 35 kilograms of plutonium-238 to power its deep-space missions — but that will not get it very far."
Title: Proposed Europa Missions
Post by: Star One on 12/03/2014 05:30 pm
Well at least one politician seems keen on a Europa mission.

Quote
Culberson — the only lawmaker who attended the public portion of the Planetary Society’s program in the Dirksen Senate office building here — was especially keen on funding a mission to Europa: Jupiter’s ice-encrusted moon with a subterranean ocean of briny water that many scientists believe harbors the heat and chemical elements necessary for life as we know it.

Culberson, for his part, is already a step beyond scientific skepticism.

“I’m convinced that when we discover life on another world, it will be in the oceans of Europa. I want to be there to be a part of that,” Culberson said in a two-minute speech that served as the unofficial kickoff for the society’s event.

Officially, NASA has no Europa mission on the books. However, instrument and mission studies on the so-called Clipper concept have been ongoing since 2012 at the NASA’s Jet Propulsion Laboratory in Pasadena, and the Johns Hopkins Applied Physics Laboratory in Laurel, Maryland. The solar-powered Clipper ship would launch in the 2020s and enter orbit around Jupiter, where it would fly by Europa multiple times to map the icy moon in greater detail than ever before.

NASA teams have said the Clipper mission would cost about $2 billion. The White House, as part of the 2015 budget request it released in April, asked the agency to study whether the mission could be done for $1 billion. In a November meeting of the NASA Advisory Council’s planetary science subcommittee, Jim Green, head of NASA’s Planetary Science Division, said NASA probably could not answer important scientific questions with a $1 billion Europa orbiter.

After the White House unveiled a 2015 budget request earlier this year that sought $15 million for Europa mission studies, Culberson bumped that figure to $100 million in the 2015 Commerce, Justice, Science spending bill that passed the full House in May. The Senate’s version of the bill, which has not made it to the floor, prescribed only $79 million for NASA’s entire outer planets program, of which Europa is only one part.

The Senate mentioned Europa by name only in the report accompanying their stalled bill, which said any mission to the icy moon should launch on the Space Launch System heavy-lift rocket NASA is building.

http://www.spacenews.com/article/civil-space/42823rep-culberson-drops-in-to-pledge-planetary-science-support
Title: Re: Proposed Europa Missions
Post by: Blackstar on 12/08/2014 11:25 pm
Europa Clipper electronics vault mockup. Photo from Twitter.
Title: Re: Proposed Europa Missions
Post by: Malderi on 12/10/2014 12:32 am
For a mission that doesn't exist, that's a nice picture.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 12/10/2014 02:11 am
JPL does some interesting mockup work. This is obviously very low fidelity, probably just to prove that they can fit things where they need to.

I've got some interesting pictures of a lunar lander design that has not yet been built. They built a full scale mockup of the thing, and a high fidelity mockup of an important part.
Title: Re: Proposed Europa Missions
Post by: Sesquipedalian on 12/10/2014 02:37 pm
I've got some interesting pictures of a lunar lander design that has not yet been built. They built a full scale mockup of the thing, and a high fidelity mockup of an important part.

Can they be posted?
Title: Re: Proposed Europa Missions
Post by: Blackstar on 12/12/2014 04:14 pm
I've got some interesting pictures of a lunar lander design that has not yet been built. They built a full scale mockup of the thing, and a high fidelity mockup of an important part.

Can they be posted?

I'm saving them for an article I'm going to publish.
Title: Re: Proposed Europa Missions
Post by: rcoppola on 12/16/2014 04:15 pm
Not sure if this was listed in another thread but as of last Saturday night through final passage of the the so-called Cromnibus bill for FY 2015 Govt funding, NASA received that $100Million to begin designing a Europa mission.

Our next great planetary (well, moon actually) mission. If there is current life in our planetary system, liquid water, under ice with warm vents providing heat energy from internal friction caused by the massive gravitational pulls of Jupiter, may very well be the place to finally find it.

So the next of many questions...will it be designed for SLS to launch?
Title: Re: Proposed Europa Missions
Post by: Blackstar on 12/16/2014 04:35 pm
1-Our next great planetary (well, moon actually) mission. If there is current life in our planetary system, liquid water, under ice with warm vents providing heat energy from internal friction caused by the massive gravitational pulls of Jupiter, may very well be the place to finally find it.

2-So the next of many questions...will it be designed for SLS to launch?

1-Maybe. Or maybe not. Congress can keep stuffing money into the Europa budget, but without a formal "new start" from OMB the mission won't happen.

2-Not yet. They'll hold off on a launch decision as long as they can. Unfortunately, holding off the design to be able to launch on either an Atlas V or SLS can become increasingly expensive (ask Alan Stern about their experience with New Horizons when they were forced to do the same for Atlas or Delta).

At the moment, it is probably easier and cheaper to design for an Atlas V launch because all the performance specs for Atlas V are well known. That cannot be said for SLS. For example, what is the acoustic environment inside the SLS payload shroud?
Title: Re: Proposed Europa Missions
Post by: rcoppola on 12/16/2014 04:40 pm
1-Our next great planetary (well, moon actually) mission. If there is current life in our planetary system, liquid water, under ice with warm vents providing heat energy from internal friction caused by the massive gravitational pulls of Jupiter, may very well be the place to finally find it.

2-So the next of many questions...will it be designed for SLS to launch?

1-Maybe. Or maybe not. Congress can keep stuffing money into the Europa budget, but without a formal "new start" from OMB the mission won't happen.

2-Not yet. They'll hold off on a launch decision as long as they can. Unfortunately, holding off the design to be able to launch on either an Atlas V or SLS can become increasingly expensive (ask Alan Stern about their experience with New Horizons when they were forced to do the same for Atlas or Delta).

At the moment, it is probably easier and cheaper to design for an Atlas V launch because all the performance specs for Atlas V are well known. That cannot be said for SLS. For example, what is the acoustic environment inside the SLS payload shroud?
Thanks for the response. In reference to the launcher decision... I imagine that "if" the SLS could cut the transit time in half, that would certainly alter how they architect the systems? Or no?
Title: Re: Proposed Europa Missions
Post by: Blackstar on 12/16/2014 05:54 pm
Thanks for the response. In reference to the launcher decision... I imagine that "if" the SLS could cut the transit time in half, that would certainly alter how they architect the systems? Or no?

Absolutely. First of all, if EC does not have to do the Venus flybys, then they can take off the thermal protection. So how long do they keep designing the vehicle with thermal protection and without it? That's two designs, more money, etc.

Also, a much shorter trip time may affect how much they have to test the spacecraft. But that could be a tricky issue. I'll provide a caveat that I'm not an expert on any of that stuff (remember, I'm a policy wonk), but generally a lot of testing is for lifetime. So they test something to see how long it will last. And if they can test it for a shorter lifetime that costs less.

So an EC that only has to last, say, three years is going to cost less to test than an EC that has to last nine years. That said, I suspect that for EC the dominant issue for testing is the radiation environment at Jupiter, and that's going to be the same no matter how long it takes to get to Europa. (I could be wrong about that. Spacecraft get tested for overall radiation dose, and flying for 5-7-9 years through the inner solar system still gives the spacecraft a lot of galactic cosmic radiation to deal with before it ever gets to Jupiter.) Bottom line is that I should stop talking about this and go find an expert.
Title: Re: Proposed Europa Missions
Post by: JasonAW3 on 12/16/2014 07:09 pm
Thanks for the response. In reference to the launcher decision... I imagine that "if" the SLS could cut the transit time in half, that would certainly alter how they architect the systems? Or no?

Absolutely. First of all, if EC does not have to do the Venus flybys, then they can take off the thermal protection. So how long do they keep designing the vehicle with thermal protection and without it? That's two designs, more money, etc.

Also, a much shorter trip time may affect how much they have to test the spacecraft. But that could be a tricky issue. I'll provide a caveat that I'm not an expert on any of that stuff (remember, I'm a policy wonk), but generally a lot of testing is for lifetime. So they test something to see how long it will last. And if they can test it for a shorter lifetime that costs less.

So an EC that only has to last, say, three years is going to cost less to test than an EC that has to last nine years. That said, I suspect that for EC the dominant issue for testing is the radiation environment at Jupiter, and that's going to be the same no matter how long it takes to get to Europa. (I could be wrong about that. Spacecraft get tested for overall radiation dose, and flying for 5-7-9 years through the inner solar system still gives the spacecraft a lot of galactic cosmic radiation to deal with before it ever gets to Jupiter.) Bottom line is that I should stop talking about this and go find an expert.

In regards to the thermal protection;  Not quite true.  The Europa Mission would be heading out into a very could region of space, so while SOME thermal protection could be removed, you're still going to have to protect a lot of very sensitive equipment from the cold out around Europa. Most thermal protection blankets work both ways, keeping heat out or cold out.

Assuming a similar but shorter mission, the mass savings is likely to be insignificant, other for power supplies.  Essentially, the same instrunments that would be for the short duration mission would be the ones that would be used on the longer term mission.

While radiation is an issue using more expensive radiation and EM hardened circuits and systems, while more expensive, would assure a longer lasting and more reliable while adding an insignicant amount of mass to the overall craft.  (Note: This only applies to hardened systems that do not require a specialized radiation shielded compartment, which could require a variety of materials from PEC to alloyed aluminium.)

Overall; a probe with the correct set of instrunments could not only be used for going simply to Europa, but could be used, using an ION drive, to do comprehensive comparitive studies of the other Jovian moons.  And perhaps beyond.  Spaghettie orbits aroundthe primary and associated moons could build up the velocity needed for orbit changes that could include the outer planets, the Kuiper belt, or possibly even the Oort cloud. 

Title: Re: Proposed Europa Missions
Post by: Jim on 12/16/2014 08:00 pm

1.  In regards to the thermal protection;  Not quite true.  The Europa Mission would be heading out into a very could region of space, so while SOME thermal protection could be removed, you're still going to have to protect a lot of very sensitive equipment from the cold out around Europa. Most thermal protection blankets work both ways, keeping heat out or cold out.

2.  Assuming a similar but shorter mission, the mass savings is likely to be insignificant, other for power supplies.  Essentially, the same instrunments that would be for the short duration mission would be the ones that would be used on the longer term mission.

3.  Overall; a probe with the correct set of instrunments could not only be used for going simply to Europa, but could be used, using an ION drive, to do comprehensive comparitive studies of the other Jovian moons.  And perhaps beyond.  Spaghettie orbits aroundthe primary and associated moons could build up the velocity needed for orbit changes that could include the outer planets, the Kuiper belt, or possibly even the Oort cloud. 


1.  Yes, quite true and you got it wrong.   There are differences in thermal blankets for keeping out heat vs holding it in

2.  Longer mission can carry more mass than the shorter mission.

3.  Not true for many reasons
a.  The instruments are specific to Europa.
b.  They are useless for outside of the Jovian system
c.  The spacecraft is not going to have the energy to leave the system
d.  There is no power for the ion drive
e. there is no power to operate past Jupiter.  You do realize that this is a solar powered mission.

These comments don't a show a knowledge of spacecraft design.
Title: Re: Proposed Europa Missions
Post by: arachnitect on 12/16/2014 10:26 pm

1-Maybe. Or maybe not. Congress can keep stuffing money into the Europa budget, but without a formal "new start" from OMB the mission won't happen.


I don't know if the answer to this is publicly available but I'm curious, who makes spaceflight decisions/recommendations at OMB? Do they have in house people who do only that, or is it a committee, or like 1 person who talks to John Holdren or something?

A certain amount of our space policy seems to be coming out of "OMB,"  presumably there are people doing this stuff but I have no idea who they actually are.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 12/17/2014 01:54 am
They have divisions within OMB. And then they have "examiners" within those divisions. There are about 4-5 people at OMB responsible for overseeing the NASA budget. That's it. The only advice they get is from their senior political appointees at OMB. They also interact with NASA.
Title: Re: Proposed Europa Missions
Post by: Proponent on 12/17/2014 04:44 pm
You do realize that this [Europa Clipper] is a solar powered mission.

I thought that was only for the SLS version, in order to avoid having to nuclear-rate SLS.

Am I wrong?  If so (entirely possible), is the Atlas V version of the spacecraft driven to use solar entirely for intrinsic reasons, or is limiting the number of differences between the two versions a significant factor?
Title: Re: Proposed Europa Missions
Post by: Proponent on 12/17/2014 04:51 pm
Thanks for the response. In reference to the launcher decision... I imagine that "if" the SLS could cut the transit time in half, that would certainly alter how they architect the systems? Or no?

Absolutely. First of all, if EC does not have to do the Venus flybys, then they can take off the thermal protection. So how long do they keep designing the vehicle with thermal protection and without it? That's two designs, more money, etc.

Also, a much shorter trip time may affect how much they have to test the spacecraft. But that could be a tricky issue. I'll provide a caveat that I'm not an expert on any of that stuff (remember, I'm a policy wonk), but generally a lot of testing is for lifetime. So they test something to see how long it will last. And if they can test it for a shorter lifetime that costs less.

So an EC that only has to last, say, three years is going to cost less to test than an EC that has to last nine years. That said, I suspect that for EC the dominant issue for testing is the radiation environment at Jupiter, and that's going to be the same no matter how long it takes to get to Europa. (I could be wrong about that. Spacecraft get tested for overall radiation dose, and flying for 5-7-9 years through the inner solar system still gives the spacecraft a lot of galactic cosmic radiation to deal with before it ever gets to Jupiter.) Bottom line is that I should stop talking about this and go find an expert.

Thanks a lot -- that's very interesting.  Two big take-aways for me.  First is the point about the faster mission possibly having significantly cheaper testing.  Obviously, that's a factor in favor of the SLS version.  It seems to me that could easily constitute a bigger savings than the reduction the cost of support for support during cruise that is afforded by the faster trajectory (which I doubt would be very significant).

The other point is that even just considering SLS increases costs, because two designs must be pursued until one is selected (assuming the mission is ever approved).
Title: Re: Proposed Europa Missions
Post by: Blackstar on 12/17/2014 04:52 pm
You do realize that this [Europa Clipper] is a solar powered mission.

I thought that was only for the SLS version, in order to avoid having to nuclear-rate SLS.

Am I wrong?  If so (entirely possible), is the Atlas V version of the spacecraft driven to use solar entirely for intrinsic reasons, or is limiting the number of differences between the two versions a significant factor?

Right now, at this moment, Europa Clipper is baselined for SLS, and baselined for solar.

But it's still a study. It's not in Phase A development. And in fact, I imagine that some people would argue that it's not even in "pre-Phase A" development. (But I'm guessing that the definitions of that are kinda squishy.) Until it actually gets a new start and gets into Phase A development things like the launch vehicle and the power supply are not set in stone. And those are decisions that will be made ABOVE the level of the people currently doing the study, at NASA Headquarters. A group of senior NASA officials are going to say at some point "Come to Washington and sit with us in a room for 10 hours and convince us that solar can do the job and is not too risky for a $2.5 billion space mission." And they'll want to be convinced before they say okay.

Now I think it will be easier to convince people after Juno's solar panels operate in Jupiter's radiation for awhile. So it is an argument that is easier to make in 2017 than it is right now.
Title: Re: Proposed Europa Missions
Post by: vjkane on 12/17/2014 04:55 pm
Is the current estimate really $2.5B?  Last I heard, it was hovering around $2B.  Is the larger figure with launch vehicle?
Title: Re: Proposed Europa Missions
Post by: Blackstar on 12/17/2014 04:56 pm
The other point is that even just considering SLS increases costs, because two designs must be pursued until one is selected (assuming the mission is ever approved).

Well, right now the cost increase is probably not all that great. They don't have hundreds of engineers working on it. The cost of considering two launch vehicles increases over time, so that's the kind of thing that they really want to nail down as soon as possible. But they probably don't have to nail it down for awhile.

As a sidenote, the EC team was at one point considering RTG, solar, and ASRG for power. They stopped considering ASRG and one of the reasons was that the ASRG program was put on hold, but another was that they didn't have the resources (people) to keep evaluating three options. So they eliminated one because of cost. That's an example of the kinds of decisions they have to make in the study phase.

Title: Re: Proposed Europa Missions
Post by: Blackstar on 12/17/2014 04:58 pm
Is the current estimate really $2.5B?  Last I heard, it was hovering around $2B.  Is the larger figure with launch vehicle?

I'm spitballing it. It's going to be in that range. And of course the cost depends upon launch vehicle, power supply, and when they actually start it. Money costs more in 2020 than it does in 2019, for example.
Title: Re: Proposed Europa Missions
Post by: Sesquipedalian on 12/17/2014 06:55 pm
But it's still a study. It's not in Phase A development. And in fact, I imagine that some people would argue that it's not even in "pre-Phase A" development.

As I recall, this was one of the arguments against dribbling out funds earmarked for Europa Clipper in increments of $12-15 million.  At some point you have to fish or cut bait; you can't hold course on a $2.5 billion program with only $15 million per year.

And now that they have $100 million to do pretty much the same thing, can they really do anything besides run in place a little faster?

Such as:

They stopped considering ASRG and one of the reasons was that the ASRG program was put on hold, but another was that they didn't have the resources (people) to keep evaluating three options. So they eliminated one because of cost.

Well the $100 million should remove that constraint, at least for the study.  Can they use any sort of programmatic maneuvering* to take the ASRG off hold status with the justification to use it for Europa Clipper?  Advancing ASRG is a tangible benefit that would be more valuable than more studies and paperwork, IMAO (in my armchair opinion).


* For clarity: yes, I know the $100 million is earmarked specifically for Europa Clipper and isn't money that NASA can reallocate to whatever program it wants on an as-needed basis.  That's why I asked if it could be maneuvered under the Europa Clipper umbrella.  Bureaucratic sleight-of-hand happens all the time; one example was the rationale to continue processing MAVEN despite the government shutdown.
Title: Re: Proposed Europa Missions
Post by: MP99 on 12/17/2014 07:44 pm
NASA has two basic Europa Clipper missions under study. The SLS one doesn't use gravity assist. It has slightly lower throw weight to Jupiter.

If the SLS verions used the gravity assist, wouldn't it then have the higher throw weight?

cheers, Martin
Title: Re: Proposed Europa Missions
Post by: vjkane on 12/17/2014 08:36 pm
re: $100M for Europa Clipper

I am suspecting that soon JPL is going to run out of pre-project activities it can do for the mission.  At this point, there's been something like $200M over 2-3 years.

You can't build this mission drips and drabs (even ignoring the requirement for an OMB-sanctioned new start).  At peak funding, the project probably will require something around $500M a year for a couple of years.

Short of a major increase in the planetary science budget, there just isn't room in the budget until the peak spending passes on the 2020 rover (and that's assuming that there's no New Frontiers missions).

I think that Congress has made its desire known.  At this point, it's up to OMB.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 12/17/2014 11:24 pm
NASA has two basic Europa Clipper missions under study. The SLS one doesn't use gravity assist. It has slightly lower throw weight to Jupiter.

If the SLS verions used the gravity assist, wouldn't it then have the higher throw weight?

cheers, Martin

Yeah, but the important issue is not mass to Europa. The trade is really time and the costs associated with that.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 12/17/2014 11:31 pm
re: $100M for Europa Clipper

I am suspecting that soon JPL is going to run out of pre-project activities it can do for the mission.  At this point, there's been something like $200M over 2-3 years.

Yeah, I think that it would be interesting to see the accounting for this so far. What has JPL done with all that money? There's really only so much you can spend without bending metal. It's things like contracts and purchasing instruments that spends real money.

I have heard--don't know how true this is--that JPL up until a year or so ago still had a lot of money left over in the Europa account. They just couldn't spend it all, or at least they couldn't spend it all on stuff that was legitimately Europa-related. So it was sitting around in the account, unspent. If you think about it, that's a really inefficient way to run a planetary program, because that money could certainly be used for other things, but instead it's sitting unused.

This is all just obscure budget politics, but what Congress has been doing for several years is not funding a Europa program, but trying to force OMB to start one. And until OMB does, it's just a really inefficient way to spend money that could be used for other things.
Title: Re: Proposed Europa Missions
Post by: vjkane on 12/18/2014 12:25 am
re: $100M for Europa Clipper

I am suspecting that soon JPL is going to run out of pre-project activities it can do for the mission.  At this point, there's been something like $200M over 2-3 years.

Yeah, I think that it would be interesting to see the accounting for this so far. What has JPL done with all that money? There's really only so much you can spend without bending metal. It's things like contracts and purchasing instruments that spends real money.

My guess is that JPL is banking the money they can't spend (as far a permissible) against the day that the mission is approved.  The other alternative I can think of is that they design and build 'prototypes' of the higher risk elements of the mission.  Any portion of the instruments outside the radiation vault would certainly count.  They could also, for example, design in the new space-borne atomic clock to vastly improve the gravity measurements, for example, which is a subsystem that is flight ready but never flown, so there's always more risk.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 12/18/2014 03:36 am
My guess is that JPL is banking the money they can't spend (as far a permissible) against the day that the mission is approved.

They can't really do that. Money lasts for two years, then it has to go back to the Treasury.
Title: Re: Proposed Europa Missions
Post by: baldusi on 12/18/2014 04:00 am
What about funding technology development, like high efficiency solar cells, validating the atomic clock in a cubesat, etc.
Title: Re: Proposed Europa Missions
Post by: vjkane on 12/18/2014 04:06 am
My guess is that JPL is banking the money they can't spend (as far a permissible) against the day that the mission is approved.

They can't really do that. Money lasts for two years, then it has to go back to the Treasury.

For the federal agencies that fund my research, they have 'spent' their funding (which expires annually) once there is a signed contract with my university, but I have up to five years (depending on the initial term and any extensions) to draw on the funds.  JPL/NASA may have similar options to commit the funds to outside organizations.
Title: Re: Proposed Europa Missions
Post by: savuporo on 12/18/2014 05:08 am
As a sidenote, the EC team was at one point considering RTG, solar, and ASRG for power. They stopped considering ASRG and one of the reasons was that the ASRG program was put on hold, but another was that they didn't have the resources (people) to keep evaluating three options. So they eliminated one because of cost. That's an example of the kinds of decisions they have to make in the study phase.

This was another case of chicken, egg, and screw technology development
http://www.planetary.org/blogs/casey-dreier/2013/20130905-no-asrgs-for-europa.html
Quote
A planned long-duration mock mission of the ASRG was canceled this summer due to budget cuts related to the sequester..According to the presented slides, the lack of any previous missions using ASRGs, as well as reliability questions of the moving piston within harsh radiation environment around Europa created an unacceptable risk engineering and cost risk for the mission.
Title: Re: Proposed Europa Missions
Post by: Sesquipedalian on 12/18/2014 04:38 pm
I'll repeat the question I asked yesterday...

Can they use any sort of programmatic maneuvering to take the ASRG off hold status with the justification to use it for Europa Clipper?  Advancing ASRG is a tangible benefit that would be more valuable than more studies and paperwork, IMAO (in my armchair opinion).
Title: Re: Proposed Europa Missions
Post by: Blackstar on 12/18/2014 09:26 pm
I'll repeat the question I asked yesterday...

Can they use any sort of programmatic maneuvering to take the ASRG off hold status with the justification to use it for Europa Clipper?  Advancing ASRG is a tangible benefit that would be more valuable than more studies and paperwork, IMAO (in my armchair opinion).

No. No money. ASRG got put on hold for a couple of reasons: the cost had started to increase (after it had been steady), and NASA's planetary budget got whacked. Something had to go. They weren't willing to shut off working missions or kill something in development. It was not an easy decision, but they had to make a decision.

I also suspect that JPL would not really want to put money into the ASRG because it's not under their roof. So they're not going to advocate for something like that.
Title: Re: Proposed Europa Missions
Post by: Sesquipedalian on 12/19/2014 04:30 am
No. No money.

There's $100 million that Europa Clipper has now that it didn't have before.  That's why I was so pedantic here (http://forum.nasaspaceflight.com/index.php?topic=27871.msg1303965#msg1303965) about saying under the umbrella of Europa Clipper.

Quote
I also suspect that JPL would not really want to put money into the ASRG because it's not under their roof. So they're not going to advocate for something like that.

That part makes sense.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 12/19/2014 05:07 pm
No. No money.

There's $100 million that Europa Clipper has now that it didn't have before.  That's why I was so pedantic here (http://forum.nasaspaceflight.com/index.php?topic=27871.msg1303965#msg1303965) about saying under the umbrella of Europa Clipper.



Except that ASRG is not Europa Clipper. If NASA tried to spend the money designated for EC on the ASRG program, they'd be in violation of the Anti-Deficiency Act. Couldn't do it.
Title: Re: Proposed Europa Missions
Post by: Sesquipedalian on 12/20/2014 08:43 pm
Except that ASRG is not Europa Clipper. If NASA tried to spend the money designated for EC on the ASRG program, they'd be in violation of the Anti-Deficiency Act. Couldn't do it.

I'm not saying take money from one program and move it to another, as I made clear here:

* For clarity: yes, I know the $100 million is earmarked specifically for Europa Clipper and isn't money that NASA can reallocate to whatever program it wants on an as-needed basis.  That's why I asked if it could be maneuvered under the Europa Clipper umbrella.  Bureaucratic sleight-of-hand happens all the time; one example was the rationale to continue processing MAVEN despite the government shutdown.

I said "put it under the umbrella", not "swap the programs".  Another way to think of it is to imagine a program manager saying "We've determined that ASRG is one of the enabling technologies for Europa Clipper and we are going to investigate it in parallel with solar".  A funding of "technology development" as baldusi said here (http://forum.nasaspaceflight.com/index.php?topic=27871.msg1304325#msg1304325).
Title: Re: Proposed Europa Missions
Post by: vjkane on 12/20/2014 11:10 pm
I said "put it under the umbrella", not "swap the programs".  Another way to think of it is to imagine a program manager saying "We've determined that ASRG is one of the enabling technologies for Europa Clipper and we are going to investigate it in parallel with solar".  A funding of "technology development" as baldusi said here (http://forum.nasaspaceflight.com/index.php?topic=27871.msg1304325#msg1304325).
If the Europa Clipper required ASRGs to do it's mission, like it depends on radiation hardened electronics, then NASA could do this.  But the Clipper mission can be done with solar panels or MMRTGs.

Also, the ASRG program hit technical problems and was about to have a major cost overrun when it was cancelled.  It would take considerably more than $100M to complete the program.  And to what purpose?  The gating factor on producing any new radioisotope units (MMRTGs, ASRGs) is rebuilding the manufacturing equipment that turns out to be severely degraded.

There are also plans to significantly improve the performance of MMRTGs.  30% sticks in my mind, but the specific number is likely wrong. 
Title: Re: Proposed Europa Missions
Post by: Blackstar on 12/20/2014 11:47 pm
I said "put it under the umbrella", not "swap the programs".  Another way to think of it is to imagine a program manager saying "We've determined that ASRG is one of the enabling technologies for Europa Clipper and we are going to investigate it in parallel with solar".  A funding of "technology development" as baldusi said here (http://forum.nasaspaceflight.com/index.php?topic=27871.msg1304325#msg1304325).

Why don't you write a "Dear NASA" letter and suggest that to them?
Title: Re: Proposed Europa Missions
Post by: Sesquipedalian on 12/21/2014 02:15 am
Why don't you write a "Dear NASA" letter and suggest that to them?

Because the people on this forum are generally more knowledgeable and responsive, even when -- as in this case -- it takes several attempts to actually get a question answered.  Back in the DIRECT days, I wrote my Congressional representatives in support of the program.  From the three people, I got a) no response, b) a form letter, and c) a self-congratulatory letter about the person's support for a NASA program totally unrelated to DIRECT.

Anyway, vjkane's post mostly answers my question.
Title: Re: Proposed Europa Missions
Post by: redliox on 12/21/2014 08:24 am
Amazing how much banter EC is generating...but that just proves how ecstatic we all are about it.

Looking at the OPAG's web page, they have a meeting coming up in February at the Ames Research Center.  Does anyone know how much of EC will be discussed then and there?  Understandably it wouldn't be the sole topic, although for the near future it's pretty much EC, Juno, and Cassini for choices.  I'd love to hear more regarding Uranus and Neptune, but Europa, Titan, and Enceladus understandably have precedence.
Title: Re: Proposed Europa Missions
Post by: redliox on 12/21/2014 08:45 am
Regarding cubesats at Europa, would they be sufficiently large enough to host a short-lived mass spectrometer experiment (ion, neutral, both)?

If they could be placed into orbit around Europa and able to operate for a few days (presuming modest miracles of technology of course), I could see them being decent candidates for observing the particle environment around the satellite.  Cameras or radar are far to huge for any cubsat to handle, but particle antennas and magnetometers are far less demanding.  The next step up would be sniffing the air and verifying by "scent" whether or not plumes exist.

If a mass spectrometer leans a bit hard on demands, perhaps the Europan cubsats could be put in a cluster of 2 sets: a set for gas analysis and a set for fields.  Again, this would depend on Europa Clipper's mass budget (and in turn SLS' if used).  As for their funding...foreign partners and universities; ESA's done well with small craft (sans Beagle 2) and cubesats are pretty much fitted for university budgets to begin with.
Title: Re: Proposed Europa Missions
Post by: kato on 12/21/2014 10:47 am
Regarding cubesats at Europa, would they be sufficiently large enough to host a short-lived mass spectrometer experiment (ion, neutral, both)?
Simple experiment:

Take the only cubesat currently on a interplanetary piggyride mission (MASCOT on Hayabusa 2, by dimensions effectively a 12U cubesat) and use its weight reserve to wrap it in shielding, and functionally replace the hopping excenter arm with some thrust system for attitude control.

The shielding would be comparable to what Juno carries. The payload would be about 3.5 kg, enough to host a single instrument comparable to Rosetta's ALICE UV imaging spectrometer (3.0 kg / 5.6 W).

With magnetometers, radio/plasma experiments or full ion spectrometers, you're usually looking at 10-15 kg weight and 10-15 W power consumption minimum with current systems.

The first downside? You have 220 Watt hours in the batteries. With ALICE you could conceivably at most squeeze 20 hours of operations out of this. Probably would end up more like 10. Then you're dead.

The second downside? Do you want a couple of them up there? With even just six of the above you're looking at 150 kg deadweight. Plus probably around 20 kg in extra blackbox equipment on your spacecraft for them for comms and for pushing them off in the first place. That's 170 kg that you could use for decent instruments. Or exactly the entire scientific payload of Juno.

If you want 'em to carry a decent ion spectrometer or magnetometer with operating times of 3-4 days, you're looking at something in the upper-end region of "cubesats", at around 75 kg. Or half a ton deadweight for carrying a 6-sat cluster. And that's assuming your host spacecraft can spare the fuel to place them in their intended orbits in the first place.

Title: Re: Proposed Europa Missions
Post by: redliox on 12/21/2014 03:27 pm
Regarding cubesats at Europa, would they be sufficiently large enough to host a short-lived mass spectrometer experiment (ion, neutral, both)?
Simple experiment:

Take the only cubesat currently on a interplanetary piggyride mission (MASCOT on Hayabusa 2, by dimensions effectively a 12U cubesat) and use its weight reserve to wrap it in shielding, and functionally replace the hopping excenter arm with some thrust system for attitude control.

The shielding would be comparable to what Juno carries. The payload would be about 3.5 kg, enough to host a single instrument comparable to Rosetta's ALICE UV imaging spectrometer (3.0 kg / 5.6 W).

With magnetometers, radio/plasma experiments or full ion spectrometers, you're usually looking at 10-15 kg weight and 10-15 W power consumption minimum with current systems.

The first downside? You have 220 Watt hours in the batteries. With ALICE you could conceivably at most squeeze 20 hours of operations out of this. Probably would end up more like 10. Then you're dead.

So a standard cubesat could operate 'nominally' for a handful of orbits about Europa; not an entire Europan orbit.  Not totally surprised but it confirms they'd be a short-lived experiment.

The second downside? Do you want a couple of them up there? With even just six of the above you're looking at 150 kg deadweight. Plus probably around 20 kg in extra blackbox equipment on your spacecraft for them for comms and for pushing them off in the first place. That's 170 kg that you could use for decent instruments. Or exactly the entire scientific payload of Juno.

If you want 'em to carry a decent ion spectrometer or magnetometer with operating times of 3-4 days, you're looking at something in the upper-end region of "cubesats", at around 75 kg. Or half a ton deadweight for carrying a 6-sat cluster. And that's assuming your host spacecraft can spare the fuel to place them in their intended orbits in the first place.

That 170 kg isn't an entire showstopper regarding a cubesat addition.  The Galileo probe was about 340kg and Huygens about 320, and both could be classified as short-lived probes.  However, your list of needs confirms they'd have to be designed as a dedicated part of the mission, not like the ill-fated Beagle 2 or MINERVA on the first Hayabusa.

Of course that 150kg now needs to be placed in orbit around Europa.  The real burden would be how much propellant that labor requires.  To minimize that burden on 'Clipper (or any other mother craft), I'd presume these sats would enter into a mildly elliptical orbit near the equator, inclined slightly but only along the parent's flight path, something along the lines of a 2-hour orbit; just stable enough for the 4 day mission max.  A solid motor or monopropellant stage could put the cluster into orbit then pop each sat off one-by-one, operating basically by a timer after the parent craft aims the whole package just prior to flyby.

Suffice to say it'd be a challenge and need to be taken seriously.  So odds are the Europa Clipper would need to be generously favored with a stronger justification from the scientists interested in Europa's atmosphere and geysers.  So the whole things would be a long-shot, though not impossible.
Title: Re: Proposed Europa Missions
Post by: TakeOff on 12/21/2014 05:03 pm
What about a flyby mission to take some close up images of potential landing sites on Europa and if lucky sample a plume, and then follow up with a lander mission? A flyby wouldn't need much radiation protection because of the short exposure, neither would a lander which is shielded by Europa itself. All probes which have been sent beyond Jupiter, have used Jupiter for gravity assist. A flyby could continue to maybe a comet, Uranus and/or a KBO. A flyby also has the advantage of getting there several years sooner than an orbiter or lander.
Title: Re: Proposed Europa Missions
Post by: savuporo on 12/21/2014 05:27 pm
Regarding cubesats at Europa, would they be sufficiently large enough to host a short-lived mass spectrometer experiment (ion, neutral, both)?
Simple experiment:

Take the only cubesat currently on a interplanetary piggyride mission (MASCOT on Hayabusa 2, by dimensions effectively a 12U cubesat) and use its weight reserve to wrap it in shielding, and functionally replace the hopping excenter arm with some thrust system for attitude control...

So a standard cubesat could operate 'nominally' for a handful of orbits about Europa; not an entire Europan orbit.  Not totally surprised but it confirms they'd be a short-lived experiment.
Well, not really no. First, MASCOT-size 12U is not a "standard" cubesat by any means. Second, MASCOT is designed to remain in close proximity to mothership, greatly simplifying the communications relay problem. (http://solarsystem.nasa.gov/docs/p456.pdf)
From spacecraft engineering perspective, i dont think you could make a ~10kg sat usefully work in Jupiters environment.

EDIT: a more up to date link : http://smsc.cnes.fr/MASCOT/GP_mascot.htm
EDIT2:
Earlier trade space analysis ( 2009 ): http://sci.esa.int/science-e/www/object/doc.cfm?fobjectid=45177
How it was built (2012) : http://www.congrexprojects.com/docs/12c12_docs/1325-lange.pdf
Title: Re: Proposed Europa Missions
Post by: vjkane on 12/21/2014 06:00 pm
The cubesats that operate in Earth orbit have it easy in many ways.  Communication is easy since ground stations are near by. Orientation can be done either using the Earth's magnetic field or the gravity gradient.  No propulsion is needed.  The sun is bright, so solar cells can be fairly small.

It is really hard to get all the functions of a fully independent spacecraft into a cubesat format.  The toughest are long distance communications and propulsion.  The first still doesn't have a really good solution.  The technologies I've seen would return a tiny stream of data even from the moon or a near Earth asteroid encounter.  The propulsion solutions tend to be low impulse, long running engines, exactly what you don't want in the harsh radiation environment around Europa.  At Europa, the solar cells needed to power a cubesat would need to be large.

JPL has solicited and received a number of proposals for cubesats that could be carried by the Europa Clipper.  Few details have been released on their goals or designs.  The only statement is, "The universities' Europa science objectives for their CubeSats would include reconnaissance for future landing sites, gravity fields, magnetic fields, atmospheric and plume science, and radiation measurements."

We can make some guesses about the designs.  I suspect that the cubesats would be released on their trajectories by the mother ship (no propulsion needed).  Communication would be to the nearby mother ship.  Batteries would supply power.

We can imagine some science scenarios.  During each pass over Europa, the Clipper craft will image a very narrow swath of terrain immediately below it.  A cubesat flying some tens of kilometers away could image an nearby swath.  A cubesat could be released ahead or behind the Clipper craft to allow spaceship to spaceship tracking for high precision gravity measurements similar to what the GRACE and GRAIL missions did.  A cubesat could be released to fly through a plume, assuming any are available.

What I don't think is being proposed is a fully independent spacecraft that would enter Europa orbit and operate independently.

On a side note, if an daughter orbiter was considered (much bigger than a cubesat), I suspect that the priorities would be simple radio tracking for gravity measurements and a magnetometer and plasma probe to study the magnetic induction of the ocean.  But with propulsion, a good radio system, solar cells, radiation vaulting, etc., you probably are looking at hundreds of kilograms and hundreds of millions of dollars.
Title: Re: Proposed Europa Missions
Post by: Jim on 12/21/2014 06:18 pm
1.  What about a flyby mission to take some close up images of potential landing sites on Europa and if lucky sample a plume, and then follow up with a lander mission?

2.   A flyby wouldn't need much radiation protection because of the short exposure, neither would a lander which is shielded by Europa itself.

3.All probes which have been sent beyond Jupiter, have used Jupiter for gravity assist. A flyby could continue to maybe a comet, Uranus and/or a KBO.

4. A flyby also has the advantage of getting there several years sooner than an orbiter or lander.

A lot of wrong here

1.  Not viable, because it is not worth the cost.  a flyby is not enough coverage for landing site scouting.

2.  Wrong on both accounts.  Deep flyby needs protection because of the intensity and it isn't a valid mission as stated in #1.    Europa would not protect a lander.

3.  not workable.  Gravity assists are targeted for the follow on trajectory.   A flyby of Europa is not going to lead to any relevant follow on mission.

4.  Not true at all.  There isn't much difference in the trajectories.

Title: Re: Proposed Europa Missions
Post by: TakeOff on 12/21/2014 07:30 pm
4.  Not true at all.  There isn't much difference in the trajectories.
Voyager and New Horizons flew by Jupiter 1½ and 1 years after launch. The only two orbiters, Galileo and Juno, take 6 and 5 years to reach Jupiter. A close flyby could very well detect suitable landing sites. And of course the mass of Europa provides radiation protection for a lander. Besides, the budget doesn't seem to allow for any orbiter. And the Jupiter orbiter like Galileo just made a few flybys of Europa anyway, as is the European JUICE mission proposed to do. Might then as well have a fast cheap dedicated flyby Europa mission. Its equipment will be 5 years more modern and science would return 5 years earlier, than an orbiter, so that a more ambitious follow on mission can be planned.
Title: Re: Proposed Europa Missions
Post by: redliox on 12/21/2014 07:58 pm
The cubesats that operate in Earth orbit have it easy in many ways.  Communication is easy since ground stations are near by. Orientation can be done either using the Earth's magnetic field or the gravity gradient.  No propulsion is needed.  The sun is bright, so solar cells can be fairly small.

It is really hard to get all the functions of a fully independent spacecraft into a cubesat format.  The toughest are long distance communications and propulsion.  The first still doesn't have a really good solution.  The technologies I've seen would return a tiny stream of data even from the moon or a near Earth asteroid encounter.  The propulsion solutions tend to be low impulse, long running engines, exactly what you don't want in the harsh radiation environment around Europa.  At Europa, the solar cells needed to power a cubesat would need to be large.

Naturally a challenge.  A lot of demands for something typically the size of a desktop computer.

We can make some guesses about the designs.  I suspect that the cubesats would be released on their trajectories by the mother ship (no propulsion needed).  Communication would be to the nearby mother ship.  Batteries would supply power.

We can imagine some science scenarios.  During each pass over Europa, the Clipper craft will image a very narrow swath of terrain immediately below it.  A cubesat flying some tens of kilometers away could image an nearby swath.  A cubesat could be released ahead or behind the Clipper craft to allow spaceship to spaceship tracking for high precision gravity measurements similar to what the GRACE and GRAIL missions did.  A cubesat could be released to fly through a plume, assuming any are available.

So they'd be like cousins to JAXA's mini-sats SELENE brought with, at best that is.
(http://global.jaxa.jp/projects/sat/selene/images/selene_main_001.jpg)

On a side note, if an daughter orbiter was considered (much bigger than a cubesat), I suspect that the priorities would be simple radio tracking for gravity measurements and a magnetometer and plasma probe to study the magnetic induction of the ocean.  But with propulsion, a good radio system, solar cells, radiation vaulting, etc., you probably are looking at hundreds of kilograms and hundreds of millions of dollars.

Have to agree with the notion of a daughter orbiter versus the cubesats, especially if there's no means to put them into Europa orbit.  We may not be ready for a lander, but a tiny orbiter could be sent and sacrificed to gain some useful knowledge, namely the plumes but also the oceans.

Ultimately, again, this depends on if a future Europa mission can take on such a burden.
Title: Re: Proposed Europa Missions
Post by: vjkane on 12/21/2014 08:03 pm
A lot of demands for something typically the size of a desktop computer.
More like the size of a loaf of bread.
Title: Re: Proposed Europa Missions
Post by: savuporo on 12/21/2014 08:49 pm
Have to agree with the notion of a daughter orbiter versus the cubesats, especially if there's no means to put them into Europa orbit.  We may not be ready for a lander, but a tiny orbiter could be sent and sacrificed to gain some useful knowledge, namely the plumes but also the oceans.
The problem, as outlined above is power and communications. Running on primary batteries is pretty much the only feasible power option in that size category at Jovian distance, solar cells wont hack it - this means very limited lifetime after separation from the carrier spacecraft. Communication is the next big issue as only relaying is feasible, and to lesser extent tracking and guidance due to distance.
For a useful lander or even just atmospheric entry probe, you'd need a lot more mass.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 12/21/2014 08:54 pm
4.  Not true at all.  There isn't much difference in the trajectories.
Voyager and New Horizons flew by Jupiter 1½ and 1 years after launch. The only two orbiters, Galileo and Juno, take 6 and 5 years to reach Jupiter. A close flyby could very well detect suitable landing sites. And of course the mass of Europa provides radiation protection for a lander. Besides, the budget doesn't seem to allow for any orbiter. And the Jupiter orbiter like Galileo just made a few flybys of Europa anyway, as is the European JUICE mission proposed to do. Might then as well have a fast cheap dedicated flyby Europa mission. Its equipment will be 5 years more modern and science would return 5 years earlier, than an orbiter, so that a more ambitious follow on mission can be planned.

This was ruled out years ago. It costs a lot of money to send something to Jupiter. The cost-benefit ratio of a flyby is bad. NASA is not going to spend 75% of the cost of an orbiting mission for 2% of the return.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 12/21/2014 09:02 pm
JPL has solicited and received a number of proposals for cubesats that could be carried by the Europa Clipper.  Few details have been released on their goals or designs.  The only statement is, "The universities' Europa science objectives for their CubeSats would include reconnaissance for future landing sites, gravity fields, magnetic fields, atmospheric and plume science, and radiation measurements."

We can make some guesses about the designs.  I suspect that the cubesats would be released on their trajectories by the mother ship (no propulsion needed).  Communication would be to the nearby mother ship.  Batteries would supply power.

A colleague of mine is currently running an approved interplanetary cubesat mission. I asked them what they thought about the prospect for cubesats for Europa and they essentially scoffed and rolled their eyes.

The qualities that make cubesats attractive in Earth orbit--and the drawbacks that make them at least acceptable for Earth orbit missions--really work against them for interplanetary missions. For example, no shielding, short lifetimes, and very low testing requirements combined with a high acceptance of risk. Simply put, they're throwaway spacecraft. But when you send something out to Mars or Europa you spend a lot of money to get it there. That alone demands longer lifetimes, higher reliability, more shielding, redundancy, and more testing. You don't want to spend a lot of money, not to mention transit time, sending something to Europa only to have it die two hours after leaving the carrier spacecraft.

So it's really doubtful you'll see cubesats at Europa, and highly unlikely you'll see them at Mars. They're just too small to perform anything worthwhile or worth the cost.
Title: Re: Proposed Europa Missions
Post by: vjkane on 12/21/2014 09:30 pm
They're just too small to perform anything worthwhile or worth the cost.
I think that JPL's SmallSat concept (~50kg and ~$50Mish) has much more potential for planetary missions. 

Current cubeSat technology is at best minimally useful for the moon and near Earth asteroids.  I view cubesats today like the home built personal computer industry of the late 1970s.  Interesting, fun, not yet very practical.

But I've learned not to scoff at the march of technology.  Cubesats will never replace major planetary spacecraft (there's a reason for larger instruments), but may in a couple of decades have their own niche.  In another 10 years or so, the quality and radiation hardening needed for deep space operations will progress.  Their capabilities will still be severely limited by the form factor (even 6U and 12U cubesats).  I expect that they eventually will play small roles as the planetary equivalent of sounding rockets to train young scientists and engineers or two deploy simple instruments at a distance from a mother craft.

Note, though, that my timeline puts useful cubesats outside the time frame of the Europa Clipper.
Title: Re: Proposed Europa Missions
Post by: hop on 12/21/2014 09:47 pm
Voyager and New Horizons flew by Jupiter 1½ and 1 years after launch. The only two orbiters, Galileo and Juno, take 6 and 5 years to reach Jupiter.
Jim, as usual, is correct. The difference between Voyager and Galileo wasn't flyby vs orbiter, it was direct vs using multiple gravity assists. The Voyagers were launched on something close to a Hohmann transfer to Jupiter, they only ended up on solar escape trajectories thanks to gravity assist.

Title: Re: Proposed Europa Missions
Post by: baldusi on 12/21/2014 09:57 pm
BTW, the radiation environment in Europa is terrible. Cubesat usually have it easy because they are deployed below the Van Allen Belt. But sending something that will last the deep space trip and won't fry during the close approach would require rad-hard electronics. So most of the savings of a cube sat are gone.
Title: Re: Proposed Europa Missions
Post by: kato on 12/21/2014 10:11 pm
Well, not really no. First, MASCOT-size 12U is not a "standard" cubesat by any means. Second, MASCOT is designed to remain in close proximity to mothership, greatly simplifying the communications relay problem. (http://solarsystem.nasa.gov/docs/p456.pdf)
Sure. Think about it as more of a standard black box approach though, we're not straightout designing something here.

A 12U cubesat has a weight margin of 24 kg. Within that you can pack exactly the weight of MASCOT and the weight of titanium shielding of around 9-10mm thickness on all sides. Using MASCOT simply allows you to have a baseline model regarding:
a) functional payload package
b) power package
c) movement package
d) communications package
In this model think about the "packages" more as size/weight/power shares awarded.

Yeah, you'll need to enlarge the communications package for operations over there. Not that much, we're not going deep-space after all, but significantly. Realistically, one would have to calculate whether stepping down to a downlink-only system could counter this enough.

We could probably make it work. In theory. With the given restriction of extremely short lifetime, and the space/weight on the host spacecraft better used for useful internal payload.

So it's really doubtful you'll see cubesats at Europa, and highly unlikely you'll see them at Mars.
Only way I could see someone spending the effort is if the weight is carried as ballast anyway. See the NASA solicitation regarding a certain Mars lander that could afford that. Of course that one has the additional benefit of a communications infrastructure in place.

If there's ever a concerted effort to land on Jupiter's moons with similar communications infrastructure in place, I could see a couple cubesats and flyby probes being taken along as similar ballast. Give it half a century or so.
Title: Re: Proposed Europa Missions
Post by: Jim on 12/21/2014 11:42 pm

1.  Voyager and New Horizons flew by Jupiter 1½ and 1 years after launch. The only two orbiters, Galileo and Juno, take 6 and 5 years to reach Jupiter.

2.  A close flyby could very well detect suitable landing sites.

3.   And of course the mass of Europa provides radiation protection for a lander. Besides, the budget doesn't seem to allow for any orbiter.

4.  And the Jupiter orbiter like Galileo just made a few flybys of Europa anyway, as is the European JUICE mission proposed to do.

5.   Might then as well have a fast cheap dedicated flyby Europa mission. Its equipment will be 5 years more modern and science would return 5 years earlier, than an orbiter, so that a more ambitious follow on mission can be planned.

More wrong on top of wrong (a recurring theme)

1.  That is a function of the spacecraft mass and not the mission.

2.  quite wrong.  You really shouldn't make statements about topics you don't know about. 

3.  It is not " of course the mass of Europa provides radiation protection"  It has nothing to do with the mass of the moon.   Radiation at Europa will cause problems and just getting there will also cause problems.

4.  And your point is?  It doesn't matter, it is insufficient for landing site selection.

5.  Wrong conclusion. again, it would not be worth the effort.

edit: added after review of other posts.
Other people have chimed in, so "maybe" it is not just me.   But then again, I have worked on 8 planetary missions, so what do I know.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 12/21/2014 11:54 pm
But I've learned not to scoff at the march of technology.  Cubesats will never replace major planetary spacecraft (there's a reason for larger instruments), but may in a couple of decades have their own niche.  In another 10 years or so, the quality and radiation hardening needed for deep space operations will progress.  Their capabilities will still be severely limited by the form factor (even 6U and 12U cubesats).  I expect that they eventually will play small roles as the planetary equivalent of sounding rockets to train young scientists and engineers or two deploy simple instruments at a distance from a mother craft.

Note, though, that my timeline puts useful cubesats outside the time frame of the Europa Clipper.

Well, I think there are two general issues involved with cubesats. One is technology, the other is engineering philosophy. Certainly the technology has advanced a lot. But even with improvements with technology, what makes cubesats possible is that people are willing to accept the severe limitations like low quality data, limited lifetimes, high risk, etc. I guess what I'm saying is that the technology improved to the point where some people have been willing to say that they are "good enough" for some applications. But there has been no fundamental technological leap that makes something that we call "a cubesat" possible now when it was not before. Really small satellites have been around a long time. Look at Vanguard 1.

But even if the technology marches on, the equation is not going to fundamentally change for planetary missions because it is so hard and expensive to get to the planets. Imagine if NASA launched five cubesats to Mars or Jupiter and all failed because of their limited redundancy and capabilities. The headlines the next day would be "Five NASA spacecraft fail at Mars" and the agency would take a publicity hit. Is the higher risk worth the reward? (Note that the two Mars spacecraft that NASA lost in 1999 were smaller and cheaper, and the agency had accepted greater risk. And yet none of that mattered when all the stories in the media were "NASA is filled with idiots who lost two spacecraft at Mars.")

I'm not going to say "never" on this, but I do think it is unlikely.

But I also think that this is missing the point. The point is not cubesats themselves. The point is (some of) the technology making them possible. What's happening is that electronics are being miniaturized. And for planetary missions that does not require that the spacecraft itself get smaller, but it can allow for greater capabilities to be carried within that spacecraft. So rather than thinking of a cubesat being launched to Mars, think in terms of far more electronics and processing capability being launched to Mars. Or Europa. Don't get caught up on the object itself, but what makes it possible. That's the important aspect.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 12/22/2014 12:56 am
What about a flyby mission to take some close up images of potential landing sites on Europa and if lucky sample a plume, and then follow up with a lander mission? A flyby wouldn't need much radiation protection because of the short exposure, neither would a lander which is shielded by Europa itself. All probes which have been sent beyond Jupiter, have used Jupiter for gravity assist. A flyby could continue to maybe a comet, Uranus and/or a KBO. A flyby also has the advantage of getting there several years sooner than an orbiter or lander.

A flyby has the disadvantage of not spending enough time at the system to collect much useful data. Flybys, for instance, can image a very small area of the surface of a planet or moon at high resolution. (Quick homework exercise: go look up the highest resolution of any planetary surface achieved by the Voyager missions. Then report back here.) So what happens if your spacecraft flies past Europa, takes a high resolution photo of a really small area, and all of it is too jagged to land on? Wasted money and opportunity since you won't get the opportunity to fly another mission for 10-20 years.

This is actually part of the debate with Europa Clipper. I don't know the current status of the discussion, but as of this past spring there was disagreement over the inclusion of a high resolution camera on the EC. I don't know why anybody would really oppose it, but certainly it costs money, mass, and could have a big impact on the mission design. But as it was told to me by somebody who had some better info than I did, there were scientists arguing that a high-resolution camera was not needed for Europa Clipper because they wanted an orbiter to follow EC and that would have the camera. He thinks that the proponents of this view assumed that they could get both an orbiter and lander in the same decade after Europa Clipper. Neither of us considers this to be a realistic belief.

As the person who told me this pointed out, and I agreed, putting off the high-res camera and hoping for an orbiter essentially means delaying any Europa lander by another two decades after Europa Clipper. If you're going to do Europa Clipper, you have to do it right, maximizing the data return to enable a lander, which is going to be an expensive and difficult mission.

Title: Re: Proposed Europa Missions
Post by: vjkane on 12/22/2014 02:55 am
Imagine if NASA launched five cubesats to Mars or Jupiter and all failed because of their limited redundancy and capabilities. The headlines the next day would be "Five NASA spacecraft fail at Mars" and the agency would take a publicity hit. Is the higher risk worth the reward?
I think only the most optimistic or ill-informed would propose launching a cubesat to Mars or Europa anytime in the foreseeable future.  What I do see is cubesats to the moon or near Earth asteroids as the planetary equivalent of sounding rockets. 

You are probably aware that NASA has just issued a request for proposals for a planetary cubesat mission responsive to Decadal Survey priorities with a $5.6M price cap.  A great way to train future lead scientists and engineers.

I also see cubesats as daughter spacecraft that deploy instruments remotely from the main spacecraft.  This will probably take awhile since, as you point out, reliability is not yet up to standards for instruments NASA funds.  However, since the weight is low, NASA may decide to carry cubesats on missions as the equivalent of sounding rockets.  The pool of experienced potential lead engineers and scientists has gotten smaller as planetary launch rates have decline.
Title: Re: Proposed Europa Missions
Post by: QuantumG on 12/22/2014 02:57 am
I think only the most optimistic or ill-informed would propose launching a cubesat to Mars or Europa anytime in the foreseeable future.  What I do see is cubesats to the moon or near Earth asteroids as the planetary equivalent of sounding rockets. 

Sounding rockets provide new and affordable scientific and engineering results every day.

Is that what you mean?
Title: Re: Proposed Europa Missions
Post by: vjkane on 12/22/2014 03:03 am
Sounding rockets provide new and affordable scientific and engineering results every day.

Is that what you mean?
Sounding rockets are great investments.  They allow testing of new instruments, provide training, and produce good but limited results (otherwise, we'd only fly only sounding rockets and give up on dedicated satellites :> ).  A great investment.  Planetary science and to a degree Earth science hasn't had the equivalent (although instruments carried in planes can provide a lot of proving for Earth-focused instruments).  I believe that cubesats can grow  into that role for planetary science.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 12/22/2014 04:29 am
Sounding rockets are great investments.  They allow testing of new instruments, provide training, and produce good but limited results (otherwise, we'd only fly only sounding rockets and give up on dedicated satellites :> ).  A great investment.  Planetary science and to a degree Earth science hasn't had the equivalent (although instruments carried in planes can provide a lot of proving for Earth-focused instruments).  I believe that cubesats can grow  into that role for planetary science.

Apropos of nothing...

Of course, the value of sounding rockets has changed a lot over time. Before satellites they were of course the only way to get data from space altitudes. During the 1960s they were used for all kinds of research, from Earth sensing to heliophysics to upper atmosphere science (a lot of that) to even planetary observations. But the numbers launched dropped a lot starting in the 1970s and through to today. I had some statistics about that a few years ago, but I think that the number of U.S. launches was in the 40s in the 1990s and then dropped to about 20 per year after 2000 and has been somewhat stuck there. That's because of limited utility but also high costs. They're not cheap and unfortunately a big chunk of that cost is overhead.

I think that the engineering value certainly dropped a lot with the drop in science value. They just don't fly long enough to provide good engineering value. (Sidenote: A friend of mine met up with a sounding rocket scientist a few years ago and was impressed by the unique characteristics of sounding rocket payloads. They have to operate instantly. No checkout. No time to deal with outgassing, etc. He said that for his huge observatory, Chandra, they spent months getting it up and running, but this guy's sounding rocket payload had to be operating and stabilized in seconds.)

I do think that the training value of sounding rockets has been undervalued for many years. I even worked on a NASA workforce study some years ago that advocated using them for systems engineering training because a person developing a sounding rocket payload had to address all aspects of design and it gave them a lot of experience useful for working on much more complex payloads. Cubesats may have some of that value, but I have my doubts that they are as good as sounding rockets, perhaps because they are so small that the designer doesn't face all of the engineering choices that are possible with a slightly bigger payload, and a rocket. For example, cubesats are stuck with a ride to orbit and get no say at all in the launch vehicle's performance. It's sorta like learning to ride a bike but you're only allowed to make right turns; you need greater freedom in order to really develop the skills.

I'm rambling. I'll stop.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 12/22/2014 04:43 am
1-You are probably aware that NASA has just issued a request for proposals for a planetary cubesat mission responsive to Decadal Survey priorities with a $5.6M price cap.  A great way to train future lead scientists and engineers.

2-I also see cubesats as daughter spacecraft that deploy instruments remotely from the main spacecraft.  This will probably take awhile since, as you point out, reliability is not yet up to standards for instruments NASA funds. 

3-However, since the weight is low, NASA may decide to carry cubesats on missions as the equivalent of sounding rockets.  The pool of experienced potential lead engineers and scientists has gotten smaller as planetary launch rates have decline.


1-Yeah, I'm aware. I also have my doubts. I tend to suspect that this is the equivalent of dangling a hook and seeing if they catch anything worthwhile. It doesn't inherently indicate confidence in a positive outcome.

2-But is there real value to this? It's not just reliability, it's utility. Is there something that can be done by separating an instrument that is worth doing? And considering that this comes with penalties (instruments on cubesats have to be smaller, you're carrying parasitic mass like additional guidance and comm instead of simply using that already on the main spacecraft) it may not be worth it compared to using all that mass and money to make the primary spacecraft better. I worry that some of the motivation right now is a case of people having decided that cubesats are the answer and now they're looking for the question.

3-On planetary missions? There's usually not much mass to spare on planetary missions. And if you tell a mission PI that they have to carry an extra 20 kg along to their destination, I think the PI is going to argue that it should go for fuel.

I'm not opposed to them per se, I just have real doubts about their utility for planetary missions. Maybe for a few niches, but it just seems really hard to figure out where they will fit in. I do think they're interesting and have potential for Earth orbital missions. But once you have to start adding in radiation hardening, redundancy, better pointing accuracy and things like that for planetary missions, you quickly end up with something that is no longer a cubesat.
Title: Re: Proposed Europa Missions
Post by: jongoff on 12/22/2014 06:19 am
Well, not really no. First, MASCOT-size 12U is not a "standard" cubesat by any means. Second, MASCOT is designed to remain in close proximity to mothership, greatly simplifying the communications relay problem. (http://solarsystem.nasa.gov/docs/p456.pdf)

For what it's worth, part of the SBIR Phase I my company just finished on Friday included a deployable cubesat patch array antenna that looked like it could theoretically close a link from Saturn/Titan back to DSN in X-Band (very low data rate though--only about 250bps at Saturn, 4kbps at Mars, didn't run the numbers on Jupiter, but somewhere in the middle). So the comms issue may be solvable.

~Jon
Title: Re: Proposed Europa Missions
Post by: mikelepage on 12/22/2014 06:27 am
I do enjoy reading the informed opinions in these threads.  I might have come to the same conclusion about including cubesats on planetary missions after a bit of thought, but thank you for putting the reasons against doing so succinctly.

The question that's been nagging me (and I hope I can get an expert response to) is: there is much enthusiasm around Europa mission concepts, but isn't it true that Callisto, being futher away from (outside?) Jupiter's radiation belts, would be a much easier candidate to design a mission for?  I understand Europa is generally considered a more interesting moon for a number of reasons, but I remember reading that Ganymede and Callisto have many of the same characteristics and possible subsurface oceans too.  Is the preference for Europa a matter of degree, or is there some characteristic I've missed that makes Europa a categorically more interesting moon than the others (particularly Callisto)? Cheers.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 12/22/2014 01:39 pm
The question that's been nagging me (and I hope I can get an expert response to) is: there is much enthusiasm around Europa mission concepts, but isn't it true that Callisto, being futher away from (outside?) Jupiter's radiation belts, would be a much easier candidate to design a mission for?  I understand Europa is generally considered a more interesting moon for a number of reasons, but I remember reading that Ganymede and Callisto have many of the same characteristics and possible subsurface oceans too.  Is the preference for Europa a matter of degree, or is there some characteristic I've missed that makes Europa a categorically more interesting moon than the others (particularly Callisto)? Cheers.

Well, consider that ESA is planning a Ganymede mission. If, as you say, Ganymede and Callisto are essentially the same, then the ESA mission has it covered.

But yes, the U.S. scientific community views Europa as significantly more interesting than the other moons, for a number of reasons.
Title: Re: Proposed Europa Missions
Post by: kato on 12/22/2014 04:00 pm
The sole reason Europa is considered more interesting is because its subsurface ocean has a simple ice cover a couple km thick, with likely ducts and cracks in the ice to connect it to the surface. Insofar it would be (comparably) easy to breach to get down to that ocean.
That's actually what part of JUICE's mission is, characterizing Callisto's and Ganymede's (likely) subsurface oceans and examining the lithosphere above. Insofar Europa is simply one step ahead of Callisto and Ganymede right now.

Title: Re: Proposed Europa Missions
Post by: ugordan on 12/22/2014 04:06 pm
Europa being thought to have its ocean in direct contact with the rock below is considered to be a big advantage from an astrobiological standpoint.
Title: Re: Proposed Europa Missions
Post by: vjkane on 12/22/2014 04:54 pm
There is a gradient of tidal effects from Jupiter on each of the major moons.  Io gets the most extreme baking and modification.  Europa is warm enough to keep its outer H2O layer almost entirely liquid (and there's a good chance that the rocky core is warm enough to support some degree of volcanic activity, which would replicate the thermal vents on the Earth's ocean floors).  Ganymede is less heated, but between that and its large size, it became internally differentiated.  Callisto is cold and appears not to have differentiated.

An explicit goal of the JUICE mission is to explore the results of the gradient on the three icy moons.  Ganymede will receive the most attention since it is the more evolved of the two moons (Callisto being the other) that lies outside the intense radiation fields.

If the extreme radiation fields didn't exist, I'm sure that ESA would have done a Europa orbiter instead of a Ganymede orbiter.  However, the radiation hardening roughly doubles the cost of the mission, and ESA doesn't have a mission class for that expensive of a mission.
Title: Re: Proposed Europa Missions
Post by: mikelepage on 12/23/2014 02:52 am
There is a gradient of tidal effects from Jupiter on each of the major moons.  Io gets the most extreme baking and modification.  Europa is warm enough to keep its outer H2O layer almost entirely liquid (and there's a good chance that the rocky core is warm enough to support some degree of volcanic activity, which would replicate the thermal vents on the Earth's ocean floors).  Ganymede is less heated, but between that and its large size, it became internally differentiated.  Callisto is cold and appears not to have differentiated.

An explicit goal of the JUICE mission is to explore the results of the gradient on the three icy moons.  Ganymede will receive the most attention since it is the more evolved of the two moons (Callisto being the other) that lies outside the intense radiation fields.

If the extreme radiation fields didn't exist, I'm sure that ESA would have done a Europa orbiter instead of a Ganymede orbiter.  However, the radiation hardening roughly doubles the cost of the mission, and ESA doesn't have a mission class for that expensive of a mission.

Very interesting! Thanks for the replies. I hadn't realised Ganymede was also outside the worst of the belts, so with its internal differentiation of course they would go for that.

Thinking out loud and going back to what some of the posters above were wanting to try with cube sats, (or at least, the principle of having "mother" and "daughter" craft), I wonder how worthwhile it would be to have a mothership insert itself into Ganymede orbit, and using this as the staging point from which a smaller orbiter (radiation hardened) to go to Europa to map possible landing sites. Then a second, daughter landing craft would be launched to that spot to start digging. Probably too complicated, but wondering if the mass saved by having a mothership without radiation hardening but that could serve as relay would be worth it.
Title: Re: Proposed Europa Missions
Post by: vjkane on 12/23/2014 02:54 am
Thinking out loud and going back to what some of the posters above were wanting to try with cube sats, (or at least, the principle of having "mother" and "daughter" craft), I wonder how worthwhile it would be to have a mothership insert itself into Ganymede orbit, and using this as the staging point from which a smaller orbiter (radiation hardened) to go to Europa to map possible landing sites. Then a second, daughter landing craft would be launched to that spot to start digging. Probably too complicated, but wondering if the mass saved by having a mothership without radiation hardening but that could serve as relay would be worth it.
Those daughtercraft would need to be full fledged interplanetary spacecraft.  That's far, far from where cubesats are now.  Maybe in two to three decades. 
Title: Re: Proposed Europa Missions
Post by: Blackstar on 12/23/2014 03:49 am
Thinking out loud and going back to what some of the posters above were wanting to try with cube sats, (or at least, the principle of having "mother" and "daughter" craft), I wonder how worthwhile it would be to have a mothership insert itself into Ganymede orbit, and using this as the staging point from which a smaller orbiter (radiation hardened) to go to Europa to map possible landing sites. Then a second, daughter landing craft would be launched to that spot to start digging. Probably too complicated, but wondering if the mass saved by having a mothership without radiation hardening but that could serve as relay would be worth it.

The smaller the spacecraft, the less capable it is. The less it can do. Things like redundancy get thrown away because you don't have the mass budget.

So, no.
Title: Proposed Europa Missions
Post by: Star One on 12/30/2014 09:24 pm
Now those water plumes at Europa seem less certain.

-- Data from Cassini's 2001 Jupiter flyby show Europa contributes less material to its surrounding environment than previously thought.

-- Unlike Saturn's known-active moon Enceladus, Europa is surrounded by very tenuous hot, excited gas.

A fresh look at data collected by NASA's Cassini spacecraft during its 2001 flyby of Jupiter shows that Europa's tenuous atmosphere is even thinner than previously thought and also suggests that the thin, hot gas around the moon does not show evidence of plume activity occurring at the time of the flyby. The new research provides a snapshot of Europa's state of activity at that time, and suggests that if there is plume activity, it is likely intermittent.

The Europa results are being presented today at the American Geophysical Union fall meeting in San Francisco and published in the Astrophysical Journal. Europa is considered one of the most exciting destinations in the solar system for future exploration because it shows strong indications of having an ocean beneath its icy crust.

Members of Cassini's ultraviolet imaging spectrograph (UVIS) team analyzed data collected by their instrument during the brief time it observed Europa in 2001, as Cassini sped through the Jupiter system en route to Saturn. The observations show that most of the hot, excited gas, or plasma, around Europa originates not from the moon itself, but from volcanoes on the nearby moon Io. In fact, from their data, the researchers calculated that Europa contributes 40 times less oxygen than previously thought to its surrounding environment.

"Our work shows that researchers have been overestimating the density of Europa's atmosphere by quite a bit," said Don Shemansky, a Cassini UVIS team member with Space Environment Technologies in Pasadena, California, who led the study. The team found that the moon's tenuous atmosphere, which was already thought to be millions of times thinner than Earth's atmosphere, is actually about 100 times less dense than those previous estimates.

A downward revision in the amount of oxygen Europa pumps into the environment around Jupiter would make it less likely that the moon is regularly venting plumes of water vapor high into orbit, especially at the time the data was acquired.

Scientists would expect that ongoing plume activity at Europa, as Cassini has observed at Saturn's moon Enceladus, would inject large amounts of water vapor into the area around Europa's orbit if the plumes were large enough, but that is not what UVIS observed.

"We found no evidence for water near Europa, even though we have readily detected it as it erupts in the plumes of Enceladus," said Larry Esposito, UVIS team lead at the University of Colorado at Boulder.

"It is certainly still possible that plume activity occurs, but that it is infrequent or the plumes are smaller than we see at Enceladus," said Amanda Hendrix, a Cassini UVIS team member with the Planetary Science Institute in Pasadena, who co-authored the new study. "If eruptive activity was occurring at the time of Cassini's flyby, it was at a level too low to be detectable by UVIS."

Indications of possible plume activity were reported in 2013 by researchers using NASA's Hubble Space Telescope, launching a wave of interest in searching for additional signs, including this effort by the UVIS team. Cassini's 2001 Jupiter flyby provided UVIS the opportunity to directly measure the environment near Europa, which is not possible with Hubble.

For more than a decade, Cassini's UVIS has observed the cold, dense doughnut of gas that encloses the orbit of Enceladus. There, the massive amount of gas being breathed into orbit around Saturn by the Enceladus plumes acts like a brake on electrons being dragged through it by Saturn's magnetic field, which rotates with the planet. This braking helps to keep down the temperature of the plasma. Apparently there is no such brake at Europa.

Since UVIS saw a hot plasma, rather than a cold one, around Europa's orbit, it suggests Europa is not outputting large amounts of gas -- including water.

Snapshots provided by missions that visited Jupiter prior to Cassini provided strong indications that Io is the major contributor of material to the environment around Jupiter, and indicated a hot, low density plasma surrounding Europa. The new results confirm that. "Io is the real monster here," Shemansky said.

"Europa is a complex, amazing world, and understanding it is challenging given the limited observations we have," said Curt Niebur, Outer Planets program scientist at NASA Headquarters in Washington. "Studies like this make the most of the data we have and help guide the kinds of of science investigations NASA should pursue in the future."

Scientists are currently using the Hubble Space Telescope to conduct an extensive six-month long survey looking for plume activity, and NASA is also studying various possible Europa missions for future exploration.

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. NASA's Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington, D.C. JPL designed, developed and assembled the Cassini orbiter. The UVIS team is based at the University of Colorado, Boulder, where the instrument was designed and built.

More information about Cassini:

http://www.nasa.gov/cassini

and

http://saturn.jpl.nasa.gov

More information about Europa:

http://solarsystem.nasa.gov/europa


Media Contact

Preston Dyches
NASA's Jet Propulsion Laboratory, Pasadena, Calif.
818-354-7013
[email protected]

2014-436

http://www.jpl.nasa.gov/news/news.php?feature=4417
Title: Re: Proposed Europa Missions
Post by: Blackstar on 12/31/2014 12:00 am
NASA was always careful when discussing the plumes on Europa, using "possible" or some other qualifier. Of course, lots of people didn't do that and dropped the qualifiers. But the possible plumes is what helped get OMB to put the $15 million in the budget for Europa studies. Sometimes that's how science works.
Title: Re: Proposed Europa Missions
Post by: redliox on 12/31/2014 06:47 pm
NASA was always careful when discussing the plumes on Europa, using "possible" or some other qualifier. Of course, lots of people didn't do that and dropped the qualifiers. But the possible plumes is what helped get OMB to put the $15 million in the budget for Europa studies. Sometimes that's how science works.

Right.  Regarding plumes this definitely deepens the mystery.  It is a matter still worth investigating but not one on the top of the list.

Since we are talking gas and plasma around Europa, how does a neutral mass spectrometer's performance compare with an ion-neutral version?  I wondered how huge a downgrade in data there's be.
Title: Re: Proposed Europa Missions
Post by: the_other_Doug on 01/08/2015 04:06 am
So -- just as a curiosity, here, not being a physicist, what would hot, low-density plasma from Io do to occasional water plumes from Europa?  Would this impact how long the indicators of water plumes would remain detectable?
Title: Re: Proposed Europa Missions
Post by: Blackstar on 01/09/2015 02:45 am
NASA was always careful when discussing the plumes on Europa, using "possible" or some other qualifier. Of course, lots of people didn't do that and dropped the qualifiers. But the possible plumes is what helped get OMB to put the $15 million in the budget for Europa studies. Sometimes that's how science works.

Right.  Regarding plumes this definitely deepens the mystery.  It is a matter still worth investigating but not one on the top of the list.


And science can be persnickety. Look at the issue of methane on Mars. The readings have been ambiguous for a long time, barely sticking out of the noise. And then Curiosity makes a discovery. These can be very difficult things to extract from noisy data.
Title: Re: Proposed Europa Missions
Post by: vjkane on 01/09/2015 02:49 am
I listened in on a presentation by Jim Green, head of NASA’s Planetary Science Division at this week’s Small Bodies Assessment Group.  Dr. Green says that NASA hopes that it will be able to use the $100M Congress added to NASA’s budget for a Europa mission to enable a New Start for the Europa Clipper program.  This is the term for when a mission goes from the wish list to an approved program.  This is the first that I had heard that NASA’s management was looking to commit to a Europa mission.  This isn’t a done deal: the President’s Office of Budget and Management (OMB) must also approve a new start, and in the past they have not been.  (Congress must also approve a new start, but the substantial funding it has already supplied suggests that it would.) We will see with the release of the Fiscal Year 2016 budget request whether OMB’s stance has changed.  IF a new start is given, then the important questions will be the total budget for the mission and when launch is planned (which might be in the mid-2020’s).
Title: Re: Proposed Europa Missions
Post by: redliox on 01/09/2015 09:17 am
I listened in on a presentation by Jim Green, head of NASA’s Planetary Science Division at this week’s Small Bodies Assessment Group.  Dr. Green says that NASA hopes that it will be able to use the $100M Congress added to NASA’s budget for a Europa mission to enable a New Start for the Europa Clipper program.  This is the term for when a mission goes from the wish list to an approved program.  This is the first that I had heard that NASA’s management was looking to commit to a Europa mission.

SWEET!

Pardon my premature enthusiasm, but it's about time we heard something both new and good.

There's a meeting for the OPAG in February.  That would be the next likely burst of news we hear specifically for Europa Clipper.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 01/09/2015 10:46 am
There's a meeting for the OPAG in February.  That would be the next likely burst of news we hear specifically for Europa Clipper.

No, you would hear it in the budget release, which is likely to happen in early March.
Title: Re: Proposed Europa Missions
Post by: redliox on 01/09/2015 11:41 am
There's a meeting for the OPAG in February.  That would be the next likely burst of news we hear specifically for Europa Clipper.

No, you would hear it in the budget release, which is likely to happen in early March.

Pointer appreciated.  Do you know what would be discussed, EC and otherwise then?
Title: Re: Proposed Europa Missions
Post by: vjkane on 01/09/2015 05:10 pm
I'm hoping that at the OPAG meeting, we get a high level summary of the results of the $1B mission exercise.  There have been enough comments in public to establish that the proposals could not meet all the scientific goals, but it would be interesting to hear the 15 minute summary.  We won't get many details since the proposals were promised confidentiality.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 01/10/2015 02:32 am
I'm hoping that at the OPAG meeting, we get a high level summary of the results of the $1B mission exercise.  There have been enough comments in public to establish that the proposals could not meet all the scientific goals, but it would be interesting to hear the 15 minute summary.  We won't get many details since the proposals were promised confidentiality.

I think you will hear that they did not meet the criteria and that is all. Nothing more. I think NASA and other parties would like all of that to be forgotten, quickly.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 01/10/2015 02:36 am
There's a meeting for the OPAG in February.  That would be the next likely burst of news we hear specifically for Europa Clipper.

No, you would hear it in the budget release, which is likely to happen in early March.

Pointer appreciated.  Do you know what would be discussed, EC and otherwise then?

Either it will be a new start in the president's budget or it won't.

What you have to understand is that there's a political game going on here: Congress keeps earmarking in Europa money, and OMB keeps trying to ignore it. But as long as it is in appropriations bills (that become law) the money has to be spent on some Europa-like activities, but not actual spacecraft design and hardware. It is enormously wasteful and inefficient to do things this way. But what some members of Congress are hoping is that OMB will realize that they cannot keep opposing it (i.e. "the will of the Congress") and will finally start the program. It's like playing a game of chicken, except that, well, the stakes are different and the loser just ends up wasting money as opposed to putting it into an actual mission.

Title: Re: Proposed Europa Missions
Post by: JH on 01/14/2015 09:29 pm
Back on the topic of cubesat parasite payloads as a part of EC, I am familiar with several of the proposals that have been funded as part of the JPL program. There are unquestionably instruments that can significantly increase scientific return and can fit onto a cubesat. To add a few details about the program: 10 studies from various institutions were funded and the proposals are targeting a 3U size with the possibility of expanding to 6U if it can be justified. Depending on the proposal's goals, either a solar powered, long(ish) lived cubesat or a battery powered, short duration cubesat might be acceptable. I can confirm that at least one proposal team is considering solar power; it is not impossible at Jupiter given the low power requirements of some of the instruments in question.
Title: Re: Proposed Europa Missions
Post by: vjkane on 01/14/2015 09:44 pm
I am familiar with several of the proposals that have been funded as part of the JPL program.
Can you say whether any propose to orbit Europe itself?

Title: Re: Proposed Europa Missions
Post by: JH on 01/14/2015 11:14 pm
Not that I am aware of. I doubt you could even fit enough Delta V into a 3U cubesat (or a 6U for that matter). Assuming you deployed the cubesat from EC shortly after JOI and were willing to wait a few years, you'd need over 600 m/s of Delta V. I think the most that I've heard of being crammed into a cubesat (not using EP, obviously) is 100-200 m/s and that takes up about half of the cubesat. Also, for planetary protection reasons you probably wouldn't want a cubesat orbiting Europa.

On the other hand, it would take relatively little Delta V (~10's of m/s) to do a series of flybys.

-typo
Title: Re: Proposed Europa Missions
Post by: vjkane on 01/15/2015 12:29 am
Not that I am aware of. I doubt you could even fit enough Delta V into a 3U cubesat (or a 6U for that matter). Assuming you deployed the cubesat from EC shortly after JOI and were willing to wait a few years, you'd need over 600 m/s of Delta V. I think the most that I've heard of being crammed into a cubesat (not using EP, obviously) is 100-200 m/s and that takes up about half of the cubesat. Also, for planetary protection reasons you probably wouldn't want a cubesat orbiting Europa.
I didn't think anyone would propose a Europa orbiter (peace, Draper Labs :> ); if the delta V didn't get you, the radiation would.  I can think of a number of non-Europa long-lived CubeSat missions -- monitoring the magnetosphere in a second (or even 3rd) location, watching the weather on Jupiter, watching the volcanoes on Io.  For multiple Europa flybys, the most obvious options are to increase the number of flybys to collect magnetic induction measurements (magnetometer and simple plasma probe), collect gravity data (ultrastable oscillator), or collect imagery (think Planetary Lab's CubeSats).  My betting is on the first two; the last requires significant data rates, and even with the mother craft for relay, that may be stretching what is reasonable.  However, any long-lived multi-flyby craft would require optical navigation, and the star trackers are very good cameras that could be made more useful for science with different filter strips on the sensor.


Title: Re: Proposed Europa Missions
Post by: JH on 01/15/2015 12:46 am
There have been orbiter proposals (flagship missions) but their durations have only been 30 days in orbit due to the rad environment. I've heard recently that longer missions may be possible. I don't remember if it is because our understanding of the environment has changed or because of technical advances.

Incidentally, your bet is good.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 01/15/2015 04:20 pm
There have been orbiter proposals (flagship missions) but their durations have only been 30 days in orbit due to the rad environment. I've heard recently that longer missions may be possible. I don't remember if it is because our understanding of the environment has changed or because of technical advances.

Incidentally, your bet is good.

I think that the later iterations of Europa orbiter missions were at 60+ days for the mission. A big part of that was a better understanding of the actual radiation doses that they would get (for instance, Europa itself shields part of the radiation, so can the orbit be maximized to take advantage of that). You'd have to look at the JPL Europa orbiter study from around 2012 or so and see what it says.
Title: Re: Proposed Europa Missions
Post by: Malderi on 01/15/2015 04:23 pm
Question about the radiation - as an software guy I should know more about this. I know some types of radiation can be more easily shielded against than others. What's the problem around Europa, then? Is the radiation something that can be shielded against, if we only had a bunch more mass to throw at the problem (impractical amounts given current launch/propulsion technology?) Or is it tougher than that? I know Juno has a "vault" for all the electronics - but not sure if that's something that can just be scaled up with more mass to solve the problem.
Title: Re: Proposed Europa Missions
Post by: vjkane on 01/15/2015 05:42 pm
Question about the radiation - as an software guy I should know more about this. I know some types of radiation can be more easily shielded against than others. What's the problem around Europa, then? Is the radiation something that can be shielded against, if we only had a bunch more mass to throw at the problem (impractical amounts given current launch/propulsion technology?) Or is it tougher than that? I know Juno has a "vault" for all the electronics - but not sure if that's something that can just be scaled up with more mass to solve the problem.
The problem at Jupiter is the combination of a very strong magnetic field (supplied by Jupiter) and a source of a humongous amount of ions (supplied by Io's volcanoes primarily).  The result is highly energetic ions that are very good at penetrating matter (unlike some kinds of radiation (vague memory says alpha radiation) where a piece of paper is good shielding).  All current Jupiter-mission designs include a vault that puts most of the sensitive electronics behind shielding (instrument sensors remain a problem because they need to be outside the vault).  There appears to be a limit as to how much shielding a spacecraft can reasonably carry - probably weight.

The other approach that Jupiter missions use is to avoid the radiation.  Juno slips past Jupiter in a relatively radiation free zone that is just above the atmosphere and has a polar orbit.  JUICE stays away from the inner Jovian system except for two brief passes by Europa.  Europa Clipper would do many flybys to limit its time in the inner system.  An Io mission would both do a limited number of flybys (most concepts seem to do 6 to 8) and has a polar orbit around Jupiter where the radiation is much less (the radiation is most concentrated in the equatorial plane).  The Europa Clipper wouldn't use a polar orbit because the encounter speeds are too high for good spectroscopy work -- the signals they need to see are faint and they need all the time they can get to collect photons.
Title: Re: Proposed Europa Missions
Post by: Malderi on 01/15/2015 05:44 pm
Question about the radiation - as an software guy I should know more about this. I know some types of radiation can be more easily shielded against than others. What's the problem around Europa, then? Is the radiation something that can be shielded against, if we only had a bunch more mass to throw at the problem (impractical amounts given current launch/propulsion technology?) Or is it tougher than that? I know Juno has a "vault" for all the electronics - but not sure if that's something that can just be scaled up with more mass to solve the problem.
The problem at Jupiter is the combination of a very strong magnetic field (supplied by Jupiter) and a source of a humongous amount of ions (supplied by Io's volcanoes primarily).  The result is highly energetic ions that are very good at penetrating matter (unlike some kinds of radiation (vague memory says alpha radiation) where a piece of paper is good shielding).  All current Jupiter-mission designs include a vault that puts most of the sensitive electronics behind shielding (instrument sensors remain a problem because they need to be outside the vault).  There appears to be a limit as to how much shielding a spacecraft can reasonably carry - probably weight.

The other approach that Jupiter missions use is to avoid the radiation.  Juno slips past Jupiter in a relatively radiation free zone that is just above the atmosphere and has a polar orbit.  JUICE stays away from the inner Jovian system except for two brief passes by Europa.  Europa Clipper would do many flybys to limit its time in the inner system.  An Io mission would both do a limited number of flybys (most concepts seem to do 6 to 8) and has a polar orbit around Jupiter where the radiation is much less (the radiation is most concentrated in the equatorial plane).  The Europa Clipper wouldn't use a polar orbit because the encounter speeds are too high for good spectroscopy work -- the signals they need to see are faint and they need all the time they can get to collect photons.


I guess what I'm asking is - if/when launch costs come down significantly - would it be possible for a longer-lived Europa orbiter mission, just by throwing a bunch more mass at the shielding problem? I know there's diminishing returns, but I'm not sure how much.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 01/15/2015 08:21 pm
I guess what I'm asking is - if/when launch costs come down significantly - would it be possible for a longer-lived Europa orbiter mission, just by throwing a bunch more mass at the shielding problem? I know there's diminishing returns, but I'm not sure how much.

I don't think it buys you all that much. You'd need a lot more shielding. Plus, as VJkane noted, the instruments are outside the shielding.

The radiation is hell. It just screws you over bad. The only decent way to deal with it is to avoid it.
Title: Re: Proposed Europa Missions
Post by: vjkane on 01/15/2015 08:55 pm
The radiation is hell. It just screws you over bad. The only decent way to deal with it is to avoid it.

Maybe instead of moving an asteroid, NASA should move Europa.
Title: Re: Proposed Europa Missions
Post by: JH on 01/15/2015 08:57 pm
I think that the later iterations of Europa orbiter missions were at 60+ days for the mission. A big part of that was a better understanding of the actual radiation doses that they would get (for instance, Europa itself shields part of the radiation, so can the orbit be maximized to take advantage of that). You'd have to look at the JPL Europa orbiter study from around 2012 or so and see what it says.

I'm fairly certain that the 2012 orbiter study was still assuming 30 days. There is depletion of hot electrons in the corotational plasma wake of Europa. I'm pretty sure that beta radiation is the most hazardous to electronics, so I would think that spending as much time as possible orbiting in the wake would be beneficial.

I just double checked and it is 30 days. If anyone is interested, the report has a section on the radiation environment and measures to shield against it starting on 144 of the PDF. Here is a download link: http://soma.larc.nasa.gov/europa/pdf_files/Europa_Study_2012_Report-Final-20120501.pdf
Title: Re: Proposed Europa Missions
Post by: vjkane on 01/15/2015 09:03 pm
I'm fairly certain that the 2012 orbiter study was still assuming 30 days. There is depletion of hot electrons in the corotational plasma wake of Europa. I'm pretty sure that beta radiation is the most hazardous to electronics, so I would think that spending as much time as possible orbiting in the wake would be beneficial.

The 2010 Jupiter Europa orbiter would have lasted a few months as I recall.  That's what ~$2B more buys you.

The Clipper proposal isn't mass starved as I recall.  If more shielding would help, I think they would use it.  The design team has said that if the spacecraft can survive 45 flybys, it can do many more.  Having the instrument sensors that are outside the vault survive is the limiting factor.
Title: Re: Proposed Europa Missions
Post by: baldusi on 01/15/2015 10:23 pm
If I understand it right, some sort of ionizing radiations generate "noise" (as in latch-ups that need a re-cycle), some slowly degrade the materials, and some have a chance of directly permanently disable a part. The last type, as any stochastic process, can be mitigated, but nothing prevents a bad luck day of happening at the beginning of the mission. You just lower your chances.
The worse part, is that to halve the chance of a radiation event, you need twice the amount of mass in front. Thus, if you want to take your reliability from 99% to 99.9% you need 10 more mass. This gets very heavy very fast. And anything outside the vault isn't protected. What's the point of a fully functional bus if you have no instruments (specially if your star/IR/sun trackers and most comm are dead).
Title: Re: Proposed Europa Missions
Post by: Blackstar on 01/16/2015 03:33 am
What's the point of a fully functional bus if you have no instruments (specially if your star/IR/sun trackers and most comm are dead).

Isn't is possible to shield them in some way? Why not feed the image into the sensor via a lens system or fiber optics and keep the sensor inside the vault?
Title: Re: Proposed Europa Missions
Post by: RonM on 01/16/2015 03:43 am
What's the point of a fully functional bus if you have no instruments (specially if your star/IR/sun trackers and most comm are dead).

Isn't is possible to shield them in some way? Why not feed the image into the sensor via a lens system or fiber optics and keep the sensor inside the vault?

Fiber optics would be good for spectral analysis, but not imaging. Mirrors would work just fine sending the light to a protected sensor. A right angle would do the trick. Don't know what to do with comm systems, unless you can pull the same right angle mirror trick with a comm laser.
Title: Re: Proposed Europa Missions
Post by: vjkane on 01/16/2015 04:21 am
Isn't is possible to shield them in some way? Why not feed the image into the sensor via a lens system or fiber optics and keep the sensor inside the vault?
There appear to be various tricks that can create partial vaults around sensors, but apparently they aren't as effective as a true vault.  The primary reason, as I understand it, that NASA is doing the Clipper instrument selection so early is so they can do a lot of radiation hardening technology development for specific instrument designs.

How ironic is it that the 1st or 2nd most interesting place in the solar system (depending on your preferences, and assuming Enceladus is 3rd) is almost as harsh to explore as Venus?
Title: Re: Proposed Europa Missions
Post by: JH on 01/16/2015 04:57 am
I tend to think that the space squids don't like company.

On the topic of partial vaults, gyromotion of the incident particles would mean that you can't really avoid exposure, just reduce it proportionally to the shielded angular area. Also, having any opening at all will probably mean a big bump in secondary radiation exposure. Secondary radiation will also be a problem if you add a bend in the opening.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 01/16/2015 04:55 pm
Yeah, I can guess why a primary camera would be difficult to shield. I was really wondering about star sensors and sun sensors, when I sort of imagine you don't need great resolution, just get the light onto an imager, which might be tucked inside better shielding. But I'm sure that they think of all of these things.
Title: Re: Proposed Europa Missions
Post by: vjkane on 01/16/2015 04:59 pm
Yeah, I can guess why a primary camera would be difficult to shield. I was really wondering about star sensors and sun sensors, when I sort of imagine you don't need great resolution, just get the light onto an imager, which might be tucked inside better shielding. But I'm sure that they think of all of these things.
My understanding is that the navigation cameras now are quite respectable cameras in their own right.  Anyone know for sure or not?
Title: Re: Proposed Europa Missions
Post by: JasonAW3 on 01/16/2015 05:21 pm
If radiation is such an issue, why not encase the whole rig in Polyethel Chloride?  It's supposed to be able to reduce the radiation damage astronauts take during a solar storm, it's far lighter than Aluminium, and would actually be able to help insulate some of the more cold ot heat sensitive components.
Title: Re: Proposed Europa Missions
Post by: JH on 01/16/2015 06:29 pm
I know that LRO included a shielding experiment that had to do with RXF1 (the structural shielding that I think you are talking about) and that the results were in line with ground based testing. I have no idea what its TRL is, though.
Title: Re: Proposed Europa Missions
Post by: jongoff on 01/16/2015 06:50 pm
Back on the topic of cubesat parasite payloads as a part of EC, I am familiar with several of the proposals that have been funded as part of the JPL program. There are unquestionably instruments that can significantly increase scientific return and can fit onto a cubesat. To add a few details about the program: 10 studies from various institutions were funded and the proposals are targeting a 3U size with the possibility of expanding to 6U if it can be justified. Depending on the proposal's goals, either a solar powered, long(ish) lived cubesat or a battery powered, short duration cubesat might be acceptable. I can confirm that at least one proposal team is considering solar power; it is not impossible at Jupiter given the low power requirements of some of the instruments in question.

Yeah, we had a solar powered concept we've been studying under an SBIR that was designed with for Titan. It's a 6U though, not a 3U, and we haven't done the thermal analysis yet (we just finished Phase 1) to see if the 3-6W of power we could get at Saturn would actually be enough. Cubesat solar at Jupiter or Saturn is probably feasible, just hard to get enough collecting area.

~Jon
Title: Re: Proposed Europa Missions
Post by: ThereIWas3 on 01/16/2015 06:52 pm
Besides using mass for shielding there are also magnetic methods.  (It works for planet Earth)  There are several engineering problems to be solved though.  Superconducting magnets, power source, and how not to mess with your stuff that is inside the field.
Title: Re: Proposed Europa Missions
Post by: JH on 01/16/2015 07:03 pm
Yeah, we had a solar powered concept we've been studying under an SBIR that was designed with for Titan. It's a 6U though, not a 3U, and we haven't done the thermal analysis yet (we just finished Phase 1) to see if the 3-6W of power we could get at Saturn would actually be enough. Cubesat solar at Jupiter or Saturn is probably feasible, just hard to get enough collecting area.

~Jon

I'm pretty impressed that you were able to squeeze a square meter of high efficiency solar arrays into a 6U cube sat. But, yeah, once you go beyond Jupiter, solar becomes crazy hard.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 01/29/2015 04:07 pm
This is an interesting article. I haven't read it all the way through, but it has some interesting observations on how Culberson squares his skepticism of climate science with his claim that he is supporting the "scientific consensus" on the need for a Europa mission:

http://news.sciencemag.org/funding/2015/01/money-chase-2016-new-head-key-house-science-spending-panel-likes-limited-government?utm_campaign=email-news-latest&utm_src=email

Title: Re: Proposed Europa Missions
Post by: Blackstar on 01/30/2015 03:46 am
Some people who want a Europa mission will be happy with the president's proposed budget.
Title: Re: Proposed Europa Missions
Post by: redliox on 01/30/2015 11:24 am
This is an interesting article. I haven't read it all the way through, but it has some interesting observations on how Culberson squares his skepticism of climate science with his claim that he is supporting the "scientific consensus" on the need for a Europa mission:

http://news.sciencemag.org/funding/2015/01/money-chase-2016-new-head-key-house-science-spending-panel-likes-limited-government?utm_campaign=email-news-latest&utm_src=email

It's encouraging to hear a few in government have genuine science interests.

Definitely would love to hear the budget details as they come, most obviously regarding Europa.
Title: Re: Proposed Europa Missions
Post by: mikelepage on 01/30/2015 03:33 pm
This is an interesting article. I haven't read it all the way through, but it has some interesting observations on how Culberson squares his skepticism of climate science with his claim that he is supporting the "scientific consensus" on the need for a Europa mission:

http://news.sciencemag.org/funding/2015/01/money-chase-2016-new-head-key-house-science-spending-panel-likes-limited-government?utm_campaign=email-news-latest&utm_src=email

It's encouraging to hear a few in government have genuine science interests.

Definitely would love to hear the budget details as they come, most obviously regarding Europa.

Also interesting that he's keen on the idea of a Europa penetrator on the first mission.  I still have trouble picturing how that would actually work though.  I mean, you need something to remain on the surface so it can transmit back anything it finds, so do you then have a tether attaching the transmitter to whatever drills down into the ice?  How long do you make that tether? :)  And how do you make this whole craft as small as it needs to be?

Title: Re: Proposed Europa Missions
Post by: vjkane on 01/30/2015 03:51 pm
Also interesting that he's keen on the idea of a Europa penetrator on the first mission.  I still have trouble picturing how that would actually work though.  I mean, you need something to remain on the surface so it can transmit back anything it finds, so do you then have a tether attaching the transmitter to whatever drills down into the ice?  How long do you make that tether? :)  And how do you make this whole craft as small as it needs to be?
Check out these links on penetrators:

http://futureplanets.blogspot.com/2010/05/europaganymede-penetrator.html

http://futureplanets.blogspot.com/2009/04/europa-hard-landers-and-penetrators.html
Title: Re: Proposed Europa Missions
Post by: Blackstar on 01/30/2015 06:18 pm
I can see a penetrator adding a lot of cost to the mission. How does it affect the baseline design? Is there room/mass for a penetrator to be added to Europa Clipper? Do they have to change a lot of the work they have already done? And how do planetary protection requirements affect this, including the cost? Up until now, EC has been designed so that nothing touches the surface ever, but adding a penetrator now means that something does touch the surface.

I'm not saying that it is a bad idea. But it may be a bad idea.
Title: Re: Proposed Europa Missions
Post by: vjkane on 01/30/2015 08:03 pm
I can see a penetrator adding a lot of cost to the mission. How does it affect the baseline design? Is there room/mass for a penetrator to be added to Europa Clipper? Do they have to change a lot of the work they have already done? And how do planetary protection requirements affect this, including the cost? Up until now, EC has been designed so that nothing touches the surface ever, but adding a penetrator now means that something does touch the surface.

I'm not saying that it is a bad idea. But it may be a bad idea.
Congressmen don't need to worry about those things.  I cannot imagine that the Clipper will carry any kind of lander.  However, the advanced work on landers that Congress funded this year may advance the data at which a lander will someday fly
Title: Re: Proposed Europa Missions
Post by: Blackstar on 01/30/2015 08:21 pm
I can see a penetrator adding a lot of cost to the mission. How does it affect the baseline design? Is there room/mass for a penetrator to be added to Europa Clipper? Do they have to change a lot of the work they have already done? And how do planetary protection requirements affect this, including the cost? Up until now, EC has been designed so that nothing touches the surface ever, but adding a penetrator now means that something does touch the surface.

I'm not saying that it is a bad idea. But it may be a bad idea.
Congressmen don't need to worry about those things.  I cannot imagine that the Clipper will carry any kind of lander.  However, the advanced work on landers that Congress funded this year may advance the data at which a lander will someday fly

I agree with that. I would also add that throwing some technology money at penetrators is not necessarily a bad thing (although throwing too much money at it, when it is not going to fly for decades, is nonsensical). There may be some better ways to spend Europa money, however. For instance, advanced sensors.
Title: Re: Proposed Europa Missions
Post by: redliox on 01/30/2015 08:46 pm
I can see a penetrator adding a lot of cost to the mission. How does it affect the baseline design? Is there room/mass for a penetrator to be added to Europa Clipper? Do they have to change a lot of the work they have already done? And how do planetary protection requirements affect this, including the cost? Up until now, EC has been designed so that nothing touches the surface ever, but adding a penetrator now means that something does touch the surface.

I'm not saying that it is a bad idea. But it may be a bad idea.
Congressmen don't need to worry about those things.  I cannot imagine that the Clipper will carry any kind of lander.  However, the advanced work on landers that Congress funded this year may advance the data at which a lander will someday fly

I agree with that. I would also add that throwing some technology money at penetrators is not necessarily a bad thing (although throwing too much money at it, when it is not going to fly for decades, is nonsensical). There may be some better ways to spend Europa money, however. For instance, advanced sensors.

A penetrator would be awesome, but I have to side with Blackstar in that it's probably impossible for the time being.  It certainly would need a good investment put into it; last thing we want to see is a repeat of Deep Space 2.  Ultimately it would depend on how much money gets thrown Europa's way, and beefing up the orbiter's instruments would be wiser, such as restoring the mass spectrometer to ion-neutral capability or adding a UV spectrometer.
Title: Re: Proposed Europa Missions
Post by: Donosauro on 01/30/2015 09:35 pm
Also interesting that he's keen on the idea of a Europa penetrator on the first mission.  I still have trouble picturing how that would actually work though.  I mean, you need something to remain on the surface so it can transmit back anything it finds, so do you then have a tether attaching the transmitter to whatever drills down into the ice?  How long do you make that tether? :)  And how do you make this whole craft as small as it needs to be?
Check out these links on penetrators:

http://futureplanets.blogspot.com/2010/05/europaganymede-penetrator.html

http://futureplanets.blogspot.com/2009/04/europa-hard-landers-and-penetrators.html

It seems like representative Culberson has in mind some much more capable kind of penetrator than those you wrote about on your blog, since he expects it to penetrate the Europan crust and to reach its ocean: "...I put in the technology money so that NASA could develop the penetrator that we'll need to get below the ice and down into its ocean."
Title: Re: Proposed Europa Missions
Post by: Blackstar on 01/31/2015 02:02 am
It seems like representative Culberson has in mind some much more capable kind of penetrator than those you wrote about on your blog, since he expects it to penetrate the Europan crust and to reach its ocean: "...I put in the technology money so that NASA could develop the penetrator that we'll need to get below the ice and down into its ocean."

Either he misunderstands what is possible, or he is talking about generic technology/study money not intended for a penetrator on the Europa Clipper. Considering how close he is to this subject, I don't think he misunderstands this stuff.

For some of those of us who worked on the Decadal Survey, we always had a worry that Culberson's zeal for Europa was so great that he would essentially unbalance the rest of the planetary science program in order to fund a Europa mission. I remember attending an event after the DS was released where he seemed skeptical/negative about the Mars cacher rover that was at the top of the list of the DS flagship missions. But for a long time his power was limited. Also, for a long time the JPL Europa option was too big to fund and would have wrecked the entire planetary budget, so it was not going to get approval from anybody.

I can say that some of the things I have heard in the past few months, and some of the things Culberson has said, indicate that he will not unbalance the planetary science program in favor of a Europa mission. He has indicated an interest in funding basic technology and in getting planetary a top-line budget equivalent to what it was several years ago before the administration started cutting it.

But this is from the above-linked article:

"Culberson’s stance leaves him open to the charge that he is substituting his judgment for that of scientific experts. That’s especially problematic for a lawmaker who emphasizes that his support for the Europa mission is driven not by his own fascination with its frozen oceans but by his desire to reinforce the consensus of the scientific community.

The consensus Culberson is referring to is a 2011 decadal study for planetary science, written by a panel convened by the U.S. National Academies. He regards such decadal studies, which identify high-priority research areas and often help set agency spending priorities, as “the gold standard” for setting NASA’s direction. And he vows that the CJS bills his panel produces will continue to require NASA “to fund and fly” the survey’s priority missions. (At the top of the report’s list was a trip to collect, and eventually return, samples from Mars, part of a multistep approach to exploring the Red Planet that NASA is pursuing.)"



Now that is written in such a way as to be a bit ambiguous. Does it mean that Culberson is going to fund all of the DS priorities, or the "priority missions"? And does that simply mean that he will make sure it funds Mars 2020 and Europa Clipper, but ignores everything else?

There is an invisible gorilla in the room, which is that the administration has essentially zeroed-out the New Frontiers program line. New Frontiers funds missions to other parts of the solar system. The New Horizons Pluto mission is a New Frontiers mission. If Culberson primarily cares about Europa Clipper and doesn't care about New Frontiers, that could leave NASA with a planetary program that essentially does Mars missions and a Europa mission and nothing else for the next decade plus--no comets, no asteroids, no Moon, no Venus, or any of the other possible missions other than the next Discovery mission selection.

And I would note that that is NOT what the Decadal Survey's priorities were. It did not say "flagships first, then all the other stuff." In fact, it put the flagships after the other stuff.

I actually suspect that Culberson knows this and I would not be surprised to see him put some money into the New Frontiers program. But right now that is uncertain.
Title: Re: Proposed Europa Missions
Post by: vjkane on 01/31/2015 03:16 am
There is an invisible gorilla in the room, which is that the administration has essentially zeroed-out the New Frontiers program line. New Frontiers funds missions to other parts of the solar system. The New Horizons Pluto mission is a New Frontiers mission. If Culberson primarily cares about Europa Clipper and doesn't care about New Frontiers, that could leave NASA with a planetary program that essentially does Mars missions and a Europa mission and nothing else for the next decade plus--no comets, no asteroids, no Moon, no Venus, or any of the other possible missions other than the next Discovery mission selection.

After the decision to do a new start for Clipper, the key question is when is the expected launch.  If it is around 2024, then current funding can support Mars 2020, Discovery missions around every 3.5 years, and Clipper but no new New Frontiers (by my budget analysis).  If Clipper is pushed to 2022 (I don't see anyway to do it before then as still do the missions in the pipeline), then the next Discovery AO would need to be pushed out.  (This is all assuming relatively flat planetary budgets.)

I am a big fan of New Frontiers missions and I am sad to see the program effectively shutting down for the next while.  That said, the planetary science community is just one stake holder in setting planetary priorities.  NASA management is another, and so are the NASA centers, OMB, Congress, and the public.  A program that includes more frequent Discovery missions and the top two priority Flagship missions is much better than I had hoped for just a couple of years ago.

We got MSL in its final form (the 2003 Decadal Survey called for a modest technology demonstration rover), Mars 2020, and now Clipper because of political issues outside the purvey of the Decacal Surveys.  Flagships get a great deal of visibility and therefore political momentum.
Title: Re: Proposed Europa Missions
Post by: baldusi on 01/31/2015 04:27 am
I was truck with hos comment that he wanted to take some of the OMB power over setting NASA's priorities. Quite interesting to this particular mission (given how they still haven't allowed an ATP).
Title: Re: Proposed Europa Missions
Post by: simonbp on 01/31/2015 05:15 am
After the decision to do a new start for Clipper, the key question is when is the expected launch.  If it is around 2024, then current funding can support Mars 2020, Discovery missions around every 3.5 years, and Clipper but no new New Frontiers (by my budget analysis).  If Clipper is pushed to 2022 (I don't see anyway to do it before then as still do the missions in the pipeline), then the next Discovery AO would need to be pushed out.  (This is all assuming relatively flat planetary budgets.)

I've heard rumblings that they might select two of the current round of Discovery proposals and then stagger their development. That would give more flexibility in terms of making a Europa mission happen while the political winds are blowing for it, and then once it is entrenched and a separate line item (like JWST), go back to a more regular Discovery schedule. But that might simply be wishful thinking on the part of those people proposing for Discovery.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 01/31/2015 03:53 pm
I've heard rumblings that they might select two of the current round of Discovery proposals and then stagger their development. That would give more flexibility in terms of making a Europa mission happen while the political winds are blowing for it, and then once it is entrenched and a separate line item (like JWST), go back to a more regular Discovery schedule. But that might simply be wishful thinking on the part of those people proposing for Discovery.

I go with wishful thinking. The problem is that delays don't save money--the proposing team still has to keep their team together during the delay and this costs NASA money. No team can guarantee that the team they said would be available in year 1 will be available in year 3, unless they are paid to be available.

This is what happened with Juno. NASA selected the mission and then immediately delayed it, and I think that increased the cost of the mission by 100 million or so.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 01/31/2015 03:57 pm
I was struck with his comment that he wanted to take some of the OMB power over setting NASA's priorities. Quite interesting to this particular mission (given how they still haven't allowed an ATP).

That's part of the ongoing struggle regarding NASA funding. There has long been the perception that OMB budget examiners have been setting NASA priorities without executive oversight or direction. I won't say if I believe that is true, but the claim has been that certain projects have been rejected (and others have been pushed) because OMB civil servants have their own priorities aside from the White House's priorities. For example, they have been opposed to both flagships in general and Mars sample return in particular, essentially for the same reason that they will end up costing lots of money.

If you look at what Culberson has done the past few years with Europa, you see that he's been trying to essentially get Congress to set the budget priorities for planetary science, following his interpretation of the Decadal Survey.
Title: Re: Proposed Europa Missions
Post by: vjkane on 01/31/2015 03:59 pm
This is what happened with Juno. NASA selected the mission and then immediately delayed it, and I think that increased the cost of the mission by 100 million or so.
I heard in some meeting or other -- I think it was an OPAG meeting -- that the Juno team did a classic job of using the extra time to do early engineering work and reduce risk.  The NASA official said there might be a lesson in the longer development time for all missions.  If there was, it wasn't followed, presumably because it adds costs to every mission.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 01/31/2015 04:01 pm
1-That said, the planetary science community is just one stake holder in setting planetary priorities.  NASA management is another, and so are the NASA centers, OMB, Congress, and the public. 

2-A program that includes more frequent Discovery missions and the top two priority Flagship missions is much better than I had hoped for just a couple of years ago.


1-That is true. I would not dispute it. I would posit the notion that the science community, NASA management (at least part of it), and Congress are all closer in agreement than OMB is.

2-I would agree. I'm not going to whine. I view this political exercise as like pushing spaghetti across a plate: you apply some pressure in one spot, then go on to another. I expect that pressure for New Frontiers will come next, possibly boosted by the fact that New Horizons is going to be an incredibly famous New Frontiers mission.

I would still add a caution/caveat: flagship missions if they go over budget can wreck the rest of the program by sucking all the money away.

And it looks like we are now going to have TWO.
Title: Re: Proposed Europa Missions
Post by: vjkane on 01/31/2015 04:12 pm
There has long been the perception that OMB budget examiners have been setting NASA priorities without executive oversight or direction. I won't say if I believe that is true, but the claim has been that certain projects have been rejected (and others have been pushed) because OMB civil servants have their own priorities aside from the White House's priorities.
I suspect that NASA's planetary program is such a minor detail in the scheme of White House officials that the OMB civil servants may be the responsible officials.  Their mandate, apparently, is to keep the programs within budget boundaries.  If the Decadal Priorities can be followed, too, that's good.  I've also heard that they have many pictures on their office walls from NASA, but that they are from the manned program.  Any thoughts, Blackstar?
Title: Re: Proposed Europa Missions
Post by: zubenelgenubi on 02/01/2015 04:31 pm
-I am sure that the people at OMB see things entirely differently than the people at NASA, or the "informed" public.
Has anyone from OMB, past or present, ever spoken about their participation in setting NASA's budget and/or budget priorities?

This might not be perceived as GLAMOROUS content, but it should be informative.

"I was there at the dawn of NASA's FY 2016 budget."
(For full effect, I suggest reading the above sentence with a Londo Mollari accent.)

Curious,
Zubenelgenubi
Title: Re: Proposed Europa Missions
Post by: zubenelgenubi on 02/02/2015 02:31 am
-I am sure that the people at OMB see things entirely differently than the people at NASA, or the "informed" public.
Has anyone from OMB, past or present, ever spoken about their participation in setting NASA's budget and/or budget priorities?

This might not be perceived as GLAMOROUS content, but it should be informative.

"I was there at the dawn of NASA's FY 2016 budget."
(For full effect, I suggest reading the above sentence with a Londo Mollari accent.)

Curious,
Zubenelgenubi

They keep a pretty low profile. And you wouldn't get a candid answer out of them anyway. That's now how Washington works.

Copy that.  And I ask pardon if am straying from the topic.

But.

Does this count for retirees?  Not those who have put in their 30 years as civil servants, but still need to watch what they say and do, so as not to wreck their chances at employment as contractors?  Or political appointees who don't want to jeopardize the next political appointment?

I mean those who have retired, and don't much care about negative consequences to telling the (perceived) truth, because they don't have to impress an employer or politicians any more.  However, they do care enough to respond to an interview request and give honest, informative answers.

If one can find them--they are assumed to be keeping a low profile.

Or am I describing a null set?

Zubenelgenubi
Title: Re: Proposed Europa Missions
Post by: Blackstar on 02/02/2015 06:01 pm
Title: Re: Proposed Europa Missions
Post by: Blackstar on 02/02/2015 06:09 pm
$30 million to start Europa.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 02/02/2015 06:12 pm
You can also see that there's no money for New Frontiers. I don't know what kind of profile the outer years budget would fund--next selection in 2019?
Title: Re: Proposed Europa Missions
Post by: redliox on 02/02/2015 06:19 pm
So, if I'm reading the various clips correctly, we finally have an official start on EC, but it would be a small flagship and not in the New Frontiers class?  If it's not an official start how is "formulation work" different from all the work done in the past ~5 years? (since they divided things into the orbiter, fly-by, and lander concepts)
Title: Re: Proposed Europa Missions
Post by: redliox on 02/02/2015 06:24 pm
You can also see that there's no money for New Frontiers. I don't know what kind of profile the outer years budget would fund--next selection in 2019?

Between Discovery, flagships, and mega-projects like either Webb or SLS I'm not surprised something gets inevitably neglected.  However I do hope they begin putting renewed emphasis on the outer planets, starting with Europa obviously but hopefully the ice giants next.  Saturn could wait a little...they've had the luck of Cassini for ~15 years now.
Title: Re: Proposed Europa Missions
Post by: vjkane on 02/02/2015 06:51 pm
You can also see that there's no money for New Frontiers. I don't know what kind of profile the outer years budget would fund--next selection in 2019?
The budget text says the next New Frontiers AO would be issued at the end of FY16 (fall 2016).  It typically takes ~2 years to select a mission, so the ramp up would start in FY19, which is what the budget ramp suggests.
Title: Re: Proposed Europa Missions
Post by: vjkane on 02/02/2015 06:54 pm
So, if I'm reading the various clips correctly, we finally have an official start on EC, but it would be a small flagship and not in the New Frontiers class?  If it's not an official start how is "formulation work" different from all the work done in the past ~5 years? (since they divided things into the orbiter, fly-by, and lander concepts)
NASA has a formulation period for all missions (this covers at least Phase A and I think possibly Phase B).  The mission  isn't officially approved until a design review at the end of the formulation period.

I read this budget as drawing out the formulation phase to support a launch in the mid-2020's.  While a somewhat longer formulation phase makes sense for a mission with the radiation challenges and hence design challenges of the Clipper, this long is basically the budget office saying, 'We heard you on Europa, it's an official project, now go away until around 2020 when the real work (and budget ramp up) occurs.'
Title: Re: Proposed Europa Missions
Post by: Blackstar on 02/02/2015 07:27 pm
So, if I'm reading the various clips correctly, we finally have an official start on EC, but it would be a small flagship and not in the New Frontiers class?  If it's not an official start how is "formulation work" different from all the work done in the past ~5 years? (since they divided things into the orbiter, fly-by, and lander concepts)

There was never a New Frontiers Europa Clipper. All of the Europa options were flagship class missions. OMB last year wanted to see if it was possible to do a Europa mission for approximately $1 billion, or around the equivalent of a New Frontiers mission. NASA asked for proposals, got six, and determined that none of them would be able to do Decadal level science (in other words, "science that the scientific community considered worthwhile"). So that effort died a quiet death.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 02/02/2015 07:29 pm
By the way, here is the summary budget briefing.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 02/02/2015 07:30 pm
Here is the full budget document.
Title: Re: Proposed Europa Missions
Post by: Star One on 02/02/2015 09:37 pm
You can also see that there's no money for New Frontiers. I don't know what kind of profile the outer years budget would fund--next selection in 2019?
The budget text says the next New Frontiers AO would be issued at the end of FY16 (fall 2016).  It typically takes ~2 years to select a mission, so the ramp up would start in FY19, which is what the budget ramp suggests.
I wonder how much consideration a mission to either the ice giants or Titan would get by then.
Title: Re: Proposed Europa Missions
Post by: ccdengr on 02/03/2015 02:27 am
NASA has a formulation period for all missions (this covers at least Phase A and I think possibly Phase B).
Certainly not Phase B, and I suspect the first FY only covers pre-phase-A activities.  For a mission with competed instruments, Phase A starts after instrument selection.  See http://fpd.gsfc.nasa.gov/NPR71205/NID.pdf
Title: Re: Proposed Europa Missions
Post by: Blackstar on 02/03/2015 03:48 am
You can also see that there's no money for New Frontiers. I don't know what kind of profile the outer years budget would fund--next selection in 2019?
The budget text says the next New Frontiers AO would be issued at the end of FY16 (fall 2016).  It typically takes ~2 years to select a mission, so the ramp up would start in FY19, which is what the budget ramp suggests.
I wonder how much consideration a mission to either the ice giants or Titan would get by then.

None. Those are going to have to wait until the next decadal survey. NASA is going to have a full plate for the next few years. And if the agency is going to take on anything more, it should be adding another Discovery and/or New Frontiers opportunity.
Title: Re: Proposed Europa Missions
Post by: Geron on 02/03/2015 05:10 am
Couldn't we do more exploration missions by saving money on launchers? If a sls launch is 1 billion, why not do 2 falcon heavies for 260 million? Then we would have an extra 740 million for another science mission!!
Title: Re: Proposed Europa Missions
Post by: vjkane on 02/03/2015 05:26 am
Couldn't we do more exploration missions by saving money on launchers? If a sls launch is 1 billion, why not do 2 falcon heavies for 260 million? Then we would have an extra 740 million for another science mission!!
Perhaps in a rational world (let me know if you find one :> ) that would make sense.  However, NASA, like many organizations, budgets within categories.  It has been decided that NASA will have an SLS launcher that will cost about $1B per launch.   To make the system viable, they have to launch every so often and the SLS budget will be sized for that rate.  They now need missions to use that launcher.  So, the SLS budget gets hit for a planetary mission (perhaps the planetary program has to transfer the equivalent of a commercial launch cost).

What scares me is that the SLS system may well never fly or only fly once or twice.  Its reason for being is a manned spaceflight mission that isn't funded and to provide jobs in key congressional districts.  I could easily see the program being cancelled before the Europa Clipper flies.  Fortunately, my fears seem to be widely held, and I suspect that a commercial launcher will be held as a backup.  There are complications from that strategy -- a commercial launch may would entail Venus flybys and that would require extra heat protection not needed if the SLS launches the mission.


Title: Re: Proposed Europa Missions
Post by: Proponent on 02/03/2015 01:21 pm
Which gives me nasty flashbacks to the effects of NASA's previous in-house launch system, the Shuttle, and its effect on Galileo.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 02/03/2015 01:43 pm
As I like to say, "it's complicated."

Whenever people get hung up on price of launch vehicles (or in fact the cost of the missions themselves) I always cringe, because first of all, I think that people on the outside focus too much on cost, and second, they often fail to recognize that often these choices are based upon factors that are more important than cost, like political support.

On the first point, I think that people focus on cost because it is easier to grasp--$1 billion is more than $500 million, for instance. That's simple. It's contained. You can make clear comparisons. But there are lots of other things involved that are not so easily defined or contained, like the value of the things that are being done for those different costs. I remember hearing the former AA for science, Ed Weiler, discuss this a bit with regards to some large space science missions. Weiler complained that people were focusing too much on a dollar amount when there were other issues. For instance, for a few hundred million more a mission could do far superior science. His point was that cost was ONE variable in the equation, but not necessarily the most important one. All the variables had to be considered.

Second, one of the reasons that a Europa Clipper mission is currently in play right now is because SLS is the launch option. If SLS was not being considered, then Europa Clipper might have less chance of happening. I know all the arguments against SLS (vjkane makes some of them above), but SLS equals political support for the mission, and without it, the mission has less chance of happening. That said, SLS also brings risks, just as vjkane mentioned. There's a risk that if SLS gets canceled, Europa Clipper could get canceled too. Or, more likely, Europa Clipper could get stuck with a lot of costs for redesigning to a new launch vehicle.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 02/03/2015 01:49 pm
Couldn't we do more exploration missions by saving money on launchers? If a sls launch is 1 billion, why not do 2 falcon heavies for 260 million? Then we would have an extra 740 million for another science mission!!

And let me add some other stuff here too:

The missions and the launch vehicles are not paid for out of the same budgets. Yeah, it's all NASA in some way, but it is accounted for in different sections of the budget that are not easily transferrable. In other words, just because you saved money on the launch vehicle does not mean that the money automatically goes into another mission. It could go to a lot of other places. It's maddening and doesn't make a lot of sense, but that's the way it works.

Now what NASA does need is a cheaper option for small missions. A decade ago NASA was paying something like $80 million for a Delta II launch, and today they are paying twice that much for an Atlas V, often with twice as much capability as they require. What they need is something a lot cheaper, because they're paying for launch capability that is not required for most Earth science, heliophysics, and some planetary missions with the Atlas V. Falcon 9 will fit that bill. But Falcon 9 is still not fully available for these kinds of launches (that has to do with contracting issues), although it soon will be.
Title: Re: Proposed Europa Missions
Post by: Malderi on 02/03/2015 03:57 pm
Question for the accountants in the room: when everybody's talking about a "$1B" or a "$2B" Europa mission, when does that counter start ticking upwards? Is that including last year's $100 million, or this year's $30 million?
Title: Re: Proposed Europa Missions
Post by: Blackstar on 02/09/2015 05:59 pm
Jeff Foust's summary of the Europa Clipper issue:

http://www.thespacereview.com/article/2691/1

He mentions that the report language states:

“The leading mission concept may require significant modification depending on what researchers learn in FY 2015 about the existence of active plumes from Europa’s south pole and the accommodations requirements in the awarded instrument proposals.”

I assume that NASA added this language and that it didn't come from OMB. I wonder if this is wiggle room language, or if they really think there is a possibility that they may have to change the instruments if they get more plume evidence. I just don't get to talk to Europa scientists all that much anymore, so I don't have the chance to ask.
Title: Re: Proposed Europa Missions
Post by: vjkane on 02/09/2015 06:26 pm
I assume that NASA added this language and that it didn't come from OMB. I wonder if this is wiggle room language, or if they really think there is a possibility that they may have to change the instruments if they get more plume evidence. I just don't get to talk to Europa scientists all that much anymore, so I don't have the chance to ask.
We may learn more at next week's OPAG meeting
Title: Re: Proposed Europa Missions
Post by: redliox on 02/09/2015 06:53 pm
I assume that NASA added this language and that it didn't come from OMB. I wonder if this is wiggle room language, or if they really think there is a possibility that they may have to change the instruments if they get more plume evidence. I just don't get to talk to Europa scientists all that much anymore, so I don't have the chance to ask.
We may learn more at next week's OPAG meeting

Reading through their agenda page, http://www.lpi.usra.edu/opag/feb2015/agenda.pdf (http://www.lpi.usra.edu/opag/feb2015/agenda.pdf), missions to Jupiter are going to be a heavy topic.  Updates on 'Clipper, JUICE, and Juno are planned, even time is given to the Io Volcano Observer.  New Horizons, the Kuiper Belt, and Enceladus are additional topics.

Wish I could attend!
Title: Re: Proposed Europa Missions
Post by: vjkane on 02/09/2015 06:57 pm
Wish I could attend!
There is almost always a call in number and a WebEx page for viewing the presentations.
Title: Re: Proposed Europa Missions
Post by: Malderi on 02/09/2015 07:07 pm
Wish I could attend!
There is almost always a call in number and a WebEx page for viewing the presentations.

Does accessing those require conference registration etc? Or are publicly accessible?
Title: Re: Proposed Europa Missions
Post by: vjkane on 02/09/2015 07:12 pm
Does accessing those require conference registration etc? Or are publicly accessible?
Publicly accessible without meeting registration
Title: Re: Proposed Europa Missions
Post by: Star One on 02/09/2015 08:11 pm

I assume that NASA added this language and that it didn't come from OMB. I wonder if this is wiggle room language, or if they really think there is a possibility that they may have to change the instruments if they get more plume evidence. I just don't get to talk to Europa scientists all that much anymore, so I don't have the chance to ask.
We may learn more at next week's OPAG meeting

Reading through their agenda page, http://www.lpi.usra.edu/opag/feb2015/agenda.pdf (http://www.lpi.usra.edu/opag/feb2015/agenda.pdf), missions to Jupiter are going to be a heavy topic.  Updates on 'Clipper, JUICE, and Juno are planned, even time is given to the Io Volcano Observer.  New Horizons, the Kuiper Belt, and Enceladus are additional topics.

Wish I could attend!

First time I've heard of the Io Volcano Observer, sounds interesting and see it's a Discovery class mission, so wonder how much chance it has in the next choice. It might get overshadowed by the not completely dissimilar but higher profile Europa Clipper which could impact its chances I suppose.
Title: Re: Proposed Europa Missions
Post by: vjkane on 02/09/2015 08:22 pm
First time I've heard of the Io Volcano Observer, sounds interesting and see it's a Discovery class mission, so wonder how much chance it has in the next choice. It might get overshadowed by the not completely dissimilar but higher profile Europa Clipper which could impact its chances I suppose.
McEwan's Io observer has been around for awhile.  It was proposed for the last competition with a Sterling RTG.  This looks to be the second or perhaps third try, which isn't unusual for Discovery concepts.

Any outer planets mission inevitably is more complex than an inner planets mission with a similar science scope.  In the last two selections, that risk factor seems to have been a major factor.
Title: Re: Proposed Europa Missions
Post by: Star One on 02/09/2015 09:06 pm

First time I've heard of the Io Volcano Observer, sounds interesting and see it's a Discovery class mission, so wonder how much chance it has in the next choice. It might get overshadowed by the not completely dissimilar but higher profile Europa Clipper which could impact its chances I suppose.
McEwan's Io observer has been around for awhile.  It was proposed for the last competition with a Sterling RTG.  This looks to be the second or perhaps third try, which isn't unusual for Discovery concepts.

Any outer planets mission inevitably is more complex than an inner planets mission with a similar science scope.  In the last two selections, that risk factor seems to have been a major factor.

One thought is maybe it will be changed to an all solar powered mission if the Sterling RTG has gone away for now.
Title: Re: Proposed Europa Missions
Post by: redliox on 02/09/2015 09:15 pm

First time I've heard of the Io Volcano Observer, sounds interesting and see it's a Discovery class mission, so wonder how much chance it has in the next choice. It might get overshadowed by the not completely dissimilar but higher profile Europa Clipper which could impact its chances I suppose.
McEwan's Io observer has been around for awhile.  It was proposed for the last competition with a Sterling RTG.  This looks to be the second or perhaps third try, which isn't unusual for Discovery concepts.

Any outer planets mission inevitably is more complex than an inner planets mission with a similar science scope.  In the last two selections, that risk factor seems to have been a major factor.

One thought is maybe it will be changed to an all solar powered mission if the Sterling RTG has gone away for now.

I believe that's the case.  I have read almost as much on the Io Observer as on Clipper, but it is a smaller concept.  It focuses on visual and thermal imaging, magnetospheres, and particle study.  It plows through a tougher environment via polar orbit and does about a dozen flybys.  Short but sweet, with the sweetness being a limited yet the best study done for Io.

If they can mitigate the radiation for a dozen orbits I think it would be worth it.  Having a trio of Jupiter orbiters investigating the Gaileans would be great!
Title: Re: Proposed Europa Missions
Post by: vjkane on 02/09/2015 09:18 pm
If they can mitigate the radiation for a dozen orbits I think it would be worth it.  Having a trio of Jupiter orbiters investigating the Gaileans would be great!
That's my hope for my golden years -- results of three simultaneous Jovian missions.

However, it has yet to be established that a Discovery proposal can convince reviewers that it can be done with the budget cap with acceptable technical and budget risk.  My fingers are crossed.
Title: Re: Proposed Europa Missions
Post by: redliox on 02/09/2015 09:24 pm
If they can mitigate the radiation for a dozen orbits I think it would be worth it.  Having a trio of Jupiter orbiters investigating the Gaileans would be great!
That's my hope for my golden years -- results of three simultaneous Jovian missions.

However, it has yet to be established that a Discovery proposal can convince reviewers that it can be done with the budget cap with acceptable technical and budget risk.  My fingers are crossed.

Ditto.  At least between 'Clipper and JUICE we can be assured Europa and Ganymede will get a thorough examination.  Once their missions are complete the priority should then shift to Enceledus and the Ice Giants.
Title: Re: Proposed Europa Missions
Post by: vjkane on 02/09/2015 09:27 pm
Ditto.  At least between 'Clipper and JUICE we can be assured Europa and Ganymede will get a thorough examination.  Once their missions are complete the priority should then shift to Enceledus and the Ice Giants.
The actuarial tables suggest that I may not be around for that next wave.  I hope (perhaps against hope) that one of the Discovery proposals for Enceladus and Titan are actually feasible within the budget cap. 
Title: Re: Proposed Europa Missions
Post by: Blackstar on 02/09/2015 09:59 pm
McEwan is a good guy. He was on one of our committees a number of years ago and he was always interesting and accessible. He is the PI on HiRISE on the Mars Reconnaissance Orbiter and I remember him being really level-headed about that. (We had a meeting shortly after somebody had released images of a landslide on Mars that they speculated was caused by water. McEwan threw, er, cold water on that claim and said that he was almost certain there was another explanation. Then he published a paper with another explanation. In short, he's not a guy who jumps to conclusions.)

My impression is that there's just no way to do that mission on a Discovery budget. But he's still going to pitch it, and his willingness to talk about it is admirable, because it keeps the subject alive. I would add that an Io Observer is an option for New Frontiers 5. Now NF-5 is probably not going to happen this decade, but it remains an option. By continuing to study an Io mission at the Discovery level, McEwan adds substance to that proposal, so that maybe when NF-5 swings around it will have a chance.

For those who do not know, every winning New Frontiers or Discovery mission has lost multiple times before. Juno was, I think, a combination of three losing Discovery mission proposals. McEwan undoubtedly knows this, and undoubtedly knows that proposing, even if you lose, helps produce a better proposal the next time. I hope that he has good acolytes who can pick up on his work.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 02/09/2015 11:26 pm
Here you go. Knock yourselves out.
Title: Re: Proposed Europa Missions
Post by: vjkane on 02/10/2015 02:49 am
My impression is that there's just no way to do that mission on a Discovery budget.
At least five sets of credible scientists and engineers have proposed Discovery missions that they thought were or will be close or within the budget: Journey to Enceladus and Titan, TiME, Enceladus Life, Enceladus sample return, and Io Observer.

MeEwan has said previously said that the biggest problem outer planet Discovery missions has faced was the cost of many years of flight to the destination.  The new Discovery rules provide a level playing field by NASA picking up the costs of reasonable missions operations outside the PI budget.

A good portion of the reason, I'm told, that outer planet missions cost more than comparable inner planets is the communications challenge.  To get high data rates requires large power systems and that drives much of the system cost.  If ways can be found to limit data rates, by investigations that are inherently low data rate (I think this is part of Juno's strategy) or by having long periods to relay saved data, then costs can be kept down.

If NASA gets the funding for regular (every 2 to 3 years), then I'm willing to bet that one of the proposals will become solid enough for NASA to accept the risk. 
Title: Re: Proposed Europa Missions
Post by: jongoff on 02/10/2015 03:24 am
There are complications from that strategy -- a commercial launch may would entail Venus flybys and that would require extra heat protection not needed if the SLS launches the mission.

VJKane,

Do you have numbers on what the Europa Clipper mass would be for the EELV version, and what the C3 they're assuming is for the SLS version? I'm guessing I can find those by digging back through the thread, but I was wondering if you had them handy. The reason I ask is that I'm curious how much of the benefit of the SLS launch you could get by just refueling the Centaur on the Atlas V 551 before departure (using a depot or a tanker). I know it's a political non-starter at this point, but as a technical point it has me curious, and I wanted to run some numbers.

~Jon
Title: Re: Proposed Europa Missions
Post by: vjkane on 02/10/2015 03:28 am
There are complications from that strategy -- a commercial launch may would entail Venus flybys and that would require extra heat protection not needed if the SLS launches the mission.

VJKane,

Do you have numbers on what the Europa Clipper mass would be for the EELV version, and what the C3 they're assuming is for the SLS version? I'm guessing I can find those by digging back through the thread, but I was wondering if you had them handy. The reason I ask is that I'm curious how much of the benefit of the SLS launch you could get by just refueling the Centaur on the Atlas V 551 before departure (using a depot or a tanker). I know it's a political non-starter at this point, but as a technical point it has me curious, and I wanted to run some numbers.

~Jon
I don't recall seeing those numbers
Title: Re: Proposed Europa Missions
Post by: jongoff on 02/10/2015 03:46 am
There are complications from that strategy -- a commercial launch may would entail Venus flybys and that would require extra heat protection not needed if the SLS launches the mission.

VJKane,

Do you have numbers on what the Europa Clipper mass would be for the EELV version, and what the C3 they're assuming is for the SLS version? I'm guessing I can find those by digging back through the thread, but I was wondering if you had them handy. The reason I ask is that I'm curious how much of the benefit of the SLS launch you could get by just refueling the Centaur on the Atlas V 551 before departure (using a depot or a tanker). I know it's a political non-starter at this point, but as a technical point it has me curious, and I wanted to run some numbers.

~Jon
I don't recall seeing those numbers


After some digging, it looks like the SLS missions were using ~85.4km^2/s^2, and both the Atlas V 551 and SLS Block I concepts had spacecraft masses around 5 metric tonnes. I'm going to run some numbers real quick.

~Jon
Title: Re: Proposed Europa Missions
Post by: jongoff on 02/10/2015 04:00 am
There are complications from that strategy -- a commercial launch may would entail Venus flybys and that would require extra heat protection not needed if the SLS launches the mission.

VJKane,

Do you have numbers on what the Europa Clipper mass would be for the EELV version, and what the C3 they're assuming is for the SLS version? I'm guessing I can find those by digging back through the thread, but I was wondering if you had them handy. The reason I ask is that I'm curious how much of the benefit of the SLS launch you could get by just refueling the Centaur on the Atlas V 551 before departure (using a depot or a tanker). I know it's a political non-starter at this point, but as a technical point it has me curious, and I wanted to run some numbers.

~Jon
I don't recall seeing those numbers


After some digging, it looks like the SLS missions were using ~85.4km^2/s^2, and both the Atlas V 551 and SLS Block I concepts had spacecraft masses around 5 metric tonnes. I'm going to run some numbers real quick.

~Jon

Ok, it looks like a refueled Centaur wouldn't cut it--I'm only getting 3600kg to a C3 of ~85-86km^2/s^2. But a refueled DCSS 5m stage looks like it would work--I'm getting ~4800kg to a C3 of 85-86km^2/s^2.

So theoretically, in a magical world where depots exist instead of SLS Block I, you could do the direct to Europa injection using a refueled Delta-IV M+ (5,2) launch, with a lot of mass to spare, you wouldn't need a DIV-H. But you would need a well-stocked propellant depot--<cue vigorous handwaving>.

As I said, it's a political non-starter, but I was morbidly curious from a technical standpoint.

Spreadsheet I used (showing C3 vs payload for a refueled DCSS and a refueled Single-Engine Centaur) attached.

~Jon
Title: Re: Proposed Europa Missions
Post by: Blackstar on 02/10/2015 04:07 am
At least five sets of credible scientists and engineers have proposed Discovery missions that they thought were or will be close or within the budget: Journey to Enceladus and Titan, TiME, Enceladus Life, Enceladus sample return, and Io Observer.

Well, lots of things get proposed to Discovery, and lots of things get rejected, and lots of scientists and engineers have thought they had a chance. That doesn't make it so. One of the space program's biggest problems is too much wishful thinking. When we did the Decadal Survey, it became pretty clear that it was impossible to send even a brick to Saturn for less than a billion dollars. I doubt that Jupiter is much better. Look at how much Juno cost, and things haven't gotten cheaper since then.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 02/10/2015 04:09 am
But you would need a well-stocked propellant depot--<cue vigorous handwaving>.

How many launches would be required to refuel that depot?
Title: Re: Proposed Europa Missions
Post by: jongoff on 02/10/2015 04:17 am
But you would need a well-stocked propellant depot--<cue vigorous handwaving>.

How many launches would be required to refuel that depot?

Well, you'd need ~27mT of prop, or maybe a little less since you wouldn't use all the DCSS prop getting a measly 4mT payload to the LEO depot--maybe on the order of 22-23mT. That would require either one Delta IV Heavy or two Falcon 9 v1.1s or about half of a Falcon Heavy or a bit more than one Atlas V 552.

In the case of the Falcon options (which would likely be the cheapest), there's the question of how you would get LOX/LH2 into a payload tanker, but my guess is the pad modifications to make that feasible might be cheaper than going the DIVH or AV552 route.

As I said, apply a modest amount of handwaving.

But that's about as far as I probably should take that hypothetical on your thread, unless you're interested. :-)

[I'm actually trying not to be as tedious as some other depot-enthusiasts we could both name.]

~Jon
Title: Re: Proposed Europa Missions
Post by: vjkane on 02/10/2015 04:59 am
When we did the Decadal Survey, it became pretty clear that it was impossible to send even a brick to Saturn for less than a billion dollars. I doubt that Jupiter is much better. Look at how much Juno cost, and things haven't gotten cheaper since then.
Hmmm.  To get a brick to fly past Saturn, you could get by with a spacecraft that only has a medium gain antenna, no instruments other than a star scanner.   So, say a 100 kg spacecraft total, perhaps even including the fuel.  Go into deep hibernation for much of the seven year flight (might be much shorter for this small of a spacecraft) x $5M per year for mission ops.  Might even be able to use solar panels (a JPL engineer told me that the same low temperature cells that work at Jupiter would also work at Saturn; you just need lots more).  That doesn't feel like a $1B mission.

The $1B box mission studies of circa 2007 assumed that highly capable spacecraft would be needed to justify a mission after Cassini, and they found that such a mission couldn't be done for less than something well over $1B as I recall.  They may be right in that base assumption, but the spacecraft they sized isn't the one you would use to take that brick past Saturn.

I worked with a lot of gifted engineers in the high tech industry, and I learned not to bet against good engineers.  At some point, advancing technology will enable a Discovery-class mission to the outer solar system.  I think that the real challenge will be whether these low-cost outer solar system will have sufficiently compelling science to win selections against inner solar system missions. 

The best way to ensure that something isn't possible is for everyone to decide it can't be done and nobody tries.  While all evidence to date argues that Blackstar is correct, I'm glad that teams are challenging the assumptions.  One of them may find a way to change the paradigm, and if they don't nothing is lost but their time.   That's the reason I give up my usual rational conservatism when it comes to engineering and costs, and cheer these guys on. 

My problem with wishful thinking is when senior managers get a fancy and mandate that we can fly Battlestar Gallactica to Jupiter (JIMO), do a Europa orbiter for $100M, say that we can push faster-cheaper-better without stop, or haul an asteroid back to the moon for about the cost of the OSIRIS-ReX mission.  (I saw plenty of examples in private industry of this, too.) 

The Discovery selection process has good checks and balances.  Only the credible will get through, and in the meantime, there's a lot of creative analysis looking for new ways to do things.
Title: Re: Proposed Europa Missions
Post by: Star One on 02/10/2015 06:31 am

When we did the Decadal Survey, it became pretty clear that it was impossible to send even a brick to Saturn for less than a billion dollars. I doubt that Jupiter is much better. Look at how much Juno cost, and things haven't gotten cheaper since then.
Hmmm.  To get a brick to fly past Saturn, you could get by with a spacecraft that only has a medium gain antenna, no instruments other than a star scanner.   So, say a 100 kg spacecraft total, perhaps even including the fuel.  Go into deep hibernation for much of the seven year flight (might be much shorter for this small of a spacecraft) x $5M per year for mission ops.  Might even be able to use solar panels (a JPL engineer told me that the same low temperature cells that work at Jupiter would also work at Saturn; you just need lots more).  That doesn't feel like a $1B mission.

The $1B box mission studies of circa 2007 assumed that highly capable spacecraft would be needed to justify a mission after Cassini, and they found that such a mission couldn't be done for less than something well over $1B as I recall.  They may be right in that base assumption, but the spacecraft they sized isn't the one you would use to take that brick past Saturn.

I worked with a lot of gifted engineers in the high tech industry, and I learned not to bet against good engineers.  At some point, advancing technology will enable a Discovery-class mission to the outer solar system.  I think that the real challenge will be whether these low-cost outer solar system will have sufficiently compelling science to win selections against inner solar system missions. 

The best way to ensure that something isn't possible is for everyone to decide it can't be done and nobody tries.  While all evidence to date argues that Blackstar is correct, I'm glad that teams are challenging the assumptions.  One of them may find a way to change the paradigm, and if they don't nothing is lost but their time.   That's the reason I give up my usual rational conservatism when it comes to engineering and costs, and cheer these guys on. 

My problem with wishful thinking is when senior managers get a fancy and mandate that we can fly Battlestar Gallactica to Jupiter (JIMO), do a Europa orbiter for $100M, say that we can push faster-cheaper-better without stop, or haul an asteroid back to the moon for about the cost of the OSIRIS-ReX mission.  (I saw plenty of examples in private industry of this, too.) 

The Discovery selection process has good checks and balances.  Only the credible will get through, and in the meantime, there's a lot of creative analysis looking for new ways to do things.

I reckon there is a reasonable chance that the march of technology will enable smaller, cheaper & faster missions to the outer solar system sometime this century but whether any of us will still be around to see this is another question entirely. More likely it's something for the next generation or two of scientists and engineers.
Title: Re: Proposed Europa Missions
Post by: redliox on 02/10/2015 09:15 am
Here you go. Knock yourselves out.

Yup, I know I've read this at least once before.  Solar power, inclined orbit, and four primary instruments plus the antenna itself for gravity study.

It's a bit bold for Discovery, but if cost could be controlled the only real concern is the same for 'Clipper: radiation damage.  Beyond that is just handling camera imaging while it zooms by Io at high speed - I was told that was a reason 'Clipper couldn't do the same trick Juno does to bypass the rad belts.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 02/10/2015 01:02 pm
But you would need a well-stocked propellant depot--<cue vigorous handwaving>.

How many launches would be required to refuel that depot?

Well, you'd need ~27mT of prop, or maybe a little less since you wouldn't use all the DCSS prop getting a measly 4mT payload to the LEO depot--maybe on the order of 22-23mT. That would require either one Delta IV Heavy or two Falcon 9 v1.1s or about half of a Falcon Heavy or a bit more than one Atlas V 552.

In the case of the Falcon options (which would likely be the cheapest), there's the question of how you would get LOX/LH2 into a payload tanker, but my guess is the pad modifications to make that feasible might be cheaper than going the DIVH or AV552 route.

As I said, apply a modest amount of handwaving.

But that's about as far as I probably should take that hypothetical on your thread, unless you're interested. :-)

[I'm actually trying not to be as tedious as some other depot-enthusiasts we could both name.]

So:

1 launch for the spacecraft
1 launch for the depot
1-2 launches for the fuel

Multiple rendezvous in LEO, plus propellant transfer.

vs.

1 SLS

or alternatively:

1 Atlas V with a VEEGA trajectory.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 02/10/2015 01:06 pm
When we did the Decadal Survey, it became pretty clear that it was impossible to send even a brick to Saturn for less than a billion dollars. I doubt that Jupiter is much better. Look at how much Juno cost, and things haven't gotten cheaper since then.
Hmmm.  To get a brick to fly past Saturn, you could get by with a spacecraft that only has a medium gain antenna, no instruments other than a star scanner.   So, say a 100 kg spacecraft total, perhaps even including the fuel.  Go into deep hibernation for much of the seven year flight (might be much shorter for this small of a spacecraft) x $5M per year for mission ops.  Might even be able to use solar panels (a JPL engineer told me that the same low temperature cells that work at Jupiter would also work at Saturn; you just need lots more).  That doesn't feel like a $1B mission.

The $1B box mission studies of circa 2007 assumed that highly capable spacecraft would be needed to justify a mission after Cassini, and they found that such a mission couldn't be done for less than something well over $1B as I recall.  They may be right in that base assumption, but the spacecraft they sized isn't the one you would use to take that brick past Saturn.

I worked with a lot of gifted engineers in the high tech industry, and I learned not to bet against good engineers.  At some point, advancing technology will enable a Discovery-class mission to the outer solar system.  I think that the real challenge will be whether these low-cost outer solar system will have sufficiently compelling science to win selections against inner solar system missions. 

The best way to ensure that something isn't possible is for everyone to decide it can't be done and nobody tries.  While all evidence to date argues that Blackstar is correct, I'm glad that teams are challenging the assumptions.  One of them may find a way to change the paradigm, and if they don't nothing is lost but their time.   That's the reason I give up my usual rational conservatism when it comes to engineering and costs, and cheer these guys on. 

My problem with wishful thinking is when senior managers get a fancy and mandate that we can fly Battlestar Gallactica to Jupiter (JIMO), do a Europa orbiter for $100M, say that we can push faster-cheaper-better without stop, or haul an asteroid back to the moon for about the cost of the OSIRIS-ReX mission.  (I saw plenty of examples in private industry of this, too.) 

The Discovery selection process has good checks and balances.  Only the credible will get through, and in the meantime, there's a lot of creative analysis looking for new ways to do things.


Juno is a $1 billion mission, not accounting for inflation applied to the next Discovery round. So any mission to Jupiter has to do the equivalent of Juno for less than half the cost.

Saturn Probe could not get below $1 billion no matter how hard JPL tried. That's my baseline for Saturn, not the billion dollar box study.

Outer planet missions are expensive.
Title: Re: Proposed Europa Missions
Post by: vjkane on 02/10/2015 02:57 pm

Juno is a $1 billion mission, not accounting for inflation applied to the next Discovery round. So any mission to Jupiter has to do the equivalent of Juno for less than half the cost.

Saturn Probe could not get below $1 billion no matter how hard JPL tried. That's my baseline for Saturn, not the billion dollar box study.

Outer planet missions are expensive.
[/quote]
Blackstar, this is not a push back on what you are saying, but I would really like to understand why outer planet missions are so much more expensive, 2-3x what an inner planet mission would be with similar capabilities.  Do you or anyone else know of a study or publication that looks at this?

I've tried several times to get back to the equivalent of PI costs as defined by the Discovery and New Frontiers programs but have failed.

The flight times are longer, but that cost is easily estimated by looking at cruise budgets for Juno and New Horizons, and it doesn't add up to 2-3x.  (For these two missions, the annual costs seem to vary between $8M and ~$18M).

Many of the missions use RTGs, but those costs again are discrete and don't add up to 2-3x.

I try to work backwards from Juno's cost, but hit roadblocks such as Juno carrying a large instrument payload that isn't comparable to what a Discovery mission would carry.  (The one publication in which I found a total mass for Juno's instruments said it was something like 174 kg (which may include shielding).  That's a far more capable payload with all the resulting drivers of spacecraft complexity than what a Discovery mission would be.

The Saturn probe mission had to cost two spacecraft (the probe must function as an independent spacecraft).  The Decadal Survey costs also carried, if memory serves me right (Blackstar, please correct me) ~50% budget reserves vs the normal 33% budget reserves for the PI costs (in other words, reserves were included for costs that that NASA absorbs outside the PI budget such as variations in appropriation streams) and the launch vehicle (which isn't in the PI budget).  Those factors make it hard to work back to the equivalent of PI costs.

For Jupiter missions that must absorb a lot of radiation, radiation hardening is a major factor.  The JUICE mission and the Clipper mission are roughly comparable in the spacecraft and instruments.  Yet the latter is ~2X the JUICE cost, and radiation hardening for Clipper is the obvious culprit.

So net, there is something I am fundamentally missing about outer planet missions that drives costs to be much higher than for inner planet missions.  I'd really like to learn what that is, and would appreciate any pointers you guys have.  Many of you know I write a blog on these topics and I would really like to do a post that explains why outer planet missions remain out of reach.

Title: Re: Proposed Europa Missions
Post by: as58 on 02/10/2015 03:30 pm
In the last Discovery round TiME made it to the final three. Surely that must mean that at least someone (other than the proposers) thought that a Discovery class outer planet mission is not completely infeasible?
Title: Re: Proposed Europa Missions
Post by: vjkane on 02/10/2015 03:38 pm
In the last Discovery round TiME made it to the final three. Surely that must mean that at least someone (other than the proposers) thought that a Discovery class outer planet mission is not completely infeasible?
I've also met several of the principles in outer planet Discovery proposals, and they were sane, sober, even conservative types who'd been around the block a few times. 

So I can't reconcile their willingness to spend their limited time proposing these missions with the fact that actual missions seem to cost 2-3X.

The Discovery proposers may be playing the long game.  They might know that it can't quite be done now, but by continuing to propose and learn, they drive mission concepts closer.  Note: This is speculation and I don't know if this is true or not.
Title: Re: Proposed Europa Missions
Post by: ccdengr on 02/14/2015 04:31 am
So I can't reconcile their willingness to spend their limited time proposing these missions with the fact that actual missions seem to cost 2-3X.
You mean the TMCO reviewers think the missions will be more expensive, right?  Frankly I think it's the fault of the overconservative cost models that are being used more than what it may actually cost.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 02/14/2015 05:08 am
So I can't reconcile their willingness to spend their limited time proposing these missions with the fact that actual missions seem to cost 2-3X.
You mean the TMCO reviewers think the missions will be more expensive, right?  Frankly I think it's the fault of the overconservative cost models that are being used more than what it may actually cost.


We're gonna all end up talking about different things and talking past each other. I'll just sound off on something that I've sounded off on before, which is that the decadal survey used Aerospace Corporation and their CATE process. CATE came up with higher cost estimates than the advocate estimates. But there was actually a good reason why that happened. CATE incorporated "threats" to the projects from outside. In other words, things that a program manager could not do anything about, like insufficient funding from NASA that led to delays, overruns, etc. An example of this was Juno, which got selected and then immediately delayed by NASA, resulting in something like $100 million extra cost to the mission. Or New Horizons, which was forced to hold the design open for either an Atlas V or Delta IV (because NASA couldn't decide) which added costs to the mission. (I think that New Horizons also got hit with a cost increase for the RTG as well.)

Now there is some validity to the claim that the cost estimating process over-estimates the costs, and this is not a good thing. But unfortunately the long history of missions shows that most missions exceed their cost estimates, very few meet them, and you can count the number of missions that came in under cost on one hand with several missing fingers. So claiming that the estimating process over-estimates costs is an argument that generally falls on deaf ears.
Title: Re: Proposed Europa Missions
Post by: vjkane on 02/14/2015 05:34 am
We're gonna all end up talking about different things and talking past each other.
To put what you said in another perspective, there are risks owned by the PI and risks owned by NASA.  In the former are the risks of implementing the spacecraft and instruments, in the latter are the risks of funding flows, overruns in supplied equipment (such as RTGs), and launch vehicle costs.

It may be that tightly focused outer planet missions could be done within the risks managed by the PIs.  The NASA-owned risks may push those outside of the acceptable envelope for PI-led missions.  (It's also possible that NASA judges the risks to the PI costs to be too high for these proposals, too.) 

I hope that the reviewer comments and NASA are giving proposers honest feedback about where their risks appear to be making outer planet missions non-competitive.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 02/14/2015 10:42 pm
It may be that tightly focused outer planet missions could be done within the risks managed by the PIs.  The NASA-owned risks may push those outside of the acceptable envelope for PI-led missions.  (It's also possible that NASA judges the risks to the PI costs to be too high for these proposals, too.) 

I hope that the reviewer comments and NASA are giving proposers honest feedback about where their risks appear to be making outer planet missions non-competitive.


I don't know if anybody has ever done a detailed assessment of the causes of cost overruns for space projects. I'm sure that Aerospace has done that internally and may have provided it to USAF and NASA and NRO, but I don't know of anything public. The public things I do know about are rather general, like GAO reports and I think the NRC did one a few years ago.

Funding instability is a killer for really big programs. Indeed, at the risk of opening up the typical SLS flamewar here (although I think the chances are slim because few people read these science threads) a number of Constellation's problems could be blamed on a lousy funding profile. The same is true for SLS. So when you never get peak funding for a development program, you slip major milestones to the right and create a much more expensive program than you have to. This is less of a risk for smaller programs like robotic spacecraft.

But I have been told by a well-known JPL engineer who is not John Casani that JPL itself treats Discovery and New Frontiers cost-capped programs differently than they do flagships. I don't know all the specifics, but I suspect that they monitor costs more closely and provide greater oversight. My point in bringing that up is that program managers/management has tools for controlling cost growth and they don't always employ them equally.

There are many known causes of cost overruns, including choosing low TRL technology for a mission, lack of sufficient margins, poor initial cost estimation, and so on. So all of those things can be monitored and controlled to some extent. Increasing the cost estimating rigor at the selection phase (which is what the decadal survey did with the CATE) is one of the levers that can be used. Not necessarily the best one, but it exists.
Title: Re: Proposed Europa Missions
Post by: vjkane on 02/15/2015 06:21 am
I don't know if anybody has ever done a detailed assessment of the causes of cost overruns for space projects. I'm sure that Aerospace has done that internally and may have provided it to USAF and NASA and NRO, but I don't know of anything public. The public things I do know about are rather general, like GAO reports and I think the NRC did one a few years ago.
I've been informally told of one analysis that found that missions under $1B rarely seriously bust their budgets while missions >$1B regularly bust their budgets.  I suspect that one reason is that for the cheaper missions, the budget cap is the defining requirement, while for the more expensive missions a set of missions goals is the defining requirement.  If you read all the new capabilities that had to be developed and tested for MSL to meet the ambitious goals, for example, it's no surprise that the mission went seriously over budget.  The mission was defined by capabilities, not budget.

Blackstar, it would probably help if you and I are clear about whether we are talking about full NASA costs (~CATE estimates) or PI costs.  When NASA announces the selection of a Discovery or New Frontiers mission, for example, they discuss the PI costs (spacecraft and instruments), but when the mission launches, they discuss full NASA costs which adds the launch vehicle, operations (under the new Discovery rules), and costs increases because of slower than expected funding ramps, etc.

For example, I went back and looked at the Decadal Survey estimates for the Saturn Probe.  The full up CATE estimate is $1.3B.  However, if you take out the 'threats' category and the launch vehicle (which would be outside a New Frontiers PI budget), the total PI cost appears to be around $800M (from eyeballing the stacked bar graph).  So this mission would appear to approximately fit within the traditional New Frontiers PI program envelope, accounting for inflation.  NASA's eventual total cost, of course, would be more, and likely near the CATE cost.  That's why the New Horizon and Juno missions total costs are substantially above the PI budgets.

Discovery and New Frontiers missions by definition are constrained to do whatever science can be done within a budget cap.  From my days in a leading high tech firm, I learned that if you told the engineering team that they had a budget of $X, they came back with capabilities and engineering costs that matched the budget.  If we then went back and told them that the budget was $1/2X, they told us what capabilities would be lost to develop a project within that budget.  It was up to us in the management team to decide whether the resulting project would be competitive and worth doing and whether the project was likely to stay within the reduced budget.

I suspect that good engineering teams can find ways to propose missions within the Discovery program that could fit within the Discovery budget that traditionally have been thought of as too expensive.  Review teams will have to decide whether the resulting science would be competitive and whether the PI budget is likely to be realistic.
Title: Re: Proposed Europa Missions
Post by: ccdengr on 02/15/2015 04:01 pm
I suspect that good engineering teams can find ways to propose missions within the Discovery program that could fit within the Discovery budget that traditionally have been thought of as too expensive.
"traditionally thought of as too expensive" means the cost models will say they're too expensive, and so such proposals won't do well in TMCO review.

See http://www.lpi.usra.edu/opag/jul2013/presentations/DiscoveryLessonsLearned.pdf for a science perspective on this.
Title: Re: Proposed Europa Missions
Post by: deltaV on 02/15/2015 08:15 pm
After some digging, it looks like the SLS missions were using ~85.4km^2/s^2, and both the Atlas V 551 and SLS Block I concepts had spacecraft masses around 5 metric tonnes. I'm going to run some numbers real quick.

Ok, it looks like a refueled Centaur wouldn't cut it--I'm only getting 3600kg to a C3 of ~85-86km^2/s^2. But a refueled DCSS 5m stage looks like it would work--I'm getting ~4800kg to a C3 of 85-86km^2/s^2.

So theoretically, in a magical world where depots exist instead of SLS Block I, you could do the direct to Europa injection using a refueled Delta-IV M+ (5,2) launch, with a lot of mass to spare, you wouldn't need a DIV-H. But you would need a well-stocked propellant depot--<cue vigorous handwaving>.

As I said, it's a political non-starter, but I was morbidly curious from a technical standpoint.

Spreadsheet I used (showing C3 vs payload for a refueled DCSS and a refueled Single-Engine Centaur) attached.

A related question is whether Falcon Heavy could send 4.8 tonnes direct to Europa (C3=86 km^2/s^2). Here are some very hacky results calculated using a simple multi-stage rocket spreadsheet. I calibrated my Falcon dry mass estimates to be consistent with the 53 tonnes to 200 km LEO figure. Without any additional upper stages Falcon Heavy can only send about 2.6 tonnes to Europa. Solid upper stages help, but not enough, e.g. FH plus a Castor 30B can do about 4.0 tonnes. A hypergolic upper stage with ISP 325s, wet mass 14 tonnes, and PMF of 0.94 could send 4.8 tonnes. Unfortunately such an aggressive PMF is unlikely to be cheap if it's even possible; compare to the Briz-M which has wet mass 22.17 tonnes, PMF 0.893, and ISP 326s.

It looks like just about any LOX-hydrocarbon or LOX/LH2 pump-fed upper stage of about 20 tonnes wet mass should be enough to send 4.8+ tonnes to Europa. Unfortunately there are very few stages of that description (most LOX-burning stages are bigger). The only suitable stages that would be demonstrated in time for this Europa mission seem to be ULA's Centaur, DCSS 4m and DCSS 5m RL-10-based stages. By my calculations any of these 3 launched on Falcon Heavy could send 7+ tonnes direct to Europa. I suspect that the cost and risks involved with outfitting a Falcon Heavy pad for hydrogen and integrating a ULA stage on the Falcon Heavy makes this not viable, especially politically. Of course Falcon Heavy could be used as an alternative to Atlas for the Venus flyby route; my conclusion is only that Falcon Heavy is not viable for launching the probe on the faster Venus-less route.

Surprisingly SLS block 1 with ICPS (which is DCSS 5m) can only send around 6 tonnes to C3=86 km/s^2 (e.g. http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20130013034.pdf), i.e. a bit less than Falcon Heavy despite being a bigger rocket. I think the reason for SLS's poor performance here is ICPS is too small relative to the large burnout mass of the SLS core so a lot of potential performance is wasted on the empty core. If SLS had a more suitable upper stage than ICPS it would do a lot better.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 02/16/2015 02:20 pm
Back in October I had lunch sitting next to a guy from Aerojet who was working on an upper stage for (I think) Falcon Heavy to enable SpaceX to compete for the Solar Probe Plus mission. Dunno if that's gone public anywhere, but it may be mentioned elsewhere on this site. Anyway, they're locked out of a number of missions unless they upgrade their hardware.

One other thing: Falcon Heavy is not using cross-feed. They're not developing it. I was at SpaceX several months ago and asked about cross-feed and was told by one of the people working on the rocket that they are not developing it. It's a potential upgrade if somebody pays for it, but they're not doing the development. So you shouldn't use it in your calculations.
Title: Re: Proposed Europa Missions
Post by: deltaV on 02/16/2015 05:56 pm
One other thing: Falcon Heavy is not using cross-feed.... So you shouldn't use it in your calculations.

I switched my spreadsheet to turn off cross-feed, re-calibrated it to match the known 45 tonnes to LEO figure for FH without cross feed (http://www.spacex.com/falcon-heavy), and found that Falcon Heavy without crossfeed plus Centaur can send about 6.2 tonnes direct to Europa. So that's still an option even without cross feed.

I'll reply to the rest of your post in the Falcon Heavy discussion thread 3.
Title: Re: Proposed Europa Missions
Post by: Robotbeat on 02/16/2015 07:29 pm
Back in October I had lunch sitting next to a guy from Aerojet who was working on an upper stage for (I think) Falcon Heavy to enable SpaceX to compete for the Solar Probe Plus mission. Dunno if that's gone public anywhere, but it may be mentioned elsewhere on this site. Anyway, they're locked out of a number of missions unless they upgrade their hardware.
...
Solar Probe Plus is an extremely high delta-v mission, so most likely they were just talking to them about a kick stage or something.

I really doubt this could be generalized to large, lower-energy payloads. It's quite possible for Falcon Heavy to beat Delta IV Heavy and Atlas V 551 to LEO and GTO while still not being quite as powerful to the extremely high delta-v trajectory that solar probe would need.

So if solar probe all you're basing the bolded text on (and it may not be), then I think it's not a justified statement, unless "a number of missions" means 1.
Title: Re: Proposed Europa Missions
Post by: deltaV on 02/16/2015 07:39 pm
Robobeat, let's move this discussion to the Falcon Heavy thread. Solar Probe Plus is off-topic here.
Title: Re: Proposed Europa Missions
Post by: baldusi on 02/17/2015 03:53 pm
The interesting part of Solar Probe Plus was that it payed for half the development of Star 48GXV. It might not cut it for SPP, but what about direct trajectory that takes as long as the Altas V VEEGA but saves the pass through the Venus environment? It could still be cheaper than the Atlas V, or at least reduce requirements and thus risk.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 02/17/2015 09:41 pm
https://astrobiology.nasa.gov/calendar/europa-plume-workshop/


Workshop on the Potential for Finding Life in a Europa Plume

DATE: Wednesday, February 18, 2015

TIME: 8:30am – 5:30pm PST

LOCATION: NASA Ames Research Center, Building 152, Moffett Field, California

On February 18, 2015, the NASA Astrobiology Institute (NAI) and the Solar System Exploration Research Virtual Institute (SSERVI) will co-host the workshop at NASA Ames Research Center, Moffett Field, California.

Current Europa missions under study by NASA are focused on answering the question “Is Europa habitable?” However, the potential presence of water plumes on the satellite could present an opportunity to pursue the question “Is there life on Europa?” Answering this question is far more challenging because measurements currently possible may provide only ambiguous results from a mission that either orbits or flies by Europa at relatively high velocity. To that end, NASA’s Planetary Science Division is convening a workshop to consider strategies to investigate Europa’s putative plumes for evidence of life. Invitees will be asked to provide feedback to NASA on the following key questions:

    What measurements are needed to detect and characterize the presence of life in an acquired sample?
    What instrumentation is needed to perform these measurements, and what is the current flight readiness of such instruments?
    What is the amount and nature of the sample needed by these instruments and what sample preparation is necessary?
    What constraints does the required nature of the sample place on the sample acquisition process?
    What challenges are present to acquiring the necessary sample and obtaining life-detection measurements from a cubesat(s) deployed by a Europa mission?

The workshop will be followed by a meeting of the Outer Planets Assessment Group on Feb. 19-20, also held at the Ames Research Center.
Title: Re: Proposed Europa Missions
Post by: tul on 02/19/2015 09:20 pm
I've got a question. Since Europa's surface is made of ice, I guess it changes over the years. So if the Europa Clipper will map the surface after it will arrive, how Long can you use this data for planning the landing of an Europa Lander?
Title: Re: Proposed Europa Missions
Post by: ugordan on 02/19/2015 09:36 pm
Long enough. Europa's surface may change quickly on geological timescales, but not on human timescales. If there are regions that change "rapidly" due to plumes, diapirism or what not, they're likely going to be quite localized.
Title: Re: Proposed Europa Missions
Post by: redliox on 02/20/2015 08:06 am
The OPAG is having its meeting now.  Thursday they talked largely about Europa and Pluto.  Today (Friday) it looks like they're having an update on current missions and mentioning plans for various small probes to the Outer Planets.  With luck we'll be getting some intriguing updates soon!
Title: Re: Proposed Europa Missions
Post by: Blackstar on 02/20/2015 05:53 pm
There was some interesting discussion of Europa Clipper yesterday. One speaker walked through the decision to use solar panels. A bunch of things led to that decision, including gaining confidence with the Juno work and some extensive testing. One interesting thing he said was that they did a lot of testing of spare Juno solar cells and they worked out well. However, there are better solar cells available (in terms of power generation) and they hope to investigate them. In other words, they can do the mission with the Juno solar cells, but it is possible that they might get even better results, but they won't know until they've done that investigation.

Also some discussion of SLS and what it brings to the table. One question was whether they can add mass to the SLS mission. The speaker said that it is possible to add some mass, but not a lot. Add too much and they will have to change the trajectory to do a flyby. He didn't provide numbers, however.

There were also some questions about the timeline. NASA has announced that they will be accepting instrument proposals. People wondered if the timeline that is assumed in the authorization bill means that development has to start now, and if NASA's timeline for instruments is incompatible with that. The answer was that NASA's instrument selection timeline is consistent with the timeline in the budget.

On Friday there was some discussion about the "billion dollar Europa" studies.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 02/20/2015 09:45 pm
http://spacenews.com/europa-clipper-team-seeking-earlier-launch/?_wcsid=FBF7A9E96BE3C2239D3BAF4A4638A03433FDA26192541BE07BCB7699D6C55D9A

Europa Clipper Team Seeking Earlier Launch

Title: Re: Proposed Europa Missions
Post by: Zed_Noir on 02/21/2015 01:54 am
http://spacenews.com/europa-clipper-team-seeking-earlier-launch/?_wcsid=FBF7A9E96BE3C2239D3BAF4A4638A03433FDA26192541BE07BCB7699D6C55D9A

Europa Clipper Team Seeking Earlier Launch

So I am guessing that the SLS launcher option is iffy for a 2022 launch. What are the alternate launcher options?
Title: Re: Proposed Europa Missions
Post by: ccdengr on 02/21/2015 03:26 am
NASA has announced that they will be accepting instrument proposals.
In fact NASA had an AO last year for Europa instruments ( http://www.nasa.gov/press/2014/july/nasa-seeks-proposals-for-europa-mission-science-instruments/ ) and the selections are supposed to be announced in April -- though what the relationship between that AO and an actual flight project was never all that clear.
Title: Proposed Europa Missions
Post by: Star One on 02/21/2015 08:45 am
http://spacenews.com/europa-clipper-team-seeking-earlier-launch/?_wcsid=FBF7A9E96BE3C2239D3BAF4A4638A03433FDA26192541BE07BCB7699D6C55D9A

Europa Clipper Team Seeking Earlier Launch

So I am guessing that the SLS launcher option is iffy for a 2022 launch. What are the alternate launcher options?

I suppose Falcon Heavy might still be too new a launcher to be entrusted with such an important mission, as I get the feeling that the dispensation that SLS gets on this wouldn't be applicable to another newish launcher. Especially as from what I have read on here they need to develop a high energy upper stage for it to be used on missions such as this.
Title: Re: Proposed Europa Missions
Post by: yokem55 on 02/21/2015 01:52 pm
http://spacenews.com/europa-clipper-team-seeking-earlier-launch/?_wcsid=FBF7A9E96BE3C2239D3BAF4A4638A03433FDA26192541BE07BCB7699D6C55D9A

Europa Clipper Team Seeking Earlier Launch

So I am guessing that the SLS launcher option is iffy for a 2022 launch. What are the alternate launcher options?

I suppose Falcon Heavy might still be too new a launcher to be entrusted with such an important mission, as I get the feeling that the dispensation that SLS gets on this wouldn't be applicable to another newish launcher. Especially as from what I have read on here they need to develop a high energy upper stage for it to be used on missions such as this.
By 2022, even only flying a few times per year, falcon heavy will have ~20 flights under its belt. If they add a centaur/rl-10 based upper, the risk is in the integration and ground ops, not the upper stage itself. SLS has its own risk structure as well, and there are some planetary folks still sore about being politically married to a launcher.
Title: Re: Proposed Europa Missions
Post by: baldusi on 02/21/2015 02:40 pm
http://spacenews.com/europa-clipper-team-seeking-earlier-launch/?_wcsid=FBF7A9E96BE3C2239D3BAF4A4638A03433FDA26192541BE07BCB7699D6C55D9A

Europa Clipper Team Seeking Earlier Launch

So I am guessing that the SLS launcher option is iffy for a 2022 launch. What are the alternate launcher options?

I suppose Falcon Heavy might still be too new a launcher to be entrusted with such an important mission, as I get the feeling that the dispensation that SLS gets on this wouldn't be applicable to another newish launcher. Especially as from what I have read on here they need to develop a high energy upper stage for it to be used on missions such as this.
By 2022, even only flying a few times per year, falcon heavy will have ~20 flights under its belt. If they add a centaur/rl-10 based upper, the risk is in the integration and ground ops, not the upper stage itself. SLS has its own risk structure as well, and there are some planetary folks still sore about being politically married to a launcher.
You can't add that. The four options are:
1) Atlas V 551 (gotta watch for replacement by NGLV)
2) SLS
3) Delta IV Heavy with kick stage (something like OrbitalATK's Star 48GXV)
4) Falcon Heavy (non cross feed) with something like OrbitalATK's Star 48GXV or whatever Aerojet comes up with.
Title: Re: Proposed Europa Missions
Post by: Star One on 02/21/2015 03:06 pm
http://spacenews.com/europa-clipper-team-seeking-earlier-launch/?_wcsid=FBF7A9E96BE3C2239D3BAF4A4638A03433FDA26192541BE07BCB7699D6C55D9A

Europa Clipper Team Seeking Earlier Launch

So I am guessing that the SLS launcher option is iffy for a 2022 launch. What are the alternate launcher options?

I suppose Falcon Heavy might still be too new a launcher to be entrusted with such an important mission, as I get the feeling that the dispensation that SLS gets on this wouldn't be applicable to another newish launcher. Especially as from what I have read on here they need to develop a high energy upper stage for it to be used on missions such as this.
By 2022, even only flying a few times per year, falcon heavy will have ~20 flights under its belt. If they add a centaur/rl-10 based upper, the risk is in the integration and ground ops, not the upper stage itself. SLS has its own risk structure as well, and there are some planetary folks still sore about being politically married to a launcher.
You can't add that. The four options are:
1) Atlas V 551 (gotta watch for replacement by NGLV)
2) SLS
3) Delta IV Heavy with kick stage (something like OrbitalATK's Star 48GXV)
4) Falcon Heavy (non cross feed) with something like OrbitalATK's Star 48GXV or whatever Aerojet comes up with.
SLS aside would all the others need gravity assists?
Title: Re: Proposed Europa Missions
Post by: vjkane on 02/21/2015 03:08 pm
NASA has announced that they will be accepting instrument proposals.
In fact NASA had an AO last year for Europa instruments ( http://www.nasa.gov/press/2014/july/nasa-seeks-proposals-for-europa-mission-science-instruments/ ) and the selections are supposed to be announced in April -- though what the relationship between that AO and an actual flight project was never all that clear.


Actually, now that I think about it, I may have mis-heard Jim Green yesterday. He may have said that the instrument selection is slipping from April to September. (I thought he was discussing the Discovery program, but I might have confused the two.)
I heard Green say that the Discovery down selection had slipped to September-ish.  They received 28 proposals.

As for the instruments, since the Clipper was not an approved mission, they could formally solicit instruments for the mission, just for some possible future mission that might resemble the Clipper or might by an orbiter or might be...

This seems to have been one of those wink, wink moments where the letter of the law was followed but everyone knew what was going on.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 02/21/2015 04:28 pm
Where did you hear 28 Discovery proposals? On Thursday Green said that he did not know how many they received. I heard Alfred McEwen say 28, but 28 was the number last year and I assumed that he made a mistake when he said that was the number for this year.
Title: Re: Proposed Europa Missions
Post by: Moe Grills on 02/21/2015 04:57 pm
Personally, I don't mind gravity-assists if it means a planned mission comes in under budget.
I have a good hunch that politicians are weary and wary of planetary mission projects that
have serious cost overruns.

BTW, I wish JUICE would end up orbiting Europa instead of doing multiple flybys. Technically it's possible; it wouldn't be harder IMHO than sending a spacecraft to orbit Mercury.
Title: Re: Proposed Europa Missions
Post by: vjkane on 02/21/2015 05:46 pm
Where did you hear 28 Discovery proposals? On Thursday Green said that he did not know how many they received. I heard Alfred McEwen say 28, but 28 was the number last year and I assumed that he made a mistake when he said that was the number for this year.
As Green was preparing to talk about the <$1B Europa proposals, he said that there had been an error in his slides the previous day that said the Discovery down selection would be in May when it should have said September.  He then said that they received 28 proposals and it would take them some time to get through them.
Title: Re: Proposed Europa Missions
Post by: Zed_Noir on 02/21/2015 09:07 pm
http://spacenews.com/europa-clipper-team-seeking-earlier-launch/?_wcsid=FBF7A9E96BE3C2239D3BAF4A4638A03433FDA26192541BE07BCB7699D6C55D9A

Europa Clipper Team Seeking Earlier Launch

So I am guessing that the SLS launcher option is iffy for a 2022 launch. What are the alternate launcher options?

I suppose Falcon Heavy might still be too new a launcher to be entrusted with such an important mission, as I get the feeling that the dispensation that SLS gets on this wouldn't be applicable to another newish launcher. Especially as from what I have read on here they need to develop a high energy upper stage for it to be used on missions such as this.
By 2022, even only flying a few times per year, falcon heavy will have ~20 flights under its belt. If they add a centaur/rl-10 based upper, the risk is in the integration and ground ops, not the upper stage itself. SLS has its own risk structure as well, and there are some planetary folks still sore about being politically married to a launcher.
You can't add that. The four options are:
1) Atlas V 551 (gotta watch for replacement by NGLV)
2) SLS
3) Delta IV Heavy with kick stage (something like OrbitalATK's Star 48GXV)
4) Falcon Heavy (non cross feed) with something like OrbitalATK's Star 48GXV or whatever Aerojet comes up with.

You think the Atlas V & Delta IV will still be flying in 2022?

My option list will be
1) Falcon Heavy with kick stage in the total expandable configuration with cross feed
2) NGLV (aka Blue Atlas) with supplemental SRMs and kick stage
3) SLS

Presuming the NGLV enters service around 2020. Historical precedence that NASA launched the New Horizon mission on the third Atlas V 500 series flight with a new unique stack configuration.
Title: Re: Proposed Europa Missions
Post by: vjkane on 02/21/2015 09:14 pm
BTW, I wish JUICE would end up orbiting Europa instead of doing multiple flybys. Technically it's possible; it wouldn't be harder IMHO than sending a spacecraft to orbit Mercury.
Designing JUICE to take the radiation of Europan orbit would probably add $2-3B to the current ~$1B budget.  That's why it makes two quick flybys and then stays away from the intense radiation belts.
Title: Re: Proposed Europa Missions
Post by: baldusi on 02/21/2015 10:34 pm
[...]
The four options are:
1) Atlas V 551 (gotta watch for replacement by NGLV)
2) SLS
3) Delta IV Heavy with kick stage (something like OrbitalATK's Star 48GXV)
4) Falcon Heavy (non cross feed) with something like OrbitalATK's Star 48GXV or whatever Aerojet comes up with.
SLS aside would all the others need gravity assists?
From what I understand, AV 551 would need a one pass through Earth and two through Venus.
We know that SpaceX is not going to develop the cross feed, at least for now, so what sort of performance to expect with a kick stage, is anyone's guess. Europa Clipper is not an under-300kg like New Horizons but a full 6,000kg or so Flagship Mission. A kick stage might be as big as a small LV upper stage. And it should be pretty reliable, so it has to have heritage or a very simple and thoroughly tested project like the Star 48GXV. And please, don't get me started on putting a Centaur on top of a FH or DIVH.
A similar situation happens with the Delta IV Heavy. It has something like a 45% extra performance to GTO. If high energy is about that, too, then you might save some GA maneuvers.
The fact is that something bigger than an AV 511, might save the Venus passes, which are big culprits in cost for the Atlas V case. It might take the same time, but saving the hotter Venus orbit passes save a lot of cost.
The ULA's NGLV is anyone's guess. It will take some time to transition, probably close to five years, since NRO won't want to commit to it until at least the first launch. And it does takes about five years for integration. Given the expected debut in 2019 for NGLV, it's quite probably that even the last Delta IV Heavy will fly by 2023 or even 2025. Which is about the expected launch date of this mission. If it were to launch on 2025 onwards, the NGLV might even get the improved upper stage by then. And if it covers the full range of performance to Delta IV Heavy, it will obviously be a contender.
Title: Re: Proposed Europa Missions
Post by: redliox on 02/24/2015 10:22 pm
The OPAG released this update from their February meeting: http://www.lpi.usra.edu/opag/feb2015/presentations/04_Clipper%20OPAG%20Feb%202015.pdf (http://www.lpi.usra.edu/opag/feb2015/presentations/04_Clipper%20OPAG%20Feb%202015.pdf)

They clearly put a lot of thought into the solar arrays, and concluded it's worth the effort.  I find it ironic that they might actually outlive the MMRTG power supply.  I'm honestly surprised they proved lighter and more efficient to use than MMRTGs, but apparently the equipment and shielding for plutonium is heftier than even a large pair of wings.  Otherwise the remaining concern is ensuring they don't affect the pointing for optical and infrared imaging.

Otherwise personally I find solar arrays more aesthetically pleasing...although that's not how engineers should think.  ;)

It also looks like there will be more meetings toward the fall of this year and then a review in July of '16.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 02/25/2015 01:00 am
They clearly put a lot of thought into the solar arrays, and concluded it's worth the effort.  I find it ironic that they might actually outlive the MMRTG power supply.  I'm honestly surprised they proved lighter and more efficient to use than MMRTGs, but apparently the equipment and shielding for plutonium is heftier than even a large pair of wings.  Otherwise the remaining concern is ensuring they don't affect the pointing for optical and infrared imaging.

I believe that one of the issues is that the MMRTGs have a faster power drop off rate than the older RTGs. Not quite sure why, but I can find out. The MMRTG was made to be more robust to survive landing on Mars. My guess would be that this includes more structure that cuts down on the heat transfer and thus the power drops off faster.

During the presentation they said that so far they have been testing spare solar cells from Juno. Those are not the most efficient arrays and the next phase of testing they want to do would be testing higher power arrays to see if they work as well.
Title: Re: Proposed Europa Missions
Post by: redliox on 02/25/2015 01:15 am
They clearly put a lot of thought into the solar arrays, and concluded it's worth the effort.  I find it ironic that they might actually outlive the MMRTG power supply.  I'm honestly surprised they proved lighter and more efficient to use than MMRTGs, but apparently the equipment and shielding for plutonium is heftier than even a large pair of wings.  Otherwise the remaining concern is ensuring they don't affect the pointing for optical and infrared imaging.

I believe that one of the issues is that the MMRTGs have a faster power drop off rate than the older RTGs. Not quite sure why, but I can find out. The MMRTG was made to be more robust to survive landing on Mars. My guess would be that this includes more structure that cuts down on the heat transfer and thus the power drops off faster.

Given how radioactive material decays, perhaps it has to do with them using less material; they may be able to generate the same amount of power or even better but a smaller stockpile inevitably falls apart faster.

During the presentation they said that so far they have been testing spare solar cells from Juno. Those are not the most efficient arrays and the next phase of testing they want to do would be testing higher power arrays to see if they work as well.

Makes sense to me.  I wager they'll want to minimize R&D so there's bound to be a lot of heritage from Juno, and looking at the IVO presentations it is even more obvious there.
Title: Re: Proposed Europa Missions
Post by: baldusi on 02/25/2015 01:49 pm
For me, the most interesting finding is that:
Quote
MCR Findings (4 of 7)
• A Class A risk classification for the mission may be overly constraining the system designs and trades, and not truly being applied consistently across the board, a Class B classification is recommended
Even a 2.1B Flagship mission is classified as a Class B payload. It might still require a Category 3 certified LV, but still less than A level mission assurance requirements. In my book that means that they are willing to take reasonable risks.
Other interesting items:
-Atlas V has a 43% mass margin vs SLS's 38% (req. is 30%). But id does require more complexity for Venus GA environment.
-It would seem that DIVH can save a few years, but requires a customized S/C and thus they won't use the extra capability.
-SLS means the simplest and fastest mission, and is the prefered method, but this is just a transfer of risk from S/C to LV certification.
-There's simply no mention of the Falcon Heavy.
-The limiting volume envelop is the Atlas V.
Title: Re: Proposed Europa Missions
Post by: Roly on 02/25/2015 02:38 pm
I found the Delta IV option very interesting; insofar as possibility of no VEEGA (I had always assumed all of the EELVs required it for any substantial S/C to Jupiter), but appreciate the programmatic complexity/risk. 

Is there any appropriately certified, or even slightly bespoke Atlas V (e.g not a remix of Titan-Centaur), that can possibly avoid the need for VEEGA?  I am assuming not, but it certainly would be interesting, given that there must be some level of unease about SLS, and issues with keeping LV options too open or too closed.   I suppose even if there was, it would not be with any kind of remotely acceptable margin. 

Apologies, this is probably very obvious; I sort of worry about VEEGA, for the SC, and for the nerves humans presiding over the SC for such prolonged cruise, after so many false starts for Europa, and after Galileo (not that it was the VEEGA, but more perhaps a residual nervousness about a major Jovian satellites mission).  And, of course, I am desperate to see its arrival, in a selfish sense.

Cheers,
Roly
Title: Re: Proposed Europa Missions
Post by: Blackstar on 03/02/2015 08:41 pm
New article on Europa plumes in Science.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 03/03/2015 04:46 pm
Presentation to OPAG.
Title: Re: Proposed Europa Missions
Post by: Jim on 03/04/2015 01:11 am

Is there any appropriately certified, or even slightly bespoke Atlas V (e.g not a remix of Titan-Centaur),


Bespoke?
Title: Re: Proposed Europa Missions
Post by: Roly on 03/04/2015 02:35 am
Apologies, in the sense of tailored; but probably the fact that I could not compose it without bespoke or tailored is telling that any such LV is not really a plausible idea...
Title: Re: Proposed Europa Missions
Post by: Jim on 03/04/2015 08:18 am
Apologies, in the sense of tailored; but probably the fact that I could not compose it without bespoke or tailored is telling that any such LV is not really a plausible idea...

Ok, but why the reference to Titan-Centaur, which is a completely different and no longer existing vehicle?
Title: Re: Proposed Europa Missions
Post by: redliox on 03/04/2015 08:34 am
Well odds are it now looks like the Delta 4 won't be the launcher option for 'Clipper:
http://spacenews.com/ula-targets-2018-for-delta-4-phase-out-seeks-relaxation-of-rd-180-ban/ (http://spacenews.com/ula-targets-2018-for-delta-4-phase-out-seeks-relaxation-of-rd-180-ban/)
This makes me wonder if the Atlas V will also be affected by ULA's desire to phase into a NGLV as well as replacing the Russian engines.  If so, this leaves Falcon (Heavy I presume) and SLS as the choice launchers.
Title: Re: Proposed Europa Missions
Post by: Roly on 03/04/2015 09:52 am
It was not well expressed; the reference to my hypothetical 'adjusted' or modified, but not radically changed EELV (which is a bit contradictory) mentioned 'not Titan-Centaur' as a boundary for the sort of changes I meant. 

That is to say, not fantastical ones, like the absurd case of an imaginary, resurrected Titan-Centaur, but moderate ones.  It was meant to gesture to something slightly enhanced or reconfigured, but not crazily impractical and futile.  Re-reading my post, Titan-Centaur was ill-chosen because it is sufficiently ludicrous that it does not provide much of an outer bound to speculation. 
Title: Re: Proposed Europa Missions
Post by: Jim on 03/04/2015 12:15 pm

This makes me wonder if the Atlas V will also be affected by ULA's desire to phase into a NGLV as well as replacing the Russian engines.  If so, this leaves Falcon (Heavy I presume) and SLS as the choice launchers.

It isn't affected, Atlas V is a choice.  Anyways, the ban was for military missions.
Title: Re: Proposed Europa Missions
Post by: redliox on 03/06/2015 07:02 pm

This makes me wonder if the Atlas V will also be affected by ULA's desire to phase into a NGLV as well as replacing the Russian engines.  If so, this leaves Falcon (Heavy I presume) and SLS as the choice launchers.

It isn't affected, Atlas V is a choice.  Anyways, the ban was for military missions.

Naturally it's a choice.  The question is will it still be a choice ten years from now; exception being if 'Clipper succeeds in launching by '22.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 03/07/2015 06:09 pm
Free event April 9 in Houston area.
Title: Re: Proposed Europa Missions
Post by: Star One on 03/07/2015 06:32 pm
Would any kind of electric propulsion such as ion propulsion be of any use for a Europa bound craft?
Title: Re: Proposed Europa Missions
Post by: redliox on 03/07/2015 08:09 pm
Would any kind of electric propulsion such as ion propulsion be of any use for a Europa bound craft?

Difficult to say.  I'd love to say it'd help but to power a decent propulsion system the craft would need arrays certainly larger than Dawn's by comparison due to the fact Jupiter is farther out and sunlight's strength drops off fast.  Juno proves we're at the cusp of solar power at Jupiter but I'm pretty sure that's nearing the limits of what's practical.

One thing I would say: en route to Jupiter it could be useful, especially if it means bypassing Venus flybys; most likely at least one Earth flyby would be necessary but it would help speed the transit to Jupiter along.  Whether or not it could do Jupiter Orbit Insertion is another matter (again just due to sunlight at that distance).
Title: Re: Proposed Europa Missions
Post by: Star One on 03/11/2015 04:03 pm
New article on Europa Clipper's progress. Mentions they'll have to make a choice soon on whether to go with the Juno solar panels or if to go with a more advanced design. Sounds also that they are only really considering Atlas V or SLS for the launcher. It sounds like SLS will be the far better choice if the cost can be resolved as well as fitting it into the SLS schedule.

http://spaceflightnow.com/2015/03/10/europa-clipper-concept-team-aims-for-launch-in-2022/
Title: Re: Proposed Europa Missions
Post by: Blackstar on 03/11/2015 06:47 pm
New article on Europa Clipper's progress. Mentions they'll have to make a choice soon on whether to go with the Juno solar panels or if to go with a more advanced design. Sounds also that they are only really considering Atlas V or SLS for the launcher. It sounds like SLS will be the far better choice if the cost can be resolved as well as fitting it into the SLS schedule.

http://spaceflightnow.com/2015/03/10/europa-clipper-concept-team-aims-for-launch-in-2022/

That looks to be written based upon somebody listening in to the comments at the OPAG meeting a few weeks ago. Here's the solar cell part:

"“We can either cash that in with less area for the (solar) arrays or more power for the system, to be determined at this point,” Goldstein said. “But we’re not counting on that new technology. We wanted existence proof to show that we had what we needed to make the jump away from (nuclear power).”

Officials hope to decide between the old or new solar cell technology by the middle of 2015, then NASA could begin buying test and flight units as part of the mission’s long-lead purchases, according to Goldstein."


If I remember correctly, they did a bunch of tests using backup Juno solar cells that they had on hand. Their next step was to get some newer solar cells and test them. I would guess that they will be putting those cells in test chambers now or soon and running the tests. I dunno what that entails. In addition to thermal/vac testing, do they also hit them with radiation? I vaguely remember hearing somebody say that cold is a bigger issue than radiation for the cells that they have tested. I don't know exactly what that means. Perhaps it is easier to model the radiation and they have to actually test for the cold. Or maybe it just means that prolonged cold is the bigger killer than radiation.

I know how thermal/vac tests work. But how do they actually test for radiation? Do they zap them in a microwave oven or equivalent? And does this have to be done while also in cold vacuum?
Title: Proposed Europa Missions
Post by: Star One on 03/11/2015 06:51 pm
I know solar cell technology in general has advanced quite a bit in recent years due to increasing investment in the technology. But I don't know how much general purpose solar cells would relate to the more specialist ones you would need for a mission such as this.
Title: Re: Proposed Europa Missions
Post by: denis on 03/11/2015 07:24 pm
I know how thermal/vac tests work. But how do they actually test for radiation? Do they zap them in a microwave oven or equivalent? And does this have to be done while also in cold vacuum?

I expect they will submit the cells to a given radiation level and type (so maybe a mixture of gamma rays and high energy protons, to check impact of displacement damages) to reach a total dose equivalent to the mission, then they'll test the cells (in cold vacuum) after irradiation. Most likely (assuming they have enough cells / money), they'll irradiate different cells to different radiation levels (below and above the expected total dose) and compare their performances, to see the degradation over the mission duration.

Contrarily to testing of electronic components, I don't think there is a need to test the cells while they are being irradiated, it can be done in separate steps (so no need to test them while being irradiated and while being in cold vacuum conditions).

Edit: although I admit I don't know if the Jupiter environment is so bad radiation-wise that there is a need for more complex/detailed testing
Title: Re: Proposed Europa Missions
Post by: philw1776 on 03/11/2015 08:56 pm
Great thread here on the state of the art on ion thrusters

http://forum.nasaspaceflight.com/index.php?topic=36787.msg0#new

and importantly, the power sources with new solar cell metrics

http://forum.nasaspaceflight.com/index.php?topic=36789.0



Title: Re: Proposed Europa Missions
Post by: TheMightyM on 03/14/2015 09:21 pm
While I have no doubt that the scientist working on Europa Clipper would love to see the mission launch in 2022, getting the funding to do so is may be challenging. Currently, Planetary Science gets about $1.35 billion a year. Europa Clipper is expected to cost near $2 billion (plus launch vehicle). So Congress is going to have to either substantially increase Planetary Science funding and/or some other missions will have to be delayed, with the “and” option being the most likely path towards a 2022 Europa Clipper launch.

What else is NASA planning to do in Planetary Science circa 2020 to 2022?. The Mars 2020 lander is the big budget item, but there’s also talk of a new Mars Orbiter in 2022. NASA is currently working through proposals for a Discovery mission and then wants to select new missions every two to three years. Finally, the next New Frontiers mission is due to be selected in 2017 and gets $100 million by 2020 in the notional out year budget (and probably more like $250 million for 2021 and 2022.) No easy choices there.
Title: Re: Proposed Europa Missions
Post by: redliox on 03/14/2015 09:51 pm
While I have no doubt that the scientist working on Europa Clipper would love to see the mission launch in 2022, getting the funding to do so is may be challenging. Currently, Planetary Science gets about $1.35 billion a year. Europa Clipper is expected to cost near $2 billion (plus launch vehicle). So Congress is going to have to either substantially increase Planetary Science funding and/or some other missions will have to be delayed, with the “and” option being the most likely path towards a 2022 Europa Clipper launch.

It has a reasonable chance to do so; it does have public support behind it or at least that of planetary scientists.  The real question is which launch vehicle will be ready by 2022.  Still regarding the probe itself, with a decent push it is possible.
Title: Re: Proposed Europa Missions
Post by: Star One on 03/14/2015 10:38 pm
While I have no doubt that the scientist working on Europa Clipper would love to see the mission launch in 2022, getting the funding to do so is may be challenging. Currently, Planetary Science gets about $1.35 billion a year. Europa Clipper is expected to cost near $2 billion (plus launch vehicle). So Congress is going to have to either substantially increase Planetary Science funding and/or some other missions will have to be delayed, with the “and” option being the most likely path towards a 2022 Europa Clipper launch.

It has a reasonable chance to do so; it does have public support behind it or at least that of planetary scientists.  The real question is which launch vehicle will be ready by 2022.  Still regarding the probe itself, with a decent push it is possible.
The Mars orbiter proposal isn't all that definite at the moment to be worrying about its cost.
Title: Re: Proposed Europa Missions
Post by: Bob Shaw on 03/15/2015 12:53 am
Sounds like poor old Venus is off the register, despite it being the only other genuinely Earth-class planet in our Solar System. If we're looking at the evolution of such planetary objects at all, then it demands much more attention. The USSR dominated past Venus research almost by accident after their early probes did well and drew political support, and since then the dearth of large-scale efforts (notwithstanding NASA's 1970/80s Pioneer and Magellan missions, and ESA's more recent repurposed Mars orbiter) has been pretty obvious. Venus is the Titan of the Inner Solar system, with lessons for all sorts of disciplines, and demands much more attention.

Here's the facts. Earth's land mass is about 30% of the planet; Venus, though smaller, has a surface area 95% of the total of the Earth including the oceans. Unlike the Earth, all of Venus is visible from orbit in exactly the same way (mostly RADAR) - the only Earth-sized planet which may make that claim. The surface of Mars is about equal to the surface area of Earth, and the Moon is about the same size as Africa - and both of these worlds are easily seen optically from orbit, and are reasonably easy to land on.

Venus isn't the low-hanging fruit in terms of planetary science, but certainly is a key aspect of the whole business of the evolution of Earth-class planets, and has been seriously undervalued.


Title: Re: Proposed Europa Missions
Post by: JH on 03/15/2015 02:21 am
I'm pretty sure Dr. Elachi (JPL director) has said that NASA will be talking to ISRO about including an Electra comm package onboard MOM II. Also, there is a lot of pent up interest in a new Venus mission, so it wouldn't be terribly surprising if a proposal is funded before too long. I know that some of the different proposal teams from the last go round have clubbed together this time, which should help their chances.
Title: Re: Proposed Europa Missions
Post by: vjkane on 03/15/2015 05:05 am
2-Agreed. I would think that simply from a programmatic perspective NASA officials, if presented with a viable Venus mission, would recognize that it has been a long time since the last NASA Venus mission and therefore Venus is due. But they have to get a viable mission that they can support.
I am thinking that NASA has received viable proposals.  Venus missions have been finalists for two New Frontiers competitions and at least one Discovery competition.  A number of groups have proposed radar mapping missions (which would address Bob Shaw's points) and various descent probes and balloon missions. 

Have you heard that there were technical or budget issues with the numerous Discovery Venus proposals?
Title: Proposed Europa Missions
Post by: Star One on 03/15/2015 08:51 am
Sounds like poor old Venus is off the register, despite it being the only other genuinely Earth-class planet in our Solar System. If we're looking at the evolution of such planetary objects at all, then it demands much more attention. The USSR dominated past Venus research almost by accident after their early probes did well and drew political support, and since then the dearth of large-scale efforts (notwithstanding NASA's 1970/80s Pioneer and Magellan missions, and ESA's more recent repurposed Mars orbiter) has been pretty obvious. Venus is the Titan of the Inner Solar system, with lessons for all sorts of disciplines, and demands much more attention.

Here's the facts. Earth's land mass is about 30% of the planet; Venus, though smaller, has a surface area 95% of the total of the Earth including the oceans. Unlike the Earth, all of Venus is visible from orbit in exactly the same way (mostly RADAR) - the only Earth-sized planet which may make that claim. The surface of Mars is about equal to the surface area of Earth, and the Moon is about the same size as Africa - and both of these worlds are easily seen optically from orbit, and are reasonably easy to land on.

Venus isn't the low-hanging fruit in terms of planetary science, but certainly is a key aspect of the whole business of the evolution of Earth-class planets, and has been seriously undervalued.

I would argue that Venus has had its fair share of recent missions whereas many of the objects in the outer solar system haven't been studied in that detail. With news only this week about the oceans beneath the surface of two further moons I would rather things like this be looked into especially when you have moons such as Io, Titan, Enceladus or planets such as Uranus & Neptune that need proper examination. To be blunt if you want missions that are going to get public support and therefore political interest to follow you're more likely to get that with the dangling hook of possible life no matter how remote a possibility that is than with a planet like Venus which has no chance of this. After all I suspect that's half the reason Mars has had many more missions than Venus.

I know it's not a very scientific answer, but missions have to get political & financial support if they are going to transit to reality and that's not always a logical process.
Title: Re: Proposed Europa Missions
Post by: vjkane on 03/15/2015 02:01 pm
Have you heard that there were technical or budget issues with the numerous Discovery Venus proposals?

Last Discovery round none made it to category 1.
That's not the same as saying that there were no credible Venus proposals. 

One way to interpret the finalists is that there was one per class of destination: terrestrial planets (InSight), small bodies (CHOPPER), outer planets (TiME).

There are several possible explanations for why no Venus missions made it to the finalist list.

It could be a prejudice towards Mars. 

It could be that the Venus missions proposed were technically and financially credible but that the science questions weren't compelling to the team that ranked the missions (which could either be seven poor proposals or a prejudice against Venus (too boring) on the part of the review teams)

It could be that the science questions were compelling but they couldn't be done within the cost cap of the Discovery program.

When there's no public data, it's hard to make any conclusions.  I suspect that the Venus community privately shared the top level results of their proposal reviews.  VEXAG has put a lot of emphasis in the last couple of years on sharpening the science priorities for Discovery class missions, so perhaps the problem was a lack of compelling science questions.
Title: Re: Proposed Europa Missions
Post by: redliox on 03/15/2015 06:29 pm
The whole Venus/Discovery/New Frontiers discussion is good but...why are we bringing this up HERE when there are distinct Discovery and New Frontiers threads?
Title: Re: Proposed Europa Missions
Post by: Star One on 03/16/2015 11:55 am

I would argue that Venus has had its fair share of recent missions

Name the recent missions to Venus. With dates.

Venus Express only just finished. Akatsuki still active & due in orbit this year.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 03/16/2015 03:36 pm

I would argue that Venus has had its fair share of recent missions

Name the recent missions to Venus. With dates.

Venus Express only just finished. Akatsuki still active & due in orbit this year.

So, "fair share" means one mission, launched in 2005, now dead, and one mission that hasn't actually reached Venus and may not work because the spacecraft is severely damaged. And before that, Magellan, launched in 1989.

So, two missions in 25 years.
Title: Re: Proposed Europa Missions
Post by: vjkane on 03/16/2015 03:46 pm
So, two missions in 25 years.
And both are focused on the atmosphere and not the surface or interior
Title: Re: Proposed Europa Missions
Post by: Star One on 03/16/2015 04:14 pm

I would argue that Venus has had its fair share of recent missions

Name the recent missions to Venus. With dates.

Venus Express only just finished. Akatsuki still active & due in orbit this year.

So, "fair share" means one mission, launched in 2005, now dead, and one mission that hasn't actually reached Venus and may not work because the spacecraft is severely damaged. And before that, Magellan, launched in 1989.

So, two missions in 25 years.
If we are going to play this game how many dedicated missions has there ever been to any of the targets I mentioned, none in most cases, which is a heck of a lot less than Venus and that was my point.
Title: Re: Proposed Europa Missions
Post by: JH on 03/26/2015 07:35 am
If we are going to play this game how many dedicated missions has there ever been to any of the targets I mentioned, none in most cases, which is a heck of a lot less than Venus and that was my point.

The lamentable truth is that, while the outer planets and their moons are A) vastly less well explored (and therefore more worthwhile scientifically, assuming the goal is to understand the solar system as a whole) and B) a much better bet for having currently habitable environments, they are A) a massive pain to get to and operate at and B) not places that people have romantic aspirations of colonizing. Venus and Mars are easy(ish) to visit, and Mars is the once and future Next Step in Human Exploration. This gives a clear pecking order: Mars, Venus, anywhere else.
Title: Re: Proposed Europa Missions
Post by: The Amazing Catstronaut on 03/26/2015 07:58 am
The lamentable truth is that, while the outer planets and their moons are A) vastly less well explored (and therefore more worthwhile scientifically, assuming the goal is to understand the solar system as a whole) and B) a much better bet for having currently habitable environments, they are A) a massive pain to get to and operate at and B) not places that people have romantic aspirations of colonizing.

I would argue that Europa has always had extremely good PR, along with good hard science reasons to go (at least with probes - I don't imagine I'm going to live to see astro/cosmo/taiko/whatevernauts touch down on that particular rock. However, most people can at least name the moon, even if they can't name any of the other moons in the same planetary system.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 03/26/2015 11:44 am
I would argue that Europa has always had extremely good PR, along with good hard science reasons to go (at least with probes - I don't imagine I'm going to live to see astro/cosmo/taiko/whatevernauts touch down on that particular rock. However, most people can at least name the moon, even if they can't name any of the other moons in the same planetary system.

Well, good PR compared to other moons of the outer solar system. But I bet that if you stopped 100 people on the street and asked them to name another moon in the solar system, you would have less than 10 who could name any moon at all. You would probably get more replies "There are other moons in the solar system?" than anything else.

But stop 100 people on the street and ask them to name another planet, and I bet that 90% would name Mars. It's much more prevalent in popular culture.
Title: Re: Proposed Europa Missions
Post by: JH on 03/26/2015 02:41 pm
I would argue that Europa has always had extremely good PR, along with good hard science reasons to go (at least with probes - I don't imagine I'm going to live to see astro/cosmo/taiko/whatevernauts touch down on that particular rock. However, most people can at least name the moon, even if they can't name any of the other moons in the same planetary system.

Europa is doing well PR wise, that is true. However, this is when it is compared to other bodies in the outer solar system. It has taken over a decade of NASA perpetually insisting on yet more studies and congress mandating over a hundred million dollars of funding that HAD to be spent on a Europa mission (in some way) for a fairly modest Europa flagship mission to actually get a fresh start. Mars, in comparison, can fall off a log and land on a flagship mission (Mars 2020 for anyone not following along). And before someone says that 2020 is in line with the Decadal Survey directive for MSR, with the most recent mission profile revision in which now essentially the rover will drill out material and then leave it in piles on the ground as it goes, it is no longer a valid step in sample return.

- typo
Title: Re: Proposed Europa Missions
Post by: JH on 03/26/2015 04:50 pm
I apologize, having looked at Farley's MEPAG presentation again, it is, in fact, in tubes. While that does alleviate my concerns about sample degradation due to exposure, the current plan still kicks a lot of the sample return burden down the road.
Title: Re: Proposed Europa Missions
Post by: vjkane on 03/26/2015 05:14 pm
And before someone says that 2020 is in line with the Decadal Survey directive for MSR, with the most recent mission profile revision in which now essentially the rover will drill out material and then leave it in piles on the ground as it goes, it is no longer a valid step in sample return.
The 2020 team has reviewed this with NASA HQ and gotten permission to proceed. 

The follow on mission always would have had a fetch rover.  Now instead of going to one location to fetch a canister, it will go pick up the individual cores. 

This is a fairly clever solution to two problems.  First, what happens if the 2020 rover falls into a sand pit a la Spirit and there's no way to retrieve the canister off the 2020 rover with its samples collected to date?  Or mechanically fails while collecting a sample in a location where another rover couldn't get in front of it to retrieve the canister? Second, what do you do if your canister is full and you then find much better samples?  The reports I've seen have looked at removing cores from the canister to replace them, but this is mechanically difficult and problematic.  We've learned from Opportunity and Spirit that the sample they would have collected during their prime missions would have been only a small portion of the samples that would have been wanted from the full missions.

I haven't seen the proposed solutions to two problems with the new strategy: how to you prevent the core from overheating (place it in the shadow of a nearby rock)?  And how do you recognize the cores after several to many years of dust have covered them between the missions?
Title: Re: Proposed Europa Missions
Post by: Blackstar on 03/26/2015 06:50 pm
I apologize, having looked at Farley's MEPAG presentation again, it is, in fact, in tubes. While that does alleviate my concerns about sample degradation due to exposure, the current plan still kicks a lot of the sample return burden down the road.

That's true. And at the MEPAG meeting a few weeks ago they said that they could reverse that decision. I think they'll hear some opinions about it. But that doesn't mean that it is not sample return. It is an issue of how to do it, not whether or not to do it.
Title: Re: Proposed Europa Missions
Post by: JH on 03/27/2015 02:04 am
My declaration that it did not qualify as part of sample return was based on the premise that the rover was leaving piles of rock dust in its wake and calling it a day.
Title: Re: Proposed Europa Missions
Post by: Bob Shaw on 03/28/2015 12:51 am
Um. Hopefully the Japanese probe makes it. They do seem to attract failure, those chaps...
Title: Re: Proposed Europa Missions
Post by: Blackstar on 03/29/2015 04:06 am
I know that this is the wrong thread for discussing Mars 2020, but it came up here so I'll add this here. During MEPAG the person discussing Mars 2020 said that the method of dropping the small sample canisters behind the rover was acceptable because they could simply follow the tire tracks with another rover and easily find the canisters. But this new data shows that some things on Mars get obscured by dust over time:

http://www.slate.com/blogs/bad_astronomy/2015/03/28/mars_scars_wind_driven_dust_fills_in_curiosity_s_impact_marks.html

Now I'm sure they have looked at the tracks left by the MERs to see how badly they have weathered, so maybe they do know what they're talking about. But maybe when they send Mars 2020 to the red planet they should equip the arm with a can of white spray paint so that it can spray a big white "X" wherever they drop a sample canister.
Title: Re: Proposed Europa Missions
Post by: bolun on 04/11/2015 08:04 am
NASA invites ESA to build Europa piggyback probe

http://spaceflightnow.com/2015/04/10/nasa-invites-esa-to-build-europa-piggyback-probe/
Title: Re: Proposed Europa Missions
Post by: redliox on 04/11/2015 09:16 am
NASA invites ESA to build Europa piggyback probe

http://spaceflightnow.com/2015/04/10/nasa-invites-esa-to-build-europa-piggyback-probe/

*like Professor Farnsworth*
'Good news everyone!'


...of course we have to see ESA's official reaction.  This certainly would be one good way to make up for the embarrassment of ExoMars and EJSM debacles.
Title: Re: Proposed Europa Missions
Post by: Alpha_Centauri on 04/11/2015 02:50 pm
This would be too soon for European RHUs/RPS I imagine, meaning penetrators are possibly the more viable option rather than a lander.  Plenty of work already done on that, e.g; http://www.bbc.co.uk/news/science-environment-23281423
Title: Re: Proposed Europa Missions
Post by: vjkane on 04/11/2015 06:02 pm
SpaceFlightNow.com has just published an article about a possible European contribution to the Europa Clipper mission: http://spaceflightnow.com/2015/04/10/nasa-invites-esa-to-build-europa-piggyback-probe/

I've also put up a quick blog post with some additional links for background information: http://futureplanets.blogspot.com/2015/04/nasas-mission-to-europa-may-get-more.html
Title: Re: Proposed Europa Missions
Post by: JH on 04/11/2015 06:50 pm
Assuming that ESA does decide to contribute a probe, I would be surprised if they chose the plume fly-through option mentioned by Jim Green. There has only been the one observation and subsequent Hubble campaigns, intended to demonstrate tidal driving, have so far failed to produce results.
Title: Re: Proposed Europa Missions
Post by: vjkane on 04/11/2015 06:58 pm
Assuming that ESA does decide to contribute a probe, I would be surprised if they chose the plume fly-through option mentioned by Jim Green. There has only been the one observation and subsequent Hubble campaigns, intended to demonstrate tidal driving, have so far failed to produce results.
And unless I've missed something, the main Europa Clipper spacecraft could do plume flybys.
Title: Re: Proposed Europa Missions
Post by: JH on 04/11/2015 08:29 pm
... debatable. The closest currently planned flybys are at 25 km altitude, which is based on somewhat optimistic extrapolation from the Enceladus plumes.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 04/12/2015 02:03 pm
A key aspect to making this work is keeping the programs as separate as possible, with Huygens as the model. That works much better than intricate cooperation.
Title: Re: Proposed Europa Missions
Post by: redliox on 04/12/2015 09:02 pm
A key aspect to making this work is keeping the programs as separate as possible, with Huygens as the model. That works much better than intricate cooperation.

I hope so as well.  Assuming they go with a full (albeit small i.e. Huygens-size) lander, how much mass might that require to do a Pathfinder-style landing in the airless (not to mention radioactive) environment of Europa.
Title: Re: Proposed Europa Missions
Post by: Star One on 04/12/2015 09:27 pm
Hope they can come up a way of making any lander last longer on the surface than Huygens did on Titan.
Title: Re: Proposed Europa Missions
Post by: vjkane on 04/12/2015 10:01 pm
I hope so as well.  Assuming they go with a full (albeit small i.e. Huygens-size) lander, how much mass might that require to do a Pathfinder-style landing in the airless (not to mention radioactive) environment of Europa.
You might want to check out these links:

http://futureplanets.blogspot.com/search?q=europa+penetrator
https://www.sciencenews.org/article/ice-distant-moon
http://sci.esa.int/science-e/www/object/doc.cfm?fobjectid=46384

Hard lander presentation: http://arc.iki.rssi.ru/conf/2009elw/presentations/presentations_pdf/session2/Hand_ELW.pdf

Penetrator presentation: http://arc.iki.rssi.ru/conf/2009elw/presentations/presentations_pdf/session7/Gowen_ELW.pdf
Title: Re: Proposed Europa Missions
Post by: Roly on 04/13/2015 05:54 am
There was an interesting study at one point, attached to the JIMO project, on a Europa Surface Science Package.  I remember a number of indicative numbers on soft c.f. hard c.f. 'crushable', published around 2004.  I think one of the observations was there was little merit in the 'intermediate' landing modes, better to pursue hard landing or soft landing. I cannot find the link, but small surface science got some preliminary attention in that period.  The mass budget, from memory, was around 350kg total system, but I could be mistaken.
Title: Re: Proposed Europa Missions
Post by: redliox on 04/14/2015 08:19 am
Something further to consider for Europa Clipper...

...by the time it launches in either the early or mid 2020s the launch vehicle choices may be this trio:  SLS, Falcon Heavy, and Vulcan.  I'm sure most of you have learned about the last one's recent announcement although exact specs are pending it seems.

If anyone can find out the capacities of the Vulcan and list them alongside SLS and FH it'd be sweet.  If SLS proves too heavy I'd hope for a launcher that would only need a single Earth flyby to get something to Jupiter.
Title: Re: Proposed Europa Missions
Post by: Jim on 04/14/2015 01:34 pm
Something further to consider for Europa Clipper...

...by the time it launches in either the early or mid 2020s the launch vehicle choices may be this trio:  SLS, Falcon Heavy, and Vulcan.  I'm sure most of you have learned about the last one's recent announcement although exact specs are pending it seems.

If anyone can find out the capacities of the Vulcan and list them alongside SLS and FH it'd be sweet.  If SLS proves too heavy I'd hope for a launcher that would only need a single Earth flyby to get something to Jupiter.

Europa Clipper is being designed for Delta IV Heavy or SLS.  Vulcan will have more performance than Delta IV Heavy so it won't be an issue.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 04/14/2015 02:21 pm
Europa Clipper is being designed for Delta IV Heavy or SLS.  Vulcan will have more performance than Delta IV Heavy so it won't be an issue.

I think it is Atlas V or SLS.

But it's still pretty early in the development stage, so I don't think that specific launcher issues are being determined.
Title: Proposed Europa Missions
Post by: Star One on 04/14/2015 03:05 pm
I wouldn't be surprised if this didn't end up on a Vulcan rather than SLS for a variety of factors.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 04/14/2015 06:45 pm
I wouldn't be surprised if this didn't end up on a Vulcan rather than SLS for a variety of factors.

I don't think anybody would be surprised if it ended up on a non-SLS rocket. That said, apparently the latest SLS figures are pretty impressive for this mission. You may hear more about that soon.
Title: Re: Proposed Europa Missions
Post by: vjkane on 04/14/2015 08:29 pm
I wouldn't be surprised if this didn't end up on a Vulcan rather than SLS for a variety of factors.

I don't think anybody would be surprised if it ended up on a non-SLS rocket. That said, apparently the latest SLS figures are pretty impressive for this mission. You may hear more about that soon.
If completed and if still operational in the mid-2020's, SLS will be an awesome launch vehicle.  Note the 'if's', though
Title: Re: Proposed Europa Missions
Post by: redliox on 04/14/2015 08:56 pm
If completed and if still operational in the mid-2020's, SLS will be an awesome launch vehicle.  Note the 'if's', though

Definitely agreed, just factoring in the alternatives.  I'm guessing the new Vulcan initially might perform slightly better than Atlas V.  If this becomes the option 'Clipper uses in the near future I just hope it at least mitigates the need for a 'Venus fry-by.'
Title: Re: Proposed Europa Missions
Post by: Jim on 04/14/2015 09:37 pm
Definitely agreed, just factoring in the alternatives.  I'm guessing the new Vulcan initially might perform slightly better than Atlas V.  If this becomes the option 'Clipper uses in the near future I just hope it at least mitigates the need for a 'Venus fry-by.'

No, there will be multiple flybys required for non SLS boosters
Title: Re: Proposed Europa Missions
Post by: RotoSequence on 04/14/2015 09:49 pm
Definitely agreed, just factoring in the alternatives.  I'm guessing the new Vulcan initially might perform slightly better than Atlas V.  If this becomes the option 'Clipper uses in the near future I just hope it at least mitigates the need for a 'Venus fry-by.'

No, there will be multiple flybys required for non SLS boosters

If they used SLS and did the flybys anyway, how much could they increase the payload mass?
Title: Re: Proposed Europa Missions
Post by: vjkane on 04/14/2015 10:11 pm
If they used SLS and did the flybys anyway, how much could they increase the payload mass?
Might not matter.  There's a strong correlation between spacecraft mass and cost.  There's only so much spacecraft ~$2B can buy.
Title: Re: Proposed Europa Missions
Post by: Jim on 04/14/2015 10:16 pm
The SLS spacecraft is actually lighter than the spacecraft for the other vehicles.  The flybys provide more energy.
Title: Re: Proposed Europa Missions
Post by: ISP on 04/14/2015 10:41 pm
From what I recall, a SLS launch will allow for a less lengthy trajectory and the exclusion of the flyby(s). However, the flyby(s) option gives the spacecraft more margin for mass changes, since you can modify the flyby trajectory to get more out of it. Can't do that with SLS, since all the velocity goes into the Jupiter transfer orbit (so it's fixed).
Title: Re: Proposed Europa Missions
Post by: baldusi on 04/15/2015 01:31 pm
From what I recall, a SLS launch will allow for a less lengthy trajectory and the exclusion of the flyby(s). However, the flyby(s) option gives the spacecraft more margin for mass changes, since you can modify the flyby trajectory to get more out of it. Can't do that with SLS, since all the velocity goes into the Jupiter transfer orbit (so it's fixed).
But you save the mass and thermal requirements for a Venusian GA.
Title: Re: Proposed Europa Missions
Post by: redliox on 04/15/2015 08:26 pm
From what I recall, a SLS launch will allow for a less lengthy trajectory and the exclusion of the flyby(s). However, the flyby(s) option gives the spacecraft more margin for mass changes, since you can modify the flyby trajectory to get more out of it. Can't do that with SLS, since all the velocity goes into the Jupiter transfer orbit (so it's fixed).
But you save the mass and thermal requirements for a Venusian GA.

And, via SLS, the time consumed by all GAs in general, but Venus is the most demanding for an outer planet-bound mission.
Title: Re: Proposed Europa Missions
Post by: JH on 04/17/2015 04:36 am
This might be interesting to a few people on here.

http://soma.larc.nasa.gov/europa/pdf_files/D-92256_EuropaClipper_ProposalInformationPackage_140529.pdf

-- Seeing how many times this has been downloaded, I've changed it to a link rather than an attachment to save Chris a little bandwidth.
Title: Re: Proposed Europa Missions
Post by: sdsds on 04/17/2015 09:59 am
This might be interesting to a few people on here.

When and why did the interplanetary trajectory for a mission launched on EELV go from VEEGA taking 6 years to EVEEGA taking 7.6 years?
Title: Re: Proposed Europa Missions
Post by: redliox on 04/17/2015 11:53 am
This might be interesting to a few people on here.

When and why did the interplanetary trajectory for a mission launched on EELV go from VEEGA taking 6 years to EVEEGA taking 7.6 years?

Maybe they found a route that was more delta-v efficient, otherwise it is a slightly dated report.  All the more reason to keep fingers crossed for the SLS route...

It was interesting to eye the schematic differences between the MMRTG and Solar versions of 'Clipper.  The majority of the changes would be with the propulsion module; a cage-like structure for the arrays mounts to the fuel tanks otherwise the upper portions of the probe remain unchanged either way - obviously smart move by the designers.  There is brief mention the solar design would require all-bipropellant maneuvers due to power drain from warming a monopropellant system.  The arrays obviously induce vibration concerns but so might the magnetometer boom from the MMRTG design, otherwise again both designs seem equal.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 04/17/2015 11:59 am
EC is a constantly evolving mission, although the general parameters are set. That report dates from a year ago, so a number of the details will have changed. A good place to look would be to go to the recent OPAG meeting site and find the briefing given there and see what it says.
Title: Re: Proposed Europa Missions
Post by: Bob Shaw on 04/18/2015 11:48 pm
Hope they can come up a way of making any lander last longer on the surface than Huygens did on Titan.

The designers of Huygens had no idea at all regarding what they were landing on, and a severely bit-rate constrained system - there was no promise of any transmission from the surface, but they got lucky; they did well to do what they did. To go further than batteries and slow data needs RTGs, which open up a whole new set of issues.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 04/19/2015 12:24 pm
To go further than batteries and slow data needs RTGs, which open up a whole new set of issues.

Yeah, one of the big issues with RTGs is planetary protection. An RTG is warm and would melt the ice. The concern is that this could then create a water pocket that Earth bacteria could grow in. I don't think anybody has done any serious analysis of this from a planetary protection standpoint. It will likely prove to be a contentious issue.

Title: Re: Proposed Europa Missions
Post by: the_other_Doug on 04/19/2015 10:15 pm
To go further than batteries and slow data needs RTGs, which open up a whole new set of issues.

Yeah, one of the big issues with RTGs is planetary protection. An RTG is warm and would melt the ice. The concern is that this could then create a water pocket that Earth bacteria could grow in. I don't think anybody has done any serious analysis of this from a planetary protection standpoint. It will likely prove to be a contentious issue.

It might be possible to rig a way for an RTG to dump its heat directionally, away from the surface.  Maybe simply thermally isolating it from the body of the lander and putting in reflectors to point waste heat up and out into the vacuum would suffice.  But it's sure not a proven technology yet.

And this reinforces a point I've made for years -- exploring places like the icy moons of the outer planets is indeed complicated by the waste heat from our probes.  They can change the environment we want to explore, sometimes so much that you can't get the data you want.  Yes, it's good to have a nice, warm room within which to use your microscope -- but not when you're trying to look closely at snowflakes.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 04/20/2015 03:17 pm
It might be possible to rig a way for an RTG to dump its heat directionally, away from the surface.  Maybe simply thermally isolating it from the body of the lander and putting in reflectors to point waste heat up and out into the vacuum would suffice.  But it's sure not a proven technology yet.

The bigger issue is accidents.


Title: Re: Proposed Europa Missions
Post by: Malderi on 05/07/2015 09:01 pm
Two tweets from Eric Berger today, a reporter from the Houston Chronicle, on his visit to JPL:

https://twitter.com/chronsciguy/status/596418594147147777
https://twitter.com/chronsciguy/status/596418801928777728

"I spent the last two days at the Jet Propulsion Laboratory and ... holy crap have these guys and gals have planned a lot of cool missions." / "Notably, it's looking more likely a 2022 Europa mission will include a lander."
Title: Re: Proposed Europa Missions
Post by: Malderi on 05/07/2015 09:18 pm
And a notional picture of the lander being discussed at JPL:

https://twitter.com/chronsciguy/status/596421392469372928
Title: Re: Proposed Europa Missions
Post by: Blackstar on 05/08/2015 02:22 am
I have my suspicions that nobody has done much thinking about the planetary protection requirements for a Europa lander. That could really trip them up.
Title: Re: Proposed Europa Missions
Post by: JH on 05/08/2015 04:29 am
I'm more concerned about where the extra billion is going to come from... It would be very bad if EC was axed because it became a Christmas tree.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 05/08/2015 12:24 pm
I'm more concerned about where the extra billion is going to come from... It would be very bad if EC was axed because it became a Christmas tree.

Right now NASA has pitched the idea of a lander to ESA, so the cost of a lander would presumably be borne by ESA. I'm not sure what JPL is considering.

JPL has a tendency of coming up with ideas that they would gladly turn into metal for large amounts of money, so it would not surprise me if JPL is doing some internal lander studies with the hopes of pitching it to NASA/Congress. The problem is that JPL has at times proven tone deaf on this kind of thing. They don't recognize that there's really only support for a cheaper option and they keep pushing more expensive options. It took a lot of effort for them to learn the lesson that the big Europa mission that they were pushing in 2009 was unaffordable and they needed something smaller and cheaper. But it would not surprise me if they now thought "Hey, we have a new start! So let's design the bigger Europa mission that we really want to build!"

Camel's nose under the tent and all that.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 05/08/2015 12:33 pm
Poking around on Berger's Twitter feed reminds me how much I hate Twitter.

But I picked up a few things. Apparently JPL is looking at a bunch of different lander iterations (nine?) with a notional cost of $700 million to $1 billion. And they're also considering using SLS with a VEEGA trajectory for a 4.7 year transit time.

Now considering that you can probably take their cost estimates and at least double them, that means an additional $1.4 to $2 billion for the mission. And the transit time goes down as well.

In other words, it starts to look like somebody is contemplating gold-plating the mission. Which is not all that surprising considering what I wrote above--it's in JPL's nature to do this. It is also the requirement of NASA HQ to reign them in. But unfortunately, this kind of activity is what makes OMB nervous and could kill the program outright. OMB does not want to approve a program that grows and grows and becomes impossible to cancel.

It's like having your dad offer to buy you a car, but instead of a nice, safe affordable car you start looking at high-end sports cars. The result is you make the old man unsure about the idea and your ability to drive any car responsibly and he rescinds the offer.
Title: Re: Proposed Europa Missions
Post by: as58 on 05/08/2015 12:55 pm
The idea that ESA would pay for the lander doesn't make sense to me. Even a simple lander would be at least a medium (but probably more realistically large) class mission and Cosmic Vision medium slots are already booked until (at least) 2024. I don't see how ESA could fund a lander for mission launching in 2022.
Title: Re: Proposed Europa Missions
Post by: Steam Chaser on 05/08/2015 02:39 pm
Poking around on Berger's Twitter feed reminds me how much I hate Twitter.

But I picked up a few things. Apparently JPL is looking at a bunch of different lander iterations (nine?) with a notional cost of $700 million to $1 billion. And they're also considering using SLS with a VEEGA trajectory for a 4.7 year transit time.

Now considering that you can probably take their cost estimates and at least double them, that means an additional $1.4 to $2 billion for the mission. And the transit time goes down as well.

In other words, it starts to look like somebody is contemplating gold-plating the mission.

Berger now has a writeup on this:

http://blog.chron.com/sciguy/2015/05/a-europa-lander-is-possible-jpl-scientists-say-and-congress-appears-likely-to-support-it/

I'm surprised they're willing to risk losing the mission by trying to add to it.  I would have thought they'd have learned a lesson about overly expensive Europa missions in their past decades of attempts.

In addition to the planetary protection issues, I'd imagine it would make more sense to wait until Europa Clipper maps the surface better before doing a lander, to allow them to select easier locations to land on, and to allow them to pick a particularly scientifically interesting landing site.

If $700M - $1B were to somehow become available, it would probably make more sense to add robostness to the base Europa Clipper mission (radiation protection, etc), or to add more instruments ... things like that.  A separate new planetary science mission, or a robotic precursor mission, might be even better.  However, Culberson seems to have been interested in a Europa lander for a long time, and that appears to be a big factor.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 05/08/2015 03:03 pm
I'm surprised they're willing to risk losing the mission by trying to add to it.  I would have thought they'd have learned a lesson about overly expensive Europa missions in their past decades of attempts.

They almost certainly don't think they are "risking" the mission. If anything, they probably think that because they have Culberson's support, the lander only makes the mission more likely.

This is actually rather typical of JPL. They are very good at what they do, but they are not terribly delicate when it comes to playing the politics. They often assume that a green light means that they have been approved to spend a lot of money and grow a mission. They then have to be beaten back down into a manageable budget. JPL flagship missions always grow. In fact, they have all kinds of incentives to do that. Competed missions like Discovery and New Frontiers can possibly be won by other organizations like APL, Goddard, independent PIs. So JPL has an incentive to grow the strategic missions and they don't care as much if the competed mission lines lose money as a result (bird in the hand is better than two in the bush, etc.).

Now the danger in this is that OMB just calls foul and yanks the money. Then we are back to the inefficient situation we were in a year ago where Congress kept stuffing cash into Europa that could not be spent on actual mission hardware.

Oh, and you can pretty much double any early estimate that JPL is providing for the lander. They are going to low-ball the cost to get it approved, then they'll discover the real cost later. This is why close management from HQ is necessary.
Title: Re: Proposed Europa Missions
Post by: Star One on 05/08/2015 03:19 pm
But surely they are looking for ESA to build & pay for any lander. That was pretty clear in the recent articles about it linked to up thread.
Title: Re: Proposed Europa Missions
Post by: Malderi on 05/08/2015 04:28 pm
The wildcard in this is really Culberson. Doesn't matter what the process or budgets or anything are, if there's a member of Congress with enough pull and time to see something like this through. If he wants a lander bad enough and plays the politics well enough, it'll happen.

The real question is how they end up doing it. Maybe the lander sticks with the orbiter for the first few flybys until they've mapped the surface well enough to identify a landing site. That'd be an interesting first, right? - a lander launched without any clue where it's going to land.
Title: Re: Proposed Europa Missions
Post by: vjkane on 05/08/2015 05:24 pm
ESA will allow scientists to propose additions to to the Clipper mission as part of the M5 call
Title: Re: Proposed Europa Missions
Post by: vjkane on 05/08/2015 05:26 pm
Don't forget that congress added $15m to the planetary budget to study Europa landers.  Dad may be encouraging the sports car. 
Title: Re: Proposed Europa Missions
Post by: as58 on 05/08/2015 05:52 pm
ESA will allow scientists to propose additions to to the Clipper mission as part of the M5 call

Do you have further info about this? Are the specifically inviting proposals for additions to Clipper? How would the schedule work? Even M5 call isn't (I think) until late this year of early next year for launch probably in the late 2020s, which seems too late for Europa Clipper.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 05/08/2015 06:27 pm
Don't forget that congress added $15m to the planetary budget to study Europa landers.  Dad may be encouraging the sports car. 

No, dad is trying to be tight with the money, and mom is encouraging the kid's dreams. After all, he's only young once, so live a little.
Title: Re: Proposed Europa Missions
Post by: llanitedave on 05/08/2015 11:19 pm
Poking around on Berger's Twitter feed reminds me how much I hate Twitter.

But I picked up a few things. Apparently JPL is looking at a bunch of different lander iterations (nine?) with a notional cost of $700 million to $1 billion. And they're also considering using SLS with a VEEGA trajectory for a 4.7 year transit time.

Now considering that you can probably take their cost estimates and at least double them, that means an additional $1.4 to $2 billion for the mission. And the transit time goes down as well.

In other words, it starts to look like somebody is contemplating gold-plating the mission. Which is not all that surprising considering what I wrote above--it's in JPL's nature to do this. It is also the requirement of NASA HQ to reign them in. But unfortunately, this kind of activity is what makes OMB nervous and could kill the program outright. OMB does not want to approve a program that grows and grows and becomes impossible to cancel.

It's like having your dad offer to buy you a car, but instead of a nice, safe affordable car you start looking at high-end sports cars. The result is you make the old man unsure about the idea and your ability to drive any car responsibly and he rescinds the offer.


Except Congress has already ordered the high-end sports car.  Now they need to find an excuse to take it out of the garage.
Title: Re: Proposed Europa Missions
Post by: redliox on 05/09/2015 12:44 am
And a notional picture of the lander being discussed at JPL:

https://twitter.com/chronsciguy/status/596421392469372928

Several things I notice about that picture:
1) Although just my POV, but it looks like suspiciously round and Huygens-like for a body plan.  I suspect ESA.
2) They're discussing a drilling option.
3) They're discussing some kind of spider-like-rover option, possibly in conjunction with drilling.

However, considering we can see "2030" clearly drawn on the board, I think we can safely guess this actually isn't part of the Europa Clipper design.  I'm pretty sure a lander (rover?) is being discussed for a separate follow-on mission.  Still cool and exciting, and makes me wish I could be in that meeting.
Title: Re: Proposed Europa Missions
Post by: redliox on 05/09/2015 12:55 am
But I picked up a few things. Apparently JPL is looking at a bunch of different lander iterations (nine?) with a notional cost of $700 million to $1 billion. And they're also considering using SLS with a VEEGA trajectory for a 4.7 year transit time.

I feel like punching the engineer who suggested that square in the face since the whole rationale for SLS was to expedite the trip and minimize the operation cost, not so much exponentially increasing mass...not to mention even those of us that support the SLS option have to admit it isn't cheap either.

In other words, it starts to look like somebody is contemplating gold-plating the mission. Which is not all that surprising considering what I wrote above--it's in JPL's nature to do this. It is also the requirement of NASA HQ to reign them in. But unfortunately, this kind of activity is what makes OMB nervous and could kill the program outright. OMB does not want to approve a program that grows and grows and becomes impossible to cancel.

It's like having your dad offer to buy you a car, but instead of a nice, safe affordable car you start looking at high-end sports cars. The result is you make the old man unsure about the idea and your ability to drive any car responsibly and he rescinds the offer.

Oy...right on all accounts here Blackstar.  Please tell me someone there recalls why EJSM was canceled!

Title: Re: Proposed Europa Missions
Post by: Blackstar on 05/09/2015 01:53 am
We can stretch the analogy into a pretzel. My point is that Congress (specifically a single member of Congress) encouraging NASA to spend a lot of money on one mission because he thinks it is cool is (pardon me for screaming in all caps here) NOT NECESSARILY A GOOD THING.

There's a lot of danger here, including OMB just zeroing out the project, meaning that it just sits in limbo burning cash, or the mission does get approved, and then does a James Webb and runs way over budget and sucks all the money out of the rest of the planetary program. Or maybe the congressional sponsor loses his seat, or his party loses control of the House or the Senate, or something, and the whole expensive project comes crashing to a halt.

NASA and JPL have spent the last five years trying to come up with a Europa mission that the country could afford, and we should be wary of any efforts to turn it into a mission that the country cannot afford.
Title: Re: Proposed Europa Missions
Post by: Malderi on 05/09/2015 04:11 am
And a notional picture of the lander being discussed at JPL:

https://twitter.com/chronsciguy/status/596421392469372928

Several things I notice about that picture:
1) Although just my POV, but it looks like suspiciously round and Huygens-like for a body plan.  I suspect ESA.
2) They're discussing a drilling option.
3) They're discussing some kind of spider-like-rover option, possibly in conjunction with drilling.

However, considering we can see "2030" clearly drawn on the board, I think we can safely guess this actually isn't part of the Europa Clipper design.  I'm pretty sure a lander (rover?) is being discussed for a separate follow-on mission.  Still cool and exciting, and makes me wish I could be in that meeting.

Not necessarily a follow-on. If the mission launches in the mid 2020's - not inconceivable - then the landing itself could certainly occur in 2030.
Title: Re: Proposed Europa Missions
Post by: Vultur on 05/09/2015 06:06 am
I have my suspicions that nobody has done much thinking about the planetary protection requirements for a Europa lander. That could really trip them up.

Isn't the ice crust like 20km thick (or 1km even over the "lakes" that might be in the crust)?

Sure there may be some surface/ocean interaction but radiation would kill "bugs" quickly so they would pretty much have to drop right into a hole leading into the ocean... seems incredibly implausible.

(leaving out the whole question of whether human-commensal/spacecraft-facility bugs would be well adapted for a hydrothermal vent or quasi Antarctic subglacial lake environment...)
Title: Re: Proposed Europa Missions
Post by: GClark on 05/09/2015 08:05 am
Just a few random thoughts...

I'm fairly sure that ESA remembers the NASA ExoMars episode.  Will they be eager to jump in on a lander for Europa?

On the subject of JPL blowing up missions, I will remind everyone of the history of the MSL - what it was supposed to be, what it became, and what happened when NASA HQ tried to impose some discipline.  Planetary Sciences is still paying for that one...
Title: Re: Proposed Europa Missions
Post by: Blackstar on 05/09/2015 01:21 pm
Isn't the ice crust like 20km thick (or 1km even over the "lakes" that might be in the crust)?

Sure there may be some surface/ocean interaction but radiation would kill "bugs" quickly so they would pretty much have to drop right into a hole leading into the ocean... seems incredibly implausible.

(leaving out the whole question of whether human-commensal/spacecraft-facility bugs would be well adapted for a hydrothermal vent or quasi Antarctic subglacial lake environment...)

Except that it's one thing to think about this stuff for a couple of minutes and dismiss it. It's another thing to put a bunch of microbiologists and spacecraft designers in a room and have them think out all of the issues. That could be a long, involved, contentious process.

I haven't dealt with planetary protection issues, but I can tell you that they are really complex, and also controversial. The people who deal with this stuff have a lot of disagreements--one group might say "it's fine, there's nothing to worry about" and another will hotly dispute that. And then they argue and argue over really complicated stuff that us mortals don't understand, like how to properly estimate the bacterial load on a spacecraft that has been sent to another planet, and whether our testing methods are really showing us all the contamination, or just the easy stuff that we know about.

As an example, there's an NRC report from around 2000 or so concerning planetary protection for Europa that has a minority dissent.

http://planetaryprotection.nasa.gov/summary/nap_europa

There are people who still argue over which side was right in that. And I believe that was for an orbiter, not something that was going to deliberately touch the surface or drill into it. And that was before we gathered all kinds of additional information. For example, we know a lot more about microbiology and organisms existing in extreme environments today than we did in 1999.

And although people fall asleep when they hear this, there is a process for doing these things, meaning that certain organizations have to meet and recommend standards, and then other groups have to interpret and implement them. And that process takes years to work through. It's not quick.

My point is that this is really complicated stuff, and I don't think anybody has considered it in depth. If they are going to start talking about Europa landers, then somebody has to be working on the planetary protection standards for it now.
Title: Re: Proposed Europa Missions
Post by: redliox on 05/09/2015 02:18 pm
Just a few random thoughts...

I'm fairly sure that ESA remembers the NASA ExoMars episode.  Will they be eager to jump in on a lander for Europa?

Wouldn't blame them.  I would hope they'd inversely recall the great success of Huygens.  I'd rather have a repeat of that is possible.  :)
Title: Re: Proposed Europa Missions
Post by: baldusi on 05/09/2015 06:33 pm
Just a few random thoughts...

I'm fairly sure that ESA remembers the NASA ExoMars episode.  Will they be eager to jump in on a lander for Europa?
One thing is to go as equal partners of an ESA led mission. Another is to be given a hike in a flagship mission. The above mentioned Cassini/Huygens is a good example. But the correct question might be about JUICE mission, and how will this impact. Even if ESA wanted to do the lander, they will already be putting most of their L-Mission money on JUICE. It would seem that the budget would end up too Jovian biased. On the other hand, if NASA were to supply an extra Atlas V 551 (or Falcon Heavy) for JUICE, ESA might do two landers for the price of one. But that's all wishful thinking. Look how many issues were to get Euro 80M for ExoMars. And a lander might well be 20X that.
Title: Re: Proposed Europa Missions
Post by: Bob Shaw on 05/09/2015 07:24 pm
And a notional picture of the lander being discussed at JPL:

https://twitter.com/chronsciguy/status/596421392469372928


Here's a transformed crop of the flip-chart in the photograph linked to above:
Title: Re: Proposed Europa Missions
Post by: Blackstar on 05/09/2015 11:06 pm
I'd note that the multi-legged lander in that drawing appears to be capable of walking. In other words, it's a rover.

Considering that nobody has ever built anything like that for another planetary body, I suspect that we can be doubtful that this would be a $700 million lander.

Title: Re: Proposed Europa Missions
Post by: Vultur on 05/10/2015 02:01 am
Oh, yeah, the politics/decisionmaking for planetary protection is definitely complex.

I just think the whole thing is somewhat of a relic of the early Space Age & addressing the wrong questions.

You can't really for-sure sterilize stuff anyway and it only takes one bacterium to start a population. Thankfully it probably doesn't matter, as any local life will be better adapted than human-commensal/spacecraft-facility immigrants. If we were introducing hydrothermal vent or Antarctic subglacial lake bacteria, that would be different.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 05/10/2015 02:08 am
You can't really for-sure sterilize stuff anyway and it only takes one bacterium to start a population.

As I understand it, the planetary protection people accept that there is nothing that can be considered complete sterilization. Nevertheless, there is a big difference between sterilized and not sterilized, which is why you're supposed to wash your hands after using the loo.
Title: Re: Proposed Europa Missions
Post by: vjkane on 05/10/2015 02:45 am
NASA invited ESA to participate with a self contained spacecraft.  A lander is only one option.  Simple landers are hard to do and can do relatively little science.  I suspect that we may see daughter craft ideas.

One issue I haven't seen mentioned is timing.  The current M4 call would fly mid decade as I recall. The M5 call that would be used for a Clipper addition presumably would have a funding curve for an even later flight
Title: Re: Proposed Europa Missions
Post by: vjkane on 05/10/2015 02:51 am
I'm skeptical about the report.  JPL concluded that we needed Clipper to scout for interesting while safe sites for a lander.  It would also be hard to define build and test a large walking rover with a heat probe by the mid-2020s.

Jpl/NASA may be considering an enhanced Clipper but I'd be shocked if it is with the rover on the flip chart
Title: Re: Proposed Europa Missions
Post by: sdsds on 05/10/2015 06:20 am
Here's a transformed crop of the flip-chart in the photograph linked to above:

It's somehow immediately reminiscent of this image (attached). It's from here (http://www.theonion.com/article/aerospace-engineers-warn-first-graders-design-for--38523).
Title: Re: Proposed Europa Missions
Post by: Vultur on 05/10/2015 06:49 am
You can't really for-sure sterilize stuff anyway and it only takes one bacterium to start a population.

As I understand it, the planetary protection people accept that there is nothing that can be considered complete sterilization. Nevertheless, there is a big difference between sterilized and not sterilized, which is why you're supposed to wash your hands after using the loo.

Yeah. I am just uncertain that the analogy to human sanitation/infection actually holds. Humans are relatively robust since we have an immune system and a certain natural bacterial "population" etc...

I still think it's ultimately irrelevant since the surface environment is deadly enough already ...but if you were talking about a submersible that would directly access the ocean, it would be a potential problem and I'm not convinced sanitation would be effective.

(I mean, most likely any local life would still outcompete it, but we don't really know the parameters...)
Title: Re: Proposed Europa Missions
Post by: Star One on 05/10/2015 09:08 am
Robotic eel for the exploration of Europa anyone!

http://www.nasa.gov/press-release/nasa-selects-advanced-space-technology-concepts-for-further-study
Title: Re: Proposed Europa Missions
Post by: Blackstar on 05/10/2015 02:06 pm
1-Yeah. I am just uncertain that the analogy to human sanitation/infection actually holds. Humans are relatively robust since we have an immune system and a certain natural bacterial "population" etc...

2-I still think it's ultimately irrelevant since the surface environment is deadly enough already ...

1-It's an analogy. It's not meant to be perfect. (And you still wash your hands, right?) My point was that the planetary protection people accept that there is no such thing as completely 100% contamination free. Nevertheless, they believe that there is a big difference between sterilized and unsterilized.

2-Take it up with a planetary protection expert. I'm sure you can convince them.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 05/10/2015 02:09 pm
I'm skeptical about the report.  JPL concluded that we needed Clipper to scout for interesting while safe sites for a lander.  It would also be hard to define build and test a large walking rover with a heat probe by the mid-2020s.

Jpl/NASA may be considering an enhanced Clipper but I'd be shocked if it is with the rover on the flip chart

All of this makes me uneasy. At a time when we should see JPL narrowing the design toward something that can be built and be affordable, we see evidence that they are holding a jam session to come up with new and exciting (and expensive) ideas. That may be happening because they think they've got an in now, that because they have a powerful sponsor they can start proposing things regardless of the costs.

I'm reminded of what Alan Stern told the Solar Probe advocates back when he was AA: "do you want 80 percent of something, or 100 percent of nothing?"
Title: Re: Proposed Europa Missions
Post by: baldusi on 05/10/2015 04:14 pm
I'm reminded of what Alan Stern told the Solar Probe advocates back when he was AA: "do you want 80 percent of something, or 100 percent of nothing?"
While I concur, if there's one division that deserves a bit of love is the heliophysics guys. On the other hand, they got a Delta IV Heavy + Star-48B. So, they are getting somethings extra.
Title: Re: Proposed Europa Missions
Post by: a_langwich on 05/10/2015 04:36 pm
I'm skeptical about the report.  JPL concluded that we needed Clipper to scout for interesting while safe sites for a lander.  It would also be hard to define build and test a large walking rover with a heat probe by the mid-2020s.

Jpl/NASA may be considering an enhanced Clipper but I'd be shocked if it is with the rover on the flip chart

All of this makes me uneasy. At a time when we should see JPL narrowing the design toward something that can be built and be affordable, we see evidence that they are holding a jam session to come up with new and exciting (and expensive) ideas. That may be happening because they think they've got an in now, that because they have a powerful sponsor they can start proposing things regardless of the costs.

I'm reminded of what Alan Stern told the Solar Probe advocates back when he was AA: "do you want 80 percent of something, or 100 percent of nothing?"

I wouldn't worry about it until you find evidence that _management_ is actually pushing inclusion of these ideas in the current clipper plans.  After all, mission planners' jobs is to come up with creative mission ideas, so they are just doing their job and telling a reporter who fuzzes out a bit on when or even if those ideas might ever be implemented.
Title: Re: Proposed Europa Missions
Post by: Vultur on 05/10/2015 10:19 pm
1-It's an analogy. It's not meant to be perfect. (And you still wash your hands, right?) My point was that the planetary protection people accept that there is no such thing as completely 100% contamination free. Nevertheless, they believe that there is a big difference between sterilized and unsterilized.

Sure. But just washing hands wouldn't be enough to save someone with no immune system.

If Europa really has “Earthlike” ocean conditions & a vulnerable ecosystem, it might be more analogous to that one female Brown Tree Snake being shipped to Guam...

Quote
2-Take it up with a planetary protection expert. I'm sure you can convince them.


Well, people who become planetary protection experts are almost by definition people who accept the premise that planetary protection is meaningful.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 05/11/2015 12:21 pm
I wouldn't worry about it until you find evidence that _management_ is actually pushing inclusion of these ideas in the current clipper plans.  After all, mission planners' jobs is to come up with creative mission ideas, so they are just doing their job and telling a reporter who fuzzes out a bit on when or even if those ideas might ever be implemented.

But here's the issue--JPL could be bypassing NASA HQ and appealing directly to their patron saint in Congress. That could then result in NASA being told "You have to include a lander or no mission at all" and then the result being that the Europa mission becomes a bloated, expensive mission that overruns (it's JPL, remember) and starts to eat the other planetary programs.

Not an unrealistic scenario at all.
Title: Re: Proposed Europa Missions
Post by: as58 on 05/11/2015 02:19 pm
According to Eric Berger's article that was linked to earlier in this thread:

Quote
[Culberson] supported the soft lander. He went so far as to say, “I will not sign a bill unless it has money for a lander.”
Title: Re: Proposed Europa Missions
Post by: Blackstar on 05/11/2015 02:44 pm
And a notional picture of the lander being discussed at JPL:

https://twitter.com/chronsciguy/status/596421392469372928


Here's a transformed crop of the flip-chart in the photograph linked to above:

Note that on the left of the larger image it says "Casani lander" as in John Casani.
Title: Re: Proposed Europa Missions
Post by: notsorandom on 05/11/2015 04:56 pm
ESA will allow scientists to propose additions to to the Clipper mission as part of the M5 call
If ESA goes about it this way then what are the realistic chances that there will be an ESA contribution? Any proposals involving the Europa mission would have to compete against all the other proposals. This potentially includes some pretty attractive runners up to the M4 call. Also the budget limits were pretty brutal for the latest call and eliminated all the beyond Earth missions. A lander even with a free ride is still going to be an expensive proposal.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 05/20/2015 01:33 am
Presidential veto threat of 2016 Commerce, Justice, and Science appropriations bill. "While directing an impractical level of funding toward the Jupiter Europa mission, the bill cuts important NASA Science programs by more than $200 million compared to the President's Budget"

https://www.whitehouse.gov/sites/default/files/omb/legislative/letters/cjs-full-committee-appropriations-letter-hal-rogers.pdf

Title: Re: Proposed Europa Missions
Post by: Zed_Noir on 05/20/2015 01:42 am
Anyone know if the Congress mandated the SLS as the EC launch vehicle?  :-\
Title: Re: Proposed Europa Missions
Post by: JH on 05/20/2015 02:34 am
It isn't mandated. I have heard that congress (read Senator Shelby's office) is putting out feelers about not only having EC launch on SLS, but also having the launch be fully funded by the SMD. Their angle is that the shorter transit time enables greater scientific return.
Title: Re: Proposed Europa Missions
Post by: Steam Chaser on 05/20/2015 03:01 am
Anyone know if the Congress mandated the SLS as the EC launch vehicle?  :-\

This gets into some side issues (SLS, ocean moons in general), but SLS is mentioned in this part of the House Appropriations report:

"Ocean Worlds Exploration Program. —The recommendation provides $226,000,000 for Outer Planets, of which not less than $140,000,000 is for the Jupiter Europa Clipper, or comparable mission, to support the process of finalizing the mission design concept that meets the scientific objectives described in the most recent Planetary Science decadal survey. To support sustained momentum in this program, NASA shall ensure that future funding requests are consistent with achieving a launch no later than 2022, with the goal of launching on a Space Launch System platform as discussed elsewhere in this report.  ... The Committee directs NASA to create an Ocean World Exploration Program whose primary goal is to discover extant life on another world using a mix of Discovery, New Frontiers and flagship class missions consistent with the recommendations of current and future Planetary Decadal surveys."

I support increasing the Planetary Science budget, but mandating SLS has some sinister overtones in terms of encouraging planetary missions that are so large they can't be managed and go off the rails, and in terms of government competing with the U.S. commercial launch industry.

If they are hurting for something for SLS to do, my opinion is they should help make Planetary Science missions more affordable rather than less (e.g.: HSF help with sample return, HSF telerobotics of planetary science assets, get a mission like Europa Clipper to its destination faster rather than making it more complex, HSF servicing of a planetary observatory, HSF at a NEO), and cooperate with commercial space rather than compete with it (e.g.: use a commercial cislunar hab as an SLS destination that commercial space can also service).

I'm also skeptical that the Planetary Decadal Survey would want to throw out their list of New Frontiers missions and replace them with this, or to add a lander to the Europa mission that they wanted descoped so it would fit in a reasonable budget, or to restrict the destination of some Discovery-class missions to ocean moons.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 05/20/2015 03:27 am

I'm also skeptical that the Planetary Decadal Survey would want to throw out their list of New Frontiers missions and replace them with this, or to add a lander to the Europa mission that they wanted descoped so it would fit in a reasonable budget, or to restrict the destination of some Discovery-class missions to ocean moons.

You might note that there's no Europa lander in the decadal survey...

Title: Re: Proposed Europa Missions
Post by: jacqmans on 05/22/2015 09:12 am
May 21, 2015
MEDIA ADVISORY M15-077
NASA TV to Air Announcement of Instruments for Europa Mission

 
NASA will announce on Tuesday, May 26, the selection of science instruments for a mission to Europa, to investigate whether Jupiter’s icy moon could harbor conditions suitable for life.

The announcement will air live on NASA Television and NASA.gov at 2 p.m. EDT from the NASA TV studio at the agency’s Headquarters, 300 E Street SW in Washington. There is limited seating in the NASA TV studio for media who would like to attend in person. To arrange access, email Laurie Cantillo at [email protected] no later than 10 a.m. Tuesday.   

NASA received 33 proposals for science instruments to fly onboard a Europa mission, which would conduct repeated close flybys of the small moon during a three-year period.

Participants in the announcement will be:
•John Grunsfeld, associate administrator for the Science Mission Directorate, NASA Headquarters
•Jim Green, director, Planetary Science Division, NASA Headquarters
•Curt Niebur, Europa program scientist, NASA Headquarters

To participate by phone, media must contact Steve Cole at 202-358-0918 or [email protected] and provide their media affiliation no later than 1 p.m. Tuesday.

Media and the public also may ask questions via Twitter using #askNASA.

For NASA TV streaming video, schedules and downlink information, visit:

http://www.nasa.gov/nasatv

For facts about Europa visit:

http://solarsystem.nasa.gov/planets/profile.cfm?Object=Jup_Europa
Title: Re: Proposed Europa Missions
Post by: vjkane on 05/22/2015 10:43 am
My plane won't land until 3 hours after the press conference.  Does NASA archive these anywhere?
Title: Re: Proposed Europa Missions
Post by: dsmillman on 05/22/2015 11:33 am
My plane won't land until 3 hours after the press conference.  Does NASA archive these anywhere?
NASA TV usually rebroadcasts press conferences in the evening.
Also the archive will probably be at:

 http://www.space-multimedia.nl.eu.org/index.php?option=com_frontpage&Itemid=1
Title: Re: Proposed Europa Missions
Post by: redliox on 05/25/2015 09:25 am
My plane won't land until 3 hours after the press conference.  Does NASA archive these anywhere?
NASA TV usually rebroadcasts press conferences in the evening.
Also the archive will probably be at:

 http://www.space-multimedia.nl.eu.org/index.php?option=com_frontpage&Itemid=1

I'll be stuck driving that day but I'm hoping to check up on the news at least later in the day.  If I had to make any bets on which instruments will make the list, it'd be the radar and the reconnaissance (i.e. the super-high-resolution) camera.  There'll surely be something in infrared and something fields/particle related, but somehow if they can't squeeze a lander (ESA-supported or otherwise) aboard they wouldn't settle for less than those two heavy-duty instruments.

This feels almost as exciting as waiting for the New Horizons Pluto fly-by...  :)
Title: Re: Proposed Europa Missions
Post by: vjkane on 05/25/2015 11:58 am
I'm betting on a rich instrument set.  From memory: topo imager, hi red imager, near ir spectrometer, radar, 2 mass specs for ices and dust, uv spec., magnetometer and plasma instrument

I'm thinking that they will fly NASA's space atomic clock for better gravity measurements
Title: Re: Proposed Europa Missions
Post by: Blackstar on 05/25/2015 01:07 pm
They're still somewhat mass and power limited even with an SLS. But I wonder if it is possible to put some kind of lasercom experiment onboard. Laser pointing from Jupiter is apparently really difficult, and we haven't even done it at Mars yet, but maybe it's possible to take a step toward developing the technology.
Title: Re: Proposed Europa Missions
Post by: redliox on 05/25/2015 07:10 pm
They're still somewhat mass and power limited even with an SLS. But I wonder if it is possible to put some kind of lasercom experiment onboard. Laser pointing from Jupiter is apparently really difficult, and we haven't even done it at Mars yet, but maybe it's possible to take a step toward developing the technology.

Would be worthwhile to test, and if it worked at Jupiter it certainly would be a boon with the heavy amount of data the probe has to deal with.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 05/25/2015 09:40 pm
Would be worthwhile to test, and if it worked at Jupiter it certainly would be a boon with the heavy amount of data the probe has to deal with.

I don't know if there is a realistic test that they could do. It may require a level of effort that is too high for this mission. And Jupiter just may not be doable for lasercom. I'm just thinking out loud that it would be nice to see some kind of effort to develop the technology because missions to the outer planets are so few and far between.

We will see more development of lasercom at Mars. NASA will be looking for every opportunity to get that technology out there.
Title: Re: Proposed Europa Missions
Post by: Star One on 05/25/2015 10:39 pm

Would be worthwhile to test, and if it worked at Jupiter it certainly would be a boon with the heavy amount of data the probe has to deal with.

I don't know if there is a realistic test that they could do. It may require a level of effort that is too high for this mission. And Jupiter just may not be doable for lasercom. I'm just thinking out loud that it would be nice to see some kind of effort to develop the technology because missions to the outer planets are so few and far between.

We will see more development of lasercom at Mars. NASA will be looking for every opportunity to get that technology out there.

If you wanted to go beyond Mars but not as far as Jupiter to test it then Ceres might be a good choice,  as I've a feeling we will be back there at some point.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 05/26/2015 12:16 am
My point is that a Europa mission is planned, so I'd like to see them take advantage of an existing opportunity to develop the technology a little further.

Title: Re: Proposed Europa Missions
Post by: JH on 05/26/2015 02:25 am
I'd be (pleasantly) surprised if any lasercom demonstration is included. I think that a lot of people involved want to take the safest possible route to getting EC launched. It is perceived as being so scientifically important (and overdue) that I don't think many will be enthusiastic about adding what might be considered a distraction. Maybe as a secondary payload so that there is minimal complication to EC's overall design...
Title: Re: Proposed Europa Missions
Post by: Blackstar on 05/26/2015 02:52 pm
Agreed. I don't expect it. I'm just saying that it would be interesting if something like that was added. I'd also add that it might not be realistic even to do a basic experiment. A colleague of mine who works for a three-letter space organization looked into the technical issues associated with lasercom and told me a couple of years ago that going beyond Mars is really tough for the technology. It has something to do with pointing requirements, I think.

As for "adding... distractions," I wish that was true, but if you've read the recent articles about this mission it is clear that JPL is trying to make it considerably bigger and more expensive. Anybody who thinks that a lander could be added for only a billion dollars has forgotten that this is JPL.
Title: Re: Proposed Europa Missions
Post by: kato on 05/26/2015 05:13 pm
Maybe as a secondary payload so that there is minimal complication to EC's overall design...
ESA is planning to use the deep-space laser communications terminal onboard the proposed AIM mission also for scientific purposes, i.e. as a laser altimeter once in orbit (therefore scrapping the separate laser altimeter once proposed for it).
Could be a good enough justification for smuggling one on an Europa orbiter as well.
Title: Re: Proposed Europa Missions
Post by: gosnold on 05/26/2015 06:17 pm
I don't get why laser comms would be more complicated at Jupiter than at Mars (excluding rad hardening).
Title: Re: Proposed Europa Missions
Post by: Blackstar on 05/26/2015 06:29 pm
Slides from the current press conference.
Title: Re: Proposed Europa Missions
Post by: jacqmans on 05/26/2015 06:41 pm
May 26, 2015
RELEASE 15-104
NASA’s Europa Mission Begins with Selection of Science Instruments
 

NASA has selected nine science instruments for a mission to Jupiter’s moon Europa, to investigate whether the mysterious icy moon could harbor conditions suitable for life.

NASA’s Galileo mission yielded strong evidence that Europa, about the size of Earth’s moon, has an ocean beneath a frozen crust of unknown thickness. If proven to exist, this global ocean could have more than twice as much water as Earth. With abundant salt water, a rocky sea floor, and the energy and chemistry provided by tidal heating, Europa could be the best place in the solar system to look for present day life beyond our home planet.
 
“Europa has tantalized us with its enigmatic icy surface and evidence of a vast ocean, following the amazing data from 11 flybys of the Galileo spacecraft over a decade ago and recent Hubble observations suggesting plumes of water shooting out from the moon," said John Grunsfeld, associate administrator for NASA’s Science Mission Directorate in Washington. “We’re excited about the potential of this new mission and these instruments to unravel the mysteries of Europa in our quest to find evidence of life beyond Earth.”

NASA’s fiscal year 2016 budget request includes $30 million to formulate a mission to Europa. The mission would send a solar-powered spacecraft into a long, looping orbit around the gas giant Jupiter to perform repeated close flybys of Europa over a three-year period. In total, the mission would perform 45 flybys at altitudes ranging from 16 miles to 1,700 miles (25 kilometers to 2,700 kilometers).

The payload of selected science instruments includes cameras and spectrometers to produce high-resolution images of Europa’s surface and determine its composition. An ice penetrating radar will determine the thickness of the moon’s icy shell and search for subsurface lakes similar to those beneath Antarctica. The mission also will carry a magnetometer to measure strength and direction of the moon’s magnetic field, which will allow scientists to determine the depth and salinity of its ocean.

A thermal instrument will scour Europa’s frozen surface in search of recent eruptions of warmer water, while additional instruments will search for evidence of water and tiny particles in the moon’s thin atmosphere. NASA’s Hubble Space Telescope observed water vapor above the south polar region of Europa in 2012, providing the first strong evidence of water plumes. If the plumes’ existence is confirmed – and they’re linked to a subsurface ocean – it will help scientists investigate the chemical makeup of Europa's potentially habitable environment while minimizing the need to drill through layers of ice.

Last year, NASA invited researchers to submit proposals for instruments to study Europa. Thirty-three were reviewed and, of those, nine were selected for a mission that will launch in the 2020s.

“This is a giant step in our search for oases that could support life in our own celestial backyard,” said Curt Niebur, Europa program scientist at NASA Headquarters in Washington. “We’re confident that this versatile set of science instruments will produce exciting discoveries on a much-anticipated mission.”

The NASA selectees are:

Plasma Instrument for Magnetic Sounding (PIMS) -- principal investigator Dr. Joseph Westlake of Johns Hopkins Applied Physics Laboratory (APL), Laurel, Maryland. This instrument works in conjunction with a magnetometer and is key to determining Europa's ice shell thickness, ocean depth, and salinity by correcting the magnetic induction signal for plasma currents around Europa.

Interior Characterization of Europa using Magnetometry (ICEMAG) -- principal investigator Dr. Carol Raymond of NASA’s Jet Propulsion Laboratory (JPL), Pasadena, California. This magnetometer will measure the magnetic field near Europa and – in conjunction with the PIMS instrument – infer the location, thickness and salinity of Europa’s subsurface ocean using multi-frequency electromagnetic sounding.

Mapping Imaging Spectrometer for Europa (MISE) -- principal investigator Dr. Diana Blaney of JPL. This instrument will probe the composition of Europa, identifying and mapping the distributions of organics, salts, acid hydrates, water ice phases, and other materials to determine the habitability of Europa’s ocean.

Europa Imaging System (EIS) -- principal investigator Dr. Elizabeth Turtle of APL. The wide and narrow angle cameras on this instrument will map most of Europa at 50 meter (164 foot) resolution, and will provide images of areas of Europa’s surface at up to 100 times higher resolution.

Radar for Europa Assessment and Sounding: Ocean to Near-surface (REASON) -- principal investigator Dr. Donald Blankenship of the University of Texas, Austin. This dual-frequency ice penetrating radar instrument is designed to characterize and sound Europa's icy crust from the near-surface to the ocean, revealing the hidden structure of Europa’s ice shell and potential water within.

Europa Thermal Emission Imaging System (E-THEMIS) -- principal investigator Dr. Philip Christensen of Arizona State University, Tempe. This “heat detector” will provide high spatial resolution, multi-spectral thermal imaging of Europa to help detect active sites, such as potential vents erupting plumes of water into space.

MAss SPectrometer for Planetary EXploration/Europa (MASPEX) -- principal investigator Dr. Jack (Hunter) Waite of the Southwest Research Institute (SwRI), San Antonio. This instrument will determine the composition of the surface and subsurface ocean by measuring Europa’s extremely tenuous atmosphere and any surface material ejected into space.

Ultraviolet Spectrograph/Europa (UVS) -- principal investigator Dr. Kurt Retherford of SwRI. This instrument will adopt the same technique used by the Hubble Space Telescope to detect the likely presence of water plumes erupting from Europa’s surface. UVS will be able to detect small plumes and will provide valuable data about the composition and dynamics of the moon’s rarefied atmosphere.

SUrface Dust Mass Analyzer (SUDA) -- principal investigator Dr. Sascha Kempf of the University of Colorado, Boulder. This instrument will measure the composition of small, solid particles ejected from Europa, providing the opportunity to directly sample the surface and potential plumes on low-altitude flybys.

Separate from the selectees listed above, the SPace Environmental and Composition Investigation near the Europan Surface (SPECIES) instrument has been chosen for further technology development. Led by principal investigator Dr. Mehdi Benna at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, this combined neutral mass spectrometer and gas chromatograph will be developed for other mission opportunities.   

NASA's Science Mission Directorate in Washington conducts a wide variety of research and scientific exploration programs for Earth studies, space weather, the solar system and the universe.

For more information about Europa, visit:

http://go.nasa.gov/europanews
Title: Re: Proposed Europa Missions
Post by: Chris Bergin on 05/26/2015 06:59 pm
I'll write it up. Was busy, but did listen to the presser. Was rather "social media" fluffy, but still useful and interesting.
Title: Re: Proposed Europa Missions
Post by: kato on 05/26/2015 08:46 pm
Just to enrich the information a bit - a quick look through the names:

Sascha Kempf (SUDA PI) - deputy PI of Cassini's CDA
Kurt Retherford (UVS PI) - deputy PI of JUICE's UVIS, PI of LRO's LAMP
Hunter Waite (MASPEX PI) - PI of Cassini's INMS
Philip Christensen (E-THEMIS PI) - PI of Osiris-REx OTES, PI of 2001 Mars Odyssey THEMIS, PI of Mars Global Surveyor TES
Donald Blankenship (REASON PI) - PI of NASA's Antarctic Operation Ice Bridge
Elizabeth Turtle (EIS PI) - Cassini Imaging Team Associate
Diana Blaney (MISE PI) - Co-Investigator for MSL ChemCam
Joseph Westlake (PIMS PI) - Cassini MIMI Associate
Carol Raymond (ICEMAG PI) - deputy PI of Dawn mission

(not for Europa:)
Mehdi Benna (SPECIES PI) - MAVEN NGIMS team member
Title: Re: Proposed Europa Missions
Post by: Blackstar on 05/26/2015 09:16 pm
I've worked with both Phil Christensen and Zibi Turtle and think highly of them.
Title: Re: Proposed Europa Missions
Post by: Star One on 05/26/2015 09:21 pm

I've worked with both Phil Christensen and Zibi Turtle and think highly of them.

Thanks for that personal insight.:)

Seems overall an interesting selection of instrumentation.
Title: Re: Proposed Europa Missions
Post by: Chris Bergin on 05/26/2015 09:24 pm
Short article for the presser with our natural angle of seeing how SLS fits in with this, per the evaluations.
http://www.nasaspaceflight.com/2015/05/nasa-selects-science-proposed-europa/
Title: Re: Proposed Europa Missions
Post by: Blackstar on 05/26/2015 09:38 pm
There was a question about lasercom--it won't be carried. NASA needs to demo it at Mars first.
Title: Re: Proposed Europa Missions
Post by: JH on 05/26/2015 10:07 pm
It has something to do with pointing requirements, I think.

This is exactly the issue. The more precise the pointing requirement, the more mass and power is needed for the ACS.

Quote
As for "adding... distractions," I wish that was true, but if you've read the recent articles about this mission it is clear that JPL is trying to make it considerably bigger and more expensive. Anybody who thinks that a lander could be added for only a billion dollars has forgotten that this is JPL.

Oh, I'm familiar with the JPL approach to flagship mission design... I was referring to the scientists who have been pushing for a Europa mission for the last decade. They are the ones who will be scared of EC growing too big to fly and will therefore probably argue against "extras".
Title: Re: Proposed Europa Missions
Post by: JH on 05/26/2015 10:13 pm
The instrument selection is predictable, but solid. I'm a little surprised to see that a dust detector got on, although I suppose that it benefited from the need for a mass spec. I'm also glad to see that a MAG made it. I had heard that it was not a core priority, which seemed odd to me.

There was a question about lasercom--it won't be carried. NASA needs to demo it at Mars first.

No surprise.
Title: Re: Proposed Europa Missions
Post by: redliox on 05/27/2015 12:58 am
Seeing something ultraviolet carried instead just exclusively infrared is refreshing.  I think they gave a good selection of choices.  Frankly I'm left wondering what else could have been carried.  Naturally assuming this probe reaches Europa in good health an endures the radiation there, it looks like it will return some interesting science.
 :)
Title: Re: Proposed Europa Missions
Post by: Targeteer on 05/27/2015 01:27 am
https://www.youtube.com/watch?v=g5GFPEEsJGQ
Title: Re: Proposed Europa Missions
Post by: redliox on 05/27/2015 04:44 pm
Now the next question I'm curious about is on EIS: are the wide and narrow cameras analogous to the previously imagined topographical and reconnaissance cameras?
Title: Re: Proposed Europa Missions
Post by: vjkane on 05/27/2015 05:16 pm
Now the next question I'm curious about is on EIS: are the wide and narrow cameras analogous to the previously imagined topographical and reconnaissance cameras?
I think so.  The press release states global coverage at 50 m, which I believe was a bit better than the stand in topo imager, and the hi resolution instrument will be able to do up to 500 times better.

Makes sense to have these in the same instrument so they can share electronics and software.

Will be interesting to learn things like color bands and whether there's any stereo capability.
Title: Re: Proposed Europa Missions
Post by: Star One on 05/27/2015 05:28 pm

Now the next question I'm curious about is on EIS: are the wide and narrow cameras analogous to the previously imagined topographical and reconnaissance cameras?
I think so.  The press release states global coverage at 50 m, which I believe was a bit better than the stand in topo imager, and the hi resolution instrument will be able to do up to 500 times better.

Makes sense to have these in the same instrument so they can share electronics and software.

Will be interesting to learn things like color bands and whether there's any stereo capability.

What about true 3D capability, is that possible.
Title: Re: Proposed Europa Missions
Post by: baldusi on 05/27/2015 05:42 pm
What's the technology behind the ice penetrating radar? What's the band, the scanning mode, etc.? I'm asking because the SAOCOM-1B and SAOCOM-CS are going to investigate a very interesting technology that enables direct ice tomography in a single pass.
Title: Re: Proposed Europa Missions
Post by: JH on 05/28/2015 07:27 am
What's the technology behind the ice penetrating radar? What's the band, the scanning mode, etc.? I'm asking because the SAOCOM-1B and SAOCOM-CS are going to investigate a very interesting technology that enables direct ice tomography in a single pass.

It should be very similar to the IPR on the EC strawman payload as roughly the same team proposed REASON. See page 48 of the linked presentation:

https://solarsystem.nasa.gov/europa/docs/ICEE_KO_Combined_20131022_RevKAL.pdf
Title: Re: Proposed Europa Missions
Post by: Roly on 05/29/2015 11:59 am
Very exciting to see the instrument announcement; I do hope there are more details soon from each team, now that the selection has taken place, though it is rather a long time to even the more optimistic launch date. 

With the bandwidth constraints, and no feasible option of laser communication, is there anything else on the horizon that might improve the compression beyond ICER-type rates, LDPC coding or similar?  It looked like the radar had on-instrument compression, would anything be suitable (mass, power) for the EIS that could not be done by the RAD750?  An FPGA or an ASIC with some added flexibility in an FPGA block? 

It still looks luxuriant compared to S-Band mission, just tend to get over-enthused when a Europa mission finally start to take some sort of shape. 
Title: Re: Proposed Europa Missions
Post by: arachnitect on 05/29/2015 04:10 pm
Very exciting to see the instrument announcement; I do hope there are more details soon from each team, now that the selection has taken place, though it is rather a long time to even the more optimistic launch date. 

With the bandwidth constraints, and no feasible option of laser communication, is there anything else on the horizon that might improve the compression beyond ICER-type rates, LDPC coding or similar?  It looked like the radar had on-instrument compression, would anything be suitable (mass, power) for the EIS that could not be done by the RAD750?  An FPGA or an ASIC with some added flexibility in an FPGA block? 

It still looks luxuriant compared to S-Band mission, just tend to get over-enthused when a Europa mission finally start to take some sort of shape. 

Forgive me if this is ignorant, but doesn't the EC mission profile give them long periods between flybys to send the data back?
Title: Re: Proposed Europa Missions
Post by: Roly on 05/29/2015 04:24 pm
I think it is more likely I was ignorant. That's a very good point, I had the impression that they were still constrained, but it may well be badly incorrect - assuming they don't upgrade the SSR, or having more/longer simultaneous observations per encounter for those where the pointing/power works out, or add lots of distant observations of the other moons.  I was looking at the data rates for the instruments, which seemed voluminous, but a number of SDT documents had quite a bit on the simulated encounters / playback I think, I shall check.

Edit: The 2012 report on the earlier iteration of the mission indicates substantial margin, though at a glance, does not include the reconnaissance camera / high res. component. 

Edit 2: 56.9 Gb per encounter including reconnaissance imager set for the more recent variant (2013); and ~>14 days between encounters, so even with the higher resolution sets, it still indicates a lot of margin.
Title: Re: Proposed Europa Missions
Post by: catdlr on 06/18/2015 12:08 am
Alien Ocean: NASA’s Mission to Europa

Published on Jun 17, 2015
Could a liquid water ocean beneath the surface of Jupiter’s moon Europa have the ingredients to support life? Here's how NASA's mission to Europa would find out.

https://youtu.be/GqTaDCt_F1Y
Title: Re: Proposed Europa Missions
Post by: Moe Grills on 07/30/2015 05:29 pm
  Wow!  I don't have the URL nor link, but I read an article that NASA project developers have suggested that the upcoming heavy-lift SLS meant to send humans back to Lunar-orbit could also carry a future (large) unmanned spacecraft to the surface (and subsurface) of Europa.
It's refreshing to read that some NASA projects can compliment other NASA projects without triggering
a competing struggle for taxpayer money.
Title: Re: Proposed Europa Missions
Post by: vjkane on 07/30/2015 05:41 pm
  Wow!  I don't have the URL nor link, but I read an article that NASA project developers have suggested that the upcoming heavy-lift SLS meant to send humans back to Lunar-orbit could also carry a future (large) unmanned spacecraft to the surface (and subsurface) of Europa.
It's refreshing to read that some NASA can compliment other NASA projects without triggering
a competing struggle for taxpayer money.
The SLS system would reduce the travel time from 4+ years (as I recall) to around 2 years.  However, this assumes that the SLS system is still viable in the mid-2020s given that the manned missions to justify it before then largely aren't funded.
Title: Re: Proposed Europa Missions
Post by: Moe Grills on 07/30/2015 05:57 pm
  Wow!  I don't have the URL nor link, but I read an article that NASA project developers have suggested that the upcoming heavy-lift SLS meant to send humans back to Lunar-orbit could also carry a future (large) unmanned spacecraft to the surface (and subsurface) of Europa.
It's refreshing to read that some NASA can compliment other NASA projects without triggering
a competing struggle for taxpayer money.
The SLS system would reduce the travel time from 4+ years (as I recall) to around 2 years.  However, this assumes that the SLS system is still viable in the mid-2020s given that the manned missions to justify it before then largely aren't funded.

Two justifications for the STS are better than one, even if one of the justifications doesn't get beyond the CAD stage.
Title: Re: Proposed Europa Missions
Post by: Star One on 07/31/2015 05:35 pm

  Wow!  I don't have the URL nor link, but I read an article that NASA project developers have suggested that the upcoming heavy-lift SLS meant to send humans back to Lunar-orbit could also carry a future (large) unmanned spacecraft to the surface (and subsurface) of Europa.
It's refreshing to read that some NASA projects can compliment other NASA projects without triggering
a competing struggle for taxpayer money.

Was it this article?

http://mobile.extremetech.com/latest/223615-nasas-upcoming-sls-could-launch-missions-to-europa-if-congress-ever-lets-it-get-off-the-ground
Title: Re: Proposed Europa Missions
Post by: Blackstar on 07/31/2015 05:45 pm
The SLS connection has been known for a few years now. This is nothing new. It only got additional attention because of the hearing on Tuesday morning. There have not been any actual new developments.

http://www.space.com/30082-nasa-sls-megarocket-planetary-missions.html?cmpid=NL_SP_weekly_2015-07-29

Title: Re: Proposed Europa Missions
Post by: Star One on 07/31/2015 05:54 pm
Looking at that article & links I guess I know where the New Horizons 2 talk originated.
Title: Re: Proposed Europa Missions
Post by: redliox on 08/02/2015 12:16 pm
Although a gravity science instrument wasn't announced, considering there will be a large HGA as part of the spacecraft, any guesses as to whether some gravity data could still be gained from the 'Clipper?
Title: Re: Proposed Europa Missions
Post by: vjkane on 08/02/2015 04:07 pm
Although a gravity science instrument wasn't announced, considering there will be a large HGA as part of the spacecraft, any guesses as to whether some gravity data could still be gained from the 'Clipper?
I emailed Curt Niebur, NASA outer planets program director (or a similar title), about this. He said that gravity studies will be part of the mission.  Since then, I seem to remember that NASA issued a statement about forming a gravity science team for the mission, but I can't find it.

During the flybys, the high gain antenna will be pointed away from Earth.  In the last detailed briefing about the spacecraft design that I saw, there were 2 or 3, as I recall, medium gain antennas that would be used for these studies.

I also wouldn't be surprised to hear that one or more the Cubesat concept studies for this mission involves gravity studies, either with direct Earth tracking or by spacecraft to spacecraft tracking.
Title: Re: Proposed Europa Missions
Post by: Star One on 08/02/2015 06:10 pm

Although a gravity science instrument wasn't announced, considering there will be a large HGA as part of the spacecraft, any guesses as to whether some gravity data could still be gained from the 'Clipper?
I emailed Curt Niebur, NASA outer planets program director (or a similar title), about this. He said that gravity studies will be part of the mission.  Since then, I seem to remember that NASA issued a statement about forming a gravity science team for the mission, but I can't find it.

During the flybys, the high gain antenna will be pointed away from Earth.  In the last detailed briefing about the spacecraft design that I saw, there were 2 or 3, as I recall, medium gain antennas that would be used for these studies.

I also wouldn't be surprised to hear that one or more the Cubesat concept studies for this mission involves gravity studies, either with direct Earth tracking or by spacecraft to spacecraft tracking.

Is there any room on it to carry a laser communication payload. Thought this would be the ideal opportunity to try this out at Jupiter distance.
Title: Re: Proposed Europa Missions
Post by: redliox on 08/02/2015 07:27 pm
Is there any room on it to carry a laser communication payload. Thought this would be the ideal opportunity to try this out at Jupiter distance.

They answered that with a distinct "no" in that Jupiter is too far for the moment.  Mars was the farthest NASA is considering.  Watch here: https://youtu.be/g5GFPEEsJGQ?t=38m14s (https://youtu.be/g5GFPEEsJGQ?t=38m14s)
Title: Re: Proposed Europa Missions
Post by: Blackstar on 08/02/2015 08:24 pm
Yeah, they need to prove that on Mars first. There are more opportunities to do it with Mars too.
Title: Re: Proposed Europa Missions
Post by: vjkane on 08/05/2015 03:58 am
Came across the link to the gravity science working group (also radiation working group)

http://science.nasa.gov/media/medialibrary/2015/07/07/GandRWGs4EST.pdf
Title: Re: Proposed Europa Missions
Post by: redliox on 08/05/2015 09:23 pm
Came across the link to the gravity science working group (also radiation working group)

http://science.nasa.gov/media/medialibrary/2015/07/07/GandRWGs4EST.pdf

Considering the deadline was July 27, that must mean the gravity science candidates are undergoing selection right now.  Nice knowing they're progressing further in several ways.  I assume they might mention gravity science stuff in next couple months, although of course there is much more to do for the mission in general.
Title: Re: Proposed Europa Missions
Post by: Don2 on 08/18/2015 01:37 am
I wrote about Europa Clipper in the Discovery proposals thread, and was asked to move the discussion over here. To recap:

"Europa Clipper could be done more cheaply. The current data for Europa is crap. When the antenna on the Galileo orbiter failed, 99% of the data return was lost. Europa today is mapped at 1-2 km/ pixel, which is weather satellite resolution. Studies of the surface of the earth use at least 200 m/pixel. Imaging sensors, particularly in the infrared, have improved enormously since the early 1980s when Galileo was built. Big improvements won't be hard.

The basics are a camera for surface morphology, an imaging infrared spectrometer for a compositional map, and a uv spectrometer to keep an eye on the magnetosphere and look at the composition of plumes from  Europa and Io. Instruments similar to the New Horizons Pluto probe should be perfectly adequate.  The main thing that needs to be added is radiation shielding, which I am assuming is cheap but heavy. You might opt for a larger antenna. Fill the rest of the mass budget with fuel, which gives you options for an interesting tour. That's it. It might be doable for a little more than the cost of New Horizons, or $900 milllion, which makes it worth two Discovery missions. Given all the interesting things to see in the Jupiter system, it is probably a good option at that price."

Some folks seem to be worried about a requirement for imaging to support a lander. We successfully  landed 3 times on Mars based on Viking imagery that was no better than 8m per pixel. Most was 150-300m per pixel. 8m per pixel needs a low altitude flyby, not an expensive camera. I personally think it is foolish to impose expensive requirements on current missions for future landers that may never fly.

Other folks claim that if we are going all the way to Europa, a small mission isn't worth the trouble. I'm sure similar arguments were made against the New Horizons probe to Pluto back in the day. NASA allegedly studied $1 billion missions, and decided they weren't worth the trouble. Isn't it interesting how none of those studies have ever been made public?

I'm not sure what Europa Clipper is supposed to cost, but the current proposal looks awfully similar to the $3.6 billion mission proposed to the decadal survey. Oh sure, it doesn't orbit Europa, but that mostly saves fuel and radiation hardening requirements. Oh yes, they are going to solar power it, but that option was also considered for the decadal survey mission. If they stay nuclear, they only need four RTGs rather then five, which probably implies a cost of around $2.8 billion. I thought Europa Clipper was sold as a small flagship?
Title: Re: Proposed Europa Missions
Post by: Blackstar on 08/18/2015 02:01 am
I wrote about Europa Clipper in the Discovery proposals thread, and was asked to move the discussion over here. To recap:

"Europa Clipper could be done more cheaply...

SNIP


I'm not sure what Europa Clipper is supposed to cost...

Okay, you start by saying it can be done more cheaply, and then you admit that you don't know what the cost is. Why should anybody take you seriously given those two statements?
Title: Re: Proposed Europa Missions
Post by: Don2 on 08/18/2015 05:43 am
OK, good catch. Europa Clipper is supposed to cost $2 billion. You can add the cost of nuclear rating SLS to that.
Title: Proposed Europa Missions
Post by: Star One on 08/18/2015 07:07 am
OK, good catch. Europa Clipper is supposed to cost $2 billion. You can add the cost of nuclear rating SLS to that.

Europa Clipper is going to be solar powered, so no nuclear rating needed.
Title: Re: Proposed Europa Missions
Post by: notsorandom on 08/18/2015 04:05 pm
Some folks seem to be worried about a requirement for imaging to support a lander. We successfully  landed 3 times on Mars based on Viking imagery that was no better than 8m per pixel. Most was 150-300m per pixel. 8m per pixel needs a low altitude flyby, not an expensive camera. I personally think it is foolish to impose expensive requirements on current missions for future landers that may never fly.
Pathfinder and the Vikings main and pretty much only criteria for landing site selection was safety. The Viking orbiter's cameras were not high enough resolution to see hazards which could doom the landers. They could see larger features such as craters, groves, and scarps but a hazard as small as 22 cm could make the Viking landing fail. Earth based radar was used extensively to gauge the smoothness of the terrain for all three landings. The reflected signal would be more diffused if it hit rough ground. The radar trick will not work at Europa due to the distance. Without high resolution imagery not only does the landing risk increase due to hazards but the potential science of a lander mission decreases. Interesting targets can be missed simply because they didn't show up in the imagery. The risk of a boring landing site increases as well.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 08/18/2015 05:34 pm
OK, good catch. Europa Clipper is supposed to cost $2 billion. You can add the cost of nuclear rating SLS to that.

Europa Clipper is going to be solar powered, so no nuclear rating needed.

He's off to a good start.
Title: Re: Proposed Europa Missions
Post by: Don2 on 08/19/2015 07:22 am

Pathfinder and the Vikings main and pretty much only criteria for landing site selection was safety. The Viking orbiter's cameras were not high enough resolution to see hazards which could doom the landers. They could see larger features such as craters, groves, and scarps but a hazard as small as 22 cm could make the Viking landing fail. Earth based radar was used extensively to gauge the smoothness of the terrain for all three landings. The reflected signal would be more diffused if it hit rough ground. The radar trick will not work at Europa due to the distance. Without high resolution imagery not only does the landing risk increase due to hazards but the potential science of a lander mission decreases. Interesting targets can be missed simply because they didn't show up in the imagery. The risk of a boring landing site increases as well.

There are sometimes multiple ways to achieve an objective. One might be obvious but very expensive. Others might be not at all obvious but very much cheaper. Are we really sure that that a high resolution camera is the only way to demonstrate landing site safety? You mention radar techniques, and that technology has improved a lot since the Viking era. The Mars people also looked at the thermal inertia of a surface to measure the boulder abundance. Is a very expensive camera really the only way?

Even if it is, is it really wise to spend a lot on a lander that might never happen? It may lose the battle for funds against other missions that offer better value for money. The concept of a single lander with no orbiter to provide support might not be very attractive. Science questions evolve, instrument technology improves, and that will drive demand for another orbiter. Laser communications will allow the mapping of larger areas at higher resolution in future.

The decadal survey did a number of mission studies involving RTGs. For a look at what $940 million might buy, look at the Trojan  Tour concept study.
 http://sites.nationalacademies.org/cs/groups/ssbsite/documents/webpage/ssb_059316.pdf (http://sites.nationalacademies.org/cs/groups/ssbsite/documents/webpage/ssb_059316.pdf)
This used New Horizons/Messenger heritage instruments, and required 2 RTGs. The Uranus orbiter concept had similar instruments, but had to go to 3 RTGs because it needed a larger communication system. Excluding the probe, the cost of that was $1.65 billion.

So why did the Jupiter Europa orbiter cost $3.9 billion? I believe the key was the instrument payload, which cost nearly six times as much as the instruments on the Trojan tour, with four times the mass and about two and a half times the power consumption. The Ice penetrating radar alone cost as much , and comsumed as much power, as the entire instrument payload on the Trojan Tour. That instrument is still on Europa Clipper.  They don't seem to be going cheap on the other instruments either. The camera is the most expensive and capable one they could possibly find.

I don't see how they are going to hit $2billion with the way things are going. The five RTGs on the Jupiter Europa Orbiter were budgeted at $336 million (including reserves), so going to solar isn't going to solve everything.

Here is a link to the decadal survey mission studies.
http://sites.nationalacademies.org/ssb/SSB_059331 (http://sites.nationalacademies.org/ssb/SSB_059331)
Title: Re: Proposed Europa Missions
Post by: redliox on 08/19/2015 08:49 am
I wrote about Europa Clipper in the Discovery proposals thread, and was asked to move the discussion over here.

I'll inject my opinions since I have a similar enthusiasm for applying smaller probes to big targets.  However, bear in mind now that we have a flagship in the making I favor creating 'Clipper over a Discovery probe.

"Europa Clipper could be done more cheaply. The current data for Europa is crap. When the antenna on the Galileo orbiter failed, 99% of the data return was lost. Europa today is mapped at 1-2 km/ pixel, which is weather satellite resolution. Studies of the surface of the earth use at least 200 m/pixel. Imaging sensors, particularly in the infrared, have improved enormously since the early 1980s when Galileo was built. Big improvements won't be hard.

No denying.  I have a copy of Atlas of the Galilean Satellites and the maps of Europa and its kin made me weep.  I dare say the data we'll get about Pluto from New Horizons, once it's fully downlinked, might readily exceed what we currently have of Europa.  It's literally like we have Mars maps from Mariner 6 & 7 with scattered postcards from Mars Surveyor tagged on to tease.  The poorest-quality regions on Europa are its Leading Hemisphere and South Pole.

The basics are a camera for surface morphology, an imaging infrared spectrometer for a compositional map, and a uv spectrometer to keep an eye on the magnetosphere and look at the composition of plumes from  Europa and Io. Instruments similar to the New Horizons Pluto probe should be perfectly adequate.  The main thing that needs to be added is radiation shielding, which I am assuming is cheap but heavy. You might opt for a larger antenna. Fill the rest of the mass budget with fuel, which gives you options for an interesting tour. That's it. It might be doable for a little more than the cost of New Horizons, or $900 milllion, which makes it worth two Discovery missions. Given all the interesting things to see in the Jupiter system, it is probably a good option at that price."

If you could dissect the mission into a specific categories like: imaging, radar, composition, fields & particles, you might be able to make several Discovery-sized missions that focus on each aspect.  However, others pointed out to me when I suggested simplifying the mission that the result becomes less science, and in turn less approval from both government (i.e. Congress and White House) and academic powers.  The result becomes a modest-offer for a distant-rich target (i.e. Europa)...which might get overpowered by a modest-offer from a nearby-easy-modest target (i.e. asteroids, Luna).  Remember how a Pluto mission took twenty years to get approved, developed, and flown?  It will be that kind of fight for Europa, in fact has been since Galileo's mission ended twelve years ago already.

Some folks seem to be worried about a requirement for imaging to support a lander. We successfully  landed 3 times on Mars based on Viking imagery that was no better than 8m per pixel. Most was 150-300m per pixel. 8m per pixel needs a low altitude flyby, not an expensive camera. I personally think it is foolish to impose expensive requirements on current missions for future landers that may never fly.

I totally have to side with the need for more imaging and mapping whether by orbiter or flybys.  Nobody wants to blow a lander either with a crash landing or a boring landing site.  We're not even at the point to guess where we should land on Europa!

Other folks claim that if we are going all the way to Europa, a small mission isn't worth the trouble. I'm sure similar arguments were made against the New Horizons probe to Pluto back in the day. NASA allegedly studied $1 billion missions, and decided they weren't worth the trouble. Isn't it interesting how none of those studies have ever been made public?

I'm not sure what Europa Clipper is supposed to cost, but the current proposal looks awfully similar to the $3.6 billion mission proposed to the decadal survey. Oh sure, it doesn't orbit Europa, but that mostly saves fuel and radiation hardening requirements. Oh yes, they are going to solar power it, but that option was also considered for the decadal survey mission. If they stay nuclear, they only need four RTGs rather then five, which probably implies a cost of around $2.8 billion.

Agreed.  The Voyager 1 could have visited Pluto but lost out to Titan science versus the uncertainty of Pluto (giant loss IMO).  You compare Europa to Pluto and you'll see similar difficulties over a similar timeline.  'Clipper is the best bet so far but is close to the Jupiter mission that was culled before it (specifically in instrument needs)...yet I still think it's the best bet for Europa.

My suggestion regarding Europa's future (say for the next ~50 years) is, firstly, to go through with 'Clipper so we gain the science and maps Galileo should have given nearly 30 years before (recall how it was meant for launch in the early 1980s instead of 1989).  Secondly, evaluate the most promising sites on Europa, as we do for Mars now, and send one, if not a series, of small Discover-class landers to study them up close.  Thirdly, send a much larger lander, either New Frontiers or flagship-class, to drill and do some deeper science on Europa...such as sending a min-sub so many Europan researchers brag/blog about.

I'm willing to back the 'Clipper, in part because it would bring a HUGE advancement in Europa data that'd allow us to jump to the step we should have been on by now: landing there!
Title: Re: Proposed Europa Missions
Post by: vjkane on 08/19/2015 04:21 pm
The basics are a camera for surface morphology, an imaging infrared spectrometer for a compositional map, and a uv spectrometer to keep an eye on the magnetosphere and look at the composition of plumes from  Europa and Io. Instruments similar to the New Horizons Pluto probe should be perfectly adequate.  The main thing that needs to be added is radiation shielding, which I am assuming is cheap but heavy. You might opt for a larger antenna. Fill the rest of the mass budget with fuel, which gives you options for an interesting tour. That's it. It might be doable for a little more than the cost of New Horizons, or $900 milllion, which makes it worth two Discovery missions. Given all the interesting things to see in the Jupiter system, it is probably a good option at that price."

If you could dissect the mission into a specific categories like: imaging, radar, composition, fields & particles, you might be able to make several Discovery-sized missions that focus on each aspect. 

Some folks seem to be worried about a requirement for imaging to support a lander. We successfully  landed 3 times on Mars based on Viking imagery that was no better than 8m per pixel.

There are some points that people proposing cheap missions to Europa should consider.  First, we know that a $1B mission to the Jovian system is possible (Juno and in the future JUICE).  We do not know if a Discovery-class ($450M) mission is possible, although the Io Volcanic Observer proposal team is making the case that it could be.  However, the independent cost analysis may find otherwise.

Second, building a spacecraft that can survive the radiation of many encounters approximately doubles the price of the mission (for example, Europa Clipper is roughly twice the cost of JUICE).  My favorite quote from one of the Europa scientists is that for $1B you can get a spacecraft that can do many encounters with Europa but you need the next $1B to add the instruments, power, communications system, etc. for a real mission.

There are two separate imaging requirements.  For geomorphological studies, the science requirement is roughly 30 to 50 m resolution, or approximately Landsat resolution.  For landing site characterization, they want as high a resolution as feasible.  Yes, we landed three landers on Mars with crappy imaging, but they all went to boring places because we didn't have the good imaging needed to find the safe spots in the interesting places.  MRO will be spending a lot of time imaging potential sites for the 2020 rover mission in high detail.

On Europa, the problem is even worse.  The places that appear to have potential ocean material near the surface inconveniently lie in the most chaotic, rugged terrains.  The Europa mission will be looking for the small spots within these landscapes where a capable orbiter could set down to do some really interesting chemistry work.

New Horizons was such a success because we knew next to nothing about Pluto.  We already know a good deal about Europa.  Answering the next set of questions requires a capable instrument suite and therefore a capable spacecraft that can survive many passes through the radiation.  This has been studied again and again by scientific and engineering teams.  They have all returned with the same answer. 
Title: Re: Proposed Europa Missions
Post by: Blackstar on 08/19/2015 05:21 pm
OPAG meeting next week:

http://www.lpi.usra.edu/opag/meetings/aug2015/agenda.pdf

Title: Re: Proposed Europa Missions
Post by: vjkane on 08/19/2015 06:25 pm
OPAG meeting next week:

http://www.lpi.usra.edu/opag/meetings/aug2015/agenda.pdf
I'm hoping to listen in but there's no information on web access for the meeting.
Title: Re: Proposed Europa Missions
Post by: Don2 on 08/20/2015 07:33 am
I'm OK with Europa Clipper if they can actually hit $2 billion. It is certainly possible to build a good science payload for that money, but they are not going to be able to meet all the requirements that people would like. If they are not willing to give anything up then they will blow out way over $3 billion. I did a bit of digging into the archives and it seems like Cassini came in at three times the initial cost, so the history with large outer planets probes is not good.

The cheaper cameras, like LORRI on New Horizons, have as much resolution as the best cameras on Cassini. On a close pass Cassini recently achieved 2.8m / pixel on one of the Saturn moons. The best camera, Hirise, is somewhere between two and a half to five times better than that.  At Jupiter, all the imagers will be limited by the ability of the telecommunications system to transmit data.

Title: Re: Proposed Europa Missions
Post by: Roly on 08/20/2015 12:01 pm
I am unsure whether this is a concern with the Europa Clipper, but I see to remember that the optical path and, more particularly, the detectors, were appreciably more complex for Jupiter's radiation environment - perhaps this escalates cost c.f. the missions in less radiation intense environments.  I think Galileo's SSI had a lot of spot shielding, and there may have been other requirements.

On using other measurements for landing sites, maybe interpretation of the radar data could not be done confidently enough - even if there was the resolution, it seemed to be oriented to different questions.  I'm not sure also whether those measurements would necessarily consume less downlink c.f. imaging (total speculation, maybe the compression on the instrument would resolve this).

I imagine if there is/was scope to evolve the optical and imaging instruments from those with inexpensive and proven heritage, it has been / will be pursued. 

OPAG will be intriguing - as a side note, was there any material emerging from the August Europa Science meeting?  The photo of the team was all I could see so far.  Very much looking forward to hearing further news on EIS. 
Title: Re: Proposed Europa Missions
Post by: notsorandom on 08/20/2015 03:01 pm
The cheaper cameras, like LORRI on New Horizons, have as much resolution as the best cameras on Cassini. On a close pass Cassini recently achieved 2.8m / pixel on one of the Saturn moons. The best camera, Hirise, is somewhere between two and a half to five times better than that.  At Jupiter, all the imagers will be limited by the ability of the telecommunications system to transmit data.
The sensor called Europa Imaging System has been selected for the Europa mission. Details are tricky to come by since it is still very early in development. However based on the abstract submitted to the AGU's 2015 fall meeting its Narrow Angle Camera will have a spatial resolution of 0.5m at 50km. You have mentioned LORRI. How does it compare? Fortunately it is pretty easy to figure out the spatial resolution of a sensor if you know the altitude and angular resolution. LORRI's IFOV is 5 μrad so we can compare New Horizon's LORRI's spatial resolution in the same scenario to EIS. The result is pretty interesting. LORRI would have a spatial resolution of 0.25 meters at 50km. If EIS is more expensive than LORRI it is not because of a superior spatial resolution. Therefore downgrading the resolution is unlikely to be a significant savings as other things than spatial resolution are driving the cost. Especially when the loss in science and utility for future missions are factored in.
Title: Re: Proposed Europa Missions
Post by: vjkane on 08/20/2015 03:18 pm
There are lots of issues with comparing cameras based only on resolutions.  Cassini's instruments were designed for the maximum science; LORRI's instruments for high resolution panchromatic with the minimal weight. Cassini's narrow angle camera has 24 filters, LORRI has none.  LORRI also represents imaging sensor technology from almost a decade later than Cassini.  If Cassini's optics had been paired with the best imaging detectors from the early 2000's (the time of LORRI's development), it likely would exceed LORRI's resolution.  (Think of the density of pixels in circa 1990 and circa 2000 digital cameras.)  The Europa mission's high resolution camera has to compensate for image smear from the very high relative speeds of the Europa flybys while LORRI was imaging from 12,500 km to hundreds of thousands of kilometers.

And then there is the radiation at Europa.  The imaging sensor and its electronics must be exposed on at least the imaging side to the radiation. 
Title: Re: Proposed Europa Missions
Post by: vjkane on 08/20/2015 03:21 pm
If they are not willing to give anything up then they will blow out way over $3 billion. I did a bit of digging into the archives and it seems like Cassini came in at three times the initial cost, so the history with large outer planets probes is not good.
What's your source for the $3B claim?  NASA's mission cost has been estimated using multiple methods.

As for Cassini's costs, have you adjusted for inflation?  There's been a bit over the last 25 years.
Title: Re: Proposed Europa Missions
Post by: Don2 on 08/21/2015 07:24 am


As for Cassini's costs, have you adjusted for inflation?  There's been a bit over the last 25 years.

So, adjusting to 2015 $.

Cassini was initially promised at $1.55 billion as part of a two spacecraft deal. The other spacecraft, called CRAF, was canceled. If they had just ordered one it would have been priced at $2billion.  It was finally delivered at $5.1 billion, which is about 3 times the initial cost.

Galileo was initially promised for a 1982 launch at $1.5 billion, and was delivered at $2.5 billion and launched in 1989. That project was very messed up by the space shuttle problems.

Voyager cost $2 billion for two spacecraft.

@notsorandom... I think you have misplaced the decimal point. LORRI's resolution would come out to 2.5m, not .25. My point in comparing the cameras is that the economical instruments aren't bad. Going for the very best can really drive up the cost, which I think is what happened on Cassini and in the Jupiter Europa orbiter design study. There isn't much information on what has been chosen for Europa Clipper, but the camera selection could give a hint as to the way things are going.
Title: Re: Proposed Europa Missions
Post by: notsorandom on 08/21/2015 02:53 pm


As for Cassini's costs, have you adjusted for inflation?  There's been a bit over the last 25 years.

So, adjusting to 2015 $.

Cassini was initially promised at $1.55 billion as part of a two spacecraft deal. The other spacecraft, called CRAF, was canceled. If they had just ordered one it would have been priced at $2billion.  It was finally delivered at $5.1 billion, which is about 3 times the initial cost.

Galileo was initially promised for a 1982 launch at $1.5 billion, and was delivered at $2.5 billion and launched in 1989. That project was very messed up by the space shuttle problems.

Voyager cost $2 billion for two spacecraft.

@notsorandom... I think you have misplaced the decimal point. LORRI's resolution would come out to 2.5m, not .25. My point in comparing the cameras is that the economical instruments aren't bad. Going for the very best can really drive up the cost, which I think is what happened on Cassini and in the Jupiter Europa orbiter design study. There isn't much information on what has been chosen for Europa Clipper, but the camera selection could give a hint as to the way things are going.
I just double checked it and think I am still correct. Lorri's Angular Resolution =  5 μrad = 0.000286 degrees. The equation is 2(TAN(1/2 Angular Resolution) * Altitude) = Spatial Resolution. So 2(TAN(0.000143o) * 50,000m) = 0.25 meters. To double check that I ran through the numbers on HiRISE because I know what the answer is. Its Angular Resolution is 1 μrad or 5.729E-5 o, orbital height 300km, and Spatial Resolution 30cm. Which is exactly what I get from that equation.

EIS really consists of two imaging sensors, the NAC and WAC. The Narrow Angle Camera, the previously discussed, has a single pan chromatic band. The Wide Angle Camera has a pretty common push broom architecture and has 6 color bands. In terms of both spatial and spectral resolution EIS actually fits pretty well in the average capabilities of previously flown sensors. As Vjkane points out blur due to velocity and radiation are other factors which will influence the design and cost of the mission. If you're going to Europa those are unavoidable costs. Even the cheapest more very basic camera will have to deal with those issues.
Title: Re: Proposed Europa Missions
Post by: vjkane on 08/21/2015 06:08 pm
Cassini was initially promised at $1.55 billion as part of a two spacecraft deal.  It was finally delivered at $5.1 billion, which is about 3 times the initial cost.
You need to be very careful about what is included in those initial costs.  Were operations included?  At ~$70M per year for almost 18 years that adds up.  Instruments?  Launch?  NASA overhead?  Did that cost cover the European contribution?

To give an example.  The InSight mission's quoted cost is ~$425M.  But that doesn't include NASA's general overhead costs, the launch, or the cost of the contributed instruments.

Generally, the Cassini mission costs out there today bundle all those costs and then inflates them to current dollars.  A dollar spent at the beginning of the project inflates to almost 2X today at 3% annual inflation.
Title: Re: Proposed Europa Missions
Post by: Star One on 08/21/2015 07:52 pm

Cassini was initially promised at $1.55 billion as part of a two spacecraft deal.  It was finally delivered at $5.1 billion, which is about 3 times the initial cost.
You need to be very careful about what is included in those initial costs.  Were operations included?  At ~$70M per year for almost 18 years that adds up.  Instruments?  Launch?  NASA overhead?  Did that cost cover the European contribution?

To give an example.  The InSight mission's quoted cost is ~$425M.  But that doesn't include NASA's general overhead costs, the launch, or the cost of the contributed instruments.

Generally, the Cassini mission costs out there today bundle all those costs and then inflates them to current dollars.  A dollar spent at the beginning of the project inflates to almost 2X today at 3% annual inflation.

And I would argue science wise they've more than got their money's worth out of Cassini.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 08/21/2015 11:54 pm
You need to be very careful about what is included in those initial costs.  Were operations included?  At ~$70M per year for almost 18 years that adds up.  Instruments?  Launch?  NASA overhead?  Did that cost cover the European contribution?

To give an example.  The InSight mission's quoted cost is ~$425M.  But that doesn't include NASA's general overhead costs, the launch, or the cost of the contributed instruments.

Generally, the Cassini mission costs out there today bundle all those costs and then inflates them to current dollars.  A dollar spent at the beginning of the project inflates to almost 2X today at 3% annual inflation.

And everything needs to be qualified, too. Keep in mind that Cassini is in an extended-extended mission phase. The cost estimates for a mission only cover it up to the end of the primary mission. That's a totally legitimate way to do it. But any big, healthy spacecraft is going to get an extended mission if there is still science left to perform.

Title: Re: Proposed Europa Missions
Post by: redliox on 08/22/2015 12:31 am
Also, when you look back to Galileo, it was granted two extended missions and returned decent science (with what the antenna limitations could allow).  Furthermore, it did all that with early '80s technology including primitive CCDs coupled to a Voyager cam and a VHS-esque magnetic tape for memory (which got partly crippled en route to Jupiter, becoming the second Achilles' heel for the mission).  Between what Galileo managed and what the Cassini continues to reward us with, I have high hopes for what a genuinely 21st century machine could achieve even against the poisonous radiation of Jupiter.

A flyby/orbiter like 'Clipper could easily get at least one mission extension.  If designed properly, I'd even willingly bet the first Pathfinder-class lander could likewise last an extra few months (though I wouldn't go so far to wager a full [Earth] year for its longevity).  Indeed, the real trick would be making a machine that can endure Jupiter's radiation for months-on-end much like a Venus lander needs to endure that planet's extreme heat; an orbiter around either planet is relatively easy.
Title: Re: Proposed Europa Missions
Post by: Star One on 08/22/2015 10:11 am

Also, when you look back to Galileo, it was granted two extended missions and returned decent science (with what the antenna limitations could allow).  Furthermore, it did all that with early '80s technology including primitive CCDs coupled to a Voyager cam and a VHS-esque magnetic tape for memory (which got partly crippled en route to Jupiter, becoming the second Achilles' heel for the mission).  Between what Galileo managed and what the Cassini continues to reward us with, I have high hopes for what a genuinely 21st century machine could achieve even against the poisonous radiation of Jupiter.

A flyby/orbiter like 'Clipper could easily get at least one mission extension.  If designed properly, I'd even willingly bet the first Pathfinder-class lander could likewise last an extra few months (though I wouldn't go so far to wager a full [Earth] year for its longevity).  Indeed, the real trick would be making a machine that can endure Jupiter's radiation for months-on-end much like a Venus lander needs to endure that planet's extreme heat; an orbiter around either planet is relatively easy.

But doesn't the electronics on space missions always lag at least ten years behind that on Earth because of the specialist requirements such as radiation hardening. Though I have seen some suggestion of using multiple CPU's to check for & correct errors in each other from radiation hits rather than such costly & extreme hardening.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 08/22/2015 01:30 pm
But doesn't the electronics on space missions always lag at least ten years behind that on Earth because

I think the rule of thumb is 5-10 years. But of course it also has to be frozen into the design at some point, and that is going to take place a few years before launch. So it could easily be 5 years old when it is frozen into the design, and 8-10 when it is launched. And then of course older by the time it reaches the destination.

I wonder if anybody has done a study of this and compiled some data.
Title: Re: Proposed Europa Missions
Post by: vjkane on 08/22/2015 03:37 pm
Just for fun for the mission's engineers, my understanding is that in general the newer the electronics, the more susceptible they are to radiation damage.  Galileo had and advantage in one with its now ancient electronics.

I know that there are efforts to design more radiation hardened electronics, but I think they lag behind the latest electronics in size and speed.  Anyone here have more solid information?
Title: Re: Proposed Europa Missions
Post by: Blackstar on 08/22/2015 03:50 pm
I know that there are efforts to design more radiation hardened electronics, but I think they lag behind the latest electronics in size and speed.  Anyone here have more solid information?

We're going to be undertaking a study of U.S. facilities and knowledge base for developing radiation-hardened electronics. That study will focus more on the testing facilities (i.e. creating an accurate radiation simulation environment) but will certainly address the current state of the art as well as the requirements.

Call me in a year and I'll be an expert. (Then I'll quickly forget everything.)
Title: Re: Proposed Europa Missions
Post by: AegeanBlue on 08/22/2015 03:52 pm
Attached is a conference presentation I found online. Look at page 27 for a graph comparing Processor Throughput for normal and radiation hardened processors. The gap is indeed about a decade
Title: Re: Proposed Europa Missions
Post by: Tim Alexander on 09/03/2015 06:14 pm
The presentations from the recent OPAG meeting are on their website now. A lot about the Europa mission (obviously) but a fair amount of other interesting information as well (RPS anyone?  :D ). Very handy for those of us who couldn't quite make the times for the real thing.

http://www.lpi.usra.edu/opag/meetings/aug2015/presentations/
Title: Re: Proposed Europa Missions
Post by: Blackstar on 09/03/2015 09:21 pm
The presentations from the recent OPAG meeting are on their website now. A lot about the Europa mission (obviously) but a fair amount of other interesting information as well (RPS anyone?  :D ). Very handy for those of us who couldn't quite make the times for the real thing.

http://www.lpi.usra.edu/opag/meetings/aug2015/presentations/

The RPS presentation was interesting. The Space News article about that said that NASA/DoE will start Pu-238 production in 2019. However, the DoE presenter said that they are actually making Pu-238 right now. It's just the final stages of turning that material into MMRTGs that will not take place for a few more years.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 09/11/2015 04:43 pm
We don't seem to have a good, current thread for this subject, so I'm going to drop this here and maybe one other place.

http://www.scientificamerican.com/article/within-nasa-a-plutonium-power-struggle/

New article on the subject. I have only read a few paragraphs, but I disagree with the premise. Things are looking better on the Pu-238 production issue than they have in a long time. DoE needs some more time (and possibly a bit more money), but stuff is finally working and the logjam is broken. And citing the Ohio politicians is an indication that the reporter may not understand what is really going on (they were making a political claim, not one based in reality).
Title: Re: Proposed Europa Missions
Post by: redliox on 09/12/2015 04:20 am
http://www.scientificamerican.com/article/within-nasa-a-plutonium-power-struggle/

New article on the subject. I have only read a few paragraphs, but I disagree with the premise. Things are looking better on the Pu-238 production issue than they have in a long time. DoE needs some more time (and possibly a bit more money), but stuff is finally working and the logjam is broken. And citing the Ohio politicians is an indication that the reporter may not understand what is really going on (they were making a political claim, not one based in reality).

Not surprised it's a slow process, but encouraging to hear your own news about production Blackstar.

Juno obviously demonstrates that we're at the point of solar power being useful at Jupiter, and that seems a reasonable benchmark.  Considering the heavy amount of science Saturn, the Ice Giants, and Kuiper Belt will demand, giving them the plutonium seems fair to properly fulfill missions.  I'd hate to see the size a solar array at Pluto would require (or better yet Eris and Sedna).  I wager your counterargument, Blackstar, would be that scientists interested in the solar system depths need convincing arguments to warrant the limited plutonium, which is limited by current technology to put payloads into orbit (especially at Neptune and beyond).

Hopefully they set guidelines.  Letting Mars hog everything is a bit of a travesty with a resource so scarce.
Title: Proposed Europa Missions
Post by: Star One on 09/12/2015 07:14 am
http://www.scientificamerican.com/article/within-nasa-a-plutonium-power-struggle/

New article on the subject. I have only read a few paragraphs, but I disagree with the premise. Things are looking better on the Pu-238 production issue than they have in a long time. DoE needs some more time (and possibly a bit more money), but stuff is finally working and the logjam is broken. And citing the Ohio politicians is an indication that the reporter may not understand what is really going on (they were making a political claim, not one based in reality).

Not surprised it's a slow process, but encouraging to hear your own news about production Blackstar.

Juno obviously demonstrates that we're at the point of solar power being useful at Jupiter, and that seems a reasonable benchmark.  Considering the heavy amount of science Saturn, the Ice Giants, and Kuiper Belt will demand, giving them the plutonium seems fair to properly fulfill missions.  I'd hate to see the size a solar array at Pluto would require (or better yet Eris and Sedna).  I wager your counterargument, Blackstar, would be that scientists interested in the solar system depths need convincing arguments to warrant the limited plutonium, which is limited by current technology to put payloads into orbit (especially at Neptune and beyond).

Hopefully they set guidelines.  Letting Mars hog everything is a bit of a travesty with a resource so scarce.

Time to move the focus away from Mars a bit especially when it comes to a resource like this.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 09/12/2015 12:48 pm
I've now read the article all the way through and although it is not completely awful, it misses or misstates a bunch of things.

First, I don't think the Russian Pu-238 was lower quality than the American Pu-238.

Second, it is totally wrong to say that NASA did not build a Europa mission because of a Pu-238 shortage. The problem was always the cost of the mission itself.

Third, there's no good discussion of the ASRG issue, which is more complex than they portray it.

Fourth, although there is certainly a Catch-22 situation--whereby the lack of Pu-238 causes it to be ruled out for missions, lowering the demand, and allowing people to claim that it is not needed and therefore they don't make more--the bigger issue is that NASA cannot afford more missions that need it. The fuel is not driving the overall level of effort.

Fifth, there was no mention of the possibility of significantly increasing the efficiency of Pu-238 production. That's a really interesting development and should have been discussed here.

Sixth, they really miss the point with solar at Europa. They portray that as an unfortunate and crippling compromise, as if the mission designers would rather use Pu-238. No. Absolutely not. Using Pu-238 is expensive, even if there is a ton of stuff sitting around. And it creates all kinds of handling and certification requirements. Lots of paperwork. When the Europa Clipper designers discovered that solar worked for their mission I suspect that they were very happy.

Seventh, the discussion of the space policy requirement I think was misleading. These decisions are really driven by budget and engineering concerns, not some policy document.


There are some other problems with the article, but you get the gist of it.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 09/12/2015 12:52 pm
I wager your counterargument, Blackstar, would be that scientists interested in the solar system depths need convincing arguments to warrant the limited plutonium, which is limited by current technology to put payloads into orbit (especially at Neptune and beyond).

There is still enough Pu-238 on hand for several more missions. And DoE is manufacturing more. So the shortage is really longer-term, not shorter-term. If NASA funded two more missions that need it, they have it available. If they fund more than that, then they need more Pu-238--which they can make. So this is an issue of program management, of having adequate material when you might need it.

Put another way, NASA cannot build more than two Pu-238 powered spacecraft in the next five years, so they're not going to use up all the material in the short term.

I listed some of the problems with the article. But my biggest issue is the tone of the article. I think things are in better shape than the reporter implies.
Title: Re: Proposed Europa Missions
Post by: zubenelgenubi on 09/12/2015 05:53 pm
re: NASA Struggles over Deep-Space Plutonium Power
http://www.scientificamerican.com/article/within-nasa-a-plutonium-power-struggle/ (http://www.scientificamerican.com/article/within-nasa-a-plutonium-power-struggle/)
by Lee Billings and the commentary here in this thread, particularly Blackstar's:

Does the article author read NSF?
If he did, then he would know that his article premise is wrong! :)

Seriously, I've learned a great deal from the NSF articles and the forum here.  The level of knowledge and thought-through analysis based on that collective knowledge here is astounding.

Thank you again to all of you.
Title: Re: Proposed Europa Missions
Post by: vjkane on 09/13/2015 12:25 am
There is a current problem with manufacturing useful pellets.  Because of this, there wasn't the opportunity to offer an MMRTG for the current Discovery competition.  I know of one mission that wasn't proposed because of this, and there are probably more.

Looking to the 2020s, Pu-238 will be available but it looks like it may be constrained if I read slides right.  We are unlikely to see flagship missions each with 3-4 MMRTGs as has been proposed in the past.  Further out than Jupiter, we may see small spacecraft with constrained data rates that have just a single or perhaps two MMRTGs.  New Horizons-class instead of Cassini- or Europa Clipper-class.
Title: Re: Proposed Europa Missions
Post by: redliox on 09/13/2015 10:03 am
Looking to the 2020s, Pu-238 will be available but it looks like it may be constrained if I read slides right.  We are unlikely to see flagship missions each with 3-4 MMRTGs as has been proposed in the past.  Further out than Jupiter, we may see small spacecraft with constrained data rates that have just a single or perhaps two MMRTGs.  New Horizons-class instead of Cassini- or Europa Clipper-class.

Sadly not surprised on them being limited to one or two MMRTGs.  Assuming two with presumably double the power New Horizons had, how much science might that support?
Title: Re: Proposed Europa Missions
Post by: Blackstar on 09/13/2015 05:15 pm
There is a current problem with manufacturing useful pellets.  Because of this, there wasn't the opportunity to offer an MMRTG for the current Discovery competition.  I know of one mission that wasn't proposed because of this, and there are probably more.


And this is a key point that the reporter missed--the problem is not with manufacturing the Pu-238, they are doing that. The current bottleneck is taking that material and then turning it into the fuel pellets. There is a slowdown there that will take a few years to fix due to a requirement for new equipment.

Pu-238 production is more complicated than I thought, but it's not extremely complicated. It's a production process, with a bunch of key steps. And some of those steps are working better than others. The reporter was not very careful with their language.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 09/13/2015 05:21 pm
Looking to the 2020s, Pu-238 will be available but it looks like it may be constrained if I read slides right.  We are unlikely to see flagship missions each with 3-4 MMRTGs as has been proposed in the past.  Further out than Jupiter, we may see small spacecraft with constrained data rates that have just a single or perhaps two MMRTGs.  New Horizons-class instead of Cassini- or Europa Clipper-class.

But all of this depends upon what missions are proposed and what they need--which is of course going to be constrained by the availability of Pu-238... BUT is also going to be enabled by the new capabilities of solar.

Look at it this way: we are now at the point where RTGs may not be needed for most of the conceivable near-term Jovian missions. That frees up RTGs for farther out missions. As one example, when we put the Io Observer into the decadal survey as a possible future New Frontiers mission, we conceived of it as an RTG-powered mission. That may no longer be a requirement. So that plutonium can now, in theory, be diverted to another mission.

I would like to see the Pu-238 production rate increased. I think that the 400 grams that they're talking about now is too low, and I'd like to know why just a couple of years ago their goal was 1.5 kilograms and now they (and by "they" I mean both NASA and DoE) have defined a much lower rate as acceptable. But it's not a horrible situation. The DoE rep at OPAG said that increasing the rate is simply a matter of money, not any fundamental technical barriers like the lack of space in a reactor. Also, she talked about a method of potentially dramatically increasing the Pu-238 production at minimal cost. I'd like to see them put some money into that in the next couple of years.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 09/13/2015 05:26 pm
re: NASA Struggles over Deep-Space Plutonium Power
http://www.scientificamerican.com/article/within-nasa-a-plutonium-power-struggle/ (http://www.scientificamerican.com/article/within-nasa-a-plutonium-power-struggle/)
by Lee Billings and the commentary here in this thread, particularly Blackstar's:

Does the article author read NSF?
If he did, then he would know that his article premise is wrong! :)

Seriously, I've learned a great deal from the NSF articles and the forum here.  The level of knowledge and thought-through analysis based on that collective knowledge here is astounding.


Well, to be honest, I don't think NSF is a great source for a reporter who wants to write something detailed and get it right. First of all, there's no good way to know who is posting and whether they are actually knowledgeable or just think that they are. Everybody's behind a username, and they're not posting their resume or anything (I don't keep my own identity secret, and if you want to look up my resume, it will take you all of 60 seconds on Google. But even I could be full of $hit, right?) Understand that NSF is a source for amateurs. If you work in various aspects of spaceflight professionally you're going to get your information from other sources, including Space News, conferences, workshops, and open meetings. Any reporter surfing a discussion board for information is being lazy.

The reporter in this story talked to some of the right sources, but made some big errors. I don't know why he made them, but they were avoidable. For instance, if he had merely asked Casey Dreier or Ralph McNutt why NASA had not previously built a Europa mission, both of them would have told the reporter that it was NOT because of a lack of plutonium. It was because of a lack of another glowing green material called dollars.

Reporters rarely run their stories past their sources for lots of reasons--they don't want to risk the story getting circulated before it is printed, they are under tight deadlines, etc. But this is a case where if the reporter had shown Ralph McNutt his draft, Ralph could have found the errors in about five minutes.
Title: Re: Proposed Europa Missions
Post by: GClark on 09/13/2015 06:01 pm
But even I could be full of $hit, right?

If this is the case, then you are in good company these days and we are lessened thereby.  I value your comments here, as they have increased my knowledge exponentially over the years.

Keep up the good etc...

(Threadjack complete, returning you to your regularly scheduled discussion.)
Title: Re: Proposed Europa Missions
Post by: Blackstar on 09/13/2015 10:26 pm
But even I could be full of $hit, right?

If this is the case, then you are in good company these days and we are lessened thereby.  I value your comments here, as they have increased my knowledge exponentially over the years.

Keep up the good etc...

(Threadjack complete, returning you to your regularly scheduled discussion.)


Well, my point was that although I've been in the space biz for a long time and done several different jobs, there are lots of things I don't know anything about, or where I know a little bit--way more than the people here--but am by no means an expert. I don't come up with grandiose space architectures for settling the Moon or sending humans to Mars because I'm not an expert. And I don't talk much about the engineering because I'm also not an expert on that. But I'm perfectly willing to accept that, say, a non-American computer programmer or grocery store manager might know a lot more about how to run NASA than I do.

I'd just suggest that before writing an article for a publication like Scientific American, a reporter should talk to a few experts and also double-check his assumptions.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 09/13/2015 10:33 pm
And since we're going to rant about this SciAm article here for awhile, here's something that the reporter missed that I think is a worthwhile story: at the recent OPAG meeting, they (I'm not sure if it was NASA or DoE) said that they were going back to the drawing boards on the ASRG program. Their reasoning was that the last baseline ASRG design was several years ago, and there have been other technology developments in heat pump technology since then. And so they think it makes sense to determine if that new technology could be applied to a new ASRG baseline design.

Remember that right now the ASRG program is essentially frozen/cancelled.

Now this sounds like a reasonable and logical thing to do. After all, if their last design is based upon outdated technology, then it makes sense to look at newer technology and determine if it can make things better.

Except... if you look into the history of the ASRG program, and also look at the 2009 NRC report about the Pu-238 situation, including the ASRGs, you'll see that one of  the problems was that NASA could never simply pick a systems design and then stick with it through full testing. They kept messing around with it, testing one design, improving it, testing a new design, and so on. They never developed something that had a lot of complete lifecycle testing done on it because they kept tinkering with it. So there was never high confidence in their system design. One of the things that the NRC report told them to do was to pick a system design and freeze it. Develop it to flight hardware status.

And now they're talking about doing that all over again. They can reasonably argue themselves into a situation where they repeat the same thing that they did in the past, always tinkering, never freezing the design.
Title: Re: Proposed Europa Missions
Post by: vjkane on 09/14/2015 02:36 am
I'm going to defend the SciAm article.  I know from my piece on the Europa Clipper in that magazine that their fact checkers are tough, as tough as any of the reviewers for my scientific papers. 

Can I save Blackstar time and just say that he will disagree?  :>

Also this is typed on my phone. So expect typos.

The story was not about the engineering of Pu-238 or the manufacture of mmrtg's.  It is about the political environment to produce Pu (I'll use this shorthand from here on), maintain funding, and the demand in terms of missions.  That's why Casey Drier who has great sources and has looked into the issue is quoted so much. Casey can say things that those in the system can't.   You may or may not agree, but Casey is smart and informed.

The Pu program needs ~10 years of continued funding to reach full production. That's political support through 10 Congresses and two more presidents. 

Billings did, in my opinion, overstate the connection to a Europa mission.  I think there's a bit of truth though. The learning that Europa clipper can use solar is recent and may (I don't know) require long times between peak power use to recharge batteries.  In any case an orbiter would have been in shade up to almost half of each orbit. All previous proposals required gobs of Pu. Yes the total mission cost was the first stumbling point. But if JEO had been approved we wouldn't have the Pu to fly it this decade. 

NASA also does have a constrained Pu supply and it is affecting mission planning. It would have been good for the author to discuss the manufacturing problems separately from the Pu supply.

I looked through the last Pu presentation from the recent opag meeting.  A couple of slides stood out:

Pu-238 Supply Status

 Total 35 kg Pu-238 isotope available for civil space;  approximately 17 kg meets specifications and balance available for blending 

Number of MMRTGs that could be fabricated using this material depends on decisions about individual missions
• Mars 2020 – Plan is to build generator with specified thermal power
• For later missions, DOE-reported estimates have varied based on the scenario being discussed:
– Scenario details matter for remaining inventory usage: assumptions about processing efficiency/losses, processing dates, launch dates, etc. 
– Scenario Approach: Maximizing power for a certain mission? Trying to extend the supply as long as possible? 

Currently envision at least 3 more MMRTGs after Mars 2020, but below specified power   • May be adjusted as Pu-238 supply project proceeds (could make fewer with higher power if future supply is assured)

And in summary:

Project to reestablish domestic Pu-238 production capability is producing excellent results • Limited production later this decade • Full rate as funds allow, mid-2020s

My read: late 2020s today look good if funding holds and political support continued.   Constrained availability until then.

As I understand it, It is uncertain when NASA will be able to offer an mmrtg to a mission. The last statement I heard was that offering one for the next New Frontiers mission (launch 2023/4?) is under evaluation. Fortunately none of the candidate missions look to absolutely require mmrtg's. If the Clipper could not use solar, it's not clear that enough Pu/pellets manufactured to be available for a mid 2020s flight. 

To answer an earlier question in this thread, simple low data rate missions to Saturn can use solar.  Any mission with high data rates will require an mmrtg to return the data.  Even when solar and Pu produce the same electrical watts, mmrtg's have an advantage. Mmrtg's have lots of spare thermal watts for heating. And any mission beyond Saturn and a scattering of inner solar system missions require mmrtg's.

So from a technical viewpoint, the Pu program is on track with opportunities for upside. From a programmatic mission selection viewpoint, NASA needs to carefully husband its supply for at least another decade.  From a political viewpoint, a decade of continued support is almost forever.  If president Trump slashes NASA's budget to improve infrastructure, will the Pu program survive?  If not, NASA has 2-3 mmrtg's for the next Decadal to allocate.
Title: Re: Proposed Europa Missions
Post by: savuporo on 09/14/2015 04:38 am
I have one thing to add here

https://icubesat.files.wordpress.com/2015/05/icubesat-2015_org-b-3-4_amrtg_ambrosi.pdf
( the old version : http://www.lcpm10.caltech.edu/pdf/posters/Ambrosi_R_posters.pdf and oblig planetary.org article

http://www.planetary.org/blogs/guest-blogs/2015/0423-can-a-nuclear-waste-help-humanity-reach-for-the-stars.html
)

They are also working on Stirling conversion.

EDIT : i think this is the latest:
http://www.unoosa.org/pdf/limited/c1/AC105_C1_2015_CRP05E.pdf
 
Title: Re: Proposed Europa Missions
Post by: Blackstar on 09/14/2015 02:54 pm
Yeah... Americium...

So there's a general attitude in the space program towards radioisotope power sources. It sorta goes like this:

-they're icky, so don't use them unless you absolutely have to
-if you have to use them, Pu-238 is the least-worst material to use for lots of reasons, including that we have a LOT of experience using it, plus it has better qualities than other materials, for instance, it does not dissolve in water
-if you don't have Pu-238, and you do have Americium, then it is an okay, choice
-Polonium is probably something best avoided

ESA is going to use Americium because they have it available, but based upon long American experience, I think they will find it a lot more expensive and difficult to develop than they expect. That has always been the case with these materials.
Title: Re: Proposed Europa Missions
Post by: savuporo on 09/14/2015 03:10 pm
ESA is going to use Americium because they have it available, but based upon long American experience, I think they will find it a lot more expensive and difficult to develop than they expect. That has always been the case with these materials.
Actually, the program is moving at a somewhat faster pace than the original planning, and yes a lot of material available.
Someone at Quora had put this together :
http://www.quora.com/How-does-ESA-plan-to-power-its-future-space-missions-if-they-dont-want-to-use-RTGs

Polonium-210 ? Russians did that a long time ago. They also operated remote lighthouses (http://englishrussia.com/2009/01/06/abandoned-russian-polar-nuclear-lighthouses/) on  Strontium-90 powered RTGs
Title: Re: Proposed Europa Missions
Post by: Blackstar on 09/14/2015 04:24 pm
Actually, the program is moving at a somewhat faster pace than the original planning,


And they're going to find that it is more difficult than they expected and will take longer than they expected.

The United States has long and extensive experience with radioisotopes. And yet every single project to use them--every single one--has ended up taking longer and costing more than planned, even stuff that everybody thought was simple.

ESA's new at this.
Title: Re: Proposed Europa Missions
Post by: savuporo on 09/14/2015 05:06 pm
I don't doubt that as with every engineering project, things will be harder and more difficult. I just pointed out though that so far the program has been going smoother than expected, and Europe has its own indigenous nuclear industry expertise, that in some respects is ahead of US - for terrestrial applications. Not to mention, Russian experts with as long experience are sometimes available for cheap ..

As with most spacey tech, this thing bearing fruit will have much more to do with continued political will to see the project through rather than particular technical challenges ( *cough* ASRG *cough* )
Title: Re: Proposed Europa Missions
Post by: LBillings on 09/14/2015 06:23 pm
Hey folks,

Author of the SciAm article here. Wasn't aware of this resource, and decided to make an account to join the conversation.

Blackstar/Dwayne, I'm a huge fan of your work, most of which I've encountered through your articles for Space Review. It's an honor to know you read the piece and that it elicited such a response! I, like you, think this is an important topic worth much more discussion.

That said, I do want to push back on a few of your assertions, if I may. You may not like how I told the story, and you may feel I misrepresented the situation, but it's neither accurate nor fair to say the piece contains a lot of big factual errors. I'm not an expert on this by any means, but I did a lot of reporting to back up what the piece contains, and I stand by it.

I agree with you that the situation is actually pretty good, certainly a lot better than it was several years ago. And that's what the piece says, both at the beginning and at the end. And I agree that solar for a Europa flyby mission is a good, viable choice -- if the story seems to imply the opposite, that's my fault and a mistake.

On the other hand, I disagree with your contention that the shortage of plutonium had nothing to do with NASA passing over concepts like the Jupiter Europa Orbiter. You say the issue was a shortage of another scarce resource -- money. Well, yes. As everyone reading this probably knows, a shortage of money tends to be the explanation for almost every inadequacy in spaceflight. But let's not act as if the shortages of money and shortages of plutonium have no relation. Producing and using plutonium for a space mission is monetarily very expensive, for a host of complicated and multidimensional reasons. So, was there enough plutonium available for something like JEO? It seems the answer is yes, just barely. But if such a mission is going to wipe out essentially your whole stockpile, you're certainly going to factor in the cost of obtaining more into your decision-making about whether to pursue that mission or not, right? These are not unrelated issues kept entirely separate from each other in watertight compartments, and anyone telling you otherwise is trying to sell you something. I think Van covered this pretty well in his earlier comment, and he's spot on about why Casey has some crucial quotes in the piece -- Casey can say things that others within or closely affiliated with NASA cannot. He can speak plainly with much less risk of reprisal.

The less-than-ideal relative quality of Russian Pu-238 was something two separate sources independently alluded to. I didn't follow up for much more detail but figured it was worth mentioning. Maybe that was a mistake.

A lot of the things you fault the piece for not including were simply left out due to space constraints. Some examples include: The intricacies of the ASRG program, the possibility of boosting Pu-238 production efficiency, and a detailed explanation of the whole pipeline to delineate between raw plutonium and fuel pellet production problems. I think the story is okay without those details, particularly considering its intended audience of general readers. Each of those examples could in truth be a story all on its own.

I could go on and address some other things you brought up, but I don't want this to get even longer than its already excessive length. The real point is I greatly appreciate your criticism, and I would be honored to talk with you more about this or other future stories -- maybe via e-mail? Thank you for reading and for the discussion.

Lee Billings
Title: Re: Proposed Europa Missions
Post by: notsorandom on 09/14/2015 06:33 pm
ESA is going to use Americium because they have it available, but based upon long American experience, I think they will find it a lot more expensive and difficult to develop than they expect. That has always been the case with these materials.
Actually, the program is moving at a somewhat faster pace than the original planning, and yes a lot of material available.
Someone at Quora had put this together :
http://www.quora.com/How-does-ESA-plan-to-power-its-future-space-missions-if-they-dont-want-to-use-RTGs

Polonium-210 ? Russians did that a long time ago. They also operated remote lighthouses (http://englishrussia.com/2009/01/06/abandoned-russian-polar-nuclear-lighthouses/) on  Strontium-90 powered RTGs
The longer half life of Am-241 may not matter too much in thermocouple based RTGs. Those break down faster than the Pu-238 does.
Title: Re: Proposed Europa Missions
Post by: savuporo on 09/14/2015 06:59 pm
The longer half life of Am-241 may not matter too much in thermocouple based RTGs. Those break down faster than the Pu-238 does.
Yep - but if you look at the details of the program, you'll find stirlings and something novel : thermo-acoustic generators (http://pamir.sal.lv/2014/cd/container/B.7.02=DidierA_Pamir14.pdf) being worked on too.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 09/14/2015 07:23 pm
I don't doubt that as with every engineering project, things will be harder and more difficult. I just pointed out though that so far the program has been going smoother than expected, and Europe has its own indigenous nuclear industry expertise, that in some respects is ahead of US - for terrestrial applications. Not to mention, Russian experts with as long experience are sometimes available for cheap ..

Certainly Europe (well, primarily France) has lots of experience with nuclear materials, including extensive experience with commercial nuclear power. I don't mean to imply that they are amateurs by any means. I'm basing my opinion upon discussions with Ralph McNutt, who delved into the American experience with these materials and discovered that even though RTGs are a very mature technology, and you would think that thermoelectric generators are pretty darned simple, this stuff has always proven harder to do than anybody expected. I'm sure the Europeans are going to discover that.

As for the Russians, well, that's an interesting issue. The Russians provided Pu-238 heat sources to China for their CE-3 mission. And they are planning to use them for their Luna-25 mission (although I am not sure if they are simply going to use them as heaters, or if they are going to generate electricity and then run heaters from them). I cannot remember if they had anything on their Phobos-Grunt spacecraft. But this implies that Russia is back doing Pu-238 RTG work (although they may not be making Pu-238).
Title: Re: Proposed Europa Missions
Post by: redliox on 09/14/2015 07:32 pm
As for the Russians, well, that's an interesting issue. The Russians provided Pu-238 heat sources to China for their CE-3 mission. And they are planning to use them for their Luna-25 mission (although I am not sure if they are simply going to use them as heaters, or if they are going to generate electricity and then run heaters from them). I cannot remember if they had anything on their Phobos-Grunt spacecraft. But this implies that Russia is back doing Pu-238 RTG work (although they may not be making Pu-238).

I recall their failed Mars '96, which crashed into the Pacific and South America, brought some worries because it had some plutonium on board - mainly with the Mars landers.  Considering Phobos-Grunt was solar powered I'd presume whatever it carried was for heating.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 09/16/2015 07:26 pm
On the other hand, I disagree with your contention that the shortage of plutonium had nothing to do with NASA passing over concepts like the Jupiter Europa Orbiter. You say the issue was a shortage of another scarce resource -- money. Well, yes. As everyone reading this probably knows, a shortage of money tends to be the explanation for almost every inadequacy in spaceflight. But let's not act as if the shortages of money and shortages of plutonium have no relation. Producing and using plutonium for a space mission is monetarily very expensive, for a host of complicated and multidimensional reasons. So, was there enough plutonium available for something like JEO? It seems the answer is yes, just barely. But if such a mission is going to wipe out essentially your whole stockpile, you're certainly going to factor in the cost of obtaining more into your decision-making about whether to pursue that mission or not, right? These are not unrelated issues kept entirely separate from each other in watertight compartments, and anyone telling you otherwise is trying to sell you something. I think Van covered this pretty well in his earlier comment, and he's spot on about why Casey has some crucial quotes in the piece -- Casey can say things that others within or closely affiliated with NASA cannot. He can speak plainly with much less risk of reprisal.

I don't have the energy to go back and dig through files, but I'm pretty sure that the Europa mission was not approved because of a lack of money and that a lack of plutonium had nothing to do with it.

If you go back to 2001, just after the planetary science decadal survey came out and ranked a Europa mission, did a lack of plutonium doom that mission? I don't know what the baseline Europa mission power requirement was as of 2001, but the 2010 JUICE study done for the second decadal survey (I was a study director on the decadal) had a Europa orbiter that required 5 MMRTGs. Let's assume that back in 2001 the Europa orbiter also would have required 5 MMRTGs. Would there have been enough? Well, we can do an easy WAG estimate of what was available:

1 MMRTG used on Curiosity
1 MMRTG assigned to Mars 2020
"at least 3 more" MMRTGs available after Mars 2020 (according to the Onuschak presentation to OPAG last month)

So that adds up to 5 MMRTGs, not counting the material allocated to New Horizons. So yeah, if NASA had decided to pursue a Europa mission in 2001/2002, they would have had sufficient material to power it. Now that means they would not have flown Curiosity, and they might not have flown New Horizons, but a lack of plutonium was not the issue. (And if they had pushed harder on the ASRG, they could have used less material for a Europa mission.)

Why was no Europa mission selected by NASA back in the early 2000s? There's no simple, definitive answer beyond cost--it's complicated and convoluted. But part of the problem was that NASA administrator Sean O'Keefe became enamored of a nuclear fission reactor program named Prometheus to power a Jupiter Icy Moons Orbiter. Prometheus/JIMO was a dumb idea, and it would have ultimately cost at least $20 billion (yeah, you read that right) to implement. But that's what NASA's leadership was interested in, and as long as NASA was officially pursuing Prometheus/JIMO, they were not going to pursue a simpler Europa orbiter. Ultimately, NASA spent over $400 million on Prometheus/JIMO--much of it at JPL--and probably got very little to show for it before the program was put out of its misery by Michael Griffin.

In the latter 2000s NASA got into an unfortunate policy dynamic. If you look at the last planetary science decadal survey mid-term assessment from 2008 (I was study director on that) it criticized NASA for not pursuing the Europa mission.

http://www.nap.edu/catalog/12070/grading-nasas-solar-system-exploration-program-a-midterm-review

(you can download it for free from there--also attached)

Just look in that report for "Europa" and see what it says. Although it does not specifically say why the mission had not been approved as of 2008 (that wasn't the committee's responsibility), it does say that it was an expensive mission and it does not mention a Pu-238 shortage as an impediment.

But what happened was that around 2006 or so NASA officials were hearing a lot of complaints that, with JIMO dead, NASA should pursue a Europa mission. So they asked about the current status of the Europa mission study, and that delayed things a little longer. Plus, they were running short of cash to do various things. And the odd policy dynamic is that the agency is LESS likely to approve a flagship mission just before a new decadal survey. By 2008/9 it was easier for agency officials to decide to wait and see what the next decadal survey said. It's always easier to not spend money than to spend it.

And if you look at the Europa mission proposal that was ultimately submitted to the 2009-11 decadal survey, it was a very expensive mission. It proved to be too much money for the planetary budget to afford. That's why it did not get first ranking in the decadal survey. It's spelled out very clearly in the decadal, essentially "Europa costs too much and JPL has to make it cheaper." They eventually did that, but it took a lot of wrangling.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 09/16/2015 07:33 pm
The less-than-ideal relative quality of Russian Pu-238 was something two separate sources independently alluded to. I didn't follow up for much more detail but figured it was worth mentioning. Maybe that was a mistake.

I'm not a Pu-238 expert, but what I've essentially heard is this:

-the Russian Pu-238 had a higher energy density than the American Pu-238 (essentially because it was newer material)
-the Russian Pu-238 had more Pu-236 impurities in it, which made it a bit more difficult to handle (more icky gamma radiation)

So from one perspective it was lower quality, but from another it was higher quality. I believe that I read that the Russian material was actually used to boost the energy density of the American Pu-238. They mixed it in and the resulting material was hotter than the American material they started with (hotter equals better).
Title: Re: Proposed Europa Missions
Post by: Blackstar on 09/16/2015 07:49 pm
I'll add one more thing to the "it's complicated" story of the latter 2000s. NASA funded several different mission studies for outer planets missions. vjkane may have more info on this, but NASA funded a series of studies called the "billion dollar box" studies to see if they could fit a Europa and Titan missions into billion dollar boxes. They couldn't. I certainly have copies of presentations about those studies somewhere, but I'd have to dig a bit, and I'm lazy right now.

Now add to this a simple fact of life when it comes to these big projects: they are all done/studied in serial. So, while JPL was working on Prometheus/JIMO, they were NOT working on a Europa orbiter mission or study. They're doing one thing or another. And when NASA funded the billion dollar box studies, it meant that for at least part of that time the people who could have been working on a Europa mission were instead working on that study.

Putting it in other words, studying something means not building it, and studying one thing means not studying another thing.

Once you consider all that, it becomes easy to see how each year in the 2000s NASA kept kicking the can down the road rather than fighting the hard fight to get a new start for a Europa mission. New starts take a lot of effort, and there just was not a lot of enthusiasm for one. Add to that the fact that Mars Science Laboratory (Curiosity) had ballooned into a $2.6 billion mission by 2009 and it was sucking all the life (and money) out of the planetary program. There was no enthusiasm either at NASA HQ or OMB to start an expensive Europa mission in the latter 2000s.
Title: Re: Proposed Europa Missions
Post by: vjkane on 09/17/2015 06:44 am
I went back and looked through the $1b box study. Which concluded there were no viable missions for less than about $1.4b in 2006 dollars. A couple of developments would be taken into account of it were redone today: 

Titan orbiter was assumed for mapping Titan at higher resolution. Based on clipper I think multiple flyby  would be considered today.

A radar (+++data) was assumed. Today a thermal band imager would be assumed (based on the Titan Saturn flagship study and the JET discovery proposal).

The big cost driver were the power and communications.  With a clipper multiflyby approach and thermal imaging, the data amount goes down significantly and there's time between encounters to transmit the data more slowly. = significantly lower costs. Using Ka band instead of X band helps too

There was little new science value assumed by more Enceladus flybys. Now we have much, much more sensitive mass spectrometers (eg, maspex).  We also know of flyby options that get as slow as 1 km/sec instead of 4

The launch vehicle was included in the cost estimates. 

Interestingly Ralph Lorenz led the Titan study for the $1b study. At the last OPAG meeting one of his slides said:

A Titan orbiter would be a strong candidate of NF-class mission

So something has changed. I hope that NASA funds a pre-Decadal project to study whether this is true
Title: Re: Proposed Europa Missions
Post by: Blackstar on 09/17/2015 11:34 am
Wasn't there also a Europa "billion dollar box" study too?

I am not at my work computer so I cannot search for it, but I thought they did the three outer planets obvious targets of Titan, Enceladus and Europa. The end result was the conclusion was that none of those targets could be done for a billion dollars.

Title: Re: Proposed Europa Missions
Post by: vjkane on 09/17/2015 12:26 pm

Wasn't there also a Europa "billion dollar box" study too?
I thought so, too, but haven't found it.

Looking at the Saturn satellite studies, they went for a given science capability such as global mapping at a given resolution.  That led to spacecraft with high power and communication capabilities. 

The Clipper breakthrough was that it was allowed to only sample Europa at high resolution and then had days to return data from each pass. The initial studies also were for just three instruments. 
Title: Re: Proposed Europa Missions
Post by: Blackstar on 09/17/2015 02:48 pm
I'll look for the Europa BDB study. If it exists, I have it somewhere.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 09/18/2015 10:29 pm
I'm still trying to figure out if there was a 2007 Europa "billion dollar box" study. I went through some old files and found this presentation. Some of the latter slides refer to a 2007 Europa study following a 2006 study. But I don't know if I have the 2007 study anywhere.

I'll have to keep looking.
Title: Re: Proposed Europa Missions
Post by: redliox on 09/18/2015 10:44 pm
I'm still trying to figure out if there was a 2007 Europa "billion dollar box" study. I went through some old files and found this presentation. Some of the latter slides refer to a 2007 Europa study following a 2006 study. But I don't know if I have the 2007 study anywhere.

I'll have to keep looking.

One of the slides compare the radiation dosage of Earthly satellites with Galileo and what a Europa Orbiter might expect.  I find it interesting to note that a satellite that could handle medium Earth orbit for a decade would outperform Galileo in terms of radiation tolerance.
Title: Re: Proposed Europa Missions
Post by: savuporo on 09/20/2015 07:24 pm
I'm still trying to figure out if there was a 2007 Europa "billion dollar box" study. I went through some old files and found this presentation. Some of the latter slides refer to a 2007 Europa study following a 2006 study. But I don't know if I have the 2007 study anywhere.

I'll have to keep looking.

Not this one by any chance ?

https://solarsystem.nasa.gov/multimedia/downloads/EE_Final_508_Public_Release.pdf

EDIT: well probably not, not a billion dollar box
Title: Re: Proposed Europa Missions
Post by: Blackstar on 09/20/2015 07:42 pm
That 2007 Europa study could indeed be the outcome of the "billion dollar box" effort. The general conclusion of that effort was that it was NOT possible to do Europa, Titan, or Enceladus missions for a billion dollars apiece, or even close to it.

Now I have heard some criticism of the studies because of that. I believe the gist of the criticism was that the studies said "you have to do X, Y, and Z and figure out if you can do it for $1 billion." Instead, they think that the studies should have started from a different premise, "What can you do for $1 billion?" That would provide different options.

Now that's a reasonable-sounding criticism, except... you have to keep in mind that from an administrator-level perspective (meaning the people who run the programs at HQ), they have to protect the overall programs from people (at OMB and Congress) who are always looking to do things cheaper and who don't understand or care all that much about the science content. Their goals include preserving the science content. So if they say "you have to do X, Y, and Z" and figure out what it will cost, that protects X, Y and Z. But if instead they say "What can you do for $1 billion?" and the answer is "We can do X," then somebody from OMB might come along and say "Okay, here's one billion dollars, go and do that mission," and all you end up with is X and nothing more. In other words, you've handed away any leverage you have with the budgeteers right from the start.

Something like this recently played out in 2014 with the call for proposals for $1 billion Europa missions. It was OMB pushing for that. NASA stipulated that the missions had to accomplish the goals established for Europa in the decadal survey. Reportedly NASA received six Europa proposals and determined that none of them could accomplish the goals in the decadal survey and so it rejected them. If that stipulation had not been there, then the result might have been a spacecraft with very little science instrumentation that did almost nothing valuable, but that somebody could call a Europa mission.

The point isn't simply to go somewhere and say that you've gone there, it is to go there and do something useful.
Title: Re: Proposed Europa Missions
Post by: savuporo on 09/20/2015 07:46 pm
Circa 2007, Laplace was also in early concept phase, and initially they pegged some costs pretty low too, like around $1B

http://sprg.isas.jaxa.jp/researchTeam/spacePlasma/staff/kshr/material/JovHP/052_JUPITER_EUROPE_Draft_proposal_V15.pdf

Indubitably, a bunch of optimists

Title: Re: Proposed Europa Missions
Post by: vjkane on 09/20/2015 11:38 pm
Circa 2007, Laplace was also in early concept phase, and initially they pegged some costs pretty low too, like around $1B

Indubitably, a bunch of optimists
The last budget quote I heard for JUICE was around 1B Euros, so that's still in line.  Under ESA accounting practices, that includes the launch but not the instrument costs or the cost of the science teams for the instruments.  (NASA does it the other way around.)  My guess is that the instruments cost more than the launch.  NASA is contributing $100M to pay for the UV spectrometer and parts of two other instruments.

Juno and JUICE are two strong arguments that missions for =<$1B can be done to the Jupiter system so long as they don't have to deal with high radiation loads.
Title: Re: Proposed Europa Missions
Post by: vjkane on 09/21/2015 12:50 am
Now I have heard some criticism of the studies because of that. I believe the gist of the criticism was that the studies said "you have to do X, Y, and Z and figure out if you can do it for $1 billion." Instead, they think that the studies should have started from a different premise, "What can you do for $1 billion?" That would provide different options.

The point isn't simply to go somewhere and say that you've gone there, it is to go there and do something useful.
Since I think that I'm the unnamed somebody, I'll reply.  As way of background, I ran product and product line definition teams for a prominent high tech company.  The highest development cost for one of the products was ~$800M, but most were much cheaper.  Revenue impacts for our decisions were in the $10Bs.

Defining a product or a mission is always an exercise in the art of the possible.  If executive staff of the company or OMB-Congress are holding your feet to the fire and making it clear that you are only going to get $X, you see what you can do for $X.  Sometimes it is much less than you'd like.  Then you need to make a call as to whether what you can get is worth the effort.  Sometimes you decide yes, sometimes no, and in the latter case the funding goes to some other project.

Sometimes a project was a high priority for the company and you knew that it had to be done right.  Then you defined the project and told executive staff what the cost would be.  (For these projects, despite our best efforts, our cost estimates always proved to be low.  High tech development is very hard to budget whether it is by the DoD, NASA, or private enterprise.)

There was always a tension between executive staff that controlled the $s and the product definition teams.  Executive staff would test our creativity by holding proposed development budgets low.  We would test their resolve by showing them how little they would get for their proposed development budgets and how much a budget increase would improve the product capabilities.

I've been following planetary mission development since the Viking mission and I have some observations.  A caveat: I don't have the insider knowledge that Blackstar has.

For planetary mission definition, it appears to be a combination of the art of the possible both from a budget and an engineering point of view.  While a low radiation dose Jupiter mission seems to be feasible for ~$1B (see Juno and JUICE), any mission that spends any time around Europa and its radiation fields seems to cost $1B just for the minimum capability spacecraft.  If you'd like a capable communications system and instruments, the cost seems to go up by $700M to $1B.

My reading of the dance between OMB and NASA on the Jupiter mission was that NASA knew it had a strong hand (Decadal requirements and strong Congressional support plus the high costs of dealing with the radiation environment).  That one was a pretty easy call.

However, there are other cases where NASA has played the game differently.  It was confident that it would have a steady stream of funding for its Mars program, and so it planned a series of incremental orbiters that fit within the annual budget cap.  No one of the missions fulfilled all the scientific priorities and it might have been cheaper to fly a single monster orbiter to do it all.  But NASA had a relatively fixed annual budget that it thought it could count on.

To take another case, I look at the Saturn probe mission that was proposed in the Decadal Survey.  To fit within the cost cap, the proposed mission appears to be the bare minimum that can be justified as scientifically credible.  The instrument suite on the probe is bare bones -- compare it to what the Pioneer Venus and Galileo probes carried or what has previously been proposed in studies of Saturn atmospheric probes.  There is no microwave radiometer instrument on the back shell for deep atmosphere composition and structure measurements (this has been proposed in previous studies).  The carrier has no instruments to characterize the state of the atmosphere or the entry site.

I'm not arguing that this wouldn't be a good expenditure of $1B -- it did make the Decadal New Frontiers list.  But this was a case where the proposal team appears to have looked to see what could be done in within a fixed cost cap and didn't look for the scientific sweet spot.

Product and mission definition is a creative process and tension can inspire creativity.  With Europa, $1B simply wouldn't do a credible mission.  For the $1B box studies for Enceladus and Titan, there was presumptions on what was credible mission.  The Enceladus team assumed an orbiter or sample return would be necessary.  They didn't consider (and the technology might not have been in sight then) what far more sensitive mass spectrometers available today might be able to achieve from flybys.  They don't appear to have asked what a Titan mission that mapped only a targeted 25% of the surface might cost and whether such a mission would be worth while.  (A lot of Titan is covered in sand dunes -- do all those dunes need high resolution coverage?  MRO's cameras were designed to image only a tiny fraction of the Martian surface but they were thought worthwhile (although the longevity of the MRO mission has resulted in almost all the surface being imaged at 6 m by CTX)).

I'm hoping that the next Decadal will again return to the question of whether there is a credible New Frontiers class Enceladus and/or Titan mission.  Three Discovery proposal teams (JET, TiME, ELF) have argued that there are credible missions for half the cost.  Perhaps they are optimistic, but would doubling the budget make them credible?  And when Ralph Lorenz, who led the Titan $1B box study, says a credible Titan orbiter could be done for $1B today, I listen.  He may be wrong, but Ralph is one hell of a smart guy and I'd never blow him off.

As Blackstar points out, for a fixed budget, you don't always get a credible scientific mission within a fixed cost cap.  The next Decadal Survey will look at that and proposed New Frontiers missions and judge them on their budgetary and scientific credibility and include only those that make the cut.

However, one thing I learned in my product definition days is that creativity takes time.  If you have a short time period, you take a lot of assumptions as fixed.  You simply don't have time to question the scientific goals.  You don't have time to look at creative scientific solutions.  I think this is why NASA has chartered the Uranus/Neptune studies so far ahead of the next Decadal Survey -- give the teams time to explore multiple creative solutions.  I'm hoping that this is just the start and that NASA will charter more such teams.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 09/21/2015 01:45 am
Since I think that I'm the unnamed somebody, I'll reply. 

Nope. Not you. I heard it from a couple of different space scientists.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 09/21/2015 02:26 am
To take another case, I look at the Saturn probe mission that was proposed in the Decadal Survey.  To fit within the cost cap, the proposed mission appears to be the bare minimum that can be justified as scientifically credible.  The instrument suite on the probe is bare bones -- compare it to what the Pioneer Venus and Galileo probes carried or what has previously been proposed in studies of Saturn atmospheric probes.  There is no microwave radiometer instrument on the back shell for deep atmosphere composition and structure measurements (this has been proposed in previous studies).  The carrier has no instruments to characterize the state of the atmosphere or the entry site.

I'm not arguing that this wouldn't be a good expenditure of $1B -- it did make the Decadal New Frontiers list.  But this was a case where the proposal team appears to have looked to see what could be done in within a fixed cost cap and didn't look for the scientific sweet spot.

I don't know or remember the details of the Saturn probe NF proposal (although that came out of my panel on the DS). But you have to consider that these mission proposals are not point proposals, they are more of a point spread proposal, meaning that the DS defined a set of minimum science requirements for each, but did not get overly prescriptive about them. There are lots of reasons for that, but consider the simple fact that they know that people will take the mission requirements and then make them much more solid and definitive with a proposal. They will actually map the science requirements to actual instruments and technologies and orbits and all of that stuff. And those proposals will have far more detail and will be far more viable than anything that the DS could produce--and they will also be produced years after the DS issued their report. And thus, at a later date (it's now looking like 2018 or so) some reviewers at NASA will look at a bunch of New Frontiers mission proposals and they will be evaluating those, much more concrete proposals. There was no way that a few scientists working for a few months in 2010 could produce anything approaching the kind of detailed proposal that a PI will produce by working with a team for a couple of years prior to a New Frontiers announcement of opportunity.

There was a cautionary tale from the 2002 DS, which defined a New Frontiers mission consisting of a Jupiter magnetospheric orbiter "with probes." That became overly prescriptive, and the Juno PI had a hard time arguing--ultimately successfully--that he could get the same data without probes. But everybody involved in the 2011 DS was aware of that lesson.

The DS can only go so far. It can only say "we think the following things are important" but cannot get too deep in the details on them. And so the people writing up the DS trust future proposers and future reviewers to make better informed decisions. And so it is possible that future reviewers may look at a Saturn probe proposal that meets all the requirements laid out in the DS, and compare it to a South Pole Aitken Basin sample return proposal that also meets all of the requirements laid out in the DS, and determine that the latter (all things being equal) provides more interesting science at that time. (There's a big asterix involved with competed missions--the final deciding authority, when given several options, does not have to make the choice based solely on science, but can make it based upon things like the overall portfolio, budget outlooks, etc.)

Now what you're describing is a bit different than the Juno example, because you're implying that the Saturn probe's science seems rather thin for the cost. But this goes back to my earlier point that they were trying to describe the general qualities of an atmospheric probe mission, not being overly specific, and everybody who works on a Saturn probe mission will be seeking to maximize the science return even above what was listed in the DS.

But it also highlights the fact that a lot of things go into getting a mission prioritized in the DS (in this case, we're talking about the most basic prioritization--getting on the New Frontiers approved missions list, or failing to do so). Part of that is personalities, meaning whoever does the best job of defining a valuable mission. But part of that is overall group dynamics and which arguments resonate at the time with the people who make the decisions. I don't remember much about the Saturn probe discussions, but part of the argument was that the last time a probe had been flown to an outer planet was Galileo in 1995 and that atmospheric science needed a probe in the future, and the earliest we could expect it to happen again would be sometime in the 2020s (or over a quarter century later). But part of that was also a trade-off against other NF missions that were then being racked and stacked. Each DS panel was generally promised one NF proposal. The giant planets panel came up with the Saturn probe because nothing else appealed to them. They knew that the science for that mission was going to be light in order to fit into the cost box, but what were they supposed to do, simply roll over and give their chit to another panel? What would they get in return? All they asked for was an opportunity to compete in New Frontiers and they got one, and now it's up to an enterprising PI to come up with a viable Saturn probe mission for the next New Frontiers competition.

(By the way, I learned a few weeks ago that somebody at JPL is working on such a proposal. Doesn't mean that it will make it to the competition, but at least somebody is going to try.)


Nobody ever claimed the DS was a perfect process, and not everybody is going to be thrilled with the outcomes. But is it good enough? Yeah, it's good enough.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 09/21/2015 03:05 am
I'm hoping that the next Decadal will again return to the question of whether there is a credible New Frontiers class Enceladus and/or Titan mission.  Three Discovery proposal teams (JET, TiME, ELF) have argued that there are credible missions for half the cost.  Perhaps they are optimistic, but would doubling the budget make them credible?

And credible to whom?

Note in my previous long-winded post I noted that there's a trade-off process involved in the DS when it comes to New Frontiers. Each panel generally got one NF slot to start. But there was strategic decision-making along the way. For example, the Mars panel gave up their NF slot. Both VISE and SPAB were generally shoe-ins (they had high scientific support, and they are considered doable). The comet mission was iffier because the cost is so high, but it was sort of a shoe-in as well. Giant planets picked a Saturn probe mission.

The problem for the satellites panel is that they have a bunch of really interesting places to go to, and they cannot get all of them because that wouldn't be fair to the other panels. So they had to pick. They had Europa, Titan, Enceladus and Io (they accepted that the Europeans would do Ganymede). They couldn't get all of them, and maybe if they had been much more ruthless they would have focused in on Europa and then one other mission. But part of the problem was that they could not limit their science requirements for Titan or Enceladus, and so they ended up with bigger missions than they could afford. The Io mission had much more limited science objectives and could fit in a NF box. So it was not simply a matter of having good studies going into the DS, I don't think they could agree on an affordable minimum set of requirements for Titan or Enceladus. If they had, they might have picked that instead of the Io mission. But I think they just spread themselves too thin.

As we all know, science and technology march on. We know a lot more about Enceladus today than in 2010, so it should be easier to define science requirements for a future Enceladus NF mission. But that community will also need to focus and prioritize ahead of time. They cannot chase all the balls.
Title: Re: Proposed Europa Missions
Post by: vjkane on 09/21/2015 11:12 am

And credible to whom?

But part of the problem was that they could not limit their science requirements for Titan or Enceladus, and so they ended up with bigger missions than they could afford. The Io mission had much more limited science objectives and could fit in a NF box. So it was not simply a matter of having good studies going into the DS, I don't think they could agree on an affordable minimum set of requirements for Titan or Enceladus. If they had, they might have picked that instead of the Io mission. But I think they just spread themselves too thin.

As we all know, science and technology march on. We know a lot more about Enceladus today than in 2010, so it should be easier to define science requirements for a future Enceladus NF mission. But that community will also need to focus and prioritize ahead of time. They cannot chase all the balls.
The science teams proposing the Saturn-system Discovery missions have solid credentials.  And all three had either APL or JPL as their implementation partners.  As you pointed out in a previous post, these proposals are too expensive to prepare to back one that obviously won't fit in a Discovery box.  Perhaps the proposers were off by 50% in their cost estimates.  That would still put them in a New Frontiers box.

I think the rest of your reply pretty much nails the central issue.  A New Frontiers Enceladus or Titan mission may be affordable, but only with a good deal of scientific discipline.  Look at what the Saturn atmospheric probe concept gave up to fit in the box.  The Discovery proposal teams have taken the discipline to focus their science.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 09/21/2015 12:33 pm

The science teams proposing the Saturn-system Discovery missions have solid credentials.


You misunderstand me because I was not clear. I'm not referring to those specific proposals. I'm referring to who decides what is credible and at what point? Well, there are multiple stages of that, with the DS being one of them and then a later New Frontiers competition being another. The members of a DS panel can hear about a proposal and decide that maybe that science is or is not worth it. But all those decisions are happening in a complex system of trade-offs and compromises. It could turn out that in the next DS there are entirely worthwhile and affordable Titan, Enceladus and Io missions in the New Frontiers class, but the satellites panel (assuming that there is a satellites panel in the next DS) is probably not going to get to propose three New Frontiers missions, they're going to have to pick only one, or at most, two. So we should not get too wrapped up in the issue of "credibility" because there are a lot of factors that determine the outcome.

In the last DS it might have been possible to come up with a decent New Frontiers class Titan mission, but the people making the choices decided that any future Titan mission had to be flagship class. And once they started down that path, they didn't look at smaller and less ambitious missions. Now maybe that was a really bad decision, considering that the Titan mission they looked at ended up costing $7 billion plus, but that's what they did.
Title: Re: Proposed Europa Missions
Post by: vjkane on 09/23/2015 01:38 am
Another article this time from Space News on Pu-238 supply and future missions.  http://spacenews.us10.list-manage.com/track/click?u=75806695e6f086874391c9624&id=93974ecb96&e=fa0fd80c45
Title: Re: Proposed Europa Missions
Post by: Blackstar on 09/23/2015 02:24 am
Another article this time from Space News on Pu-238 supply and future missions.  http://spacenews.us10.list-manage.com/track/click?u=75806695e6f086874391c9624&id=93974ecb96&e=fa0fd80c45


The article says this:

"Where no alternative for a radioisotope power appears possible, NASA has simply taken a pass. Such was the case in 2012 when NASA passed on two nuclear-powered missions and selected the solar-powered Mars lander InSight as its 12th Discovery mission."

That's kind of an odd way to put it. The missions under consideration, TiME and CHOPPER, would have used ASRGs. We don't know why NASA selected InSight instead of one of those missions (my guess is a-cost, and b-NASA wanted to do a Mars mission), but if they had selected one of them, NASA would have had to continue funding the ASRG.
Title: Re: Proposed Europa Missions
Post by: Vultur on 09/27/2015 04:33 pm
The problem for the satellites panel is that they have a bunch of really interesting places to go to, and they cannot get all of them because that wouldn't be fair to the other panels. So they had to pick.

Is that good for planetary science as a whole? If there is more interesting stuff in the satellites it seems to me they should get more missions...
Title: Re: Proposed Europa Missions
Post by: GClark on 09/27/2015 05:27 pm
Is that good for planetary science as a whole? If there is more interesting stuff in the satellites it seems to me they should get more missions...

The job of the Decadal Survey is to recommend a balanced portfolio of missions.  Thus, no matter how many compelling missions any one panel can come up with, they only get to recommend one or two to the final list(s).  It enforces some discipline on the panelists - pick the very best.
Title: Re: Proposed Europa Missions
Post by: vjkane on 09/27/2015 05:32 pm
That's kind of an odd way to put it. The missions under consideration, TiME and CHOPPER, would have used ASRGs. We don't know why NASA selected InSight instead of one of those missions (my guess is a-cost, and b-NASA wanted to do a Mars mission), but if they had selected one of them, NASA would have had to continue funding the ASRG.
If I remember correctly, the ASRG program was facing some serious development problems, something like a year or two behind and $100M over budget.  (Anyone have a better memory or old article filing system?)  Selecting either of those two missions might well have meant a serious increase in mission cost to cover the ASRG and a slip in the mission launch date.  NASA has said that the ASRG problems was not a factor in deciding to select InSight; maybe there were issues such as seriously greater development risk with TiME and CHopper.  We'll never know.
Title: Re: Proposed Europa Missions
Post by: vjkane on 09/27/2015 05:44 pm
job of the Decadal Survey is to recommend a balanced portfolio of missions.  Thus, no matter how many compelling missions any one panel can come up with, they only get to recommend one or two to the final list(s).  It enforces some discipline on the panelists - pick the very best.
GClark got it exactly right.  The outer planets panel got the Saturn probe, small bodies got a comet sample return and a Trojan asteroid review, and inner planets got a lunar sample return and Venus lander.  Since it appears there will be only one selection during the period of the current Decadal, adding more candidates doesn't really help.  If there had been two selections then an Io mission and a lunar network mission would have been added to the list.

Reading tea leaves for the next Decadal, the outer planets panel will have to choose among the Saturn probe, Io mission, a Titan mission, and an Enceladus mission.  It's likely they will get just two slots.  It may be that the Io mission could be done as a Discovery mission (at least McEwan thinks so, and he's pretty credible).  The Decadal Panel might simply list a Saturn icy moon mission and let individual proposers specify how the science gets divided between Titan and Enceladus.  A mission that focuses on one can always do some flybys of the other.  This idea may break down if the next Decadal decides that the next mission to Titan should be either a lake lander or a balloon since either would leave the carrier craft with pretty minimal capabilities unless another space agency contributes either the Titan probe or the carrier.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 09/27/2015 05:46 pm
The problem for the satellites panel is that they have a bunch of really interesting places to go to, and they cannot get all of them because that wouldn't be fair to the other panels. So they had to pick.

Is that good for planetary science as a whole? If there is more interesting stuff in the satellites it seems to me they should get more missions...

But who says there's more interesting stuff in the satellites? There are plenty of Mars scientists who don't care one bit about Titan or Io or Europa. There are plenty of people who care more about giant planets than they do about their satellites.

There's actually no way to divide all of this stuff up that will satisfy everybody. I've heard people complain that Mars was a separate panel and it really should have been lumped in with the inner planets panel, where it would have coexisted with Mercury, Venus and the Moon. But if we did it that way, then Mars would have dominated that panel because Mars research and interest--and political support--is substantial. So you have to make choices, and the choices that the steering committee came up with were: inner planets, Mars, giant planets, primitive bodies, and satellites.

As somebody already noted above, the DS puts a framework on the planetary science community and seeks to achieve a certain balance, so that all of the subcommunities get a shot. It's the most equitable way to do it.

Title: Re: Proposed Europa Missions
Post by: Blackstar on 09/27/2015 05:50 pm
The outer planets panel got the Saturn probe, small bodies got a comet sample return and a Trojan asteroid review, and inner planets got a lunar sample return and Venus lander.  Since it appears there will be only one selection during the period of the current Decadal, adding more candidates doesn't really help.  If there had been two selections then an Io mission and a lunar network mission would have been added to the list.

I'd highlight the fact that the Moon got two shots at New Frontiers in the DS. That's significant (no other target got two opportunities). But I was at a LEAG meeting a few years ago and a lunar scientist complained that the Moon got short shrift in the Decadal Survey. It just goes to show that somebody will always complain that their slice of pie is not big enough, even if it's bigger than everybody else's. And they'll always find a reason to justify a larger slice of the pie. So that's why we establish rules and try to enforce them.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 09/27/2015 05:53 pm
If I remember correctly, the ASRG program was facing some serious development problems, something like a year or two behind and $100M over budget.  (Anyone have a better memory or old article filing system?)  Selecting either of those two missions might well have meant a serious increase in mission cost to cover the ASRG and a slip in the mission launch date.  NASA has said that the ASRG problems was not a factor in deciding to select InSight; maybe there were issues such as seriously greater development risk with TiME and CHopper.  We'll never know.

Your memory jibes with mine on that. Of course the ASRG was being paid for by NASA separate from the Discovery budget, so the costs would not have sunk Discovery itself. But that would have required money to come out of something else in the planetary budget.

With some of the recent squawking from Ohio about reviving the ASRG, we should remember that it was not in good shape a few years ago. I'd like to see that program revived, but it needs money and NASA doesn't have that money at the moment. Also probably needs very careful management and oversight as well. We don't know what was falling apart just before cancellation, but that big cost overrun indicates that they were doing something wrong with the development program.
Title: Re: Proposed Europa Missions
Post by: Alpha_Centauri on 10/06/2015 07:51 am
ESA has released the preliminary studies it conducted into additions to the Clipper mission that will inform any cooperation proposal, thought these might be of interest.

http://sci.esa.int/trs/56474-clipper-esa-orbiter-cleo-and-clipper-esa-penetrator-clep/

CLEO/I - Clipper ESA Orbiter/Io would be a Jupiter orbiter that conducts close flybys of Io [or alternatively CLEO/E a Europa flyby mission for plume studies, though this seems less favoured]
http://sci.esa.int/science-e/www/object/doc.cfm?fobjectid=56432 (Large PDF)

Or

CLEP - Clipper ESA Penetrator [Europa]
http://sci.esa.int/science-e/www/object/doc.cfm?fobjectid=56433 (Large PDF)
Title: Re: Proposed Europa Missions
Post by: notsorandom on 10/06/2015 01:26 pm
Thanks for posting that information about ESA's potential contributions. There are a few interesting items of note. The proposal for the Io/Europa Clipper ESA Orbiter (CLEO) at least now retains the Clipper name thought he document notes that NASA has changed the mission's name. The Io version of CLEO is 16.75 kg overweight. One for dealing with this are to have the spacecraft make only one flyby on a hyperbolic course out of the Jovian system. The Europa version of the craft is not overweight but its science is less compelling to ESA. It would study the plumes. Though at this point they have not been confirmed as existing so its a gamble if CLEO would have anything to do when it got there. There is a trade for both options to use EM as a relay or independently communicate back to Earth.

The second option is a penetrator (CLEP). CLEP consists of two parts the penetrator and Penetrator Delivery System. The PDS preforms the targeting and breaking, bringing the penetrator down to an impact velocity of 300 m/s. A lander was determined to not fit withing the mass budget. The penetrator would require 4 dedicated Europa flybys from EM in order to position the penetrator for release and serve as a communications relay. The PDS uses a Star 24 solid rocket with a mass of 218.1 kg and delivering 2.66 km/s of breaking Delta V.  The targeting accuracy is an ellipse 300km wide.
Title: Re: Proposed Europa Missions
Post by: vjkane on 10/06/2015 01:48 pm
I'll have a blog post on these two studies in a week or so.  One other note on the Io option is that to get almost within the weight limit, the spacecraft design sacrifices redundancy.  Perhaps a risky move given the radiation.

Also, I think these are proof of concept studies (they were finished about a year ago I believe although just recently posted), and I haven't read anything that says that these are the only options to be considered.  ESA could also do a Europa multifly craft to greatly increase the number of gravity and magnetometer measurements, both of which need as many flybys as possible.  ESA could do a Jupiter orbiter that constantly watches Jupiter's weather and/or Io's volcanoes.  If I can think of alternatives, the professionals could do a lot better.
Title: Re: Proposed Europa Missions
Post by: Alpha_Centauri on 10/06/2015 02:15 pm
Correct these are proof of concepts, the idea is to provide an evidence base to teams interested in proposing a cooperative Europa mission to CV mission calls. Other concepts of course can be proposed, but it is likely that if a mission is proposed it will be some kind of variation of the above.
Title: Re: Proposed Europa Missions
Post by: notsorandom on 10/06/2015 02:24 pm
All of these ESA proposals are independent spacecraft and not add-on instruments to the EM spacecraft. There has to be a good reason for that. Perhaps it is because as they said about the CLEO Europa option there isn't much extra science beyond what EM can do aside from looking at the plumes which would need an independent spacecraft.
Title: Re: Proposed Europa Missions
Post by: Alpha_Centauri on 10/06/2015 03:02 pm
Having clean interfaces in cooperations is favoured by NASA as any scheduling issues that may affect the contributed element cause far less risk to the main mission.  It also avoids complicated funding arrangements.
Title: Re: Proposed Europa Missions
Post by: vjkane on 10/06/2015 03:09 pm
I think that one reason for an independent spacecraft as opposed to an attached instrument is that there's fairly little time for non-Europa observations.  The spacecraft collects a lot of data at each flyby and then spends most of the rest of orbit dumping it to Earth.  Since the antenna is fixed to the spacecraft, the instruments can't be pointed to another target.  As I remember from past presentations, there's some slack in each orbit, but there didn't appear to be enough for observing campaigns like JUICE will do prior to entering Ganymede orbit.

And a clean interface is easier than adding an instrument that has to be powered, managed, and fitted into an already crowded instrument deck.

A question for anyone knowledgeable about the ESA M5 call.  As I recall, the M5 mission is expected to launch in the late 2020s (M4 in the mid-2020s, I believe).  This is several years later than the most pessimistic NASA Europa mission launch that I've seen.  How are these two schedules reconciled?
Title: Re: Proposed Europa Missions
Post by: notsorandom on 10/06/2015 03:56 pm
It looks like most of these ESA proposals would need EM to act as a relay. Add-on instruments would be able to use more of the mass and money budget as there is less other stuff needed. So more instruments means more data to transmit vs less instruments on an independent spacecraft. To keep things as neat a clean as possible an instrument package could be largely independent sharing only power and communications. Sort of how Philae acted when Rosetta flew by Mars.

It seems like add-ons to EM would get more science for the buck. That could be untrue however. EM already has a capable instrument suite and there might not be much else to do withing the orbit and capabilities of the EM spacecraft.
Title: Re: Proposed Europa Missions
Post by: Alpha_Centauri on 10/06/2015 04:00 pm
A question for anyone knowledgeable about the ESA M5 call.  As I recall, the M5 mission is expected to launch in the late 2020s (M4 in the mid-2020s, I believe).  This is several years later than the most pessimistic NASA Europa mission launch that I've seen.  How are these two schedules reconciled?

M missions are scheduled for relatively long development phases and some technology development.  The launch dates are indicative of this, but are not set in stone. If a mission is proposed requiring little development and can be built on a shorter schedule then the launch can be earlier.

That said, it just occurred to me that these concept missions seem scaled smaller than a typical M mission.  And of course no launch cost, which normally comes from the mission budget. I wonder if they may be looking to run them on an S class mission with significant national instrument contributions?  Note the blurb doesn't actually state it's for M-class CV.  S3 should launch far sooner than M5.
Title: Re: Proposed Europa Missions
Post by: as58 on 10/06/2015 06:01 pm
A question for anyone knowledgeable about the ESA M5 call.  As I recall, the M5 mission is expected to launch in the late 2020s (M4 in the mid-2020s, I believe).  This is several years later than the most pessimistic NASA Europa mission launch that I've seen.  How are these two schedules reconciled?

From ESA's announcement of upcoming M5 call (http://sci.esa.int/cosmic-vision/56198-announcement-of-the-plans-for-the-issuing-of-a-call-for-a-medium-size-mission-for-launch-in-2029-2030-m5/):
Quote
The planned launch date for the M5 mission is 2029-2030. The actual launch date of the mission is likely to be driven by the mission's complexity and development schedule, rather than by the budget profile. In particular, missions of lower complexity (and thus likely of lower cost) might have a faster development schedule and thus an earlier launch date. The actual launch date for missions with enabling international participation (i.e., missions for which the implementation schedule depends on significant contributions from a partner) or for contributions to partner-led missions is likely to be driven in large part by the partner's technical schedule, and not necessarily by the ESA budget profile.

It seems that a contribution to a partner-led mission could be done much sooner than late 2020s. Probably not as soon as 2022-23, but I doubt NASA Europa mission is launching quite that soon either.
Title: Re: Proposed Europa Missions
Post by: denis on 10/06/2015 07:02 pm
A question for anyone knowledgeable about the ESA M5 call.  As I recall, the M5 mission is expected to launch in the late 2020s (M4 in the mid-2020s, I believe).  This is several years later than the most pessimistic NASA Europa mission launch that I've seen.  How are these two schedules reconciled?

M missions are scheduled for relatively long development phases and some technology development.  The launch dates are indicative of this, but are not set in stone. If a mission is proposed requiring little development and can be built on a shorter schedule then the launch can be earlier.

That said, it just occurred to me that these concept missions seem scaled smaller than a typical M mission.  And of course no launch cost, which normally comes from the mission budget. I wonder if they may be looking to run them on an S class mission with significant national instrument contributions?  Note the blurb doesn't actually state it's for M-class CV.  S3 should launch far sooner than M5.

I think you are right, the target mass is 250kg which makes it similar size than CHEOPS (S1) and much smaller than other M-class missions (1.5 to 2 tons).

The website says "... in defining a potential mission of opportunity...". Missions of opportunity are missions that do not necessarily fall in the predefined schedule of S/M/L missions of the science program (the only part of ESA that is compulsory to member states). So if there is a good concept with enough interest of some member states who are willing to finance it, the mission could be adopted without taking on of the existing S slots (or a new S slot could be added).
Title: Re: Proposed Europa Missions
Post by: as58 on 10/06/2015 07:36 pm

I think you are right, the target mass is 250kg which makes it similar size than CHEOPS (S1) and much smaller than other M-class missions (1.5 to 2 tons).

The website says "... in defining a potential mission of opportunity...". Missions of opportunity are missions that do not necessarily fall in the predefined schedule of S/M/L missions of the science program (the only part of ESA that is compulsory to member states). So if there is a good concept with enough interest of some member states who are willing to finance it, the mission could be adopted without taking on of the existing S slots (or a new S slot could be added).

In the same sentence it also says "... in the frame of future Cosmic Vision calls." Huygens wasn't much larger (318 kg), and it was the first medium-size mission in Horizon 2000.
Title: Re: Proposed Europa Missions
Post by: vjkane on 10/06/2015 07:58 pm
Any kind of a lander would probably have so much tech development required that it would at least be a Medium class mission.

The Io probe as listed, has to act as an independent spacecraft with propulsion and deep space communications, so that feels like Medium rather than small class.

A Jupiter/Io continuous observatory that basically gets dropped by NASA's craft into a Jupiter orbit might be more like CHEOPS and might be a Small class mission (although there are lots of design differences between Earth and Jupiter orbits).
Title: Re: Proposed Europa Missions
Post by: redliox on 10/06/2015 08:28 pm
I definitely like how ESA's offered some great options to the Europa mission.  The Io craft would be the most useful and unique, although of course radiation and fuel would be the biggest challenges; until something like the Io Observer could be sent it'd be the best shot as some decent fresh data on Io, outside of the 'Clipper doing some distant imaging.  The Europa Penetrator would be the second best idea although it seems to be almost exclusively seismic data it'd gather (but still hella-useful), while the Europa craft might be useful at least since it'd carry a more extensive mass spectrometer versus the neutral one 'Clipper is stuck with; otherwise not sure what a tiny Europa craft could offer the 'Clipper itself wouldn't already be doing.
Title: Re: Proposed Europa Missions
Post by: vjkane on 10/06/2015 08:43 pm
I definitely like how ESA's offered some great options to the Europa mission. 
Just to be clear, these are proof of concept studies, not "offers"
Title: Re: Proposed Europa Missions
Post by: Alpha_Centauri on 10/06/2015 09:18 pm
Now I've had the chance to take a deeper look I see there are small mentions of need to fit an M cost cap in the reports.

In the same sentence it also says "... in the frame of future Cosmic Vision calls." Huygens wasn't much larger (318 kg), and it was the first medium-size mission in Horizon 2000.

Mass doesn't matter so much, complexity does.  These are simpler, more focused, concepts than Huygens. And even then Huygens came out at what would be the cheaper end of a modern Cosmic Vision M mission.  In the case of the Io option, that probe has more in common with SMART 1 which cost ~ 100 MEuro. I suspect the Io probe especially would come far under cap.
Title: Re: Proposed Europa Missions
Post by: Star One on 10/30/2015 09:14 pm
Blogging on the possible ESA ride along passenger.

http://futureplanets.blogspot.co.uk/2015/10/a-european-spacecraft-to-accompany.html?m=1
Title: Re: Proposed Europa Missions
Post by: yokem55 on 11/17/2015 06:50 pm
Arstechnica has a somewhat fluffy piece on the efforts of Rep. Culburtson to get a soft lander added to the Europa mission. http://arstechnica.com/science/2015/11/attempt-no-landing-there-yeah-right-were-going-to-europa/ (http://arstechnica.com/science/2015/11/attempt-no-landing-there-yeah-right-were-going-to-europa/)
Title: Re: Proposed Europa Missions
Post by: Blackstar on 11/17/2015 08:23 pm
Arstechnica has a somewhat fluffy piece on the efforts of Rep. Culburtson to get a soft lander added to the Europa mission. http://arstechnica.com/science/2015/11/attempt-no-landing-there-yeah-right-were-going-to-europa/ (http://arstechnica.com/science/2015/11/attempt-no-landing-there-yeah-right-were-going-to-europa/)

"The JPL engineers have concluded the best way to deliver the lander to Europa’s jagged surface is by way of a sky crane mechanism, like the one successfully used in the last stage of Curiosity’s descent to the surface of Mars. With four steerable engines and an autonomous system to avoid hazards, the lander would be lowered to the moon’s surface by an umbilical cord.

Although the SLS rocket has been designed to lift as much as 70 tons into low-Earth orbit, it can only propel a small fraction of that across the 800 million kilometers of space to Jupiter, and fuel and the Clipper will consume most of that mass. The engineers have calculated they can spare a total of about 510 kg for the sky crane and lander, and of the 230 kg lander, about 20 to 30 kg can be given over to scientific instruments. That may seem slight, but it’s equivalent to what the Spirit and Opportunity rovers had to work with on Mars.

That payload would contain a mass spectrometer to identify any complex biological molecules. The engineers are also trying to add a second type of spectrometer, based on Raman scattering, to provide independent confirmation of any significant findings. “Honestly,” Culberson said, “if you’re going to go all that way to determine if there’s life on another world, why wouldn’t you double-check it?”

To gather samples for the spectrometers, the lander will have a scooper and sampling arm with at least one set of counter-rotating saw blades that could penetrate to a depth of about 10 cm. At Europa’s low surface temperatures, its ice is harder than steel."

And

"Scientists will attempt to find this hardware a landing site near an active crevasse. If the Hubble telescope data is correct, this would offer a potential opening to the ocean far below. Ideally, if the lander can be placed near a vent, it might sample spouts from the ocean below. The engineers are also working through the feasibility of more exotic options, such as bots that might detach from the lander and examine the crevasses.

On Europa’s harsh surface, the battery-powered lander would have about a 10-day lifespan, although solar cells might extend that further. But with dim sunlight and continual radiation, the lander’s functional time would necessarily be short.

Finally, the JPL engineers are working on a “plume probe,” not as part of the lander but which would detach from the Clipper and fly close to the moon’s surface, perhaps 2 km or lower, to obtain samples and relay that data back to the Clipper."
Title: Re: Proposed Europa Missions
Post by: Blackstar on 11/17/2015 08:46 pm
Something from that article:

"It’s not clear why NASA ultimately embraced the Europa mission."

Actually, it was not NASA that was opposed to the Europa mission, and it was not NASA that "ultimately embraced" the mission. It was up to the Office of Management and Budget to decide to include a Europa new start in the president's budget request. And there is nothing all that mysterious about it--OMB kept putting in zero dollars for Europa and Congress (Culberson) kept adding in big piles of money for Europa. This went on for a few years, and it is an inefficient way to do anything. It also puts OMB behind the cart getting dragged rather than in front of the cart doing the pulling. So OMB gave in and added the money for Europa. NASA was stuck between Congress and OMB on this one.
Title: Re: Proposed Europa Missions
Post by: vjkane on 11/17/2015 08:47 pm
Oy vey.  Mission goals have the potential to explode until the whole thing gets killed.

Much better to set up a program of missions like was done at Mars.

And I'm not surprised about the skycrane.  Mars is just pesky with that atmosphere requiring a heat shield.  Terminal terrain navigation could search for relatively small spots of smoothness.  I would be surprised if the lander didn't end up something like Mars Pathfinder, with petals for self righting (the interesting places appear to have really rough surfaces).  Petals could also have solar cells.

Hmmm, how about a small rover.

20-30 kg of instruments would allow a really rich scientific payload, although its not clear if that's just instruments or all the equipment needed to power, operate, and return data from the instruments.  If the latter, then it's really tight.
Title: Re: Proposed Europa Missions
Post by: Malderi on 11/17/2015 08:59 pm
Oy vey.  Mission goals have the potential to explode until the whole thing gets killed.

Much better to set up a program of missions like was done at Mars.

And I'm not surprised about the skycrane.  Mars is just pesky with that atmosphere requiring a heat shield.  Terminal terrain navigation could search for relatively small spots of smoothness.  I would be surprised if the lander didn't end up something like Mars Pathfinder, with petals for self righting (the interesting places appear to have really rough surfaces).  Petals could also have solar cells.

Hmmm, how about a small rover.

20-30 kg of instruments would allow a really rich scientific payload, although its not clear if that's just instruments or all the equipment needed to power, operate, and return data from the instruments.  If the latter, then it's really tight.


Power will be very tight. Radiation tolerance will be really tough. The electronics on this thing are going to present a very, very interesting challenge. Downlink will be a pain since the Clipper will be flying off into the sunset, so either they'll do some interesting orbits with the mothership or get very small windows of downlink (or get very, very tiny windows of direct to Earth bandwidth).
Title: Re: Proposed Europa Missions
Post by: yokem55 on 11/17/2015 09:46 pm
From the article:
Quote
At that time, the massive Space Launch System rocket NASA is developing could deliver it to Jupiter in 4.6 years. Once there, the lander would separate from the Clipper, parking in a low-radiation orbit.

Any guesses as to how much delta-v it would take to take the lander from a relatively high, but low-radiation Jupiter orbit to a soft landing on Europa? And what kind of propulsion system would that take? Hydrazine? A Star-xx solid?
Title: Re: Proposed Europa Missions
Post by: vjkane on 11/17/2015 09:48 pm
From the article:
Quote
At that time, the massive Space Launch System rocket NASA is developing could deliver it to Jupiter in 4.6 years. Once there, the lander would separate from the Clipper, parking in a low-radiation orbit.

Any guesses as to how much delta-v it would take to take the lander from a relatively high, but low-radiation Jupiter orbit to a soft landing on Europa? And what kind of propulsion system would that take? Hydrazine? A Star-xx solid?
They would probably do gravity assists for changing the orbit, but only the minimum number needed.  Clipper will do many more to find the right landing site.

Given this architecture, the lander is a full spacecraft in its own right and could launch later.
Title: Re: Proposed Europa Missions
Post by: zubenelgenubi on 11/17/2015 10:45 pm
Europa orbiter/lander mission design question:

Europa orbits within the co-rotating inner section of Jupiter's magnetosphere.

The magnetospheric plasma, sweeping around Jupiter at approximately once/10 hours, would constantly "lap" Europa, which completes one orbit in approximately 3.5 days.

Europa is a synchronous rotator ("day" = "year").

Could a Europan orbiter use a Molniya or Tundra type orbit, with "apo-Europa" above the leading Europan hemisphere?

The orbiter would stay in the "shadow" of the Jovian magnetosphere (relatively speaking--I'm sure it will still be exposed to some radiation inside any magnetic "shadow") as much as possible.  And, the orbiter would return to "hover" at apo-Europa over the same region repetitively--perhaps over a lander's latitude/longitude?

The lander would not have continuous communication with the orbiter, but it would have regular, predictable communications windows.  And there would be more windows, as the orbiter would survive longer than otherwise.
Title: Re: Proposed Europa Missions
Post by: vjkane on 11/17/2015 10:58 pm
Europa orbiter/lander mission design question:

Europa orbits within the co-rotating inner section of Jupiter's magnetosphere.

The magnetospheric plasma, sweeping around Jupiter at approximately once/10 hours, would constantly "lap" Europa, which completes one orbit in approximately 3.5 days.

Europa is a synchronous rotator ("day" = "year").

Could a Europan orbiter use a Molniya or Tundra type orbit, with "apo-Europa" above the leading Europan hemisphere?

The orbiter would stay in the "shadow" of the Jovian magnetosphere (relatively speaking--I'm sure it will still be exposed to some radiation inside any magnetic "shadow") as much as possible.  And, the orbiter would return to "hover" at apo-Europa over the same region repetitively--perhaps over a lander's latitude/longitude?

The lander would not have continuous communication with the orbiter, but it would have regular, predictable communications windows.  And there would be more windows, as the orbiter would survive longer than otherwise.

As your question/analysis implies, the leading hemisphere receives much less radiation than the trailing.  Analyses of orbiter lifetimes always take this into account. 

My guess is that any lander would have direct to Earth communications for a critical subset of the data.  Galileo managed 10 bps with a low gain antenna.  An antenna such as Curiosity carries (or as it may be substantially enhanced for the 2020 rover, would do much better).  Spectroscopy experiments produce relatively low data rates.  Its the imaging and seismography that kills you.
Title: Re: Proposed Europa Missions
Post by: notsorandom on 11/18/2015 01:34 am
...Given this architecture, the lander is a full spacecraft in its own right and could launch later.
The lander would need to loiter for a while while a good landing site was found. That implies a power system which can keep it going while in orbit around Jupiter. I wonder if they would try to use that same system on the surface or jettison it like the cruise stage of the Mars lander.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 11/18/2015 11:49 am
...Given this architecture, the lander is a full spacecraft in its own right and could launch later.
The lander would need to loiter for a while while a good landing site was found. That implies a power system which can keep it going while in orbit around Jupiter. I wonder if they would try to use that same system on the surface or jettison it like the cruise stage of the Mars lander.

Go back and look at the JPL study of a Europa lander around 2012 or so. I probably posted it up-thread.
Title: Re: Proposed Europa Missions
Post by: notsorandom on 11/18/2015 01:49 pm
...Given this architecture, the lander is a full spacecraft in its own right and could launch later.
The lander would need to loiter for a while while a good landing site was found. That implies a power system which can keep it going while in orbit around Jupiter. I wonder if they would try to use that same system on the surface or jettison it like the cruise stage of the Mars lander.

Go back and look at the JPL study of a Europa lander around 2012 or so. I probably posted it up-thread.
As VJKane said the lander would essentially be a separate spacecraft. Either launched together with the Europa Mission or not. I'm wondering how it would be powered. The Europa Mission will be solar. That solution seems to be harder to pull off for a lander. The arrays might be big and bulky and less tolerant to gee forces from the landing engines. I reread the presentations you suggested. They discuss either RTG power or batteries. That study also assumed that the orbiter would carry the lander until shortly before the landing. With the lander loitering separately waiting for a good landing site to be found that would seem to make batteries alone a much less favorable trade. If they use an RTG then the power issues become much less of a concern yet the orbiter itself is using solar.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 11/18/2015 04:35 pm
As VJKane said the lander would essentially be a separate spacecraft. Either launched together with the Europa Mission or not. I'm wondering how it would be powered. The Europa Mission will be solar. That solution seems to be harder to pull off for a lander. The arrays might be big and bulky and less tolerant to gee forces from the landing engines. I reread the presentations you suggested. They discuss either RTG power or batteries. That study also assumed that the orbiter would carry the lander until shortly before the landing. With the lander loitering separately waiting for a good landing site to be found that would seem to make batteries alone a much less favorable trade. If they use an RTG then the power issues become much less of a concern yet the orbiter itself is using solar.

Just to clarify, I think we have diverged a bit here.

What JPL is currently looking at is a lander that would accompany the Europa Clipper spacecraft on its mission. So far that has been conceived as a mini lander, relatively small and simple. (Of course, the article indicates that they have settled on a skycrane landing system--how simple does that sound?)

However, I believe that what we started to discuss a few posts ago (vjkane referred to the lander "launching later") was how to do an entirely separate lander spacecraft.

Any lander is going to need some high resolution photos of the potential landing site. That is going to require that the Clipper make some passes to get those photos before any lander is deployed. Also, note that in the article JPL is talking about a high degree of autonomy in the landing system, including hazard avoidance. That has not been flown yet, and nothing like what they are proposing for the lander has even been tested. So, they've got--what?--under six years to design, develop, and test an entirely new technology. And this is something that they've been studying for about nine months now, right?

(As an aside: I wonder about guidance and control reliability requirements in a high radiation environment. Imagine that your little lander is coming down to land and is about to deploy from the skycrane and a stray electron or neutron or whatever else is whizzing around in that environment just above Europa smacks into just the right spot on the control computer circuitry. Will it cause a reset just at the worst possible time? I am far from an expert here, but it strikes me that there's a difference between using a skycrane at Mars and using one at Europa where the radiation is higher. You're going to need more redundancy and reliability and stuff. Gotta work all those angles.)

And how much is it going to cost?
Title: Re: Proposed Europa Missions
Post by: zubenelgenubi on 11/18/2015 07:04 pm
Europa orbiter/lander mission design question:

Europa orbits within the co-rotating inner section of Jupiter's magnetosphere.

The magnetospheric plasma, sweeping around Jupiter at approximately once/10 hours, would constantly "lap" Europa, which completes one orbit in approximately 3.5 days.

Europa is a synchronous rotator ("day" = "year").

Could a Europan orbiter use a Molniya or Tundra type orbit, with "apo-Europa" above the leading Europan hemisphere?

The orbiter would stay in the "shadow" of the Jovian magnetosphere (relatively speaking--I'm sure it will still be exposed to some radiation inside any magnetic "shadow") as much as possible.  And, the orbiter would return to "hover" at apo-Europa over the same region repetitively--perhaps over a lander's latitude/longitude?

The lander would not have continuous communication with the orbiter, but it would have regular, predictable communications windows.  And there would be more windows, as the orbiter would survive longer than otherwise.

As your question/analysis implies, the leading hemisphere receives much less radiation than the trailing.  Analyses of orbiter lifetimes always take this into account. 

My guess is that any lander would have direct to Earth communications for a critical subset of the data.  Galileo managed 10 bps with a low gain antenna.  An antenna such as Curiosity carries (or as it may be substantially enhanced for the 2020 rover, would do much better).  Spectroscopy experiments produce relatively low data rates.  Its the imaging and seismography that kills you.

Thanks for the information.  I guessed, but did not KNOW, such details of mission planning.

Also, I didn't know that seismography data is high data-rate.  If it's not too off-topic, how so?
Title: Re: Proposed Europa Missions
Post by: vjkane on 11/18/2015 07:32 pm
Europa orbiter/lander mission design question:

Europa orbits within the co-rotating inner section of Jupiter's magnetosphere.

The magnetospheric plasma, sweeping around Jupiter at approximately once/10 hours, would constantly "lap" Europa, which completes one orbit in approximately 3.5 days.

Europa is a synchronous rotator ("day" = "year").

Could a Europan orbiter use a Molniya or Tundra type orbit, with "apo-Europa" above the leading Europan hemisphere?

The orbiter would stay in the "shadow" of the Jovian magnetosphere (relatively speaking--I'm sure it will still be exposed to some radiation inside any magnetic "shadow") as much as possible.  And, the orbiter would return to "hover" at apo-Europa over the same region repetitively--perhaps over a lander's latitude/longitude?

The lander would not have continuous communication with the orbiter, but it would have regular, predictable communications windows.  And there would be more windows, as the orbiter would survive longer than otherwise.

As your question/analysis implies, the leading hemisphere receives much less radiation than the trailing.  Analyses of orbiter lifetimes always take this into account. 

My guess is that any lander would have direct to Earth communications for a critical subset of the data.  Galileo managed 10 bps with a low gain antenna.  An antenna such as Curiosity carries (or as it may be substantially enhanced for the 2020 rover, would do much better).  Spectroscopy experiments produce relatively low data rates.  Its the imaging and seismography that kills you.

Thanks for the information.  I guessed, but did not KNOW, such details of mission planning.

Also, I didn't know that seismography data is high data-rate.  If it's not too off-topic, how so?

Capable seismometers observe at high time frequencies across a large number frequencies with high fidelity.  The InSight seismometer will produce a nominal 48Mbits/sol.  That is likely with a lot of pre-processing of the data to compress it and to return higher fidelity for likely events.  One problem with pre-processing it is that you need to know what signals you are looking for.  I suspect that InSight will have periods were they return larger amounts of no or less processed data so they can analyze them on Earth to learn what those signals look like.  (This is had been the proposed strategy for previous Martian seismometer experiments; I'm extrapolating that InSight will do something similar.)  A Europan lander won't have time for sending back uncompressed data to allow tuning of future returns.  The radiation would have killed it.

That said, a Europa seismometer might look for only the big, noisy events and could ignore many frequencies and compress more.  That said, I'm sure you're still looking at Mbits/Earth day.

http://www.lpi.usra.edu/meetings/lpsc2012/pdf/1493.pdf
Title: Re: Proposed Europa Missions
Post by: llanitedave on 11/18/2015 07:42 pm
Arstechnica has a somewhat fluffy piece on the efforts of Rep. Culburtson to get a soft lander added to the Europa mission. http://arstechnica.com/science/2015/11/attempt-no-landing-there-yeah-right-were-going-to-europa/ (http://arstechnica.com/science/2015/11/attempt-no-landing-there-yeah-right-were-going-to-europa/)

"The JPL engineers have concluded the best way to deliver the lander to Europa’s jagged surface is by way of a sky crane mechanism, like the one successfully used in the last stage of Curiosity’s descent to the surface of Mars. With four steerable engines and an autonomous system to avoid hazards, the lander would be lowered to the moon’s surface by an umbilical cord.

Although the SLS rocket has been designed to lift as much as 70 tons into low-Earth orbit, it can only propel a small fraction of that across the 800 million kilometers of space to Jupiter, and fuel and the Clipper will consume most of that mass. The engineers have calculated they can spare a total of about 510 kg for the sky crane and lander, and of the 230 kg lander, about 20 to 30 kg can be given over to scientific instruments. That may seem slight, but it’s equivalent to what the Spirit and Opportunity rovers had to work with on Mars.

That payload would contain a mass spectrometer to identify any complex biological molecules. The engineers are also trying to add a second type of spectrometer, based on Raman scattering, to provide independent confirmation of any significant findings. “Honestly,” Culberson said, “if you’re going to go all that way to determine if there’s life on another world, why wouldn’t you double-check it?”

To gather samples for the spectrometers, the lander will have a scooper and sampling arm with at least one set of counter-rotating saw blades that could penetrate to a depth of about 10 cm. At Europa’s low surface temperatures, its ice is harder than steel."

And

"Scientists will attempt to find this hardware a landing site near an active crevasse. If the Hubble telescope data is correct, this would offer a potential opening to the ocean far below. Ideally, if the lander can be placed near a vent, it might sample spouts from the ocean below. The engineers are also working through the feasibility of more exotic options, such as bots that might detach from the lander and examine the crevasses.

On Europa’s harsh surface, the battery-powered lander would have about a 10-day lifespan, although solar cells might extend that further. But with dim sunlight and continual radiation, the lander’s functional time would necessarily be short.

Finally, the JPL engineers are working on a “plume probe,” not as part of the lander but which would detach from the Clipper and fly close to the moon’s surface, perhaps 2 km or lower, to obtain samples and relay that data back to the Clipper."
Elsewhere I read that the ICPS of Block 1 was scheduled for only one or at most two of the initial missions.  I know the EUS of Block 1B isn't a sure thing yet, but it seems more likely it will be available by the time the Europa mission can be launched, and the ICPS would be retired by then.  Won't that make a difference in the possible payload and mission choices?
Title: Re: Proposed Europa Missions
Post by: redliox on 11/18/2015 08:48 pm
Elsewhere I read that the ICPS of Block 1 was scheduled for only one or at most two of the initial missions.  I know the EUS of Block 1B isn't a sure thing yet, but it seems more likely it will be available by the time the Europa mission can be launched, and the ICPS would be retired by then.  Won't that make a difference in the possible payload and mission choices?

Not to dwell long on it, but presuming the SLS is utilized between the 2018 and 2023 flights I see possibilities, but they may hinge on NASA getting approval for EUS ultimately.  The spare ICPS could be used to launch a probe in the years between Orion flights...just to keep SLS going.  However, assuming EUS funding is received swiftly, there may be priority to test fly it.  In short, we could see either a dual Block 1 and Block 1B flight or a single 1B.  Hopefully both, since I'd hope they don't waste money crew-rarting the spare.  Best to put EUS talk in the SLS threads...

As for the talk on a Europa lander, that seems borderline madness for the here-and-now.  I'd say use either the ESA penetrator idea or wait until well after the (formerly known as) 'Clipper mission does its mapping job.  It's a bit premature to actually build a full lander right now.  Design, conceptualize for sure...but we should designate it as a proper mission and do a proper job when the time's right even if it's 15 years after 'Clipper's flight.

JPL trying to worm its fingers into the fiscal cookie jar for more eh?  Where's the Congressional nun with a ruler when you need her?  :P
Title: Re: Proposed Europa Missions
Post by: zubenelgenubi on 11/19/2015 09:06 pm
If Europa exploration will be a continuing pursuit by NASA (Europa Clipper, followed by proposed Europa orbiter and proposed Europa lander), then, at some point in time, should a separate Europa exploration line item in the NASA budget be initiated?

Running the concept up the flagpole; will anyone salute?
Or might I as well ask for a rainbow-maned astronaut pegasus-pony?
Title: Re: Proposed Europa Missions
Post by: vjkane on 11/19/2015 09:24 pm
If Europa exploration will be a continuing pursuit by NASA (Europa Clipper, followed by proposed Europa orbiter and proposed Europa lander), then, at some point in time, should a separate Europa exploration line item in the NASA budget be initiated?

Running the concept up the flagpole; will anyone salute?
Or might I as well ask for a rainbow-maned astronaut pegasus-pony?

The proposed House of Representatives' funding bill for NASA would establish an Ocean Worlds program that would essentially set up such a line.  Would presumably include Europa, Enceladus, Titan, among others.
Title: Re: Proposed Europa Missions
Post by: zubenelgenubi on 11/19/2015 09:28 pm
re: Ocean Worlds program--that's a great idea!  Thank you for the information.
Title: Re: Proposed Europa Missions
Post by: JH on 11/19/2015 11:26 pm
JPL trying to worm its fingers into the fiscal cookie jar for more eh?  Where's the Congressional nun with a ruler when you need her?  :P

In this situation JPL is actually being spurred on by the very member of congress that would normally reign it in. I'm sure you saw the part in the article where Elachi's team was listing possible approaches and prefaced the soft lander option with "this would be expensive" only to have Culberson immediately tell them to do it. I'm not surprised by this, as I've heard from several people that what Culberson really wants is to drill through the ice and send down a sub. Asking for only a soft lander is him showing restraint.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 11/19/2015 11:59 pm
heard from several people that what Culberson really wants is to drill through the ice and send down a sub. Asking for only a soft lander is him showing restraint.

I've heard Culberson himself say this.

Keep in mind that the ice is considered to be several kilometers thick. We don't even do that with big drill rigs today, let alone know how to do it entirely robotically with a far smaller craft. So people who advocate this usually preface it by saying that we'd do it at a crevasse. But we still don't know if there are any places where the water gets relatively close to the surface.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 11/20/2015 12:09 am
re: Ocean Worlds program--that's a great idea!  Thank you for the information.

There was a workshop on this last month.

The intention of the people pushing it (besides science, some of them are interested in, well, more, expensive missions) is to get it established much like the Discovery and New Frontiers mission lines, with regular funding and a cadence of missions. Note that Discovery and New Frontiers are mission lines that are treated as hands-off by Congress and to a lesser extent by OMB (when it comes to choosing missions). NASA makes the selections, not people in Congress or the White House.

The problem with an Ocean Worlds mission line is that the other mission lines are essentially agnostic for targets. Discovery is open to any science goal and planetary target that somebody wants to propose. New Frontiers has a list of possible missions provided by the decadal survey, but it is broad and includes the entire solar system. An Ocean Worlds mission line would essentially limit the targets to only a few things, worlds with water, of course. So it would be more equivalent to NASA's Mars Program, which used to be treated as a sort of second planetary program on its own, but has been greatly reduced and absorbed into the overall planetary program. Note also that the decadal survey (meaning the scientific community) did not say to establish an ocean worlds mission line, Congress has directed that based upon no scientific advice. so the next decadal survey will probably have something to say about whether it is a good idea or not. And I'd add that establishing an ocean worlds mission line requires money, and that is going to have to be taken from somewhere else. So what should NASA do? Reduce Discovery and New Frontiers to one selection each per decade and put the money into the ocean worlds program? A whole buncha questions that have to be asked and answered. I'm agnostic on the idea, but implementing it will be problematic.



Title: Re: Proposed Europa Missions
Post by: Blackstar on 11/20/2015 12:13 am
If Europa exploration will be a continuing pursuit by NASA (Europa Clipper, followed by proposed Europa orbiter and proposed Europa lander), then, at some point in time, should a separate Europa exploration line item in the NASA budget be initiated?

Keep in mind that it is impossible to do any Europa mission cheap. Too far, radiation is bad, difficult operations, yadda yadda yadda.

So... if you establish a mission line to do this, what you are in effect doing is establishing a mission line for large flagship missions that cost several billion dollars apiece. Where does the money come from to do that? Do you eliminate all the other missions? And if you decide that there will be a bunch of Europa (or ocean world) flagship missions, then are you essentially saying that there will be no flagship missions for other targets like Venus, Mars, comets, Kuiper Belt, ice giants, etc.? Does doing this remove big parts of the solar system from future exploration?
Title: Re: Proposed Europa Missions
Post by: vjkane on 11/20/2015 02:53 am
The important questions of programmatic balance aside...

The geologic mapping of Europa requires a mission on the order of $2B, and that will be NASA's [Clipper] Europa mission.  The old Mars program created the $2.4B Curiosity rover mission, so this class of mission isn't impossible in a dedicated program.

The small lander described in Eric's article is essentially a completely independent spacecraft that will orbit Jupiter on its own for 2-3 years before the landing.  It could be a stand alone mission if it carried the extra fuel to enter orbit.  The article suggests that the deliver spacecraft/lander would be around $500M, so that could fit within a continuing program.  There is the question of a data relay spacecraft.

The Juno and JUICE missions are both about $1B, so capable New Frontiers-class outer planet missions are possible.  The radiation at Europa roughly doubles the cost (curse the universe for Europa's placement!), so this class of spacecraft can't be used for Europa.  It's hard to imagine what else might be done for either Ganymede or Callisto after JUICE.

However, this class of mission outfitted with select, more capable instruments than Cassini for targeted Titan and/or Enceladus missions would probably be possible.  The last Decadal Survey assumed orbiters, which raised the cost.  However, borrowing from the Clipper flyby approach and newer concepts for slow flyby Saturn orbits for Enceladus, the next missions could be cheaper than the previous Decadal Survey assumed.  Costs would be higher than the Jupiter spacecraft because RTGs are really needed at Saturn unless you have a very low data rate mission (such as a Saturn atmospheric probe).

Titan is also the easiest major body in the solar system to land on or float a balloon in the atmosphere.  Studies have suggested that such missions might cost around $1B.  There again is the question of data relay.

So, the Europa Clipper mission aside, what might a program of sequential ~$1B missions might look like?

The Europa Clipper team has stated that the limiting factor on the life of the spacecraft will be its instrument heads that have to be exposed to the radiation.  The Clipper could serve as a long-lived data relay craft, or a second, simpler data relay craft could launched.  Then a series of smallish landers like those described in the article might be flown.

Or at Saturn, a New Horizon's-class orbiter might fly modern instruments through the plumes of Enceladus and perhaps carry a thermal imager for higher resolution imaging of Titan.  Both have been proposed as Discovery missions, and even if the costs estimates are off by a factor of two, then you have a New Frontiers-class mission.  This orbiter could also serve as a long-lived communications relay for a series of Titan landers or balloons.

Two big caveats.  First, this is armchair program imagining and should be thought of as a thought experiment to think about whether there is even a conversation worth having.  Real analyses might shoot big holes into these thoughts.  Second, unless the planetary program gets a budget boost of perhaps $500M a year, do we want to make the program an Ocean Worlds program plus perhaps Discovery missions?  Good arguments could be made either way.


Title: Re: Proposed Europa Missions
Post by: Blackstar on 11/20/2015 03:07 am
The article suggests that the deliver spacecraft/lander would be around $500M, so that could fit within a continuing program. 

JPL is advocating a mission and says it would cost $500 million. Why would anybody believe that?

These are multi-billion dollar missions. They are not simple missions. They are not easy missions. The things people are proposing or would propose do entirely new things with new technologies.

Very expensive.
Title: Re: Proposed Europa Missions
Post by: baldusi on 11/20/2015 09:36 pm
May I ask if there's any chance that a new budget line comes with a new budget addition?
I'm asking because even a 2.5B mission per decade is 250M per year. And the travel time alone to the Water Worlds is around that. In the overall budget 250M seems quite possible. In fact, pork and lobbied lines usually have higher swings.
Title: Re: Proposed Europa Missions
Post by: vjkane on 11/20/2015 09:52 pm
May I ask if there's any chance that a new budget line comes with a new budget addition?
I'm asking because even a 2.5B mission per decade is 250M per year. And the travel time alone to the Water Worlds is around that. In the overall budget 250M seems quite possible. In fact, pork and lobbied lines usually have higher swings.
You can't go on average funding needed because the bulk of the money is spent in 18 to 24ish (depending on mission size).  Probably the reasonable funding level would be $500M/year.  Take that out of the existing budget and blows out the ability to do much of anything else except perhaps the Discovery program.

Someone want to expand NASA's budget (not take $500M from Earth Science for example), I'm all for it.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 11/20/2015 11:49 pm
May I ask if there's any chance that a new budget line comes with a new budget addition?

There is a chance that a new budget line can come with a new budget addition. But who is going to provide that bump up? The White House? Or Congress?

One thing I would note is that the ocean worlds line that has been proposed was not mentioned in the last decadal survey. So there is no scientific consensus that says it should be done. It has become rather common in the past decade or so to not approve a mission (or a funding line) unless there is clear scientific consensus for it. So you can expect political opposition to such a proposal as well.

Title: Re: Proposed Europa Missions
Post by: david1971 on 11/21/2015 12:30 am
I just wanted to say that threads like this one are the reason I read this site everyday.  It's hard to find this S/N in a place that isn't so technical that it just for a small cadre of experts.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 11/21/2015 01:50 am
Thinking about this some more, there is a way that you could do an ocean worlds program that would not bust the entire planetary science budget, but it comes with a cost and it has limitations.

One way to do it would be to establish it as the equivalent of the New Frontiers program with the same cost cap and overall rules, meaning that the decadal survey picks a list of possible missions, and then they are competitively bid. NF is roughly 1 billion dollars right now, and it might be possible for NASA to do two of them in a decade (previously they did almost three). What you could possibly do is say that NASA will do 1 New Frontiers mission per decade, and 1 Ocean Worlds mission per decade and alternate.

Now what are the limitations? The first is that you cripple the NF program and all the missions that it could do, such as comet cryo sample return, South Pole Aitken Basin sample return, Venus in situ exploration, and the others. So you just reduce access to the rest of the solar system by roughly half. The other limitation is that you rule out the big, expensive, scientifically productive ocean worlds missions in favor of smaller ones. So almost certainly no Europa lander, no Enceladus sample return, limited science at Titan, etc. And I can guarantee you that the advocates for an ocean worlds program want big missions, not ones that are cost-capped at $1 billion. So the advocates will not want that kind of cost cap. They want the ability to do missions that cost a lot more than that.

The other limitation is that the only way this is likely to get approved is if it is a competitive program, meaning that anybody with a mission idea that fits the list can compete, just like New Frontiers. And the advocates for the ocean worlds program include a lot of JPL people who don't want to have to compete against APL or Goddard or some university scientist in Colorado. They want flagship-class missions that are automatically given over to JPL. So the advocates are not going to like that either.

Title: Re: Proposed Europa Missions
Post by: Steam Chaser on 11/21/2015 04:05 am
I think the Ocean Moons line is a bad idea, and would prefer more of a "food pyramid" approach with the smaller (i.e. less expensive) competed missions on the wide bottom of the pyramid.  Have the most frequent missions be competed smaller Discovery missions, have less frequent competed larger New Frontiers missions in selected priority areas, and then if any funding is left do whatever predefined huge flagship missions can be afforded after those priorities.  If I remember, that's pretty close to what the Decadal Survey advised.

We might even be getting to the point where it makes sense to add an even wider, lower cost layer of the pyramid below the Discovery missions, given various trends (growing capabilities of cubesats and other smallsats, potential commercial spacecraft from the likes of Astrobotic, Moon Express, Planetary Resources, and others, the overall NASA need for HSF robotic precursor missions, possible collaboration missions between Planetary Science and Space Technology directorates, possible hosting on other nations' planetary missions, possible upcoming availability of rides to deep space aboard SLS or a deep space variant of Spaceflight Industries missions, etc).

However, maybe the Ocean Worlds approach would work starting by splitting New Frontiers as Blackstar described.  Using that as a base, maybe one or more of the following would help it work:

- Make the Ocean Worlds line more generic, like "Outer Worlds" or something like that so it could include Io (a New Frontiers priority), Ice Giants (one of the Flagship priorities), and/or the Gas Giants themselves (so the New Frontiers Saturn probe would be included).  Allowing 2 of the 7 New Frontiers priorities to be in the scope of this new line would reduce the pain of having New Frontiers cut in half.

- The whole idea seems like a sort of alliance between the SLS and JPL factions.  Reading between the lines, I think they want SLS to launch these Ocean World missions.  So ... let the SLS budget line pay for the rocket as partial compensation for causing havoc to Planetary Science, allowing a greater mission budget to be available for the spacecraft, etc.

- When JWST is complete, apply some of that budget wedge to this line.  Most should go to Astrophysics, but I think some of it, for all intents and purposes, came from Planetary Science in the first place.  Let's suppose $100M/year (out of JWST's $683M/year or something like that - I don't remember exactly) goes to Planetary Science to flesh out the Ocean (or Outer) Worlds line.  That would give a budget wedge of $1B/decade for the new line, which is comparable to the size of the New Frontiers split Blackstar described.  By the time JWST flies, the political balance of power, particularly in the Senate, might have shifted enough to allow an SLS/JPL faction to accomplish this.

- There is already a budget wedge in Planetary Science for the Europa mission, so that could also be part of the Ocean (or Outer) Worlds line.

One possibly good thing about an Ocean Worlds line is that you could say to Culberson and the other backers that since there is a line, there's no urgent need to add the lander to the current Europa mission.  Let the current Europa mission map the moon so we know where it's safe to land, and so we have more information and time to allow us to make a lander that can answer good questions.  Another Europa mission would likely be coming along later, so there wouldn't be as much urgency to add it to the current one.  Hopefully not doing the lander now would also help the current Europa mission stay on budget and schedule.
Title: Re: Proposed Europa Missions
Post by: vjkane on 11/21/2015 05:46 am
Based on mission options for the outer planet moons, there are a couple of ways that an Ocean Worlds program could be funded (assuming that the planetary program's budget is significantly increased).

Because Europa sits in the midst of an intense radiation belt, almost any mission that will significantly enhance our understanding of this moon will require missions >$1.5B.  The only exception I see would be if predictable plumes are discovered by the Europa clipper, in which case a dedicated follow on plume fly-through or sample return mission could be cheaper.  Short of that, furthering the exploration of Europa would likely require dedicating the next 2-3 Flagship mission slots to Europa.  The cost would be no sample return from Mars and probably no Uranus or Neptune mission.

Flagship missions tend to be chosen through political decisions.  What became the Curiousity mission was approved by the first planetary Decadal Survey as only a modest technology demonstration mission.  The 2020 rover mission was approved through a political decision driven by OMB.  It would not surprise me if the Flagships for the 2020s and 2030s are also chosen through the political process. 

It appears that *modest* Titan and/or Enceladus missions might be done within the New Frontiers budget cap.  If so, then a new mission program could be inserted by stretching out the time between Flagship missions and probably the current New Frontiers program.  It is unclear whether such missions would have the scientific return within this cost cap to win the backing of the next Decadal Survey given other candidate ~$1B missions.  (I suspect such missions would be competitive, but my opinion is just that.)

The core problem for the planetary program is an embarrassment of riches.  Mars becomes only more interesting the more we explore it in depth, and a sample return mission is the next obvious goal.  Europa, Enceladus, and Titan are, in my opinion, equally important targets.  The ice giants cry out for an orbital mission with an atmospheric probe.

Simply put, short of a big increase in the budget for the planetary program, there will be big losers once the winner(s) of the 'what do we focus on' is/are chosen.

Perhaps the Ocean Worlds program, if it becomes reality, might be the Europa Clipper mission (plus a small lander?) and a New Frontiers class mission to Titan and/or Enceladus for the 2020s.  (There are opportunities for international collaboration in the latter.)  That would be the least disruptive option I see to the overall planetary program.

Title: Re: Proposed Europa Missions
Post by: NovaSilisko on 11/21/2015 09:58 am
Would I be considered an insane dreamer to hope for an actual budgetary increase to NASA overall to help fund this program?
Title: Proposed Europa Missions
Post by: Star One on 11/21/2015 10:31 am
May I ask if there's any chance that a new budget line comes with a new budget addition?

There is a chance that a new budget line can come with a new budget addition. But who is going to provide that bump up? The White House? Or Congress?

One thing I would note is that the ocean worlds line that has been proposed was not mentioned in the last decadal survey. So there is no scientific consensus that says it should be done. It has become rather common in the past decade or so to not approve a mission (or a funding line) unless there is clear scientific consensus for it. So you can expect political opposition to such a proposal as well.

And there is the downside of doing a review of such things every ten years that scientific priorities can shift considerably within that period.


Based on mission options for the outer planet moons, there are a couple of ways that an Ocean Worlds program could be funded (assuming that the planetary program's budget is significantly increased).

Because Europa sits in the midst of an intense radiation belt, almost any mission that will significantly enhance our understanding of this moon will require missions >$1.5B.  The only exception I see would be if predictable plumes are discovered by the Europa clipper, in which case a dedicated follow on plume fly-through or sample return mission could be cheaper.  Short of that, furthering the exploration of Europa would likely require dedicating the next 2-3 Flagship mission slots to Europa.  The cost would be no sample return from Mars and probably no Uranus or Neptune mission.

Flagship missions tend to be chosen through political decisions.  What became the Curiousity mission was approved by the first planetary Decadal Survey as only a modest technology demonstration mission.  The 2020 rover mission was approved through a political decision driven by OMB.  It would not surprise me if the Flagships for the 2020s and 2030s are also chosen through the political process. 

It appears that *modest* Titan and/or Enceladus missions might be done within the New Frontiers budget cap.  If so, then a new mission program could be inserted by stretching out the time between Flagship missions and probably the current New Frontiers program.  It is unclear whether such missions would have the scientific return within this cost cap to win the backing of the next Decadal Survey given other candidate ~$1B missions.  (I suspect such missions would be competitive, but my opinion is just that.)

The core problem for the planetary program is an embarrassment of riches.  Mars becomes only more interesting the more we explore it in depth, and a sample return mission is the next obvious goal.  Europa, Enceladus, and Titan are, in my opinion, equally important targets.  The ice giants cry out for an orbital mission with an atmospheric probe.

Simply put, short of a big increase in the budget for the planetary program, there will be big losers once the winner(s) of the 'what do we focus on' is/are chosen.

Perhaps the Ocean Worlds program, if it becomes reality, might be the Europa Clipper mission (plus a small lander?) and a New Frontiers class mission to Titan and/or Enceladus for the 2020s.  (There are opportunities for international collaboration in the latter.)  That would be the least disruptive option I see to the overall planetary program.

You didn't even mention Pluto which to my mind has certainly put itself on the scientific map this year.
Title: Re: Proposed Europa Missions
Post by: redliox on 11/21/2015 11:33 am
Based on mission options for the outer planet moons, there are a couple of ways that an Ocean Worlds program could be funded (assuming that the planetary program's budget is significantly increased).

Because Europa sits in the midst of an intense radiation belt, almost any mission that will significantly enhance our understanding of this moon will require missions >$1.5B.  The only exception I see would be if predictable plumes are discovered by the Europa clipper, in which case a dedicated follow on plume fly-through or sample return mission could be cheaper.  Short of that, furthering the exploration of Europa would likely require dedicating the next 2-3 Flagship mission slots to Europa.  The cost would be no sample return from Mars and probably no Uranus or Neptune mission.

Flagship missions tend to be chosen through political decisions.  What became the Curiousity mission was approved by the first planetary Decadal Survey as only a modest technology demonstration mission.  The 2020 rover mission was approved through a political decision driven by OMB.  It would not surprise me if the Flagships for the 2020s and 2030s are also chosen through the political process. 

It appears that *modest* Titan and/or Enceladus missions might be done within the New Frontiers budget cap.  If so, then a new mission program could be inserted by stretching out the time between Flagship missions and probably the current New Frontiers program.  It is unclear whether such missions would have the scientific return within this cost cap to win the backing of the next Decadal Survey given other candidate ~$1B missions.  (I suspect such missions would be competitive, but my opinion is just that.)

The core problem for the planetary program is an embarrassment of riches.  Mars becomes only more interesting the more we explore it in depth, and a sample return mission is the next obvious goal.  Europa, Enceladus, and Titan are, in my opinion, equally important targets.  The ice giants cry out for an orbital mission with an atmospheric probe.

Simply put, short of a big increase in the budget for the planetary program, there will be big losers once the winner(s) of the 'what do we focus on' is/are chosen.

Perhaps the Ocean Worlds program, if it becomes reality, might be the Europa Clipper mission (plus a small lander?) and a New Frontiers class mission to Titan and/or Enceladus for the 2020s.  (There are opportunities for international collaboration in the latter.)  That would be the least disruptive option I see to the overall planetary program.

You didn't even mention Pluto which to my mind has certainly put itself on the scientific map this year.

I'd suggest one addendum that'd be a convergence of the topics of Pluto, Ice Giants, and Ocean Worlds: Triton.

Triton's the most remote, positively confirmed geologically active world (Pluto's ice volcanoes are still under debate) with a variety of quirks that make it kin to the other 3 ocean worlds (Europa, Titan, Enceladus) with Pluto as a close cousin.  It may itself have some liquid like Titan and Ganymede in its structure, albeit to a lesser extent since it is rockier like Europa.  Although it would be difficult to reach, it should be added to the targets in fairness.  Instead of radiation at Europa we'd have to deal with time and decelerating first around Neptune and possibly again around Triton itself.

Might be wise to direct this Ocean Worlds talk to a different thread although Europa technically is one of them.  Europa just has the luck of being the closest of the lot.  :)
Title: Re: Proposed Europa Missions
Post by: Blackstar on 11/21/2015 01:58 pm
May I ask if there's any chance that a new budget line comes with a new budget addition?

There is a chance that a new budget line can come with a new budget addition. But who is going to provide that bump up? The White House? Or Congress?

One thing I would note is that the ocean worlds line that has been proposed was not mentioned in the last decadal survey. So there is no scientific consensus that says it should be done. It has become rather common in the past decade or so to not approve a mission (or a funding line) unless there is clear scientific consensus for it. So you can expect political opposition to such a proposal as well.

And there is the downside of doing a review of such things every ten years that scientific priorities can shift considerably within that period.

No. Scientific priorities have not shifted. And they don't shift that quickly. And there is also the mid-term review that helps address this.

I'm not sure I want to write the 2000 words it will take to address all of those issues, but scientific priorities have been pretty consistent over a long term. You can look at the most recent decadal survey (for the uninitiated, I was one of the two study directors leading that) and pretty much every major scientific priority listed in that one you can find in the previous one, and most of those you can find in previous high-level scientific advisory documents going back decades. Why was Mars sample return in there so high? Because it was high in 2001, and high 10 years earlier, and high in the 1980s and so on.

And here's the important thing to understand: that is a good thing, and it is also a VITAL thing.

From the perspectives of the politicians, they don't know anything about this science stuff. So increasingly over the past few decades they have decided to let the scientists determine the priorities. But in order for them to trust the scientists to do that, the scientists also have to be responsible. And one measure of responsibility is consistency. If they keep changing their minds about what is important every few years or so, it says that they don't know what is important. And they won't get the money. They shouldn't get the money. (A corollary to that is that if the scientists keep arguing with each other over what is important, then it is clear that they have no consensus, and they won't get the money.)

The decadal survey also has mechanisms for dealing with changes in scientific priorities. Discovery missions, for instance, can go to any target as long as the science is justified. Suppose that tomorrow some scientist with a telescope suddenly discovers a really super interesting asteroid floating out near Mars. The Discovery program would be perfect for funding a spacecraft to go look at it. So, new scientific discovery, and a method for funding a mission to go investigate it.

Similarly, the New Frontiers program has a full range of missions that cover a lot of different targets. If Venus suddenly becomes more interesting in the next year (say, evidence of active volcanoes turns up), then New Frontiers could result in a Venus mission.

There is already a tremendous amount of flexibility in the way the overall program works for selecting missions. It is not broken. It works quite well, requiring only some minor tweaking here and there to address new situations and requirements.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 11/21/2015 02:10 pm
Flagship missions tend to be chosen through political decisions.  What became the Curiousity mission was approved by the first planetary Decadal Survey as only a modest technology demonstration mission.  The 2020 rover mission was approved through a political decision driven by OMB.  It would not surprise me if the Flagships for the 2020s and 2030s are also chosen through the political process. 

This really misstates what happened. Curiosity is an outlier as it sort of grew into a flagship class mission (it was originally scoped at $700 million), and it sort of grew into its scientific goals. It was never "politically" selected. It ended up being a really good mission, and the right mission to fly. But the real failing during the previous decade was that Europa was not approved as a mission even though the decadal survey said to do it. (Long story there.)

You have the 2020 story backwards. Mars 2020 is the MAX-C mission that was prioritized in the decadal survey. Pretty much the way it works is that no major science mission can be funded unless it is first endorsed by the NRC (in this case through the decadal survey). So the planetary decadal endorsed the MAX-C mission. (And honestly, if JPL had proposed a Europa mission that would not have busted the budget, that one would have ended up on top instead.)

What then happened was that OMB did not want to fund a caching rover for Mars. They thought it would be too expensive, plus they didn't want to start down the road of Mars sample return, because that's expensive and OMB didn't like the JWST experience and did not want to get stuck with another very expensive science program. So they tried to prevent that rover from happening. In the end, there was no scientific support for any other kind of rover, and Curiosity made a spectacular landing which seemed to erase opposition (what I suspect happen is that the president himself said that he was impressed with Curiosity and it was the kind of thing NASA should do more of, and "poof!" OMB got quiet).

Mars 2020 is an example of the value and the power of the decadal survey, because the DS outlined the mission to do, and any efforts to do a different mission fell apart.

Now I'll agree that there is more politics involved in the big mission selections. But that does not mean that there is no logic to what happens and how it happens. There is a process that provides input to the political decisions that get made.
Title: Proposed Europa Missions
Post by: Star One on 11/21/2015 02:53 pm
Based on mission options for the outer planet moons, there are a couple of ways that an Ocean Worlds program could be funded (assuming that the planetary program's budget is significantly increased).

Because Europa sits in the midst of an intense radiation belt, almost any mission that will significantly enhance our understanding of this moon will require missions >$1.5B.  The only exception I see would be if predictable plumes are discovered by the Europa clipper, in which case a dedicated follow on plume fly-through or sample return mission could be cheaper.  Short of that, furthering the exploration of Europa would likely require dedicating the next 2-3 Flagship mission slots to Europa.  The cost would be no sample return from Mars and probably no Uranus or Neptune mission.

Flagship missions tend to be chosen through political decisions.  What became the Curiousity mission was approved by the first planetary Decadal Survey as only a modest technology demonstration mission.  The 2020 rover mission was approved through a political decision driven by OMB.  It would not surprise me if the Flagships for the 2020s and 2030s are also chosen through the political process. 

It appears that *modest* Titan and/or Enceladus missions might be done within the New Frontiers budget cap.  If so, then a new mission program could be inserted by stretching out the time between Flagship missions and probably the current New Frontiers program.  It is unclear whether such missions would have the scientific return within this cost cap to win the backing of the next Decadal Survey given other candidate ~$1B missions.  (I suspect such missions would be competitive, but my opinion is just that.)

The core problem for the planetary program is an embarrassment of riches.  Mars becomes only more interesting the more we explore it in depth, and a sample return mission is the next obvious goal.  Europa, Enceladus, and Titan are, in my opinion, equally important targets.  The ice giants cry out for an orbital mission with an atmospheric probe.

Simply put, short of a big increase in the budget for the planetary program, there will be big losers once the winner(s) of the 'what do we focus on' is/are chosen.

Perhaps the Ocean Worlds program, if it becomes reality, might be the Europa Clipper mission (plus a small lander?) and a New Frontiers class mission to Titan and/or Enceladus for the 2020s.  (There are opportunities for international collaboration in the latter.)  That would be the least disruptive option I see to the overall planetary program.

You didn't even mention Pluto which to my mind has certainly put itself on the scientific map this year.

I'd suggest one addendum that'd be a convergence of the topics of Pluto, Ice Giants, and Ocean Worlds: Triton.

Triton's the most remote, positively confirmed geologically active world (Pluto's ice volcanoes are still under debate) with a variety of quirks that make it kin to the other 3 ocean worlds (Europa, Titan, Enceladus) with Pluto as a close cousin.  It may itself have some liquid like Titan and Ganymede in its structure, albeit to a lesser extent since it is rockier like Europa.  Although it would be difficult to reach, it should be added to the targets in fairness.  Instead of radiation at Europa we'd have to deal with time and decelerating first around Neptune and possibly again around Triton itself.

Might be wise to direct this Ocean Worlds talk to a different thread although Europa technically is one of them.  Europa just has the luck of being the closest of the lot.  :)

In one of the astronomy magazines I was reading recently they were making a argument that a strong case should be put forward for the prioritisation of Pluto in the next decadal survey on geology alone let alone other factors such as any internal ocean.
Title: Re: Proposed Europa Missions
Post by: vjkane on 11/21/2015 04:16 pm
I'll re-enforce Blackstar's point.  Consensus on missions to fly build slowly and are relatively stable.  For the major missions (New Frontiers and Flagship), the only serious addition to that list I can think of is Enceladus based on Cassini's findings.  The last Decadal Survey looked at a number of flavors of Enceladus missions.  It concluded that the options were too expensive and that for the $s, Europa was a higher priority.  I also suspect they concluded that the community should let Cassini complete its studies first, and since the last Decadal, our understanding of Enceladus has greatly deepened.

As an example, the focus on Mars built over decades and has resulted in a steady stream of missions with both of the Flagship missions for the 2000s and 2010s being Mars rovers.  Perhaps the political consensus will shift to Ocean Worlds, perhaps not.  I've learned to never underestimate the political power of the Mars community.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 11/21/2015 04:40 pm
I'll re-enforce Blackstar's point.  Consensus on missions to fly build slowly and are relatively stable.  For the major missions (New Frontiers and Flagship), the only serious addition to that list I can think of is Enceladus based on Cassini's findings.  The last Decadal Survey looked at a number of flavors of Enceladus missions.  It concluded that the options were too expensive and that for the $s, Europa was a higher priority.  I also suspect they concluded that the community should let Cassini complete its studies first, and since the last Decadal, our understanding of Enceladus has greatly deepened.

Well, Saturn Probe was also new. But not completely new. There is a long lineage of atmospheric probe proposals and a community interested in them. So adding that to NF was not unusual or surprising. If NASA does another large Jupiter or Saturn orbiter in the next few decades, there will be proposals to put a probe on it because there are scientists who still want the data.

But to add to vjkane's point, I could create a list of "lessons" of planetary science, or maybe "laws" of planetary science. These would include things that are simply the way stuff has worked over the decades. One of those laws is that virtually any mission that gets approved (with rare exception) has been proposed before in some form, usually for decades. For example, the first Mercury orbiter proposal was in 1974, but it did not happen until MESSENGER got there in 2011. That's over three decades. Juno, arriving at Jupiter next year, was proposed in various forms back into the 1990s, and I am sure that the class of science observations it will conduct can be traced back to the 1970s.

Long lineage is what makes stuff happen. That's just how it works. Planetary scientists don't, and should not, go chasing after each new shiny object.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 11/21/2015 04:43 pm
In one of the astronomy magazines I was reading recently they were making a argument that a strong case should be put forward for the prioritisation of Pluto in the next decadal survey on geology alone let alone other factors such as any internal ocean.

We'll see. I love the Pluto data. But there are also a lot of other fascinating subjects to go after. The ice giants of course are still almost unexplored. And doing a major next step at Pluto is going to be much more expensive than New Horizons. If you had $2 billion to spend going back to Pluto to do more detailed study, or spending $2 billion to orbit Uranus or Neptune, which mission do you think would return more data for that expenditure?

Okay, that's not even a tough question: that money spent on an ice giant mission is going to return far more data.
Title: Re: Proposed Europa Missions
Post by: vjkane on 11/21/2015 05:00 pm
We'll see. I love the Pluto data. But there are also a lot of other fascinating subjects to go after. The ice giants of course are still almost unexplored. And doing a major next step at Pluto is going to be much more expensive than New Horizons. If you had $2 billion to spend going back to Pluto to do more detailed study, or spending $2 billion to orbit Uranus or Neptune, which mission do you think would return more data for that expenditure?

Okay, that's not even a tough question: that money spent on an ice giant mission is going to return far more data.

Triton likely is as interesting as Pluto and one or two (I can't remember which) of the Uranian moons look to be ocean worlds in their own right.
Title: Re: Proposed Europa Missions
Post by: vjkane on 11/21/2015 05:11 pm
Long lineage is what makes stuff happen. That's just how it works. Planetary scientists don't, and should not, go chasing after each new shiny object.
The Discovery program is the one place where individual science teams get to propose to chase after their preferred shiny object.  But even then, any proposal that doesn't tie the proposed mission back to key and long standing questions posed by the planetary community and codified into the Decadal Survey isn't going to get funded.  The creativity comes in finding small highly focused missions that can tackle bits and pieces of the big questions.
Title: Re: Proposed Europa Missions
Post by: vjkane on 11/21/2015 05:20 pm
Now I'll agree that there is more politics involved in the big mission selections. But that does not mean that there is no logic to what happens and how it happens. There is a process that provides input to the political decisions that get made.
Green has said in meetings that OMB told NASA that they could take a Curiosity class rover as the Flagship for this decade or have no Flagship.  A Mars rover fit with NASA's overall focus on Mars, and it was believed that the cost would be constrained because we'd already flown this design.  There were politics, as there always is for big money projects. (The latest cost estimates put the 2020 rover within 75% of the cost of Curiosity adjusted for inflation.)
Title: Re: Proposed Europa Missions
Post by: Star One on 11/21/2015 06:34 pm

In one of the astronomy magazines I was reading recently they were making a argument that a strong case should be put forward for the prioritisation of Pluto in the next decadal survey on geology alone let alone other factors such as any internal ocean.

We'll see. I love the Pluto data. But there are also a lot of other fascinating subjects to go after. The ice giants of course are still almost unexplored. And doing a major next step at Pluto is going to be much more expensive than New Horizons. If you had $2 billion to spend going back to Pluto to do more detailed study, or spending $2 billion to orbit Uranus or Neptune, which mission do you think would return more data for that expenditure?

Okay, that's not even a tough question: that money spent on an ice giant mission is going to return far more data.

Really I would say that's debatable. Pluto is proving to be such a unique object, I mean it's geology alone is an incredibly mishmash of types. We have also only seen properly one side of it, plus there is the totality of its unusual moon system. The problem with Triton is it isn't a pristine KBO it has no doubt been altered by its position as a moon of Neptune. The processes on Pluto are separated from any influence of a giant planet.

I would argue that Eris would be a better target than Triton to see how it compares to Pluto as similar sized object also free of influence from a giant planet.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 11/21/2015 06:50 pm
Green has said in meetings that OMB told NASA that they could take a Curiosity class rover as the Flagship for this decade or have no Flagship.  A Mars rover fit with NASA's overall focus on Mars, and it was believed that the cost would be constrained because we'd already flown this design.

OMB opposed the Mars caching rover. Go back and look at 2012 articles in Space News. The whole summer 2012 effort to look at alternatives was a result of OMB objecting to the mission that was in the decadal survey. In the end, they came around.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 11/21/2015 06:55 pm
Really I would say that's debatable. Pluto is proving to be such a unique object, I mean it's geology alone is an incredibly mishmash of types. We have also only seen properly one side of it, plus there is the totality of its unusual moon system. The problem with Triton is it isn't a pristine KBO it has no doubt been altered by its position as a moon of Neptune. The processes on Pluto are separated from any influence of a giant planet.


It isn't really. The ice giants were prioritized in the last decadal survey, Pluto was not. That gives them heritage (meaning that scientists can say "We said this was important before and we are saying that it is still important," which is a much more powerful political argument than "Hey! Something new and cool!"). Plus, we're comparing planetary systems consisting of icy planets with large atmospheres and multiple moons, as well as magnetic fields, etc., with a relatively small rock. Pluto is interesting, but it does not have the scientific constituency or the breadth that the ice giants do. It is a far harder argument to spend significantly more money on Pluto than on an ice giant mission.

But if some of the Pluto pictures come back and reveal a monument, then all bets are off.
Title: Re: Proposed Europa Missions
Post by: JH on 11/21/2015 07:58 pm
I would say that Pluto definitely punched well above its weight in terms of scientific interest so that an eventual return mission isn't out of the question. Before the encounter many expected a boring ice ball and therefore dismissed the possibility of follow-up missions being justified. Those sentiments have now evaporated--I haven't talked to a single person who was skeptical beforehand who hasn't been extremely impressed with the encounter results--but the Pluto system being demonstrated to be interesting and important doesn't bounce it to the head of the line. Really, what has happened is that the Pluto system has joined the (already crowded) pantheon of systems that people agree we don't know enough about.

On the other hand, Alan Stern is a steely willed individual...
Title: Proposed Europa Missions
Post by: Star One on 11/21/2015 08:27 pm
Really I would say that's debatable. Pluto is proving to be such a unique object, I mean it's geology alone is an incredibly mishmash of types. We have also only seen properly one side of it, plus there is the totality of its unusual moon system. The problem with Triton is it isn't a pristine KBO it has no doubt been altered by its position as a moon of Neptune. The processes on Pluto are separated from any influence of a giant planet.


It isn't really. The ice giants were prioritized in the last decadal survey, Pluto was not. That gives them heritage (meaning that scientists can say "We said this was important before and we are saying that it is still important," which is a much more powerful political argument than "Hey! Something new and cool!"). Plus, we're comparing planetary systems consisting of icy planets with large atmospheres and multiple moons, as well as magnetic fields, etc., with a relatively small rock. Pluto is interesting, but it does not have the scientific constituency or the breadth that the ice giants do. It is a far harder argument to spend significantly more money on Pluto than on an ice giant mission.

But if some of the Pluto pictures come back and reveal a monument, then all bets are off.

But is that a fair comparison as at the time of the last survey we only had limited knowledge about Pluto compared to what we know now, so no wonder there wasn't the constituency behind it, especially as a lot of people just expected it to be a boring planetary body?
Title: Re: Proposed Europa Missions
Post by: Vultur on 11/21/2015 09:44 pm
Second, unless the planetary program gets a budget boost of perhaps $500M a year, do we want to make the program an Ocean Worlds program plus perhaps Discovery missions?  Good arguments could be made either way.

IMO ... definitely, especially if it's far enough off that it doesn't mean dropping Mars 2020 with its Raman spectrometer (sample caching/MSR, I don't care so much about because of Mars meteorites and the potential for human missions which could return samples).

Europa Enceladus & Titan are the most interesting things in the solar system (besides Earth) by a rather large margin. Looking for organics/life on Mars should be done since it's "right next door", but...
Title: Re: Proposed Europa Missions
Post by: Blackstar on 11/21/2015 11:04 pm
But is that a fair comparison as at the time of the last survey we only had limited knowledge about Pluto compared to what we know now, so no wonder there wasn't the constituency behind it, especially as a lot of people just expected it to be a boring planetary body?

It absolutely is a fair comparison. Uranus and Neptune are virtually unexplored. In fact, you could say that they are LESS explored than Pluto, because New Horizons had better instruments than Voyager 2. So we have tons of data on Pluto, limited data on those other two really big planets and their satellites.

It's also totally true because the ice giants are more complex. Pluto may be fascinating, but it's also a rock. Uranus and Neptune have a core, a thick atmosphere, and lots of satellites, plus magnetic fields. Those things add up, but they also multiply. They are complex systems.

Hang around planetary scientists for any period of time and you start to get a sense of this. I know a bunch of asteroid scientists. They love asteroids and think they're really cool. Then I go talk to another scientist and he just scoffs at the asteroids. Bah! No atmosphere! No volatiles! No complex chemistry! They think it is pointless to devote any time to the rocks, they think we should focus on planets that have lots more stuff going on.

The data from Pluto is not going to change that fundamental dynamic. And consider, for example, that there are far more scientists interested in planetary atmospheres than who worked on the Pluto mission. So they are going to be biased towards missions that can look at stuff they care about.
Title: Re: Proposed Europa Missions
Post by: Archibald on 11/22/2015 07:58 pm
re: Ocean Worlds program--that's a great idea!  Thank you for the information.

According to this paper
http://www.sciencedirect.com/science/article/pii/S0019103506002016

Europa
Mimas
Enceladus
Tethys
Dione
Rhea
Iapetus
Miranda
Ariel
Umbriel
Titania
Oberon
Charon
Pluto

Quote
Based on the assumption that the satellites are differentiated and using an equilibrium condition between the heat production rate in the rocky cores and the heat loss through the ice shell, we find that subsurface oceans are possible on Rhea, Titania, Oberon, Triton, and Pluto and on the largest TNO's 2003 UB313, Sedna, and 2004 DW.

So there is no lack of possible targets for such a program. Mais issue (as usual) is money...
Title: Re: Proposed Europa Missions
Post by: Vultur on 11/22/2015 08:30 pm
What - no Titan? It definitely has seas (although of methane/ethane rather than water).
Title: Re: Proposed Europa Missions
Post by: vjkane on 11/23/2015 12:57 pm
What - no Titan? It definitely has seas (although of methane/ethane rather than water).

At the workshop last month they considered Titan to be an ocean world.
As I recall, the case for Titan as an ocean world is quite strong.  I have the vague memory that the ocean may be neither in contact with the surface nor with the silicate core.

Perhaps a more interesting list would be bodies where the ocean might be in contact with the silicate core.
Title: Re: Proposed Europa Missions
Post by: Archibald on 11/23/2015 03:45 pm
Wait -  Titan would thus have two oceans - a methane ocean on the surface, and a water ocean under the surface ?  :o
Title: Re: Proposed Europa Missions
Post by: vjkane on 11/23/2015 04:33 pm
Wait -  Titan would thus have two oceans - a methane ocean on the surface, and a water ocean under the surface ?  :o
Yes.  Check out:

http://www.astrobio.net/topic/solar-system/saturn/titan/titans-subsurface-ocean/

http://science.nasa.gov/science-news/science-at-nasa/2014/02jul_saltyocean/
Title: Re: Proposed Europa Missions
Post by: truth is life on 12/04/2015 03:44 pm
Before the encounter many expected a boring ice ball and therefore dismissed the possibility of follow-up missions being justified.
IMHO, anyone expressing this sentiment was being foolish. If there's one consistent lesson to take away from our exploration of the outer solar system, right since the 1970s, it's that there are no boring worlds. Io and Europa were supposed to be dead chunks of rock. Triton was a frozen hunk of ice. And Enceladus was surely boring. Wrong, wrong, wrong. Always bet on interesting.
Title: Re: Proposed Europa Missions
Post by: Archibald on 12/04/2015 04:16 pm

These days what is crazy is those subterranean lakes  of liquid water popping everywhere on the solar system - from Europa to the kuiper belt. With tidal forces replacing the Sun as source of energy to melt the ice into water.
Title: Re: Proposed Europa Missions
Post by: llanitedave on 12/04/2015 07:19 pm
Before the encounter many expected a boring ice ball and therefore dismissed the possibility of follow-up missions being justified.
IMHO, anyone expressing this sentiment was being foolish. If there's one consistent lesson to take away from our exploration of the outer solar system, right since the 1970s, it's that there are no boring worlds. Io and Europa were supposed to be dead chunks of rock. Triton was a frozen hunk of ice. And Enceladus was surely boring. Wrong, wrong, wrong. Always bet on interesting.


Sure, but that doesn't help Pluto any because it has to compete with dozens of other very interesting worlds.
Title: Re: Proposed Europa Missions
Post by: Star One on 12/04/2015 11:10 pm

Before the encounter many expected a boring ice ball and therefore dismissed the possibility of follow-up missions being justified.
IMHO, anyone expressing this sentiment was being foolish. If there's one consistent lesson to take away from our exploration of the outer solar system, right since the 1970s, it's that there are no boring worlds. Io and Europa were supposed to be dead chunks of rock. Triton was a frozen hunk of ice. And Enceladus was surely boring. Wrong, wrong, wrong. Always bet on interesting.

And that's just our Solar System let alone the universe at large.
Title: Re: Proposed Europa Missions
Post by: redliox on 12/13/2015 03:30 am
Relatively fresh news: ESA' granted JUICE approval to build through Airbus.  It's mentioned here among numerous other sites: http://sci.esa.int/juice/57014-jupiter-mission-contract-ceremony/ (http://sci.esa.int/juice/57014-jupiter-mission-contract-ceremony/)
Quote
Airbus Defence & Space SAS in France was announced as the prime contractor in July when ESA approved the €350 million contract.

The contract covers the design, development, integration, test, launch campaign and in-space commissioning of the spacecraft. The Ariane 5 launch is not included and will be procured later from Arianespace.

The 10 state-of-the-art instruments were approved by ESA in February 2013 and are being developed by teams spanning 16 European countries, the USA and Japan, under national funding.

The spacecraft will be assembled at Airbus Defence and Space GmbH in Friedrichshafen, Germany.

So ESA is getting the ball rolling for JUICE now.  I'm curious if there are any specifics on the Airbus design.  The current batch of images seem to show a version of JUICE that has cross-shaped solar arrays akin to communication satellites.  In any case, it is good to see progress moving and can only hope we'll hear from 'Clipper in time.

...on a side note, it will be interesting to see which of the two will reach Jupiter first!
Title: Re: Proposed Europa Missions
Post by: AegeanBlue on 12/14/2015 01:57 am

...on a side note, it will be interesting to see which of the two will reach Jupiter first!

Europa Clipper. JUICE has a convoluted orbit picking up energy in the inner solar system before getting to Jupiter. Europa Clipper will be on a direct ascent orbit to Jupiter, just like the Pioneers and the Voyagers before it
Title: Re: Proposed Europa Missions
Post by: vjkane on 12/14/2015 04:04 am

...on a side note, it will be interesting to see which of the two will reach Jupiter first!

Europa Clipper. JUICE has a convoluted orbit picking up energy in the inner solar system before getting to Jupiter. Europa Clipper will be on a direct ascent orbit to Jupiter, just like the Pioneers and the Voyagers before it
That is assuming that SLS completes development.  At least one new president and a couple of new Congresses.  If it doesn't, Europa Clipper launches later and takes the same slow route as JUICE.
Title: Re: Proposed Europa Missions
Post by: Star One on 12/14/2015 06:26 am


...on a side note, it will be interesting to see which of the two will reach Jupiter first!

Europa Clipper. JUICE has a convoluted orbit picking up energy in the inner solar system before getting to Jupiter. Europa Clipper will be on a direct ascent orbit to Jupiter, just like the Pioneers and the Voyagers before it
That is assuming that SLS completes development.  At least one new president and a couple of new Congresses.  If it doesn't, Europa Clipper launches later and takes the same slow route as JUICE.

I'd a thought SLS is too far along for easy cancellation.
Title: Re: Proposed Europa Missions
Post by: Zed_Noir on 12/14/2015 09:22 am


...on a side note, it will be interesting to see which of the two will reach Jupiter first!

Europa Clipper. JUICE has a convoluted orbit picking up energy in the inner solar system before getting to Jupiter. Europa Clipper will be on a direct ascent orbit to Jupiter, just like the Pioneers and the Voyagers before it
That is assuming that SLS completes development.  At least one new president and a couple of new Congresses.  If it doesn't, Europa Clipper launches later and takes the same slow route as JUICE.

I'd a thought SLS is too far along for easy cancellation.

Will the Congressional critters fund the EUS upper stage? Otherwise you are struck with the  iCPS upper stage on top of the SLS. Which is only a little better than a Delta IV Heavy with a solid kick stage.
Title: Re: Proposed Europa Missions
Post by: AegeanBlue on 12/14/2015 03:06 pm

Will the Congressional critters fund the EUS upper stage? Otherwise you are struck with the  iCPS upper stage on top of the SLS. Which is only a little better than a Delta IV Heavy with a solid kick stage.


I am under the impression that EUS is in FY2016 funding. The omnibus seems to be pretty far along, we might see this week but my sense from the news article is that the EUS was already in the House version of NASA's budget and that the Senate accepted it. The support that the Europa mission gets from Sen Shelby is that it will serve as the test mission for the EUS enabled SLS, or at least that is my understanding
Title: Re: Proposed Europa Missions
Post by: NovaSilisko on 12/16/2015 06:55 am
Quote
Jeff Foust
‏@jeff_foust
That planetary figure includes $175M for a Europa mission that “shall include an orbiter with a lander” with a 2022 target launch date.

https://twitter.com/jeff_foust/status/677031184128438272

Huh.
Title: Proposed Europa Missions
Post by: Star One on 12/16/2015 06:56 am
Quote
Jeff Foust
‏@jeff_foust
That planetary figure includes $175M for a Europa mission that “shall include an orbiter with a lander” with a 2022 target launch date.

https://twitter.com/jeff_foust/status/677031184128438272

Huh.

That seems to be setting quite a high bar on capabilities and the timescale to deliver them?
Title: Re: Proposed Europa Missions
Post by: NovaSilisko on 12/16/2015 07:00 am
Yeah, as I mentioned in my tweet to Foust, it's basically asking for huge cost overruns and delays, now...
Title: Re: Proposed Europa Missions
Post by: Yet.another.newbie on 12/16/2015 07:08 am
Is the $175M funding for 1 year only, or for the entire project?
Title: Re: Proposed Europa Missions
Post by: NovaSilisko on 12/16/2015 07:10 am
Is the $175M funding for 1 year only, or for the entire project?

It's for the next year.
Title: Re: Proposed Europa Missions
Post by: Yet.another.newbie on 12/16/2015 07:31 am
Is the $175M funding for 1 year only, or for the entire project?

It's for the next year.

Hmm. If they get that amount per year for the next 6 years to 2022, that'd bring the project cost to $1B. ... Which is a lot less that Curiosity's $2.5B. I see your point!
Title: Re: Proposed Europa Missions
Post by: Alpha_Centauri on 12/16/2015 08:02 am
Quote
Jeff Foust
‏@jeff_foust
That planetary figure includes $175M for a Europa mission that “shall include an orbiter with a lander” with a 2022 target launch date.

https://twitter.com/jeff_foust/status/677031184128438272

Huh.

That seems to be setting quite a high bar on capabilities and the timescale to deliver them?

I'm surprised they haven't ordered it to be crewed...[sarcasm]
Title: Re: Proposed Europa Missions
Post by: Star One on 12/16/2015 12:58 pm

What you have to understand is that this is a form of budgetary chicken--Congress is going to keep adding the money in for Europa in order to force the President to fund the Europa mission, and the President (OMB) is going to keep dragging its feet. The threat inherent (implicit) in the congressional move is that if the President keeps dragging his feet, then the money is going to be wasted--it is not enough to actually build a spacecraft, but it is way more than is required for studies and basic hardware development. It is a really inefficient way to do things.

I worked on the planetary decadal survey and I don't remember a Europa lander being recommended there...

I don't know enough about US politics on this matter but I thought missions such as this were always funded via Congress?
Title: Proposed Europa Missions
Post by: Star One on 12/16/2015 06:58 pm
I don't know enough about US politics on this matter but I thought missions such as this were always funded via Congress?

Well, yeah, but it's complex and full of subtleties. Most times a new project has to be initiated in the president's budget request. Congress then appropriates the money. If the administration does not really want a project to happen, they can drag their heels on the implementation and the money gets spent very inefficiently. Essentially, it's like the administration telling all the workers to sit around on their hands and not do anything useful.

In order for a project to properly work, the administration has to plan out a multi-year budget profile--year 1, 2, 3, 4 and so on. That indicates a commitment by them to not only spend the money in the coming year, but to ask for money in following years and keep working toward the goal. To date the administration has really dragged its heels on this. They only agreed to a "new start" on the Europa mission because Congress (Culberson) kept appropriating the money. The money kept piling up there and getting spent inefficiently, because the administration did not want to commit to a big expensive Europa mission. Eventually they gave in, but they did so reluctantly.

In addition, Culberson is writing things into law (like the lander and the SLS launch) that very few people have actually asked for. The science community outlines its priorities in the decadal survey. You might look at the decadal survey and see what it says about the requirement for a Europa lander...

I doubt the decadal survey or any science really will be all that relevant if this just turns into yet another political football between a Democratic White House & Republican Congress, which from the sound of it is exactly what it is in danger of becoming.
Title: Proposed Europa Missions
Post by: Star One on 12/16/2015 09:12 pm
I doubt the decadal survey or any science really will be all that relevant if this just turns into yet another political football between a Democratic White House & Republican Congress, which from the sound of it is exactly what it is in danger of becoming.

I'm moderately optimistic on this one. But I want to see an affordable Europa mission, not something that is going to be ridiculously expensive. There is some reason to be concerned.

Doesn't someone have to blink first between the two of them for common sense to prevail?
Title: Re: Proposed Europa Missions
Post by: llanitedave on 12/17/2015 12:02 am
I volunteer to blink on both their behalfs.
Title: Re: Proposed Europa Missions
Post by: JH on 12/17/2015 02:17 am
I doubt the decadal survey or any science really will be all that relevant if this just turns into yet another political football between a Democratic White House & Republican Congress, which from the sound of it is exactly what it is in danger of becoming.

This is one of those strange cases where interparty/interbranch conflict isn't the primary culprit. It's Culberson using the fact that his party is in power to pursue a personal ambition.

As a side note: the planetary community is strongly split over this lander development. Many are worried about it pushing the mission over the edge into being axed, but a (seemingly growing) number are under the impression that it'll make it through with the lander. I'm not sure if they are counting on Culberson staying in his position long enough for momentum to carry it or if they simply aren't thinking.
Title: Re: Proposed Europa Missions
Post by: NovaSilisko on 12/17/2015 02:26 am
Here's a question though, maybe I've missed something - do they mean a Jupiter orbiter and Europa lander or a Europa orbiter and Europa lander?

The first one I could see being done more (very relatively speaking) easily, with a separate launch for the lander. The second possibility is what worries me more given it would need a massive redesign.
Title: Re: Proposed Europa Missions
Post by: redliox on 12/17/2015 07:35 am
Here's a question though, maybe I've missed something - do they mean a Jupiter orbiter and Europa lander or a Europa orbiter and Europa lander?

The first one I could see being done more (very relatively speaking) easily, with a separate launch for the lander. The second possibility is what worries me more given it would need a massive redesign.

Jupiter orbiter with multiple Europa flybys, deploying a Europa lander.

This would have to be a small lander. I have a hard time figuring out how they get to that point. One of the big challenges for a lander is the requirement for good landing site photography. So they somehow have to do that with the orbiter before deploying the lander. And how do they define "good" photography?

I'd also ask about science-per-dollar for the lander. Can a lander that is small enough to fit on this mission, and will only last a short time on the Europa surface, do anything useful for the high cost? JPL has estimated this as $700 million to $1 billion.* What will we get for that amount of money? That is the equivalent of another New Frontiers mission. Will it provide a New Frontiers mission's worth of data?

The joys of putting a price on science, eh Blackstar?  ;)

Surprised a lander is mentioned...but then again, maybe it is implied as a future mission, not necessarily glued directly to 'Clipper (until they come up with a better acronym or name I'm gonna stick with 'Clipper).  After all, if 'Clipper is successful the successor is guaranteed to be a lander.  Blackstar is right about Culberson pushing his influence, but NASA might be able to interpret it several ways: small piggy-back, ESA partnership, or large future mission.  We'll have to see...

My personal opinion: I'd hope for the ESA-option.
Title: Re: Proposed Europa Missions
Post by: JH on 12/17/2015 08:04 am
They are still debating cumulative rad exposure vs imaging coverage (how many flybys to wait before picking a landing site and going in). Peak panchromatic resolution will be 0.5 m with near-global coverage at the 50 level. That's with the currently selected NAC.
Title: Re: Proposed Europa Missions
Post by: as58 on 12/17/2015 08:05 am

The joys of putting a price on science, eh Blackstar?  ;)

Surprised a lander is mentioned...but then again, maybe it is implied as a future mission, not necessarily glued directly to 'Clipper (until they come up with a better acronym or name I'm gonna stick with 'Clipper).  After all, if 'Clipper is successful the successor is guaranteed to be a lander.  Blackstar is right about Culberson pushing his influence, but NASA might be able to interpret it several ways: small piggy-back, ESA partnership, or large future mission.  We'll have to see...

My personal opinion: I'd hope for the ESA-option.

ESA seems to be willing to do a joint mission, such options are specifically mentioned in M5 plans. But I don't believe ESA plans are compatible with launch in early 2020s.
Title: Re: Proposed Europa Missions
Post by: notsorandom on 12/17/2015 01:43 pm

The joys of putting a price on science, eh Blackstar?  ;)

Surprised a lander is mentioned...but then again, maybe it is implied as a future mission, not necessarily glued directly to 'Clipper (until they come up with a better acronym or name I'm gonna stick with 'Clipper).  After all, if 'Clipper is successful the successor is guaranteed to be a lander.  Blackstar is right about Culberson pushing his influence, but NASA might be able to interpret it several ways: small piggy-back, ESA partnership, or large future mission.  We'll have to see...

My personal opinion: I'd hope for the ESA-option.

ESA seems to be willing to do a joint mission, such options are specifically mentioned in M5 plans. But I don't believe ESA plans are compatible with launch in early 2020s.
My understanding is that ESA is adding the option to piggyback on the Europa Mission in the M5 opportunity. A proposal can be made which involves partnering with NASA on the Europa Mission but that proposal is not guaranteed to win the M5 competition. ESA has made no firm commitment, just that they will allow a Europa Mission add-on to compete against all the other proposals. Is that still the case?
Title: Re: Proposed Europa Missions
Post by: muomega0 on 12/17/2015 02:27 pm
The joys of putting a price on science, eh Blackstar?  ;)
Blackstar is right about Culberson pushing his influence, but NASA might be able to interpret it several ways: small piggy-back, ESA partnership, or large future mission.  We'll have to see...

My personal opinion: I'd hope for the ESA-option.

Creating a 'flagship'! mission forced on Science that must be completed by 2022 with a lander for the uncrewed SLS before the scientific community can do the necessary research to determine whether that's a place we want to send a lander.   The first (real?) SLS mission, since 2005, will now total well over $40B.  "And just to make sure Bolden and others at NASA headquarters got the message, he wrote the requirement right into the law." (http://arstechnica.com/science/2015/12/congress-nasa-must-not-only-go-to-europa-it-must-land/)   The actually launch with alone will cost $3B, bettere spent on everything else.  Buying expensive things NASA does not need. (https://www.youtube.com/watch?v=kJ4SSvVbhLw)

SLS/Orion are the gifts that keep on giving. Lets all celebrate success! (http://forum.nasaspaceflight.com/index.php?topic=37330.msg1458329#msg1458329)
Title: Re: Proposed Europa Missions
Post by: sdsds on 12/18/2015 03:53 am
It's pretty clear: Congress doesn't fund science missions for the same reasons scientists seek funding from Congress. So it's nice when things happen to align. But its not something we should expect on a regular basis!

Setting science return aside entirely, isn't it obvious why Congress wants a lander as part of a Europa mission? I think I can summarize the concept in one word: "Philae."
Title: Re: Proposed Europa Missions
Post by: Star One on 12/18/2015 09:38 am

It's pretty clear: Congress doesn't fund science missions for the same reasons scientists seek funding from Congress. So it's nice when things happen to align. But its not something we should expect on a regular basis!

Setting science return aside entirely, isn't it obvious why Congress wants a lander as part of a Europa mission? I think I can summarize the concept in one word: "Philae."

Nothing wrong with that if it results in such a mission been green-lighted.;)
Title: Re: Proposed Europa Missions
Post by: Proponent on 12/18/2015 11:30 am
The most recent decadal survey does not call for a Europa lander.  Such a thing is obviously potentially very interesting, but the scientists whose jobs are to determine the best use of the available resources do not believe it's the right way to go.  If the politicians were to boost funding for planetary science so that the lander did not squeeze the rest of the planetary program, it would still be a win from the planetary scientits' point of view.  But such a funding boost is unlikely, especially when you consider that even a Europa orbiter was recommended by the decadal survey only given a robust planetary-science budget (otherwise the survey recommends a Uranus orbiter and probe instead).

But perhaps I should just be impressed that America is blessed with brilliant scientist-politicians like Rep. Culberson who know better than all of those stupid PhD scientists! :)
Title: Re: Proposed Europa Missions
Post by: Star One on 12/18/2015 12:13 pm

The most recent decadal survey does not call for a Europa lander.  Such a thing is obviously potentially very interesting, but the scientists whose jobs are to determine the best use of the available resources do not believe it's the right way to go.  If the politicians were to boost funding for planetary science so that the lander did not squeeze the rest of the planetary program, it would still be a win from the planetary scientits' point of view.  But such a funding boost is unlikely, especially when you consider that even a Europa orbiter was recommended by the decadal survey only given a robust planetary-science budget (otherwise the survey recommends a Uranus orbiter and probe instead).

But perhaps I should just be impressed that America is blessed with brilliant scientist-politicians like Rep. Culberson who know better than all of those stupid PhD scientists! :)

I am no fan of politicians but really should we keep moaning if they are giving you money?
Title: Re: Proposed Europa Missions
Post by: sdsds on 12/18/2015 06:06 pm
It's pretty clear: Congress doesn't fund science missions for the same reasons scientists seek funding from Congress.

You extrapolate from this one example to a sweeping generalization like that?

Honestly it's more an interpolation to science of a more general trend. Newly manufactured C-27J Spartans delivered directly to the boneyard, for example. And it isn't just in the U.S. The EU has had its "butter mountain." Admittedly it's a generalization. But unlike in a market-driven economy, when funding comes from government the goods and services produced are not always the "rational best" choices.

Sorry if that seems off-topic, but it's a direct response to the notion of "extrapolation," and it ties back to why some science is funded and other science is not. The point about Congressional legislation requiring input from the science community is a good one. Personally I attribute that to the good work of individual members of Congress who are attempting to change the status quo of federal funding priorities.... I feel it is not just fair, but down-right patriotic to laud those efforts, while nonetheless berating Congress as a whole.

Title: Re: Proposed Europa Missions
Post by: redliox on 12/18/2015 07:14 pm
The most recent decadal survey does not call for a Europa lander.  Such a thing is obviously potentially very interesting, but the scientists whose jobs are to determine the best use of the available resources do not believe it's the right way to go. 
The secondary issue is cost-vs-benefit. If this lander costs $1 billion and operates for a few days, is it worth skipping an entire New Frontiers mission for that?

In general I have to say, given choice, waiting for a larger, full-fledged lander is the wiser option.  Still, while pricey, a billion dollars to solve a few essential questions about the outer solar system's most habitable world (Enceladus would be 2nd) might be worthwhile.  Naturally, it'd depend on if a piggyback-lander, ESA or NASA-built, could be properly managed...which is obviously tricky with only a billion for an ambitious quest.

I'd suggest two avenues a small, short-lived lander might pursue: seismology and chemistry.  While the 'Clipper's radar will offer very strong evidence, a seismometer would be even better confirmation an ocean exists under Europa.  Secondly, drilling into the ice even by a few centimeters should tell if there's unique chemistry happening both from below and through radiation-alternation; the chemistry results would be affected by where it lands, but I'd say odds are most regions of Europa should have some chemical traces of churning with the subsurface, just some are more pristine than others.

Going with seismology and chemistry as the priorities, a small lander needs three primary instruments: a seismometer, a wet-chemistry lab, and a camera.  The instruments themselves could be derived from Phoenix and InSight, which themselves were fairly cheap landers (compared to monstrous programs like JWST or Curiosity at least), perhaps with a drill system borrowed from Philae (ESA anyone?).  If there were to be a 4th instrument, I'd suggest a microscope; while unlikely on the irradiated surface, nothing would justify a billion well-spent than seeing a microbe or worm wiggling under a lens.

Just my thoughts, but I'm still two-parts favoring a large, separate lander with one-part favoring a potential piggyback lander.
Title: Re: Proposed Europa Missions
Post by: AegeanBlue on 12/18/2015 08:15 pm
Government's function is to cover a number of needs of its citizens (or its subjects in less free states) using limited resources. Now in theory a government prioritizes what needs it covers based on its urgency or importance, in practice though what is covered when is based on the political power of those who benefit, the return on maintaining or expanding power and prestige of those who appropriate money and the ideologies and prejudices of those in power.

Europa Clipper, like the entire planetary science program is a prestige project for the United States. Earth Science does have added value on data acquired, space science (for the most part) does not. Europa Clipper's function for the appropriators is to demonstrate that America is The Greatest in the World Today. Having a lander demonstrates that, Philae style. On the other hand if there are too many overruns the lander becomes the sacrificial part of the mission that keeps the rest of the mission going through its sacrifice, Europa Clipper's Iphigenia. I wonder if a penetrator, like the one described by vj Kane in his blog would cover Culberson's lander requirement.
Title: Re: Proposed Europa Missions
Post by: llanitedave on 12/18/2015 09:56 pm
The most recent decadal survey does not call for a Europa lander.  Such a thing is obviously potentially very interesting, but the scientists whose jobs are to determine the best use of the available resources do not believe it's the right way to go. 
The secondary issue is cost-vs-benefit. If this lander costs $1 billion and operates for a few days, is it worth skipping an entire New Frontiers mission for that?

In general I have to say, given choice, waiting for a larger, full-fledged lander is the wiser option.  Still, while pricey, a billion dollars to solve a few essential questions about the outer solar system's most habitable world (Enceladus would be 2nd) might be worthwhile.  Naturally, it'd depend on if a piggyback-lander, ESA or NASA-built, could be properly managed...which is obviously tricky with only a billion for an ambitious quest.

I'd suggest two avenues a small, short-lived lander might pursue: seismology and chemistry.  While the 'Clipper's radar will offer very strong evidence, a seismometer would be even better confirmation an ocean exists under Europa.  Secondly, drilling into the ice even by a few centimeters should tell if there's unique chemistry happening both from below and through radiation-alternation; the chemistry results would be affected by where it lands, but I'd say odds are most regions of Europa should have some chemical traces of churning with the subsurface, just some are more pristine than others.

Going with seismology and chemistry as the priorities, a small lander needs three primary instruments: a seismometer, a wet-chemistry lab, and a camera.  The instruments themselves could be derived from Phoenix and InSight, which themselves were fairly cheap landers (compared to monstrous programs like JWST or Curiosity at least), perhaps with a drill system borrowed from Philae (ESA anyone?).  If there were to be a 4th instrument, I'd suggest a microscope; while unlikely on the irradiated surface, nothing would justify a billion well-spent than seeing a microbe or worm wiggling under a lens.

Just my thoughts, but I'm still two-parts favoring a large, separate lander with one-part favoring a potential piggyback lander.
Don't know if you can do it in a few days, but the best way to discover whether there's life in Europa's oceans is via paleontology.  If there are any visible areas of ice that are the remnants of liquid plumes ejected from Europa's interior, those plumes would probably have carried any organisms living in that water, and then entombed them in ice when it froze onto the surface.  There may be fossil remnants of those organisms that can be detected.
Title: Re: Proposed Europa Missions
Post by: davey142 on 12/19/2015 01:38 am
While I do agree with the sentiment here that a lander might make the mission too expensive, the recent budget deal congress passed is a pretty clear signal that congress is willing to give NASA the money. The increase for both SLS (including ordering NASA to bypass ICPS) and for Planetary Science is making me cautiously optimistic that a flagship, orbiter + lander mission might not break the bank.
Title: Re: Proposed Europa Missions
Post by: redliox on 12/19/2015 08:37 am
While I do agree with the sentiment here that a lander might make the mission too expensive, the recent budget deal congress passed is a pretty clear signal that congress is willing to give NASA the money. The increase for both SLS (including ordering NASA to bypass ICPS) and for Planetary Science is making me cautiously optimistic that a flagship, orbiter + lander mission might not break the bank.

What's the total cost of the Europa mission including SLS?

That should be the next billion dollar question: will the SLS be part of the mission cost or will it be treated separately?  I can only assume separately, and previously in the Discovery program the launcher was treated as a "freebie" as long as the probe wouldn't overload it.  If 'Clipper is given a free ride, I'd wager a handful of mini-missions would ride along too; as in cube-sats like for EM-1.  Perhaps a new premise could be set that for every large mission (flagship or frontier), a half-dozen tiny ones accompany it aboard an SLS launch.  If it is to be used for probes (as it should be), it would be only fair to include smaller packages to make the most out of a gigantic rocket.
Title: Re: Proposed Europa Missions
Post by: Star One on 12/19/2015 09:22 am
While I do agree with the sentiment here that a lander might make the mission too expensive, the recent budget deal congress passed is a pretty clear signal that congress is willing to give NASA the money. The increase for both SLS (including ordering NASA to bypass ICPS) and for Planetary Science is making me cautiously optimistic that a flagship, orbiter + lander mission might not break the bank.

What's the total cost of the Europa mission including SLS?

That should be the next billion dollar question: will the SLS be part of the mission cost or will it be treated separately?  I can only assume separately, and previously in the Discovery program the launcher was treated as a "freebie" as long as the probe wouldn't overload it.  If 'Clipper is given a free ride, I'd wager a handful of mini-missions would ride along too; as in cube-sats like for EM-1.  Perhaps a new premise could be set that for every large mission (flagship or frontier), a half-dozen tiny ones accompany it aboard an SLS launch.  If it is to be used for probes (as it should be), it would be only fair to include smaller packages to make the most out of a gigantic rocket.

Agree. I am sure even with a direct flight to Jupiter there will still be performance to spare for smaller secondary missions. Perhaps you could fit in some kind of smaller mission to another money maybe such as Io.
Title: Re: Proposed Europa Missions
Post by: vjkane on 12/19/2015 06:38 pm
IMO, Blackstar has nailed it.  The spacecraft plus lander will cost $3Bish and the SLS launch will be $1Bish (from memory; the heaviest lift standard launchers are, again from old memories) around $500Mish.

Over the holidays, I'm going to write a blog post about the coming planetary budget crunch.  On deck, per planned AOs and Congressional mandates: 2 Discovery missions (2x$600-650Mish), 1 New Frontiers ($1Bish), Mars 2020 (>$2.5B), and Europa mission ($4Bish) (all costs with launches and operations). 

That's a big elephant for the snake to swallow.
Title: Re: Proposed Europa Missions
Post by: redliox on 12/19/2015 07:51 pm
IMO, Blackstar has nailed it.  The spacecraft plus lander will cost $3Bish and the SLS launch will be $1Bish (from memory; the heaviest lift standard launchers are, again from old memories) around $500Mish.

Sounds about right; that's why I said NASA might include tiny missions that piggyback with the launcher, not 'Clipper itself not unlike how Ariane 5 can send up 2 satellites to GTO.  In the SLS' case it'd be one flagship probe to Jupiter with a handful of cubesats that might visit anything between NEOs to the Trojans.  With or without an added lander for Europa, NASA might do something like this to justify the $1 billion on a non-Orion flight.
Title: Re: Proposed Europa Missions
Post by: redliox on 12/20/2015 07:53 pm
A few sites are claiming there's a part of the new budget, around $25 million, that is being set aside for development for a Europa lander.  This could still be for either a small 'Clipper piggyback or a later, larger lander but either way it seems they're taking landing on Europa seriously on top of the 'Clipper project already.  Assuming this turns out to be the piggyback option, it becomes a matter of micromanaging the 'Clipper's time between relaying the lander's science while performing its own.  This isn't an impossible task, the Cassini proves that (not to mention Cassini had to suffer a delay in releasing Huygens due to the doppler issue), but the crucial difference beyond added cost is that radiation won't allow indefinite operation.  So the question I pose is: when should the lander be deployed during 'Clipper's primary mission?

There are 4 options I see, each happening at a different point in 'Clipper's mission with different ramifications on both spacecraft:

1 - Release before orbit insertion: Just as Galileo did with its probe, 'Clipper could possibly directly aim the lander at Europa to save the fuel burden (either direct landing or gravity assists).  This would probably be the option with the largest effect on the lander both in design and needing to select a landing site with only current data.

2 - Start of Europa campaign: After the Callisto & Ganymede flybys set 'Clipper into a ~36 day orbit with Europa, the lander could be set to do its job swiftly to minimize its burden on 'Clipper's science and utilize 'Clipper while it is still young and functional for an assured relay.  As with first option, main disadvantage is using only current data for landing site selection while otherwise burdening 'Clipper with fuel needs for JOI.

3 - Middle of Europa campaign: Possibly after at least four months of flying by Europa and obtaining new data, the lander could be released, benefiting from a better selection.  More fuel burden for the 'Clipper and possibly risk of accumulated radiation damage to the lander.

4 - End of primary mission: The 'Clipper could first focus on its nominal mission while lugging the lander around Jupiter.  As before, there would be the benefit of fresh science from 'Clipper but the disadvantage, as in option 3, is accumulated rad damage...although at the end of the mission it would be the health of both 'Clipper and the lander to worry about.

Again, assuming they seriously add a piggyback lander to the project, out of the 4 options I laid out I'd suggest going with the first.  The 'Clipper itself would be the more important half, and while ground truth would be vital at Europa a decent map with data obtained over years is more vital.  The lander would have to manage its own arrival at Europa, meaning a mini-rocket of its own attached, but with the SLS option (especially if it's the EUS in play) such a burden could be accommodated reasonably.

I'm still surprised at the lander option suddenly given, but I'm not going to view it as a curse on 'Clipper.  The 'Clipper itself is pretty assured.  They just have to be certain whether or not they could pull of essentially a 'Europan Pathfinder.'
Title: Re: Proposed Europa Missions
Post by: Alpha_Centauri on 12/31/2015 07:55 am
Thought I'd post this here,

https://www.ucl.ac.uk/mssl/planetary-science/EuropaPenetratorWorkshop

Gives the timescale for when we might find out more about the proposed ESA contributions that will be put forward for M5.

And the penetrator is dubbed 'Akon'

Edit: also here's a recent update on development of the penetrator, they're currently testing impact resistant batteries and are preparing to design the comms.

http://congrexprojects.com/docs/default-source/15c17_-proocedings/s2-6---chruch_uk_space_pen_presentation_to_esa_conf_nov15_1.pdf?sfvrsn=2
Title: Re: Proposed Europa Missions
Post by: redliox on 01/01/2016 11:57 pm
Thought I'd post this here,

https://www.ucl.ac.uk/mssl/planetary-science/EuropaPenetratorWorkshop

Gives the timescale for when we might find out more about the proposed ESA contributions that will be put forward for M5.

And the penetrator is dubbed 'Akon'

Edit: also here's a recent update on development of the penetrator, they're currently testing impact resistant batteries and are preparing to design the comms.

http://congrexprojects.com/docs/default-source/15c17_-proocedings/s2-6---chruch_uk_space_pen_presentation_to_esa_conf_nov15_1.pdf?sfvrsn=2

Sounds promising.  I wish Deep Space 2 had this kind of technology behind it.
Title: Re: Proposed Europa Missions
Post by: vjkane on 01/04/2016 02:52 am
I've published a blog post on the Europa lander for anyone interested in (hopefully) informed speculation given how little is known.

http://futureplanets.blogspot.com/2015/12/a-lander-for-nasas-europa-mission.html

Title: Re: Proposed Europa Missions
Post by: redliox on 01/04/2016 07:35 am
I've published a blog post on the Europa lander for anyone interested in (hopefully) informed speculation given how little is known.

http://futureplanets.blogspot.com/2015/12/a-lander-for-nasas-europa-mission.html

Read it and liked it.   :)

So, going by what Eric Berger implied in the article you cite, he's suggesting a chemistry mission?  If the quest is to find evidence of life, or an environment that would support it ala Curiosity, chemistry would be foremost.  I would agree both the mass and Raman spectrometer are good ideas, especially if they can capitalize in advancements made since the construction days of Galileo and Cassini-Huygens.  Something vital about Europa would be revealed.

I'm wondering how the magnetometer and plasma instruments would handle a rough landing if they're deployed to collect data in orbit.  In most cases magnetometers necessitate being on long and somewhat flimsy-looking booms...though I assume there are ways to make a spacecraft magnetically clean or to get useful readings out of it in a stowed state.

If something lands, the seismometer should be a must, as damnable the data rates may be.  The communication bandwidth issue you mention is good to think on; a bold soul would suggest putting an optical link on the lander instead of 'Clipper...but that'd be a huge stretch to manage on what will be a complex engineering matter (though, I would think putting the laser target on a planetary body instead of a fast-moving probe would offer a hint more stability; at least they'd know where to aim the beam).  To the point, a seismometer would verify the ocean on Europa with verifying any potential tectonic/volcanic activity a bonus.  I'd even vote to sacrifice an imager if it meant a working seismometer.  Hopefully there would be a way to accommodate it, the 2 chemistry instruments, and an imager.

Should be interesting seeing what comes out of the next lander study.
Title: Re: Proposed Europa Missions
Post by: notsorandom on 01/04/2016 02:07 pm
...To the point, a seismometer would verify the ocean on Europa with verifying any potential tectonic/volcanic activity a bonus.  I'd even vote to sacrifice an imager if it meant a working seismometer...
A very basic imager would be needed to deploy a seismometer. A seismometer needs to go on the surface to get away from the vibration of the lander. To do that an imager and robotic arm are needed. InSight has an imager but it is a panchromatic sensor which isn't suitable for much beyond placing the instruments. That mission had to make the choice for a minimal camera system due to cost. Since no imager has ever been taken to the surface of Europa funding should be easier to find compared to a flat boring area on Mars.
Title: Re: Proposed Europa Missions
Post by: vjkane on 01/04/2016 03:48 pm
In reply to several comments:

On the seismometer, I've never seen a Europa lander proposal that would place the instrument on the surface (although this may be a detail that was left out of the summaries that are often publicly available).  Remember, though, there's no wind on Europa, which is one of the key reasons for getting the instrument off the lander on Mars.  Also, the immense tides on Europa should cause easy to measure seismic activity.  The InSight SEIS instrument was looking for movement as subtle as that caused by the tides from Phobos.

For the magnetometer, I presume that on a small lander it will either be on the spacecraft or only only a short boom -- space and mass would be tight.  Might have two or more magnetometers at different locations to help model and then subtract the signal from the spacecraft.

As for the plasma instrument, it could be on the descent stage.  Don't remember a plasma instrument being included in any lander instrument complement.

I wonder if any European team will suggest a very minimal Europa orbiter that would carry just a magnetometer, a plasma instrument, and precise radio tracking.  Magnetic field and gravity measures are high priority, but hard to build up enough global data in a multi-flyby mission (I believe that the Europa mission achieves  a threshold set of measurements late in the primary mission).  A small orbiter could have lots of shielding and would have low data rates and hence low power needs.  Even a few weeks in orbit might provide much better measurements, but this is my speculation.  Would be interested to know whether this would be useful or not.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 01/04/2016 03:58 pm
How do you detect life it if it being spewed up in the plumes from Europa? Here's a discussion:

http://authors.elsevier.com/a/1SJ6i4L-YETCE

Download the pdf for free for the next 30 days from that site.
Title: Re: Proposed Europa Missions
Post by: baldusi on 01/04/2016 04:11 pm
There's something that kind of sounds strange to me. Why send the lander on the same flight to then wait two years or so in a parking orbit. Wouldn't it make much more sense to make a minimal lander later and send it four years later? A Delta IV Heavy can do 2 tonnes to C3=82km²/s². That should be plenty. And you get four extra years to spread the budget expenditure and you can squeeze all the Clipper information.
It would preclude the option of data relay. But it would seem risky to me to depend on a single pass to actually get your data back.
Title: Re: Proposed Europa Missions
Post by: vjkane on 01/04/2016 04:24 pm
There's something that kind of sounds strange to me. Why send the lander on the same flight to then wait two years or so in a parking orbit. Wouldn't it make much more sense to make a minimal lander later and send it four years later? A Delta IV Heavy can do 2 tonnes to C3=82km²/s². That should be plenty. And you get four extra years to spread the budget expenditure and you can squeeze all the Clipper information.
It would preclude the option of data relay. But it would seem risky to me to depend on a single pass to actually get your data back.
I agree that this does sound strange.  Assuming that Berger got it straight (and his reporting his good on other topics) then I can only imagine that this is being done to (1) fly it on the same mission per Culberson's directive (2) buy time to build up high resolution imaging of potential landing sites (3) its lighter/cheaper/smaller to detach early rather than to carry the extra shielding to stay with the main spacecraft during all its forays into the high radiation belts.

I think that an alternative would be to team with the Europeans (they build the lander, JPL builds the skycrane descent system, split the instruments, Europe launches?) and launch a couple of years later.  Might even be the mass/budget to fly two.
Title: Re: Proposed Europa Missions
Post by: rbarry55 on 01/04/2016 04:25 pm
Is a RTG  being considered for the lander?   Or will Jupiter's radiation kill a lander in a few days making long term power a mute issue?
Title: Re: Proposed Europa Missions
Post by: Star One on 01/04/2016 04:30 pm

I've published a blog post on the Europa lander for anyone interested in (hopefully) informed speculation given how little is known.

http://futureplanets.blogspot.com/2015/12/a-lander-for-nasas-europa-mission.html

Thanks for that. Not sure I agree with your editorialise comments as I'd favour the most ambitious mission possible as who knows when another opportunity for this kind of project is going to roll around.
Title: Re: Proposed Europa Missions
Post by: GClark on 01/04/2016 06:57 pm
$$$$$

I come down on the side of the Clipper mission as it has been developed to date.  The fastest way to get this mission killed is to 'Christmas Tree' it and have the budget blow up.

JPL has so far exercised great restraint, designing a mission that will accomplish high priority science on the lowest possible budget.  Add too much stuff on and OMB will nuke it fast.  They're already reluctant to authorize a New Start for this - how about we don't give them an excuse to go all passive-aggressive on us?

Especially on a mission that has to survive two Administrations and three Congresses just to get to launch.

Title: Re: Proposed Europa Missions
Post by: Blackstar on 01/04/2016 09:22 pm
Is a RTG  being considered for the lander?

No.
Title: Re: Proposed Europa Missions
Post by: baldusi on 01/04/2016 09:40 pm
Is a RTG  being considered for the lander?

No.
RHU?
Title: Re: Proposed Europa Missions
Post by: Blackstar on 01/05/2016 12:48 am
Is a RTG  being considered for the lander?

No.
RHU?

Is a RTG  being considered for the lander?

No.
RHU?

Probably. Battery power is finite and you don't want to waste it on heaters to keep the electronics warm. That said, any Pu-238 on Europa creates problems, because it can create a melted spot in the ice that could allow Earth microbes to survive. So they have to design for this possibility.
Title: Proposed Europa Missions
Post by: Star One on 01/06/2016 04:43 pm
ESA wants to be a part of NASA’s mission to Europa

Quote
NASA asked the European Space Agency last year whether it was interested in contributing to the Europa mission, and Gimenez said in an interview with Spaceflight Now that the answer is yes.

“We will participate with no cost to NASA by us contributing something equivalent to a half-billion euros in cost to ESA,” Gimenez said. “Now, where it goes depends on the cooperation.

“This is a NASA mission, and we are happy to be a junior partner with NASA,” Gimenez told Spaceflight Now in December. “It’s our natural partnership with the U.S., and we will be very happy to do it. Now, they have to tell us the profile of the mission, what they want to do, and where do we have a role. But certainly we would appreciate the opportunity.”

Quote
“We are ready and interested,” Gimenez said. “As I said to my colleague in the U.S., we cannot allow Americans to go to Europa without Europeans. We have to be part of it. We think that it is natural, but certainly we will not lead, so we have to wait.”

Gimenez said ESA is taking its cues from NASA on Europa, so Europe will wait for a formal invitation before making the next move, which could come as soon as this year in the form of a request for mission proposals from the European science community.

“In all the discussions we have had, NASA is very open to our cooperation, but again, they have to define it,” Gimenez said. “It is a complicated mission. For Europa, in particular, we need a lot of mass. This is a very harsh environment (due to high radiation doses at Jupiter).”

http://spaceflightnow.com/2016/01/05/esa-wants-to-be-a-part-of-nasas-mission-to-europa/
Title: Re: Proposed Europa Missions
Post by: vjkane on 01/06/2016 04:47 pm
ESA wants to be a part of NASA’s mission to Europa

Quote
NASA asked the European Space Agency last year whether it was interested in contributing to the Europa mission, and Gimenez said in an interview with Spaceflight Now that the answer is yes.

“We will participate with no cost to NASA by us contributing something equivalent to a half-billion euros in cost to ESA,” Gimenez said. “Now, where it goes depends on the cooperation.

“This is a NASA mission, and we are happy to be a junior partner with NASA,” Gimenez told Spaceflight Now in December. “It’s our natural partnership with the U.S., and we will be very happy to do it. Now, they have to tell us the profile of the mission, what they want to do, and where do we have a role. But certainly we would appreciate the opportunity.”

http://spaceflightnow.com/2016/01/05/esa-wants-to-be-a-part-of-nasas-mission-to-europa/

Not clear if there's the mass margin for both NASA's lander and a European probe, or that there's not.  NASA may not yet know; they've only been studying the lander serious, I believe, for a few months.  Anyone know for sure how long?
Title: Re: Proposed Europa Missions
Post by: Alpha_Centauri on 01/06/2016 06:59 pm
Quote
The call would have a special emphasis on Europa, but any space science mission could be proposed and be eligible for the competition, according to Favata.

Because the top guys essentially prejudging the outcome is not gonna go down like a cold cup of sick with the rest of the science community...

As far as I'm aware pretty much most past proposals, plus a whole lot more, are planning to respond to the M5 call.  It's the first real opportunity since M3 and lots of cool ideas are being floated which I'm not sure a Europa contribution could beat in a fair fight. 
Title: Re: Proposed Europa Missions
Post by: vjkane on 01/06/2016 07:09 pm
Quote
The call would have a special emphasis on Europa, but any space science mission could be proposed and be eligible for the competition, according to Favata.

Because the top guys essentially prejudging the outcome is not gonna go down like a cold cup of sick with the rest of the science community...

As far as I'm aware pretty much most past proposals, plus a whole lot more, are planning to respond to the M5 call.  It's the first real opportunity since M3 and lots of cool ideas are being floated which I'm not sure a Europa contribution could beat in a fair fight.

I also wonder about using M5 as the funding mechanism.  $550M for a 250 kg probe and NASA provides the launch seems like vast overkill.  Thoughts anyone?
Title: Re: Proposed Europa Missions
Post by: Star One on 01/06/2016 07:41 pm

Quote
The call would have a special emphasis on Europa, but any space science mission could be proposed and be eligible for the competition, according to Favata.

Because the top guys essentially prejudging the outcome is not gonna go down like a cold cup of sick with the rest of the science community...

As far as I'm aware pretty much most past proposals, plus a whole lot more, are planning to respond to the M5 call.  It's the first real opportunity since M3 and lots of cool ideas are being floated which I'm not sure a Europa contribution could beat in a fair fight.

But I would doubt that any of those would be going to high value target like Europa. I don't blame ESA wanting to have a piece of the action.
Title: Re: Proposed Europa Missions
Post by: redliox on 01/06/2016 07:50 pm
I also wonder about using M5 as the funding mechanism.  $550M for a 250 kg probe and NASA provides the launch seems like vast overkill.  Thoughts anyone?

I think it might fit like a glove, although of course ESA would have its members do a vote as they always do for their various missions.  In a way the setup would be parallel to what Cassini-Huygens went through: a NASA-supplied flyby-orbiter delivering a ESA lander to the moon of a giant planet; the main difference lays with the moon's environment: irradiated and no atmosphere.

I see 3 ways ESA might go about this between what the congressman wants and Vjkane's prior references to daughter spacecraft:

1) Io flyby orbiter: If we can't land, this seems a worthwhile, viable option since not as much fuel is required and its mission would interfere less with 'Clipper's.
2) Europa penetrator: The UK seems to be pushing well with this option, and it might be better prepared than Deep Space 2 was at Mars.  If it can crash land  safely, this might be slightly less cumbersome than developing a lander.
3) Europa lander: Might be a small pain for 'Clipper to drag along, but considering ESA has experience with Huygens, Philae, and (very soon) Schiaparelli there should be a way for them to deliver a Pathfinder-esque package to Europa.

A partnership with ESA is probably the best way to grant Culberson's wish...as adding another half-billion to 'Clipper might ruin its appeal as others are pointing out.  Grand as the idea is of getting down to Europa within my own lifetime, if ESA can't do this we should wait until 'Clipper completes its mission.  A small lander could give us interesting results, but a large, more matured lander, would easily be worth the wait.
Title: Re: Proposed Europa Missions
Post by: vjkane on 01/06/2016 07:54 pm
I also wonder about using M5 as the funding mechanism.  $550M for a 250 kg probe and NASA provides the launch seems like vast overkill.  Thoughts anyone?

I think it might fit like a glove, although of course ESA would have its members do a vote as they always do for their various missions.  In a way the setup would be parallel to what Cassini-Huygens went through: a NASA-supplied flyby-orbiter delivering a ESA lander to the moon of a giant planet; the main difference lays with the moon's environment: irradiated and no atmosphere.


My point is the $550M for a 250 kg probe with launch costs covered by NASA seems very expensive.  There's a pretty good correlation between mission costs and spacecraft masses.
Title: Re: Proposed Europa Missions
Post by: Alpha_Centauri on 01/06/2016 07:59 pm
I also wonder about using M5 as the funding mechanism.  $550M for a 250 kg probe and NASA provides the launch seems like vast overkill.  Thoughts anyone?

Indeed I mentioned this previously, it seems overkill especially if they go with the penetrator as plenty of development work has already been funded and instrumentation will be naturally limited.  But they do seem to be taking the M5 route. All I'm thinking is perhaps they are expecting extra expense in fast-tracking this, since M5 launch is nominally right at end of the 2020s.

But I would doubt that any of those would be going to high value target like Europa. I don't blame ESA wanting to have a piece of the action.

Really? Since I heard there might be an Enceladus plume-sniffing orbiter with a proposed piggybacked American Titan boat for instance...
Title: Re: Proposed Europa Missions
Post by: Star One on 01/06/2016 08:36 pm

I also wonder about using M5 as the funding mechanism.  $550M for a 250 kg probe and NASA provides the launch seems like vast overkill.  Thoughts anyone?

Indeed I mentioned this previously, it seems overkill especially if they go with the penetrator as plenty of development work has already been funded and instrumentation will be naturally limited.  But they do seem to be taking the M5 route. All I'm thinking is perhaps they are expecting extra expense in fast-tracking this, since M5 launch is nominally right at end of the 2020s.

But I would doubt that any of those would be going to high value target like Europa. I don't blame ESA wanting to have a piece of the action.

Really? Since I heard there might be an Enceladus plume-sniffing orbiter with a proposed piggybacked American Titan boat for instance...

No free launch though.
Title: Re: Proposed Europa Missions
Post by: Alpha_Centauri on 01/06/2016 08:57 pm
But more than just a few hours of fame.

And the free ride simply highlights why it is ridiculous to spend $550m on it.  Can't help feeling if it is just a penetrator, with minimal data rates and limited science data collection, that $550m is a waste of money.  It is not like it would even go where we would really like to go on Europa.
Title: Re: Proposed Europa Missions
Post by: as58 on 01/06/2016 09:01 pm
I also wonder about using M5 as the funding mechanism.  $550M for a 250 kg probe and NASA provides the launch seems like vast overkill.  Thoughts anyone?

Indeed I mentioned this previously, it seems overkill especially if they go with the penetrator as plenty of development work has already been funded and instrumentation will be naturally limited.  But they do seem to be taking the M5 route. All I'm thinking is perhaps they are expecting extra expense in fast-tracking this, since M5 launch is nominally right at end of the 2020s.

Yeah, it feels like a lot of money for such a small probe with free launch. I also wonder how the funding schedule would work, it seems that they'd have to move M5 funding several years earlier. ESA already has a lot of science missions slated for launch in the first half of 2020s. Basically Europa mission would have to be developed simultaneously with M3 mission (PLATO), which is scheduled for launch in 2024. Experience gained in looking for money to build ExoMars will come handy...
Title: Re: Proposed Europa Missions
Post by: kato on 01/07/2016 01:13 am
Huygens was "about" 460 million Euro including the instruments, in 2012 EUR - with inflation that's 480 million EUR to today.

See https://www.esa.int/esaSC/SEM77EUZJND_0_spk.html

ESA basically just picked the same ballpark number again, especially given that design, size and scope would likely be similar as for Huygens.
Title: Re: Proposed Europa Missions
Post by: vjkane on 01/07/2016 02:09 am
Huygens was "about" 460 million Euro including the instruments, in 2012 EUR - with inflation that's 480 million EUR to today.

See https://www.esa.int/esaSC/SEM77EUZJND_0_spk.html

ESA basically just picked the same ballpark number again, especially given that design, size and scope would likely be similar as for Huygens.
The 550M Euro figure comes from the standard cost for ESA Medium class missions (the M4 call was less because the M3 mission is over budget).  By ESA budgeting rules, this amount covers launch (paid for by NASA if the selected mission is a piggyback on NASA's mission), spacecraft, and operations.  Instruments are paid for by the member nations separately.

Huygens was a heavily instrumented probe, which may have driven up the cost above the usual $s (or Euros) per kilogram curve.  Here is the full quote from the link above:

"NASA’s investment in Cassini represents a total of approximately 2100 million Euros. ESA’s contribution for the Huygens probe is about 360 million Euros. An additional investment of about 100 million Euros by universities and research institutes funded the development of the instruments on board Huygens. ASI’s contribution for the high-gain antenna, portions of three science instruments on board Cassini and one full instrument on board Huygens, is about 145 million Euros. All figures are adjusted to today’s economic conditions. "
Title: Re: Proposed Europa Missions
Post by: Star One on 01/08/2016 07:51 pm
A poster over on US seems to be calling into question if this could be a solar alone mission?

http://www.unmannedspaceflight.com/index.php?s=&showtopic=7810&view=findpost&p=228924 (http://www.unmannedspaceflight.com/index.php?s=&showtopic=7810&view=findpost&p=228924)
Title: Re: Proposed Europa Missions
Post by: kato on 01/09/2016 03:23 pm
A lander, not the flyby mission. Different requirements.
Title: Proposed Europa Missions
Post by: Star One on 02/02/2016 05:57 pm
NASA weighing dual launches of Europa orbiter and lander

Quote
Splitting the mission into two launches could allow the clipper spacecraft to remain on a fast track. Niebur said that, given current funding trends where Congress has allocated significantly more for the mission than NASA has requested, a clipper spacecraft alone could be technically ready for launch as soon as 2022.

“If you put a very capable lander on there, I think that’s going to slow things down a bit,” he added. “Do you put them all on the same spacecraft and launch them on the same rocket, or do you split them onto separate rockets? That’s also an option we could consider.”

Quote
Niebur said that, separate from the discussion about a lander, NASA was examining several smaller “augmentations” to the clipper spacecraft. One example he mentioned is a cubesat-sized spacecraft that would fly through plumes of water ice ejected by Europa. Other additions to the clipper spacecraft could address studies of Europa’s gravitational field.

The current spacecraft design has about 250 kilograms of spare mass to support those or other additions to the clipper spacecraft separate from the lander. Those augmentations, he said, would not affect the primary science mission of the main spacecraft and its suite of 10 instruments NASA announced last year.

http://spacenews.com/nasa-weighing-dual-launches-of-europa-orbiter-and-lander/
Title: Re: Proposed Europa Missions
Post by: redliox on 02/03/2016 09:18 pm
Is there any word regarding how the Outer Planet Assessment Group meeting went on the 1st and the 2nd?  Talk on the Europa (Clipper) was supposed to be prominent according to their online schedule, seconded with talks on New Horizons, Cassini, and brief discussion on the Ice Giants.  I was hoping by new some news leaked if nothing else.
Title: Re: Proposed Europa Missions
Post by: Star One on 02/03/2016 09:22 pm

Is there any word regarding how the Outer Planet Assessment Group meeting went on the 1st and the 2nd?  Talk on the Europa (Clipper) was supposed to be prominent according to their online schedule, seconded with talks on New Horizons, Cassini, and brief discussion on the Ice Giants.  I was hoping by new some news leaked if nothing else.

Well the article I linked to above came out of OPAG.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 02/04/2016 12:11 am
I was hoping by new some news leaked if nothing else.

These meetings are open to the public. You are free to attend. Even more, most of them are webcast, so you could listen in. Nothing secret, therefore nothing to "leak."
Title: Re: Proposed Europa Missions
Post by: Borklund on 02/04/2016 07:39 am
Do you know if they are archived and available anywhere?
Title: Re: Proposed Europa Missions
Post by: Tim Alexander on 02/04/2016 07:52 am
Usually the presentations are put up here http://www.lpi.usra.edu/opag/ after a couple of days.
Title: Re: Proposed Europa Missions
Post by: redliox on 02/04/2016 08:17 am
Usually the presentations are put up here http://www.lpi.usra.edu/opag/ after a couple of days.

It's like the anxiety of Christmas all over again...
Title: Re: Proposed Europa Missions
Post by: vjkane on 02/04/2016 03:01 pm
Usually the presentations are put up here http://www.lpi.usra.edu/opag/ after a couple of days.

It's like the anxiety of Christmas all over again...
OPAG can be up to a couple of weeks or more before the presentations are posted (VEXAG a month or two; MEPAG and SBAG the next day, often).

I listened to much of the meeting and a friend sent me notes on what I missed.  The Space News article covered the big news -- including the lander would add more mass to the mission than the orbiter spacecraft.  There was a lot of talk about how to develop a plan for the Ocean Worlds missions.  Since there isn't a program with a separate budget, it looks like it will be more identifying science goals and mission chunks (Discovery, New Frontiers, Flagship) that would address compelling portions of those goals.  The Venus community has dome the equivalent in the last year or so (and two of those chunks are now Discovery finalists).  There is a good sized chunk of funding for Ocean Worlds tech development that may address much of the cost problem.

So, don't expect anything that will be terribly exciting.  Almost all the good stuff was said in the discussion and therefore wasn't captured in the presentations.  One tidbit -- NASA will be pushing to do concept studies for the next Decadal Survey well before the start of the survey.  Doing 38(?) of them in parallel for the last Survey nearly broke the system.  Specific comments were that the cost estimates often were not seen as credible, and there was no time to study a range of concepts with different price points.  For example, the Enceladus studies were conceived of as a Flagship class mission and there wasn't time to study cheaper options.  Someone who was on the Titan lake lander concept said that he tried to get cheaper options examined but there wasn't time and a mindset of what the scale of the mission should have been; having TiME come in at approximately half the estimated cost, was he said, an embarrassment.  (Peace, Blackstar, I'm only reported what was said.) 

From my previous career planning high tech products, I can say that concept studies done quickly either are wildly optimistic or conservative.  It takes time to get examine alternatives especially if a team is designing to a price point, and that is what NASA wants to do by starting studies early.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 02/04/2016 04:10 pm
I listened to much of the meeting and a friend sent me notes on what I missed.  The Space News article covered the big news -- including the lander would add more mass to the mission than the orbiter spacecraft.


I'm going to break up my replies into several posts for clarity. So the lander thing is something that people with a close ear to the ground have suspected was coming for a while. The reason is that the existing Europa Clipper mission (not officially called that anymore) is fairly mature, and a lander is not really compatible with it for lots of reasons. Think of it like designing a two-door sedan and then somebody tells you that you have to use it to haul lumber--the overall frame is done and in order to add that extra mission you have to take it apart and start over. There are lots of reasons that this is true, but one of them is that a lander will require good imagery of potential landing sites, and you cannot get that until late in the EC mission, if at all. So do you carry that lander around for the entire mission as a parasite and then only land it at the end, just before your flyby spacecraft is about to die? Note that this also increases the overall mission risk, because if the flyby spacecraft dies halfway through the mission, you cannot do the lander. That's just one example, but there are apparently a lot of others, including the high mass for a lander (Europa has some real gravity, so it's not like the Rosetta mission).

There are a lot of other things I could say about this, but I won't do that here. I'll respond to some of the other points in some additional posts.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 02/04/2016 04:21 pm
There was a lot of talk about how to develop a plan for the Ocean Worlds missions.  Since there isn't a program with a separate budget, it looks like it will be more identifying science goals and mission chunks (Discovery, New Frontiers, Flagship) that would address compelling portions of those goals.  The Venus community has dome the equivalent in the last year or so (and two of those chunks are now Discovery finalists).  There is a good sized chunk of funding for Ocean Worlds tech development that may address much of the cost problem.

One of the purposes of the Assessment Groups (OPAG, MEPAG, VEXAG, SBAG, LEAG) is to establish science requirements for their subjects and to constantly refine and update those science requirements. They are supposed to be consistent with the Decadal Survey, and they also help to feed forward into the next Decadal Survey. They do these things regularly. I am not very familiar with all of them, but I think that VEXAG has put more emphasis on this than the other groups, but they all do it to some extent. And when NASA is looking at a specific mission, they will create a dedicated Science Definition Team, or SDT.

One of the problems with Ocean Worlds is that it was created by a politician, and not by the scientists. For all the other topics the science community has been developing these science requirements for decades. They've been doing it a long time. Ocean Worlds has just popped up, and it has very little pedigree. If somebody comes along and asks "What are the requirements for Ocean Worlds science? What are the objectives?" they will not get a single succinct and coherent answer. They'll get a lot of mumbling and differing opinions. That is a problem. (It's actually a much bigger problem than those of us outside of all of this can comprehend.)

One reason that it is a problem is that it is hard to review a proposal when you don't know what the standards are. Think of it this way: if you take a class and the teacher tells you that 90% and up is an A, 80-89% is a B, 70-79% is a C and so on, you know exactly what the grading standard is. But if the teacher doesn't have that standard to begin with, then he doesn't know how to make decisions. Should he fail somebody who has a 59% but pass somebody who has a 60%? So, suppose two people propose OW missions--one is going to Titan and the other is going to Enceladus. Which mission is more important scientifically? Without twenty years of an AG working out the science requirements, it is going to be difficult for a reviewer to say that Mission X is more scientifically important than Mission Y. They don't have a set of standards to grade against, and the Decadal Survey is not much of a guide on this because there was no Ocean Worlds program in the DS.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 02/04/2016 04:38 pm
So, don't expect anything that will be terribly exciting.  Almost all the good stuff was said in the discussion and therefore wasn't captured in the presentations.  One tidbit -- NASA will be pushing to do concept studies for the next Decadal Survey well before the start of the survey.  Doing 38(?) of them in parallel for the last Survey nearly broke the system.  Specific comments were that the cost estimates often were not seen as credible, and there was no time to study a range of concepts with different price points.

This is generally true--not enough mission concept studies had been done before the Decadal Survey. But the people who complain about this often fail to give NASA credit for stepping up and funding a lot of mission concept studies during the DS. NASA spent a LOT of money on the Decadal Survey. Funding the survey itself cost a bit, but the mission concept studies probably cost NASA over $5 million to do (I've got numbers written down somewhere in my notes). It's not fair to simply complain and whine and not give credit where it is due.

As for the "cost estimates were not seen as credible" issue, there is validity to that claim, but it's a complex discussion. And keep in mind that there is a tendency for the people who are advocating something to argue that it will be cheap, but nobody on the outside believes that. Have we all forgotten that from 2005-2009 there was a constant drumbeat about NASA missions blowing past their cost estimates? It was not just JWST and MSL, but there were problems with other missions like Dawn and Kepler. Remember that Alan Stern, when he was Associate Administrator for the Science Mission Directorate, made cost discipline a major issue. The reason that the CATE process was imposed (it was required by Congress) was because too many science programs were blowing past their budgets. Now that NASA has had 5+ years of pretty good cost discipline on their science projects, a bunch of scientists are now taking advantage of short memories and complaining about cost estimates imposed upon them from outside.

As I said, there is validity to the argument, but it's not a complaint that will win much sympathy with outsiders and budgeteers at OMB and Congress.

As for the range of concepts with various price points, that's a valid issue. But even when that is done, somebody is going to complain that their specific option did not get a fair hearing. You'll always find somebody to complain about something.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 02/04/2016 05:10 pm
For example, the Enceladus studies were conceived of as a Flagship class mission and there wasn't time to study cheaper options.  Someone who was on the Titan lake lander concept said that he tried to get cheaper options examined but there wasn't time and a mindset of what the scale of the mission should have been; having TiME come in at approximately half the estimated cost, was he said, an embarrassment.  (Peace, Blackstar, I'm only reported what was said.) 


I don't remember the details on the Enceladus studies. But one problem with hindsight is that it tends to compress the past and it is difficult to remember what was happening and when it was happening. We know a lot more about Enceladus today than we did in 2009 when the Decadal Survey was kicking off, or a few years earlier when people would have conducted more mission studies. Even if NASA had performed an Enceladus mission study in 2007 would they have had enough information about it to do "the range of studies with different price points" that people are talking about today?

In addition, you cannot do everything. You have to prioritize, you have to make resource allocation decisions--deciding that you will study mission concept X and you don't have enough time or money to study mission concept Y or Z. And the people who are pushing Y or Z are going to be angry and they are going to complain, but, well, there's no way to make everybody happy and making them happy requires making somebody else unhappy. The people running the NASA planetary program, and the people running the Decadal Survey, had to make choices. And they had to look at the entire solar system, not just individual parts of it.

My own observation of the Satellites Panel from the 50,000 foot level was that they were never going to get Europa and Titan and Enceladus, and so they needed to recognize that early on and cull their options. They may have taken a little longer to do that than they should. But if you compare them to the Mars Panel, that group decided very early on that they were going to put all their focus, and all their capital, on the MAX-C rover. They very deliberately decided to not submit a Mars New Frontiers mission option. They made a tough call and they lived with it.
Title: Re: Proposed Europa Missions
Post by: vjkane on 02/04/2016 05:12 pm
So, don't expect anything that will be terribly exciting.  Almost all the good stuff was said in the discussion and therefore wasn't captured in the presentations.  One tidbit -- NASA will be pushing to do concept studies for the next Decadal Survey well before the start of the survey.  Doing 38(?) of them in parallel for the last Survey nearly broke the system.  Specific comments were that the cost estimates often were not seen as credible, and there was no time to study a range of concepts with different price points.

This is generally true--not enough mission concept studies had been done before the Decadal Survey. But the people who complain about this often fail to give NASA credit for stepping up and funding a lot of mission concept studies during the DS. NASA spent a LOT of money on the Decadal Survey. Funding the survey itself cost a bit, but the mission concept studies probably cost NASA over $5 million to do (I've got numbers written down somewhere in my notes). It's not fair to simply complain and whine and not give credit where it is due.

As for the "cost estimates were not seen as credible" issue, there is validity to that claim, but it's a complex discussion. And keep in mind that there is a tendency for the people who are advocating something to argue that it will be cheap, but nobody on the outside believes that. Have we all forgotten that from 2005-2009 there was a constant drumbeat about NASA missions blowing past their cost estimates? It was not just JWST and MSL, but there were problems with other missions like Dawn and Kepler. Remember that Alan Stern, when he was Associate Administrator for the Science Mission Directorate, made cost discipline a major issue. The reason that the CATE process was imposed (it was required by Congress) was because too many science programs were blowing past their budgets. Now that NASA has had 5+ years of pretty good cost discipline on their science projects, a bunch of scientists are now taking advantage of short memories and complaining about cost estimates imposed upon them from outside.

As I said, there is validity to the argument, but it's not a complaint that will win much sympathy with outsiders and budgeteers at OMB and Congress.

As for the range of concepts with various price points, that's a valid issue. But even when that is done, somebody is going to complain that their specific option did not get a fair hearing. You'll always find somebody to complain about something.
I want to emphasize that I am NOT criticizing either the Decadal Survey team or NASA on the concept studies.  The first planetary Decadal did not, if I remember correctly, do systematic mission studies or cost studies.  The second did, and a learning was that doing a few dozen at once and quickly was much better than none, but starting early would be a good thing to do the next time, and NASA is.  Fortunately, the priorities for planetary science evolve slowly, so there's a good idea of which missions to prioritize for study. 
Title: Re: Proposed Europa Missions
Post by: vjkane on 02/04/2016 05:19 pm
For example, the Enceladus studies were conceived of as a Flagship class mission and there wasn't time to study cheaper options.  Someone who was on the Titan lake lander concept said that he tried to get cheaper options examined but there wasn't time and a mindset of what the scale of the mission should have been; having TiME come in at approximately half the estimated cost, was he said, an embarrassment.  (Peace, Blackstar, I'm only reported what was said.) 

I don't remember the details on the Enceladus studies. But one problem with hindsight is that it tends to compress the past and it is difficult to remember what was happening and when it was happening. We know a lot more about Enceladus today than we did in 2009 when the Decadal Survey was kicking off, or a few years earlier when people would have conducted more mission studies. Even if NASA had performed an Enceladus mission study in 2007 would they have had enough information about it to do "the range of studies with different price points" that people are talking about today?
Blackstar can probably comment on this more, but at the time, there appeared to be an assumption that orbiters were needed to advance Enceladus and Titan studies meaningfully.  Now we have the Europa multiflyby design to show another way (biggest change -- power and comms requirements drop dramatically with time between encounters to return data between encounters).  There are also new trajectory designs that provide very low flyby speeds at Enceladus.  There also have been three teams that have put extensive time into defining three Discovery-class missions.  I see this as a case of the community internalizing the results of the Decadal concept studies and looking for less expensive alternatives.  Exactly how things should work.
Title: Re: Proposed Europa Missions
Post by: vjkane on 02/04/2016 05:26 pm
One of the problems with Ocean Worlds is that it was created by a politician, and not by the scientists. For all the other topics the science community has been developing these science requirements for decades. They've been doing it a long time. Ocean Worlds has just popped up, and it has very little pedigree. If somebody comes along and asks "What are the requirements for Ocean Worlds science? What are the objectives?" they will not get a single succinct and coherent answer. They'll get a lot of mumbling and differing opinions. That is a problem. (It's actually a much bigger problem than those of us outside of all of this can comprehend.)
Curt Niebur, outer planets program director, said that the Ocean Worlds proposers would be at disadvantage compared to the other New Frontiers because the goals and design concepts would be less mature.  He also said, that based on the three Discovery proposals, Ocean Worlds proposals should be able to rise to the top of the competition.  On the other hand, it wasn't clear from the meeting how much money NASA is putting into defining the science goals and funding mission concept studies.  The SAG team was practically begging Niebur for admin support for their effort and Niebur seemed to be elusive.  Perhaps this will be clearer by the next meeting.  All of this is new to NASA and the community.  At one point in the meeting, someone from NASA (Niebur?) said that the decision to include Ocean Worlds in New Frontiers was made in a two week period, presumably following the approval of the FY16 NASA budget directing NASA to pursue an Ocean Worlds program.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 02/04/2016 05:45 pm
He also said, that based on the three Discovery proposals, Ocean Worlds proposals should be able to rise to the top of the competition.

Well, New Frontiers will also include competitors that competed in previous New Frontiers (and Discovery) competitions. And they have the benefit of having much clearer science goals established over a long period of time. A reviewer looking at, say, a South Pole-Aitken Basin sample return mission proposal can easily look at what it does and compare it to the science requirements established over the past fifteen years or so and determine if it satisfies those requirements. That's much harder to do for a set of science goals that have not even been established yet for Ocean Worlds.

Title: Re: Proposed Europa Missions
Post by: Arb on 02/04/2016 06:18 pm
One of the problems with Ocean Worlds is that it was created by a politician, and not by the scientists. For all the other topics the science community has been developing these science requirements for decades. They've been doing it a long time. Ocean Worlds has just popped up, and it has very little pedigree. If somebody comes along and asks "What are the requirements for Ocean Worlds science? What are the objectives?" they will not get a single succinct and coherent answer. They'll get a lot of mumbling and differing opinions. That is a problem. (It's actually a much bigger problem than those of us outside of all of this can comprehend.)
Which leads to the question, how might the community go about establishing science requirements for Ocean Worlds and how much time does that need; initially and then refined?
Title: Re: Proposed Europa Missions
Post by: Blackstar on 02/04/2016 06:31 pm
Which leads to the question, how might the community go about establishing science requirements for Ocean Worlds and how much time does that need; initially and then refined?

As I said, normally this is a process that is underway for years, and constantly being updated.

I'm sure that somebody could establish science requirements in a couple of minutes, a couple of hours, a day, or a week. The question then is how credible are they? And does the community as a whole agree with those requirements?
Title: Proposed Europa Missions
Post by: Star One on 02/04/2016 07:26 pm
From following Alan Stern's tweets it looks like there might be a follow up Pluto mission that will go into the mix for the next Decadal survey.
Title: Re: Proposed Europa Missions
Post by: Jim on 02/04/2016 08:07 pm
Looks like there won't be an SLS configuration for Europa Clipper since ICPS is only flying once.
Title: Re: Proposed Europa Missions
Post by: Tim Alexander on 02/04/2016 08:40 pm
Is there no chance of it using an EUS then?
Title: Re: Proposed Europa Missions
Post by: vjkane on 02/04/2016 09:06 pm
From following Alan Stern's tweets it looks like there might be a follow up Pluto mission that will go into the mix for the next Decadal survey.
There will probably be 20-50 missions proposed in the white papers submitted to the process.  A smaller number will be considered in more depth.

A follow on mission to Pluto would need to be at least New Frontiers class.  A fundamental problem is that to get to Pluto in any reasonable time, you need to fly really, really fast, making it impossible (at least with today's boosters) to carry enough fuel to slow down at the other end (a problem with Neptune orbiter proposals, too).  Maybe you could use low power (RTG) electric propulsion (proposed but not flown for other missions; don't know if this would be enough to slow down).

If you can only do a flyby, I think it will be hard for a follow up mission to compete with the existing and possible new candidate missions for New Frontiers and Flagship.  How do you fundamentally enhance our understanding of Pluto or the solar system with another flyby.  If you see anything from Stern addressing this, please post a link.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 02/04/2016 10:42 pm
If you can only do a flyby, I think it will be hard for a follow up mission to compete with the existing and possible new candidate missions for New Frontiers and Flagship.  How do you fundamentally enhance our understanding of Pluto or the solar system with another flyby.  If you see anything from Stern addressing this, please post a link.


Yeah, I agree. Pluto was a scientifically fascinating target the first time because a) we knew nothing about it, and b) we knew nothing about the class of objects that it represents. So a flyby provided a huge increase in data. But what could a second flyby reveal that would be that big a step? My guess is that they'll have a penetrator or something like that to add on, but even then that's not much.

NASA has a general philosophy of "flyby, orbit, land, rove" that makes a lot of sense.
Title: Re: Proposed Europa Missions
Post by: Star One on 02/04/2016 10:49 pm

If you can only do a flyby, I think it will be hard for a follow up mission to compete with the existing and possible new candidate missions for New Frontiers and Flagship.  How do you fundamentally enhance our understanding of Pluto or the solar system with another flyby.  If you see anything from Stern addressing this, please post a link.


Yeah, I agree. Pluto was a scientifically fascinating target the first time because a) we knew nothing about it, and b) we knew nothing about the class of objects that it represents. So a flyby provided a huge increase in data. But what could a second flyby reveal that would be that big a step? My guess is that they'll have a penetrator or something like that to add on, but even then that's not much.

NASA has a general philosophy of "flyby, orbit, land, rove" that makes a lot of sense.

A Pluto orbiter would be a heck of a technical challenge to resolve.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 02/05/2016 03:09 am

If you can only do a flyby, I think it will be hard for a follow up mission to compete with the existing and possible new candidate missions for New Frontiers and Flagship.  How do you fundamentally enhance our understanding of Pluto or the solar system with another flyby.  If you see anything from Stern addressing this, please post a link.


Yeah, I agree. Pluto was a scientifically fascinating target the first time because a) we knew nothing about it, and b) we knew nothing about the class of objects that it represents. So a flyby provided a huge increase in data. But what could a second flyby reveal that would be that big a step? My guess is that they'll have a penetrator or something like that to add on, but even then that's not much.

NASA has a general philosophy of "flyby, orbit, land, rove" that makes a lot of sense.

A Pluto orbiter would be a heck of a technical challenge to resolve.

I'm sure SpaceX could do it. They can do anything.
Title: Re: Proposed Europa Missions
Post by: vjkane on 02/05/2016 04:44 am
The OPAG presentations are up

http://www.lpi.usra.edu/opag/meetings/feb2016/presentations/
Title: Re: Proposed Europa Missions
Post by: Eric Hedman on 02/05/2016 05:10 am
I'm sure SpaceX could do it. They can do anything.
Now that is funny! ;) ;D :o
Title: Re: Proposed Europa Missions
Post by: redliox on 02/05/2016 08:22 am
While not specifically scientific, I love the sense of humor among Jovian scientists.  ;D
Title: Re: Proposed Europa Missions
Post by: Arb on 02/05/2016 05:34 pm
Which leads to the question, how might the community go about establishing science requirements for Ocean Worlds and how much time does that need; initially and then refined?

As I said, normally this is a process that is underway for years, and constantly being updated.

I'm sure that somebody could establish science requirements in a couple of minutes, a couple of hours, a day, or a week. The question then is how credible are they? And does the community as a whole agree with those requirements?

Quite so. But that doesn't really move the conversation on. Let's try a slightly different question.

Given a need/desire to move quickly and a 'can do' attitude, what might be a reasonable minimum time to establish credible science requirements that have community agreement?
Title: Re: Proposed Europa Missions
Post by: Blackstar on 02/05/2016 06:04 pm
Given a need/desire to move quickly and a 'can do' attitude, what might be a reasonable minimum time to establish credible science requirements that have community agreement?

Think about that a bit. Then think about it a bit more.

How would anybody be able to answer that question? You're talking about doing something that would then convince a lot of people. But there's no way to determine how much or how long it will take to convince all those people, because, well, they're PEOPLE. In the past it has taken a long time to get everybody lined up.

Apparently during OPAG there were a few people who talked about how great it was that they now had an Ocean Worlds program that could do the stuff that they thought was really really cool. And apparently somebody posed a counter-question: Would you be happy if NASA had inserted the Moon into this program instead of ocean worlds? (And the answer to that is no--almost certainly some of the people dancing with joy now were really annoyed a decade ago when NASA--at presidential initiative--created a lunar program and started stuffing missions into it.*)

I know that peoples' eyes glaze over when I discuss this, but there is a process for getting the scientific community onboard and moving in the right direction. And that process actually works fairly well. And what's happening now is that the process is being bypassed. That will make some people happy, but it has ramifications.




*The now-ended Lunar Quest program line was part of that, and generally it did not interfere with the NASA science program, it augmented it. So it's not really what is happening now. But it's close enough to be useful for the question. You can find a bit about it here:

http://www.nasa.gov/mission_pages/lunarquest/main/#.VrTxsxgtUhQ

Title: Re: Proposed Europa Missions
Post by: vjkane on 02/05/2016 06:15 pm
As for how long to reach consensus, that depends on the question and the class of mission.

I suspect that nearly everyone would agree that improving the chemical analyses of Enceladus' plumes with modern mass spectrometers (which the proposed ELF mission would have done) is a top priority.

Go one level below that, and it gets much, much harder.  Is it more important to study the size and salinity of Enceladus' interior ocean (a top priority for Europa), map the surface geology of Titan using the spectral windows (a top priority for Europa; was included in the JET proposal), analyze the chemistry of Titan's lakes (the TiME proposal), or fly a balloon in Titan's atmosphere?  Each represents different scientific questions, so which questions are most important.

The Venus community spent a lot of time prioritizing their science goals and then mapping those goals to different classes of missions.  See the first two documents at this link: http://www.lpi.usra.edu/vexag/

My guess is that you are probably a couple of years from a similar document for Ocean Worlds.

Title: Re: Proposed Europa Missions
Post by: redliox on 02/05/2016 08:47 pm
Getting back to Europa...

Reading through the presentations, I get a strong vibe that preserving the flyby orbiter (whether you call it 'Clipper or otherwise) is foremost, which is both wise and something I agree with.  The orbiter itself has its instruments, bypassed the development curse of nuclear power, and is maturing well.  So now it becomes a question of whether a daughter craft will accompany or not...

The ESA presentations appear to emphasize the penetrator or mini-orbiter options.  Naturally, of course, compared to Europa (Clipper) they are in the table napkin sketch stage; however, it seems the UK in particular is starting to step up on the penetrator option to the point it's even been dubbed "Akon" after a javelin given to the mythical Europa as a gift from Zeus...which seems a fitting title.  The mini-orbiters probably have more support outside the UK though, as there were more scientists/project leaders listed for them whereas the penetrator named only 1.  Outside of those possibilities, ESA seems to imply it'll contribute instruments/hardware to a NASA orbiter or lander, but won't fully develop a soft lander entirely.

As Blackstar predicted it was overall a minor update, but still the fresh news was encouraging.  I'd like to see a UK-led ESA push for the penetrator as it'd be the smallest possible mini-probe that could find unique science the flyby orbiter could not, which is the big disadvantage for a Europa-focused mini-orbiter (although the Io variant I could get behind).  The next news I'd like to hear would be whether the Europa mission gets fully approved for an SLS flight, and whether it'd be the Block I or Block IB version.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 02/05/2016 08:49 pm
As for how long to reach consensus, that depends on the question and the class of mission.

I suspect that nearly everyone would agree that improving the chemical analyses of Enceladus' plumes with modern mass spectrometers (which the proposed ELF mission would have done) is a top priority.

Go one level below that, and it gets much, much harder.  Is it more important to study the size and salinity of Enceladus' interior ocean (a top priority for Europa), map the surface geology of Titan using the spectral windows (a top priority for Europa; was included in the JET proposal), analyze the chemistry of Titan's lakes (the TiME proposal), or fly a balloon in Titan's atmosphere?  Each represents different scientific questions, so which questions are most important.

From my limited understanding of how this is done and how the community approaches it, generally the most important science is the stuff that is considered "fundamental," meaning that it answers a major question about the solar system as a whole, or a whole class of objects in the solar system. If you look at the science goals for a number of the New Frontiers missions like South Pole-Aitken Basin Sample Return, you will see that the science goals are often to answer things like "how did the solar system form?" or "where did the Moon come from?" or "what role did the late heavy bombardment play in key processes on Earth?" (I'm paraphrasing these things, probably badly.)

Put another way, "when did life form on planet Earth?" is a much bigger and more important question than "when did giraffes get their long necks?" Applying that to this subject, if they can identify science questions where answering it for one body like Enceladus provides lots of insight into other bodies, like Europa, Ganymede, even Earth, then that science will be considered more valuable and more scientists will say "Yeah, that's important to know and we support missions that will answer that."

Title: Re: Proposed Europa Missions
Post by: Blackstar on 02/05/2016 09:05 pm
Getting back to Europa...

Reading through the presentations, I get a strong vibe that preserving the flyby orbiter (whether you call it 'Clipper or otherwise) is foremost, which is both wise and something I agree with. 

To expand upon this a bit, as I noted earlier, JPL has been working on the design now for about four years. It's still in Phase A (or maybe pre-Phase A?) status, but it's actually quite mature for that stage. (That's something that we could certainly dive into much deeper. From what I understand, the longer missions stay in this stage, the less likely they are to encounter problems when they go into hardware development. Push them out of Phase A early and chaos and budget overruns ensue.)

And that's where NASA is in a bit of a bind, because they have been given a set of somewhat contradictory requirements. If they really are going to try and make the 2022 launch date, then they need to preserve as much of the design work as they can and not change too much. But if they add in a lander, or a bunch of new instruments, or whatever, that can create all kinds of shifts in the design and that can create big problems. This is the challenge of systems engineering: you reach a point in the design where every new change affects EVERYTHING ELSE.

So, for instance, deciding that instead of the older technology camera you want to add the newer/better technology camera means that the camera weighs more and is a little larger, and this changes the center of gravity, and it also pushes another instrument a few centimeters to the side, changing the CG even more, and that requires changes to the electrical wiring and the power supply, and also to the control software, and it also means that you're going to have to add a little bit of propellant, which shifts the CG again, which affects the software and then it requires shifting the RCS thrusters or the control moment gyros to handle those new requirements and that forces other changes and so on and on and on and on...

So what the designers want to do is lock down all the major decisions like instrument size and mass and power requirements and get everybody to stop changing stuff. They want to be fine tuning the design, not careening all over the place. And that is vital to making a target launch date.

So here we are, clock ticking, six years to launch (2022 is, yes, six years from now), and that's probably not enough time to build a major spacecraft without screwing everything up, and it is certainly not enough time to build that major spacecraft plus a lander that is still very immature in design.

Go back and read that Space News article linked above and you'll understand why they're talking this way now. It's crunch time, do we want a Europa spacecraft that can probably be launched in six years, or do we want to keep mucking around with the design for a few more years and maybe launch it in seven, nine, ten years?
Title: Re: Proposed Europa Missions
Post by: redliox on 02/05/2016 09:27 pm
Getting back to Europa...

Reading through the presentations, I get a strong vibe that preserving the flyby orbiter (whether you call it 'Clipper or otherwise) is foremost, which is both wise and something I agree with. 

To expand upon this a bit, as I noted earlier, JPL has been working on the design now for about four years. It's still in Phase A (or maybe pre-Phase A?) status, but it's actually quite mature for that stage. (That's something that we could certainly dive into much deeper. From what I understand, the longer missions stay in this stage, the less likely they are to encounter problems when they go into hardware development. Push them out of Phase A early and chaos and budget overruns ensue.)

And that's where NASA is in a bit of a bind, because they have been given a set of somewhat contradictory requirements. If they really are going to try and make the 2022 launch date, then they need to preserve as much of the design work as they can and not change too much. But if they add in a lander, or a bunch of new instruments, or whatever, that can create all kinds of shifts in the design and that can create big problems. This is the challenge of systems engineering: you reach a point in the design where every new change affects EVERYTHING ELSE.

No arguments here; I was just glad when the instrument selections came through and adding in the UV spectrograph was enough of a bonus to hear; a UV imager tended to be a less demanding device whereas optical/thermal imagers and mass spectrometers were data/power munchers.  Whatever else is added between now and the ~'22 launch date should be kept minimal, be it new instrument or daughter spacecraft, especially since the current orbiter can generate enough science to put Galileo (even if its antenna fully deployed) to shame.

Go back and read that Space News article linked above and you'll understand why they're talking this way now. It's crunch time, do we want a Europa spacecraft that can probably be launched in six years, or do we want to keep mucking around with the design for a few more years and maybe launch it in seven, nine, ten years?

Actually read said-article before it was ever quoted on Nasaspaceflight.  Ultimately I don't think forcing the Europa mission to have a soft-or-otherwise-large lander is possible for all the reasons you thoroughly explained.  If something is to be added, it should be small and semi-independent like Huygens was for Cassini (or more accurately akin to DS2 for Mars Polar Lander with better engineering); but naturally things like the support structure as well as power cables are things even a smaller probe would demand.  The demands of the penetrator mission, for instance, might not be so much for power but rather aiming it.

ESA should be the linchpin regarding lander-or-no-lander, otherwise NASA should firmly state the lander must be a separate mission for better or worse.  I'm excited Congressmen are being generous toward Planetary Science for a change but it shouldn't compromise a promising mission.
Title: Re: Proposed Europa Missions
Post by: vjkane on 02/05/2016 10:48 pm
From my limited understanding of how this is done and how the community approaches it, generally the most important science is the stuff that is considered "fundamental," meaning that it answers a major question about the solar system as a whole, or a whole class of objects in the solar system. If you look at the science goals for a number of the New Frontiers missions like South Pole-Aitken Basin Sample Return, you will see that the science goals are often to answer things like "how did the solar system form?" or "where did the Moon come from?" or "what role did the late heavy bombardment play in key processes on Earth?" (I'm paraphrasing these things, probably badly.)

Put another way, "when did life form on planet Earth?" is a much bigger and more important question than "when did giraffes get their long necks?" Applying that to this subject, if they can identify science questions where answering it for one body like Enceladus provides lots of insight into other bodies, like Europa, Ganymede, even Earth, then that science will be considered more valuable and more scientists will say "Yeah, that's important to know and we support missions that will answer that."

I partially disagree, and partially agree.  There are some missions that can provide insights to processes central to how the solar system formed or to a large number of worlds.  The New Frontiers candidates appear to be selected with that in mind.  Several of the Discovery missions have tended to be more single world focused.  GRAIL and InSight, for example, really focused on single worlds.

It was suggested at the OPAG meeting that a central theme for Ocean Worlds would be deep sea oceanography, which would include the Earth.  So a science priority list might be built around the fundamental questions of how oceans work similarly and differently.

I think there will also be a significant amount of prioritization of questions unique to each body.  As an analogy, for Mars there has been a focus on finding locations with a history of prolonged surface water.  That isn't a set of goals transferable to any other world in our solar system.  Similarly, it may be decided that understanding the chemistry of Titan's lakes is incredibly important even though they are unique in the solar system.

I suspect that for anyone interested in this topic, a good place to start would be to look at the goals for Europa, which have been defined in great detail.  Then apply them to Enceladus and Titan.  Understand what the surface geology and composition tells you about processes (probably done for Enceladus by Cassini, barely started for Titan).  Study the depth and composition of the ocean (gravity, radar, magnetometry, sample any plumes).  Land at any areas with very interesting surface chemistry.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 02/05/2016 11:35 pm
As an analogy, for Mars there has been a focus on finding locations with a history of prolonged surface water.  That isn't a set of goals transferable to any other world in our solar system.

But that's because those goals are part of the larger goal of searching for habitability and signs of past or current life on Mars, which is a big, fundamental question.

That's why I mentioned the SPAB mission--to an outsider it seems boring because it is just going to bring back some samples from a single spot on the Moon. But the science is pretty fundamental and could answer some big questions.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 02/05/2016 11:42 pm
No arguments here; I was just glad when the instrument selections came through and adding in the UV spectrograph was enough of a bonus to hear; a UV imager tended to be a less demanding device whereas optical/thermal imagers and mass spectrometers were data/power munchers. 

Someday somebody is going to write a history of this mission and hopefully they will capture the convoluted and often bizarre early maneuvering to get it underway. (Then again, I suspect that all major space science projects have bizarre and convoluted origin stories--that's certainly true of both MSL/Curiosity and JWST.)

Culberson kept shoving money into the budget for a Europa mission that did not actually exist. It did not have a "new start" to begin detailed design. There are limits to how much money you can spend in that situation, even for JPL which has all kinds of inventive ways of spending a lot of money. From what I heard, the money was simply piling up in the accounts, and JPL couldn't spend much of it because until they start development and put dozens of engineers on the task order, they have internal limits on their spending. So NASA came up with the clever idea of buying the instruments before entering development on the spacecraft based upon the assumption that the spacecraft can eventually be designed around a good suite of instruments. I don't know if that is true--maybe they are just asking for a mess--but I think it was the only reasonable response to the situation, until the president's budget included the new start. Choosing the instrument suite was a great way to solve that money problem, because they could then send $10 million to instrument team X, and $12 million to instrument team Y, and so on, and the money no longer just sat in an account, unspent, and angrying-up the congressman who gave it to them.
Title: Re: Proposed Europa Missions
Post by: sdsds on 02/06/2016 05:36 am
Looks like there won't be an SLS configuration for Europa Clipper since ICPS is only flying once.

Is there no chance of it using an EUS then?

I'm confused but....

Is there a need for an ICPS, or would a stock 5m DCSS be sufficient?
Title: Re: Proposed Europa Missions
Post by: redliox on 02/06/2016 05:46 am
Is there no chance of it using an EUS then?

Considering the EUS would need a flight test I mainly presumed that the Europa mission would be the guinea pig in exchange for using the vehicle "free of charge."  Frankly though I'd like to hear actual news confirming what vehicle it will fly on, not just 'either the SLS or Altas V' retort.
Title: Re: Proposed Europa Missions
Post by: Arb on 02/06/2016 04:24 pm
Re the science requirements thing; it turned into a most interesting and educational discussion. Thank you, gentlemen.
Title: Re: Proposed Europa Missions
Post by: Jim on 02/07/2016 12:26 pm

Considering the EUS would need a flight test I mainly presumed that the Europa mission would be the guinea pig in exchange for using the vehicle "free of charge."  Frankly though I'd like to hear actual news confirming what vehicle it will fly on, not just 'either the SLS or Altas V' retort.

EM-2 is EUS with Orion
Title: Re: Proposed Europa Missions
Post by: redliox on 02/07/2016 09:49 pm

Considering the EUS would need a flight test I mainly presumed that the Europa mission would be the guinea pig in exchange for using the vehicle "free of charge."  Frankly though I'd like to hear actual news confirming what vehicle it will fly on, not just 'either the SLS or Altas V' retort.

EM-2 is EUS with Orion

That's been known for a little while, the question is...especially with any delays to EM-2, whether Europa's flight could still get squeezed in beforehand on the first EUS.
Title: Re: Proposed Europa Missions
Post by: sdsds on 02/07/2016 11:22 pm
the question is...especially with any delays to EM-2, whether Europa's flight could still get squeezed in beforehand on the first EUS.

Could we call that an "EM 1.5?" <chortle>
Title: Re: Proposed Europa Missions
Post by: Jim on 02/08/2016 03:00 am

That's been known for a little while, the question is...especially with any delays to EM-2, whether Europa's flight could still get squeezed in beforehand on the first EUS.

What delays?  If there are any delays, they will be EUS driven and not Orion driven.  The push is going to be on EM-2.   Plus Europa is not going on SLS with an EUS.
Title: Re: Proposed Europa Missions
Post by: Star One on 02/08/2016 06:24 am


That's been known for a little while, the question is...especially with any delays to EM-2, whether Europa's flight could still get squeezed in beforehand on the first EUS.

What delays?  If there are any delays, they will be EUS driven and not Orion driven.  The push is going to be on EM-2.   Plus Europa is not going on SLS with an EUS.

Do you mean it's not going on SLS full stop?
Title: Re: Proposed Europa Missions
Post by: NovaSilisko on 02/08/2016 05:19 pm
Jim, are you stating an opinion or something you know is really going to happen?
Title: Re: Proposed Europa Missions
Post by: Blackstar on 02/11/2016 04:18 pm
http://www.spacepolicyonline.com/news/nasa-fy2017-budget-request-sets-up-familiar-battles-with-congress

"Sending a probe to Europa is a passion of Rep. John Culberson (R-TX) who chairs the House appropriations subcommittee that funds NASA.  He is confident that NASA will find signs of life there, making this a mission of critical importance in his view.   He has added substantial funds for such a mission for the past three years.  In the FY2016 budget, he funded the program at $175 million (the request was $30 million), specified that it include a lander as well as an orbiter and that it be launched in 2022 using SLS.  For FY2017, NASA is requesting only $49.6 million and projecting a launch in the late 2020s on an Evolved Expendable Launch Vehicle (EELV), not SLS.  (NASA Chief Financial Officer David Radzanowski stressed today during a media telecon describing the budget request that NASA is not precluding an SLS launch, but does not have pricing details yet on which to base a cost estimate.)  NASA's budget documents say that accelerating the mission from the late 2020s to 2022 "is not recommended, given potential impacts to the rest of the Science portfolio."  As required, NASA provided the budget profile that would be needed to achieve a 2022 launch:  $194 million in FY2017, $272 million in FY2018, $456 million in FY2019, $678 million in FY2020, and $482 million in FY2021."
Title: Re: Proposed Europa Missions
Post by: redliox on 02/13/2016 11:29 am
So nominally the Europa mission is being budgeted for Atlas V partially because they can predict that expense better?  I would hope somewhere someone is attempting to account for SLS' expense, but I understand the precaution since the vehicle still has yet to be flight tested (not to mention being just-plain-huge).  The only other thought on launcher is, going the SLS route, was it planned for Europa to fly Block I or Block Ib originally?  Odds seem to imply a EUS route unless NASA decides to use the spare for Europa.

Assuming the Atlas V route, how extensive was the 'long-route' to Jupiter?
Title: Re: Proposed Europa Missions
Post by: Zed_Noir on 02/13/2016 01:05 pm
So nominally the Europa mission is being budgeted for Atlas V partially because they can predict that expense better?  I would hope somewhere someone is attempting to account for SLS' expense, but I understand the precaution since the vehicle still has yet to be flight tested (not to mention being just-plain-huge).  The only other thought on launcher is, going the SLS route, was it planned for Europa to fly Block I or Block Ib originally?  Odds seem to imply a EUS route unless NASA decides to use the spare for Europa.

Assuming the Atlas V route, how extensive was the 'long-route' to Jupiter?

Not necessary the Atlas V. If NASA can not meet the 2022 launch date. Then there will be other EELV class launchers available after the Atlas V & Delta IV is phased out in the early 2020s.

IMO the Europa mission is not going to fly before 2024 if the lander is part of the mission.

In one of the SLS threads it was mention that the EM-2 flight mightl not be using the EUS stage.

Title: Re: Proposed Europa Missions
Post by: Blackstar on 02/13/2016 06:34 pm
So nominally the Europa mission is being budgeted for Atlas V partially because they can predict that expense better?

I'm not sure that is the only reason. Keep in mind that NASA has a list of approved launch vehicles and their characteristics (these are all covered under a launch services contract that the agency has with its providers). Thus choosing Atlas is relatively easy to do for planning purposes because they know exactly how long it takes to build, what it can do, and what it costs for a given configuration. SLS is still much more of a moving target. It's sort of the difference between buying off the shelf and buying custom made.

And also keep in mind that SMD (Planetary Sciences Division) will only pay the cost of an Atlas to HEOMD for an SLS. In other words, if the SLS is going to cost the science division more than an Atlas, they don't want it. But that still requires HEOMD to pay the full cost of the SLS. And that still requires the overall NASA budget to account for it. So adding an SLS launch to NASA's manifest also requires more money in the budget to pay for it.

I am still doubtful that they'll ever fly the Europa mission on an SLS, but it remains a viable option. But it is also problematic for budgeting purposes.
Title: Proposed Europa Missions
Post by: Star One on 02/13/2016 10:16 pm
So nominally the Europa mission is being budgeted for Atlas V partially because they can predict that expense better?

I'm not sure that is the only reason. Keep in mind that NASA has a list of approved launch vehicles and their characteristics (these are all covered under a launch services contract that the agency has with its providers). Thus choosing Atlas is relatively easy to do for planning purposes because they know exactly how long it takes to build, what it can do, and what it costs for a given configuration. SLS is still much more of a moving target. It's sort of the difference between buying off the shelf and buying custom made.

And also keep in mind that SMD (Planetary Sciences Division) will only pay the cost of an Atlas to HEOMD for an SLS. In other words, if the SLS is going to cost the science division more than an Atlas, they don't want it. But that still requires HEOMD to pay the full cost of the SLS. And that still requires the overall NASA budget to account for it. So adding an SLS launch to NASA's manifest also requires more money in the budget to pay for it.

I am still doubtful that they'll ever fly the Europa mission on an SLS, but it remains a viable option. But it is also problematic for budgeting purposes.

I am assuming if they do end up using Atlas it will be in the most powerful 551 configuration for this mission? Would they need to use an additional third stage as featured on New Horizons?
Title: Re: Proposed Europa Missions
Post by: sdsds on 02/14/2016 05:13 am
I am assuming if they do end up using Atlas it will be in the most powerful 551 configuration for this mission? Would they need to use an additional third stage as featured on New Horizons?

Atlas V 551 with Centaur was the original mission design. C3 of 15 km^2/s^2; launch mass of 3582 kg, launch in November 2021. At least those were the numbers presented by Donahue and Sauvageau in, "The Space Launch System Capabilities for Beyond Earth Missions." A pdf of that paper is attached to a post in a related thread:

I was under the impression Atlas on a VEEGA could throw more too. I went looking for the exact figures. I found this document which I am attaching that states that SLS can throw more on a direct trajectory than an Atlas V 551 can on a VEEGA trajectory. It is the table on page 6:
Atlas V 551 (VEEGA) = 3,582kg, SLS Block 1 = 4,380kg, and SLS Block 1b = 8,920kg.

Are there better figures out there which show Atlas as being able to get more mass on a VEEGA trajectory or SLS with less on a direct trajectory?
Title: Re: Proposed Europa Missions
Post by: Kesarion on 02/16/2016 12:45 pm
The current design seems to be ~5t, though Goldstein said SLS would allow aditional grow.
Title: Re: Proposed Europa Missions
Post by: redliox on 02/16/2016 05:33 pm
So it will be double Galileo's mass and possess a HGA that's side-mounted instead of axial-mounted?  Are there any further details available beyond the instrument listing?
Title: Re: Proposed Europa Missions
Post by: Kesarion on 02/16/2016 06:04 pm
So it will be double Galileo's mass and possess a HGA that's side-mounted instead of axial-mounted?  Are there any further details available beyond the instrument listing?


Well, not really. Here is the Von Karman Lecture: http://www.ustream.tv/recorded/82974311

 I'm also curious as to why they placed the HGA on a side. I personally like it from an estetic stand point, it gives it a unique feel. The previous configuration looked like a Cassini with solar pannels .


Also Papalardo talked about using Gravity Science for EM as a 10th instrument, although this isn't realy news since the latest OPAG meeting showed it. Apperently, the GS could be used to messure the dinamics of the mantle during an expended mission, accomplishing most of the science an Orbiter could do.

Also I don't know why they decided to revert to using a boom for the MAG. Is there any benefit in doing so insead of placing it at the end of a solar panel like JUNO? I'd greatly apreciate if somebody could give an informed speculation.
Title: Re: Proposed Europa Missions
Post by: JH on 02/16/2016 08:21 pm
It might have something to do with more magnetic contamination as a result of REASON being moved onto the solar arrays. That being said, the justification for ICEMAG being so tricked out (2 TFG's and 2 SVH's) was to enable robust cross calibration in order to overcome spacecraft noise.
Title: Re: Proposed Europa Missions
Post by: redliox on 02/17/2016 08:53 am
They mentioned considering the Falcon Heavy as a launch vehicle choice.  Do we know how much oomph it could provide a Jovian mission?  Offhand I know it's supposed to do better than an Atlas V but I assume at least 1 gravity assist would be required to get it all the way there.
Title: Re: Proposed Europa Missions
Post by: ugordan on 02/17/2016 11:05 am
They mentioned considering the Falcon Heavy as a launch vehicle choice.  Do we know how much oomph it could provide a Jovian mission?  Offhand I know it's supposed to do better than an Atlas V but I assume at least 1 gravity assist would be required to get it all the way there.

Yes, all hype and claimed numbers aside, I'm skeptical FH would be near the capability of launching it on a direct trajectory. It probably could, however, haul quite a bit of mass onto a gravity assist trajectory where the C3 requirement isn't as high and so its lower Isp doesn't hurt as much.
Title: Re: Proposed Europa Missions
Post by: Star One on 02/17/2016 11:45 am

They mentioned considering the Falcon Heavy as a launch vehicle choice.  Do we know how much oomph it could provide a Jovian mission?  Offhand I know it's supposed to do better than an Atlas V but I assume at least 1 gravity assist would be required to get it all the way there.

Yes, all hype and claimed numbers aside, I'm skeptical FH would be near the capability of launching it on a direct trajectory. It probably could, however, haul quite a bit of mass onto a gravity assist trajectory where the C3 requirement isn't as high and so its lower Isp doesn't hurt as much.

I'd thought a maxed out Vulcan would offer more than the FH here.
Title: Re: Proposed Europa Missions
Post by: redliox on 02/17/2016 04:00 pm
I did some digging around in the SpaceX forums and found some figures Hyperion5 quoted on back in May:

http://forum.nasaspaceflight.com/index.php?topic=35419.1320
Quote
Rocket   Falcon Heavy
PLF Mass   4,000 kg
PLF separation   231 seconds
Payload to LEO (185 km x 185 km x 28 deg)   60,539 kg
Payload to GTO (-1800 m/s (18 degrees))   24,236 kg
Payload to GTO (-1500 m/s (18 degrees))   21,141 kg
Payload to GSO   10,968 kg
Payload to Moon (TLI)   17,692 kg
Payload to Mars   14,419 kg
Payload to Venus   15,135 kg
Payload to Jupiter (direct)   3,090 kg
Payload to Mercury   5,353 kg

So while no SLS or Saturn V, the FH would be able to put ~2/3 of the Europa mission's mass onto a direct flight. or presumably 2/3 of the required velocity for a ~5000 kg vehicle.  Even factoring in an additional 300 kg (the budgeted mass for a small lander), this still equates to better than half.  So at least 1 Earth flyby would be required, or possibly a double Earth flyby with no Venus fry-bys required.
Title: Proposed Europa Missions
Post by: Star One on 02/17/2016 04:12 pm
I did some digging around in the SpaceX forums and found some figures Hyperion5 quoted on back in May:

http://forum.nasaspaceflight.com/index.php?topic=35419.1320
Quote
RocketFalcon Heavy
PLF Mass4,000 kg
PLF separation231 seconds
Payload to LEO (185 km x 185 km x 28 deg)60,539 kg
Payload to GTO (-1800 m/s (18 degrees))24,236 kg
Payload to GTO (-1500 m/s (18 degrees))21,141 kg
Payload to GSO10,968 kg
Payload to Moon (TLI)17,692 kg
Payload to Mars14,419 kg
Payload to Venus15,135 kg
Payload to Jupiter (direct)3,090 kg
Payload to Mercury5,353 kg

So while no SLS or Saturn V, the FH would be able to put ~2/3 of the Europa mission's mass onto a direct flight. or presumably 2/3 of the required velocity for a ~5000 kg vehicle.  Even factoring in an additional 300 kg (the budgeted mass for a small lander), this still equates to better than half.  So at least 1 Earth flyby would be required, or possibly a double Earth flyby with no Venus fry-bys required.

That's a better performance than I was expecting. So once it is qualified by NASA for their payloads it might be the best alternative to SLS for this mission. Is that with total performance dedicated to the mission and no fly back of the first stages?
Title: Re: Proposed Europa Missions
Post by: redliox on 02/17/2016 06:41 pm
That's a better performance than I was expecting. So once it is qualified by NASA for their payloads it might be the best alternative to SLS for this mission.

I think so too; the cost might be easier to adopt as opposed to the SLS which no one seems to have an exact price on yet.  It might be able to handle an Ice Giant mission, granted said mission would have to be smaller than Europa and probably require flybys of Earth and Jupiter or Saturn to reach target.  I know Musk had good reason to brag about his baby since it can deliver larger payloads that the shuttle could in a clean, efficient manner.

Is that with total performance dedicated to the mission and no fly back of the first stages?

I'm pretty sure the heavier missions go no fly back to give the maximum oomph from the first stage; I think their reusability option works best for medium-size or smaller payloads in LEO.  A further factor to consider is whether a third stage will be involved; I don't know if a Falcon flight has included a third stage yet since their payloads thus far are within Cislunar space.
Title: Re: Proposed Europa Missions
Post by: Zed_Noir on 02/17/2016 06:51 pm
I did some digging around in the SpaceX forums and found some figures Hyperion5 quoted on back in May:

http://forum.nasaspaceflight.com/index.php?topic=35419.1320
Quote
RocketFalcon Heavy
PLF Mass4,000 kg
PLF separation231 seconds
Payload to LEO (185 km x 185 km x 28 deg)60,539 kg
Payload to GTO (-1800 m/s (18 degrees))24,236 kg
Payload to GTO (-1500 m/s (18 degrees))21,141 kg
Payload to GSO10,968 kg
Payload to Moon (TLI)17,692 kg
Payload to Mars14,419 kg
Payload to Venus15,135 kg
Payload to Jupiter (direct)3,090 kg
Payload to Mercury5,353 kg

So while no SLS or Saturn V, the FH would be able to put ~2/3 of the Europa mission's mass onto a direct flight. or presumably 2/3 of the required velocity for a ~5000 kg vehicle.  Even factoring in an additional 300 kg (the budgeted mass for a small lander), this still equates to better than half.  So at least 1 Earth flyby would be required, or possibly a double Earth flyby with no Venus fry-bys required.

That's a better performance than I was expecting. So once it is qualified by NASA for their payloads it might be the best alternative to SLS for this mission. Is that with total performance dedicated to the mission and no fly back of the first stages?

Since it was from last May. Is the Falcon Heavy performance figures from @Hyperion5 with the Full Throttle uprated Merlin-1D engines? (not a L2 member)

Also the possibility of a bigger upper stage for the Falcon Heavy with the Raptor engine might be available by the early 2020s.
Title: Re: Proposed Europa Missions
Post by: Tim Alexander on 02/21/2016 01:06 pm
I was curious about the Cubesat studies JPL issued last(ish) year, and scraped together a bit of information from various sources which might be of interest to people.

Starting from the JPL proposal announcement: http://www.nasa.gov/content/jpl-selects-europa-cubesat-proposals-for-study and the Cubesat presentation (and also the list of posters) from the recent OPAG meeting: http://www.lpi.usra.edu/opag/meetings/feb2016/presentations/day-2/04-Planetary-Smallsats.pdf and followed by some googling I found some useful presentations and posters.

Out of the 10 concept studies funded, 6 put posters online from the OPAG meeting.

ERDOS:  Europa Radiation and Dust Observation Satellite
http://www.lpi.usra.edu/opag/meetings/feb2016/posters/18-ERDOS.pdf
Stanford
3U Battery powered, flyby; impact panels for dust and a conventional rad. detection chip.

The DARCSIDE Concept Study for a CubeSat at Europa
http://www.lpi.usra.edu/opag/meetings/feb2016/posters/20-chanover_darcside.pdf
NM State
3U Solar powered, flyby; detects drag from atmosphere on solar panels, spluttering ion detector.
NMSU press release: https://newscenter.nmsu.edu/Uploads/get/30233/virginia_20150730_NMSU%20researchers%20propse%20concept%20to%20study%20Europa's%20atmosphere.pdf

Atmosphere and Plume Explorer (APEX) CubeSat Study
http://www.lpi.usra.edu/opag/meetings/feb2016/posters/21-APEX.pdf
Illinois
6U Solar powered, Europa and Io flyby; Neutral Ion Composition of Atmospheres (Mass Spectrometer)

Enhanced electromagnetic sounding of Europa’s ocean using CubeSats
http://www.lpi.usra.edu/opag/meetings/feb2016/posters/22-Crary.pdf
Colorado (Boulder)
Multiple 1U CubeSats for flyby magnetometry, (one released per pass for the first few flybys of Europa)

Europa CubeSat for High-Resolution 3D Ice Fracture Mapping and Landing Site Reconnaissance
http://www.lpi.usra.edu/opag/meetings/feb2016/posters/23-Europa-Cubesat.PDF
ASU
3U battery powered low altitude, targeted (eg, 400km along a ridge), flyby; pair of cameras for imaging and topography.

The Jovian Particles and Fields Survey CubeSat Mission
http://www.lpi.usra.edu/opag/meetings/feb2016/posters/24-Spencer.pdf
Georgia Tech/Aerospace Corp
6U Solar powered, 4-16 flybys; magnetometry and array of radiation sensors

Two more were mentioned, but not put online. I found some more info at various places (lpsc abstracts are gold 🙂)

Mini-MAGGIE: CubeSat MAGnetism and Gravity Investigation at Europa
http://www.hou.usra.edu/meetings/lpsc2016/pdf/1928.pdf
http://spacegrant.alaska.edu/content/mini-maggie (Video is quite interesting)
Alaska Fairbanks
3U Solar powered, magnetometer.

EPEC: The Europa Plume and Exosphere Cubesat
Georgia Tech
Two design options: 6U solar, multiple flyby, cold gas thrusters, dust detector, small MS
                             2x 3U battery, single flyby, dust detector only
Aim to get better data (presumably through a higher sample rate) by going closer to the surface where more dust and particle are (more risk -> undesirable for the main spacecraft, but not for a more expendable Cubesatperhaps...)
http://www.lpi.usra.edu/opag/meetings/feb2017/posters/Schmidt-1.pdf

One more was found by googling relevant terms and is easily the most comprehensive information found. This is the whole concept report, and contains a lot of useful, more broad based info on CubeSats at Europa:
https://www.slideshare.net/mobile/CaseySteuer/jpl-rsa-1513471-europa-cubesat-concept-study-characterizing-subsurface-oceans-with-a-cubesat-magnetometer-payload-smallsat
Michigan

This makes 9, although the Jovian Particles and Fields is apparently/maybe more associated with the Aerospace Corporation, with the two universities not listed here being Southern California and Washington, Seattle. Any information on these 2/3 would be most welcome!

The two concepts I personally found the most interesting are the APEX with its super cool trajectory (Io flyby!) and massive MS instrument, and the Imaging Cubesat from ASU with its plan of doing targeted, 3D imaging for 400km down the length of a ridge on Europa.
The multiple 1U magnetometer based concept I think really demonstrates the usefulness and complementary nature of Cubesat science as well.

I hope people find this interesting!

Edit 1: minor corrections
Edit 2: added information on EPEC
Edit 3: further EPEC information from Feb 2017 OPAG meeting
Title: Re: Proposed Europa Missions
Post by: vjkane on 02/23/2016 04:02 pm
I was curious about the Cubesat studies JPL issued last(ish) year, and scraped together a bit of information from various sources which might be of interest to people.


Thank you for doing this!
Title: Re: Proposed Europa Missions
Post by: redliox on 02/23/2016 04:25 pm
The two concepts I personally found the most interesting are the APEX with its super cool trajectory (Io flyby!) and massive MS instrument, and the Imaging Cubesat from ASU with its plan of doing targeted, 3D imaging for 400km down the length of a ridge on Europa.

Those two also stood out the most to me.  APEX's visit to Io would make a great finale to their mission not to mention possibly finding more details on Europa's atmosphere and plumes than 'Clipper itself might.  ASU's idea is ambitious for a cubesat, although I'm unsure one ridge would be enough of an advantage versus 'Clipper's complete mapping of Europa.
Title: Re: Proposed Europa Missions
Post by: notsorandom on 02/23/2016 05:11 pm
The two concepts I personally found the most interesting are the APEX with its super cool trajectory (Io flyby!) and massive MS instrument, and the Imaging Cubesat from ASU with its plan of doing targeted, 3D imaging for 400km down the length of a ridge on Europa.

Those two also stood out the most to me.  APEX's visit to Io would make a great finale to their mission not to mention possibly finding more details on Europa's atmosphere and plumes than 'Clipper itself might.  ASU's idea is ambitious for a cubesat, although I'm unsure one ridge would be enough of an advantage versus 'Clipper's complete mapping of Europa.
The Europa Imaging System will be able to return targeted imagery up to about 1 meter in resolution. AUS's cubesat proposal will do 0.2 to 0.3 meters. Interestingly this is about the same difference between the Mars Global Surveyor and its successor Mars Reconnaissance Orbiter. MRO discovered that the initial prime landing site for Mars Phoenix had too many rocks and boulders. Phoenix couldn't land on any rocks bigger than 0.35 to 0.45 meters. I don't know if the imagery before that was taken at MGS's highest resolution. If it was it would be a good argument for getting that higher resolution imagery.
Title: Re: Proposed Europa Missions
Post by: redliox on 02/23/2016 08:06 pm
The two concepts I personally found the most interesting are the APEX with its super cool trajectory (Io flyby!) and massive MS instrument, and the Imaging Cubesat from ASU with its plan of doing targeted, 3D imaging for 400km down the length of a ridge on Europa.

Those two also stood out the most to me.  APEX's visit to Io would make a great finale to their mission not to mention possibly finding more details on Europa's atmosphere and plumes than 'Clipper itself might.  ASU's idea is ambitious for a cubesat, although I'm unsure one ridge would be enough of an advantage versus 'Clipper's complete mapping of Europa.
The Europa Imaging System will be able to return targeted imagery up to about 1 meter in resolution. AUS's cubesat proposal will do 0.2 to 0.3 meters. Interestingly this is about the same difference between the Mars Global Surveyor and its successor Mars Reconnaissance Orbiter. MRO discovered that the initial prime landing site for Mars Phoenix had too many rocks and boulders. Phoenix couldn't land on any rocks bigger than 0.35 to 0.45 meters. I don't know if the imagery before that was taken at MGS's highest resolution. If it was it would be a good argument for getting that higher resolution imagery.

I recall reading that resolution from ASU's proposal.  If they can't deliver either a small lander or a penetrator perhaps the senators supporting the Europa project could be convinced this is a better option.
Title: Re: Proposed Europa Missions
Post by: Tim Alexander on 02/24/2016 06:53 am
I think that the best per pixel resolution of EIS NAC is approximately X cm for a flyby at X km (NAC has an IFOV of 10 urad), making the best images 25cm per pixel. Of course one pixel makes it near impossible to resolve anything, and typically 4 to 5 are needed (making about 1m resolution). I guess it depends on how one defines resolution  ::)

EIS lpsc abstract: http://www.hou.usra.edu/meetings/lpsc2016/pdf/1626.pdf
2015 OPAG presentation on EIS: http://www.hou.usra.edu/meetings/lpsc2016/pdf/1626.pdf

On the targeting, my understanding was that EIS is gimballed (30 degrees), and mounted on the same (hugely cost saving) common instrument panel as several other instruments which is also gimballed. However as they can only really image directly(ish) under the flyby without taking a steeply increasing penalty in resolution, they are somewhat at the mercy of the where the flyby goes. While many of the flybys do go over many interesting areas they are obviously quite unlikely to track a single feature like a ridge over a long distance. Ridges appear to be very important geologically on Europa, possibly as a mechanism for forming new terrain as they split apart, and along with the chaos regions, might be as close as we can get (physically) to the oceans.

The attached picture illustrates this quite well and is from a 2014 presentation to OPAG (http://www.lpi.usra.edu/opag/jan2014/presentations/9_Clipper.pdf)
On the ridges: http://www.nature.com/ngeo/journal/v7/n10/full/ngeo2245.html (Abstract gets the idea across).

This is a very interesting report on trajectory selection for the Europa mission as well, which I haven't gone through all of yet, but at the very least explains the trade offs and challenges of designing a flyby route, and has a cool explanation of possible contingency plans (some flybys are much more important than others).
http://www.trylam.com/files/AAS-15-657_Europa_2015_final.pdf

Having read through the longer concept study about a magnetometry Cubesat I can also see why it would be very useful to have a way of measuring the magnetic field over the course of a hundred hours or so in one go at Europa. The depth of the ocean measurement is related very much to this: as Europa is embedded in a pair (amongst others) of superposed, time varying, periodic fields, the magnetic induction response (on the order of 1-10nT) can be measured and depth and salinity derived from it. To stay for two full periods of the longer of the two is about 150 hours (from memory), and the measurement can only be taken from within about one Europa radius. It appears that this is one of the arguments for a magnetometer on  a small orbiter or lander (Akon penetrator anyone :) ! )
Title: Re: Proposed Europa Missions
Post by: NovaSilisko on 03/03/2016 05:13 pm
There have been a number of tweets on the Europa mission today, but this one stood out to me:

Quote
Jeff Foust @jeff_foust

Elachi: Europa orbiter and lander will be two separate spacecraft, not attached to each other.

I am glad to find this is the case (or had it already been confirmed?)
Title: Re: Proposed Europa Missions
Post by: Jim on 03/03/2016 05:52 pm

Elachi: Europa orbiter and lander will be two separate spacecraft, not attached to each other.


That will make ground ops easier and also make the missions not dependent on SLS
Title: Re: Proposed Europa Missions
Post by: Blackstar on 03/03/2016 06:36 pm
That statement does not indicate that they will be separate launches.

However, everybody I've talked to about this indicates that you just cannot do the two missions together--not from a mass standpoint, launcher standpoint, science standpoint, or operations.
Title: Re: Proposed Europa Missions
Post by: vjkane on 03/03/2016 06:45 pm
Notes from today's hearing as well as relevant tweets

Ocean Worlds Hearing 2016-03-03

Van’s notes

Culberson: We will take care of science and NASA in the budget
Elachi: We need a well thought out integrated program like we have at Mars.  Culberson: I agree
Lunine: Titan is a test of the universality of life and the best approach is to land on the lakes
Lunine: Enceladus didn’t surprise us, it shocked us
Elachi: A lander would do good science but would also provide an engineering pathfinder toward more capable landers in the future
Lunine: A Europa lander is essential with a mass spectrometer for confirmation of complex organics.  We must test the ices directly especially below the surface.  A Raman spectrometer can tell us things about the structure of the organic molecules that a mass spectrometer cannot.
Elachi: A lander would be a pyramid like Pathfinder to allow self righting
Elachi: Plan now is to have the orbiter and lander as separate spacecraft.  They could launch together or separately.  If together, than even on an SLS at least one Earth flyby would be needed.


Marcia Smith ‏@SpcPlcyOnline 

Hrg is on "ocean worlds" and JPL Dir Elachi incl Mars in that bin because it USED to have oceans.
Elachi: don't need to decide now. Have 2 yrs to choose which launcher. F9H is another option. Looking at all of the options.
Elachi: looking at orbiter and lander as separate spacecraft. Could put both on one SLS, or launch separately and get there faster.
Culberson: impt to use SLS for Europa? One or two? Elachi: EELV takes 7/5 yrs to get to Jupiter. SLS=2.5 yrs. Saves 5 yrs of mission ops.
Culberson: how much $ does planetary sci NEED in FY17 to keep everything on track? Elachi: ask NASA. Depends on when you want missions.
Lunine: Enceladus provides most straightforward way to look for life bc orbiter can just fly thru plumes [not have to land].
Cornell's Jonathan Lunine: Europa, Enceladus and Titan all have salty oceans as Cassini and Galileo data prove. Europa is top priority.
Elachi: SLS will get spacecraft to Jupiter in 2-2.5 yrs instead of 6-7. If lander is really heavy cld do 1 Earth flyby & get there in 4 yrs
Elachi: for Europa, need (1) orbiter for detailed map, which NASA is doing; (2) modest lander; (3) tech program for eventual submarine
Hrg is on "ocean worlds" and JPL Dir Elachi incl Mars in that bin because it USED to have oceans.
Sbcmt Chm Culberson: OMB's (he says OMB's, not President's) FY17 request for NASA is disappointing, aggravating.

Jeff Foust ‏@jeff_foust

Culberson now asking about WFIRST and search for exoplanets.
Elachi, on Pu-238 and RTGs: what’s available now, and new production, are satisfactory for near-term missions.
Culberson: other moons that may have subsurface oceans? Lunine: Callisto, Triton are candidates.
Lunine: first proposal I wrote for a Europa mission instrument was in 1999. “It’s past time to get to Europa.”
Elachi: Europa orbiter and lander will be two separate spacecraft, not attached to each other.
This is probably one of the few House hearings in history to discuss the merits of Raman spectroscopy.
Elachi: up to NASA to decide when to issue AO for Europa lander instruments. Seeking members for science definition team now.
Lunine: essential that a Europa lander be able to sample the surface. “We may get lucky with that in situ analysis” and detect life.
Lunine: mission as constructed today is designed to determine habitability of Europa; then determine if life exists there.
Elachi: even if launched at same time, orbiter would get to Europa first, survey potential landing sites for lander.
Elachi does mention in passing the Falcon Heavy as another option for launching Europa missions.
Elachi: if you launch Europa orbiter and lander together on 1 SLS, still need to do flybys to get there. Faster if launched on separate SLSs
Culberson: discovery of life on another world will galvanize support for NASA and ensure funding.
Culberson asks Elachi how much $ NASA planetary should get. Elachi says it depends on when you want missions to happen.
Jonathan Lunine of Cornell: Enceladus offers the most straightforward way for looking for signs of life, by sampling its plumes.
Elachi: don’t have to make a decision on launch vehicle for Europa mission (EELV-class or SLS) for 2-3 years.
Elachi: a Europa lander would capitalize on “skycrane” technology used on MSL and Mars 2020.
JPL director Charles Elachi kicking off his opening statement talking about… Mars.
Ranking member Rep. Honda says his interest in Ocean Worlds program is second only to Culberson’s.
Culberson: “very disappointing and aggravating” OMB cut planetary science funding in NASA FY17 budget request.
Culberson: we’ve made sure by law that NASA will fund and fly a mission to Europa, given its priority in planetary sci decadal survey.
Rep. John Culberson, leading off Ocean Worlds hearing: JPL is the “gold standard” for NASA flight centers; should be replicated elsewhere.
McNamee: still studying possible inclusion of “helicopter” on Mars 2020. Cubesats eliminated from consideration. #mepag

Title: Re: Proposed Europa Missions
Post by: NovaSilisko on 03/03/2016 06:54 pm
Quote
Elachi: if you launch Europa orbiter and lander together on 1 SLS, still need to do flybys to get there. Faster if launched on separate SLSs

Two SLS launches has me a little worried... Then again, we've been complaining about a lack of missions for SLS for a long time, so hey.


Quote
Hrg is on "ocean worlds" and JPL Dir Elachi incl Mars in that bin because it USED to have oceans.

That... doesn't strike me as what they intended it to be about.
Title: Re: Proposed Europa Missions
Post by: redliox on 03/03/2016 07:38 pm
That was an interesting update.  Three things among Van's comments stood out to me in particular:

1) If required, either by a heavy lander or a smaller launcher, an Earth flyby lengthens the trip to 4 years.  I could live with that if the science is good.
2) Launching the orbiter and lander separately seems preferred; there seems to be confusion whether they'll indeed be separate or not.
3) The lander seems to be slowly coming together, conceptually at least; instruments and even a pyramid-shape with a Pathfinder-style approach seem implied.

A few thoughts occur to me on how a dual-mission of orbiter-lander could go.  While keeping the lander separate, the orbiter could still include a small package; either the UK penetrator, ESA mini-flyer (to either Europa or Io), or one or two of the cubesats with the latter being the easiest to accommodate.  If launched simultaneously, but still split, the orbiter could be prioritized to take the direct route while the lander intentionally is put on a 4-7 year gravity-assisted route; the physics to land on Europa won't change but it would allow the orbiter team time to find the optimal site for the lander.  When it does arrive, the lander probably would have to settle for a short lifespan (maybe 30-60 days tops to be REALLY optimistic) and surface science; from the comments it sounds like chemistry would be its priority although hopefully seismology and imaging would be next in line.  All promising and the best we can do with current technology.
Title: Re: Proposed Europa Missions
Post by: redliox on 03/03/2016 07:44 pm
Quote
Elachi: if you launch Europa orbiter and lander together on 1 SLS, still need to do flybys to get there. Faster if launched on separate SLSs

Two SLS launches has me a little worried... Then again, we've been complaining about a lack of missions for SLS for a long time, so hey.

2 SLS seems a bit much, even for the sake of giving the SLS an itinerary list.  Personally, I'd suggest either one SLS for both spacecraft, an SLS for orbiter with Falcon Heavy for lander, or two FHs.  Optimally I'd suggest the middle setup to get the orbiter there fast while giving the lander a cheaper-yet-efficient ride.
Title: Re: Proposed Europa Missions
Post by: Star One on 03/03/2016 09:05 pm

Quote
Elachi: if you launch Europa orbiter and lander together on 1 SLS, still need to do flybys to get there. Faster if launched on separate SLSs

Two SLS launches has me a little worried... Then again, we've been complaining about a lack of missions for SLS for a long time, so hey.

2 SLS seems a bit much, even for the sake of giving the SLS an itinerary list.  Personally, I'd suggest either one SLS for both spacecraft, an SLS for orbiter with Falcon Heavy for lander, or two FHs.  Optimally I'd suggest the middle setup to get the orbiter there fast while giving the lander a cheaper-yet-efficient ride.

The orbiter could take the quick trip to gather info about potential landing sites while the lander takes the slow way round.
Title: Re: Proposed Europa Missions
Post by: vjkane on 03/03/2016 09:40 pm
The orbiter could take the quick trip to gather info about potential landing sites while the lander takes the slow way round.
The orbiter is four years into its definition.  The lander is barely a few months into its development.  Unless you delay the orbiter, the lander should launch later.
Title: Re: Proposed Europa Missions
Post by: baldusi on 03/03/2016 10:35 pm
That's, at least, what I hope will happen.
Title: Re: Proposed Europa Missions
Post by: RonM on 03/03/2016 11:23 pm
Quote
Elachi: if you launch Europa orbiter and lander together on 1 SLS, still need to do flybys to get there. Faster if launched on separate SLSs

Two SLS launches has me a little worried... Then again, we've been complaining about a lack of missions for SLS for a long time, so hey.

The good thing about two SLS launches is if the lander is canceled or delayed it will not interfere with the orbiter mission.

If SLS is not cancelled, then NASA will be building one every year to maintain the production line. With those costs already figured into the SLS budget, putting a science mission on SLS is really just a matter of figuring out how to do the accounting. The money will be spent.
Title: Re: Proposed Europa Missions
Post by: Zed_Noir on 03/04/2016 03:00 am
A question about using the Falcon Heavy for the Europa mission. Will the transit time to Europa be less than the baseline EELV?
Title: Re: Proposed Europa Missions
Post by: Don2 on 03/04/2016 06:12 am
Elachi should think long and hard before trying to include Mars in the Ocean Worlds program. That seems to run counter to everything the Ocean Worlds people are trying to achieve. What Culbertson seems to be after is a program to find life in the outer solar system. The best opportunity there is not Europa, it is the plumes of Enceladus. There are very interesting claims being made for those missions and the price tag is potentially quite affordable.

For Europa we should forget about drilling 1000m through the ice and launching submarines into the ocean. That is never going to happen. On earth, lava comes to the surface in places like Hawaii and maybe there is someplace on Europa where liquid water is not too far down. We can't currently spot ice volcanoes on Europa because our maps are crap. We don't know much about the surface of Europa, but what we do know is not very encouraging for the survival of organics. Sulfuric acid and space radiation will destroy organics over time, and that will go a lot faster inside an instrument like a mass spectrometer which heats the material. We don't have good enough maps to identify interesting landing sites, and NASA can't afford to build a lander anyway.
Title: Re: Proposed Europa Missions
Post by: redliox on 03/04/2016 09:12 am
A question about using the Falcon Heavy for the Europa mission. Will the transit time to Europa be less than the baseline EELV?

I pondered about the same thing too.  I actually dug into the Falcon Heavy threads and found this (not to mention posted it within this thread too), courtesy of Hyperion5:
Quote
Rocket   Falcon Heavy
PLF Mass   4,000 kg
PLF separation   231 seconds
Payload to LEO (185 km x 185 km x 28 deg)   60,539 kg
Payload to GTO (-1800 m/s (18 degrees))   24,236 kg
Payload to GTO (-1500 m/s (18 degrees))   21,141 kg
Payload to GSO   10,968 kg
Payload to Moon (TLI)   17,692 kg
Payload to Mars   14,419 kg
Payload to Venus   15,135 kg
Payload to Jupiter (direct)   3,090 kg
Payload to Mercury   5,353 kg

Considering the Europa mission is going to weigh ~5,000 kg that means the FH can deliver 2/3 of the mass directly to Jupiter.  It is only going to need a modest push to get it finally to Jupiter, so most likely 1 Earth flyby just like Juno.  As for timeline, vjkane mentioned Elachi here:

Elachi: SLS will get spacecraft to Jupiter in 2-2.5 yrs instead of 6-7. If lander is really heavy cld do 1 Earth flyby & get there in 4 yrs

The FH specs Hyperion5 mentioned are just under a year old, more than likely still relevant.  The FH would make a fine alternative to SLS.  But, to answer your question, YES.  ;)
Title: Re: Proposed Europa Missions
Post by: Star One on 03/04/2016 02:05 pm

A question about using the Falcon Heavy for the Europa mission. Will the transit time to Europa be less than the baseline EELV?

I pondered about the same thing too.  I actually dug into the Falcon Heavy threads and found this (not to mention posted it within this thread too), courtesy of Hyperion5:
Quote
RocketFalcon Heavy
PLF Mass4,000 kg
PLF separation231 seconds
Payload to LEO (185 km x 185 km x 28 deg)60,539 kg
Payload to GTO (-1800 m/s (18 degrees))24,236 kg
Payload to GTO (-1500 m/s (18 degrees))21,141 kg
Payload to GSO10,968 kg
Payload to Moon (TLI)17,692 kg
Payload to Mars14,419 kg
Payload to Venus15,135 kg
Payload to Jupiter (direct)3,090 kg
Payload to Mercury5,353 kg

Considering the Europa mission is going to weigh ~5,000 kg that means the FH can deliver 2/3 of the mass directly to Jupiter.  It is only going to need a modest push to get it finally to Jupiter, so most likely 1 Earth flyby just like Juno.  As for timeline, vjkane mentioned Elachi here:

Elachi: SLS will get spacecraft to Jupiter in 2-2.5 yrs instead of 6-7. If lander is really heavy cld do 1 Earth flyby & get there in 4 yrs

The FH specs Hyperion5 mentioned are just under a year old, more than likely still relevant.  The FH would make a fine alternative to SLS.  But, to answer your question, YES.  ;)

I haven't really kept up to date with the FH, but isn't part of the issue with it that it lacks a high energy upper stage at the moment?
Title: Re: Proposed Europa Missions
Post by: ugordan on 03/04/2016 02:23 pm
Do we really have to have this thread going back to FH discussion every two weeks?
Title: Re: Proposed Europa Missions
Post by: matthewkantar on 03/04/2016 04:18 pm
to what extent would any life be identifiable in a plume exposed to vacuum and radiation?  I want them to hold out for a lander. Congress is interested in this, c'mon people, get the money for a drill or a boat.

Matthew
Title: Re: Proposed Europa Missions
Post by: AegeanBlue on 03/04/2016 06:14 pm
You just mentioned the magic word: money. If it gets too expensive, it can go the way of CRAF. If it does not get cancelled, it can hobble down everything else, the way that Curiosity's overruns ate a Discovery and possibly a New Frontiers mission. Culberson is in favor of the mission, he has been sending money on top of the usual budget, but what is telling us that if he falls from grace (usually for reasons unrelated to space) we wont be seeing the money not so much disappear as much as being taken out from elsewhere in Planetary Science? We are in a weird place, let's wait what will come of the November elections before we can judge about the lander
Title: Re: Proposed Europa Missions
Post by: Blackstar on 03/04/2016 06:20 pm
I want them to hold out for a lander. Congress is interested in this, c'mon people, get the money for a drill or a boat.

Or why not a submarine? Or a manned mission to Europa?

I want 80% of something instead of 100% of nothing.

But I think it's important to recognize that even if we could do a very ambitious mission now it is probably not the best way to do it. A series of missions over a longer period of time allows for people to spend more time analyzing the data and formulating better questions. Science takes time. Things have to be learned and discussed and distributed.
Title: Re: Proposed Europa Missions
Post by: Don2 on 03/04/2016 06:58 pm
It's worth pointing out that even on Earth mass spectrometers operate under vacuum. The sample has to be heated and evaporated before it is sent to the detectors. At Enceladus the moon is taking care of the first stage for us.

A presentation for a plume sniffer mission called the  Enceladus Life Finder states:

' ELF conducts three tests for life.
The first test looks for a characteristic “flat” distribution
of amino acids [8], the second determines whether
the carbon number distribution in fatty acids or isoprenoids
is biased toward a particular rule (even, odd, or
divisible by a small integer) [9], and the third measures
carbon and hydrogen isotopic ratios, together with the
abundance of methane relative to other alkanes, to assess
whether the values fall in the range for biological
processes.'

http://www.hou.usra.edu/meetings/lpsc2015/pdf/1525.pdf

There are several problems with a Europa lander. One is that the radiation environment will kill any lander within days. The second is that we don't know where to land. Current thinking is that the ice shell is between 1 and 30 km thick. Either is too thick to drill. The surface conditions appear to be very hostile to organic molecules and there is no guarantee that a future orbiter will spot any organic rich regions on the surface. A lander could help to determine the origin of Europa by measuring the isotope ratios present in the surface ices. LIBS and Raman instruments could measure the elemental abundance and mineralogy of the brown stuff seen in the Galileo photos. A wet chemistry experiment could discover which salts are present, which would tell us something about the chemistry of the underlying ocean. Measuring the strength of the ice and the radiation environment could help to design a future drilling mission, if anywhere thin enough to drill can be found. However, it is not possible to guarantee any results on organics, let alone life.
Title: Re: Proposed Europa Missions
Post by: JH on 03/04/2016 09:55 pm
I should mention that the "thin shell" theory (the one in which Europa's ice shell is only a few km thick) is all but dead. There are very few people in the community who don't think that the ice shell is closer to 30 km thick.
Title: Re: Proposed Europa Missions
Post by: redliox on 03/05/2016 04:11 am
I should mention that the "thin shell" theory (the one in which Europa's ice shell is only a few km thick) is all but dead. There are very few people in the community who don't think that the ice shell is closer to 30 km thick.

I wouldn't be surprised if the ice shell on Europa varies just like crustal thickness varies on Earth; oceanic and continental crusts have distinct differences and considering water ice is "just another rock" out in the outer solar system, it's not unreasonable to think it would behave any differently (in an overall sense, of course the chemistry differs).  The only way to settle and confirm which hypothesis is right is with more data - radar from the orbiter and seismic readings from a lander.

I want them to hold out for a lander. Congress is interested in this, c'mon people, get the money for a drill or a boat.

Or why not a submarine? Or a manned mission to Europa?

I want 80% of something instead of 100% of nothing.

But I think it's important to recognize that even if we could do a very ambitious mission now it is probably not the best way to do it. A series of missions over a longer period of time allows for people to spend more time analyzing the data and formulating better questions. Science takes time. Things have to be learned and discussed and distributed.

Agreed.  I was very surprised a lander got wedged in.  I'm pretty sure a small, short-lived surface lander is the best we can do with current technology.  Maybe in another 30 years we could drill into Europa, but only if we get lucky in detecting shallower lakes.  I hope they treat the lander more and more like a separate mission so it won't compromise the orbiter's.
Title: Re: Proposed Europa Missions
Post by: zubenelgenubi on 03/06/2016 04:11 pm
I should mention that the "thin shell" theory (the one in which Europa's ice shell is only a few km thick) is all but dead. There are very few people in the community who don't think that the ice shell is closer to 30 km thick.

I wouldn't be surprised if the ice shell on Europa varies just like crustal thickness varies on Earth; oceanic and continental crusts have distinct differences and considering water ice is "just another rock" out in the outer solar system, it's not unreasonable to think it would behave any differently (in an overall sense, of course the chemistry differs).  The only way to settle and confirm which hypothesis is right is with more data - radar from the orbiter and seismic readings from a lander.
Re: Landers of the further future reaching liquid water on Europa

What about "perched lakes," as mentioned in this November 2011 on-line article in Sky & Telescope, Europa’s Subsurface Lakes (http://www.skyandtelescope.com/astronomy-news/europas-subsurface-lakes/)?  They might be only 2 kilometers under the surface.  Autonomous drilling to 2 km depth is preferable to drilling 30 km.
Title: Re: Proposed Europa Missions
Post by: vjkane on 03/06/2016 05:22 pm
What about "perched lakes," as mentioned in this November 2011 on-line article in Sky & Telescope, Europa’s Subsurface Lakes (http://www.skyandtelescope.com/astronomy-news/europas-subsurface-lakes/)?  They might be only 2 kilometers under the surface.  Autonomous drilling to 2 km depth is preferable to drilling 30 km.
The ice penetrating radar on the orbiter will look for both differences in ice shell thickness and perched lakes.

However, deep drilling in ice (even 2 km) is hard on Earth, and we lack the technology to do it on an icy moon, especially one in an intense radiation field.

Another goal for the orbiter will be to find a landing site where there is a good chance that nature has recently delivered subsurface water to the surface.  The ideal site would have:

1. An active plume (or several).  Nothing like real time delivery.  Failing that:

2. Surface composition that includes organics and salts.  I believe that spectral measurements can suggest how recently the material was delivered.

3. Fractured surface suggesting that the ice shell was broken to allow water on to the surface
Title: Re: Proposed Europa Missions
Post by: JH on 03/06/2016 05:31 pm
Historically, there have been two distinct models for Europa's ice shell: one in which the shell is thin (several km thick), another in which the ice shell is thick (~30 km thick). Spatial variations in thickness within each model would occur, but they should not (there is no known mechanism by which they could) be order of magnitude differences.

The reason that the thin shell theory is no longer in favor has to do with surface topography of Europa's ice shell. Basically, a thin layer of water ice cannot sustain the altitude variations of 100's of meters observed on Europa.

Subsurface lakes, as suggested by Schmidt et al. (Nature, 2011), are currently the most popular mechanism by which there could be liquid water close enough to the surface that it might possibly be accessible. The problem with these theorized subsurface lakes is that they are the result of solid ice convection (no liquid water within them is thought to have originated directly from the main ocean) and they are relatively transient. This means that, even if the ocean is habitable and has life, life may not be present in the lakes and the chemistry of the lakes may not even be indicative of conditions in the ocean.
Title: Re: Proposed Europa Missions
Post by: baldusi on 03/06/2016 08:24 pm
Well, Europa has some special situation that could make drilling feasible. Namely, the ice is in vacuum. If you used and RTG to sublimate the ice very slowly, it should just evaporate. Main issue (besides comm) should be vapor deposition on the tunnel walls.
Title: Re: Proposed Europa Missions
Post by: vjkane on 03/06/2016 10:06 pm
Well, Europa has some special situation that could make drilling feasible. Namely, the ice is in vacuum. If you used and RTG to sublimate the ice very slowly, it should just evaporate. Main issue (besides comm) should be vapor deposition on the tunnel walls.
that depends on the speed of the melting as you suggest.  clearly when water seeps up from below the ice (either shell fracturing or impact) not all of the exposed water sublimates.  most apparently freezes
Title: Re: Proposed Europa Missions
Post by: llanitedave on 03/07/2016 10:26 pm
What about "perched lakes," as mentioned in this November 2011 on-line article in Sky & Telescope, Europa’s Subsurface Lakes (http://www.skyandtelescope.com/astronomy-news/europas-subsurface-lakes/)?  They might be only 2 kilometers under the surface.  Autonomous drilling to 2 km depth is preferable to drilling 30 km.
The ice penetrating radar on the orbiter will look for both differences in ice shell thickness and perched lakes.

However, deep drilling in ice (even 2 km) is hard on Earth, and we lack the technology to do it on an icy moon, especially one in an intense radiation field.

Another goal for the orbiter will be to find a landing site where there is a good chance that nature has recently delivered subsurface water to the surface.  The ideal site would have:

1. An active plume (or several).  Nothing like real time delivery.  Failing that:

2. Surface composition that includes organics and salts.  I believe that spectral measurements can suggest how recently the material was delivered.

3. Fractured surface suggesting that the ice shell was broken to allow water on to the surface


This in spades.  If a recent impact or hydro-volcanism has brought water up from deeper layers, and if life exists on Europa, then the equivalent of fossils should be embedded within that ice.  I don't think deep drilling is necessary at all.  We just need a way to establish stratigraphic sequences.
Title: Re: Proposed Europa Missions
Post by: vjkane on 03/07/2016 10:41 pm
This in spades.  If a recent impact or hydro-volcanism has brought water up from deeper layers, and if life exists on Europa, then the equivalent of fossils should be embedded within that ice.  I don't think deep drilling is necessary at all.  We just need a way to establish stratigraphic sequences.
Ice turns out to be a great shield against radiation effects.  So if the lander can get down a meter or two, the material may be pretty pristine
Title: Re: Proposed Europa Missions
Post by: redliox on 03/08/2016 05:19 am
This in spades.  If a recent impact or hydro-volcanism has brought water up from deeper layers, and if life exists on Europa, then the equivalent of fossils should be embedded within that ice.  I don't think deep drilling is necessary at all.  We just need a way to establish stratigraphic sequences.
Ice turns out to be a great shield against radiation effects.  So if the lander can get down a meter or two, the material may be pretty pristine

Perhaps the 2nd lander to Europa could invest in that technology, especially if its mission focuses on long-term studies like seismic observation.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 03/08/2016 03:07 pm
http://spacenews.com/nasa-pressing-ahead-with-studies-of-a-europa-lander/

NASA pressing ahead with studies of a Europa lander

by Jeff Foust — March 8, 2016

WASHINGTON — Despite what a key member of Congress called a “very disappointing” budget request, NASA is taking steps to develop a lander that could accompany an orbiter mission to Jupiter’s icy moon Europa.

In late February, NASA’s planetary science division sent a letter to scientists requesting applications to join a science definition team (SDT) for the proposed lander. The goal of the SDT, the letter stated, is “defining the science objectives and feasibility of specific lander mission concept focused on assessing the habitability of and searching for life on Europa.”

NASA expects to form the SDT later in March, to be followed by a series of teleconferences and face-to-face meetings. The letter doesn’t state when the SDT would complete its work and disband, but the letter does request information on applicants’ availability over the next 12 months.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 03/10/2016 07:46 pm
http://aviationweek.com/space/lawmaker-hopes-search-life-will-boost-nasa-s-support

Title: Re: Proposed Europa Missions
Post by: truth is life on 03/10/2016 08:23 pm
However, deep drilling in ice (even 2 km) is hard on Earth, and we lack the technology to do it on an icy moon, especially one in an intense radiation field.

Well, there is one method that was studied in the 1960s and 1970s for drilling tunnels on Earth that seems highly applicable--the nuclear subterrene. You use a nuclear reactor (in the range of a few megawatts thermal, so it's in line with 'ordinary' aerospace reactor proposals, if on the large side) to melt a hole through. They actually tested the concept at that time (on Earth, obviously), but with electrical instead of nuclear heating due to the scale, so I would guess that it would be at TRL 3 or maybe 4 depending on how useful you think those tests are at proving feasibility. Probably not much worse than any other possible method of drilling through Europan ice.

I think it's fairly obvious why this never really caught on (and besides all the issues you can think of, it was actually slower than ordinary TBMs are nowadays), but there are also obvious advantages to using it to drill holes through icy moon crusts. Well, if you can get anyone to go along with dumping a used multi-megawatt reactor in an icy moon ocean, at least.
Title: Re: Proposed Europa Missions
Post by: baldusi on 03/10/2016 11:49 pm
I always loved the subterrene because it can do something that TBM can't do: Drill a non circular tunnel profile, an optimal catenary, for example.
But that advantage is lost on Europa. From my understanding you actually want to drill by melting "slow" so the water sublimates and escapes. 2km of crushed ice over you are not easy to deal with. If it sublimates and escapes into the vacuum of space, you solve a lot of issues.
Title: Proposed Europa Missions
Post by: Star One on 03/31/2016 08:53 pm
Eric Berger – Verified account ‏@SciGuySpace

No free rides on SLS for science payloads, NASA's Bolden says. "The science community is going to have to pay for launch vehicles."

https://mobile.twitter.com/SciGuySpace/status/715541138145325056
Title: Re: Proposed Europa Missions
Post by: Blackstar on 03/31/2016 11:36 pm
Eric Berger – Verified account ‏@SciGuySpace

No free rides on SLS for science payloads, NASA's Bolden says. "The science community is going to have to pay for launch vehicles."

https://mobile.twitter.com/SciGuySpace/status/715541138145325056

Well, what the science leadership at NASA has been saying for awhile now is that they'll pay the cost of an EELV (essentially a top line Atlas V) and no more. They don't want to get stuck with the full cost of an SLS. If they do, they won't buy it. I don't think this statement from Bolden is inconsistent with that.
Title: Re: Proposed Europa Missions
Post by: notsorandom on 04/01/2016 02:28 am
Will the selection of the launch vehicle happen soon enough that Bolden will still be administrator when it happens?
Title: Re: Proposed Europa Missions
Post by: Star One on 04/01/2016 06:35 am
Eric Berger – Verified account ‏@SciGuySpace

No free rides on SLS for science payloads, NASA's Bolden says. "The science community is going to have to pay for launch vehicles."

https://mobile.twitter.com/SciGuySpace/status/715541138145325056

Well, what the science leadership at NASA has been saying for awhile now is that they'll pay the cost of an EELV (essentially a top line Atlas V) and no more. They don't want to get stuck with the full cost of an SLS. If they do, they won't buy it. I don't think this statement from Bolden is inconsistent with that.

Would that be the same as New Horizons a 551 + upper stage?
Title: Re: Proposed Europa Missions
Post by: redliox on 04/02/2016 04:16 am
Sweet find Blackstar!  Looks pretty much as alluded to: small pyramid design akin to Mars Pathfinder...with modern options like Skycrane.
Title: Re: Proposed Europa Missions
Post by: Star One on 04/02/2016 10:17 am
I suppose you're not going to see rovers on places like Europa until autonomous technology is far more advanced because of the communication delays.
Title: Re: Proposed Europa Missions
Post by: hop on 04/02/2016 09:28 pm
I suppose you're not going to see rovers on places like Europa until autonomous technology is far more advanced because of the communication delays.
I don't think so, a daily cycle as used for Mars rovers should work fine. The reason you won't see a Europa rover any time soon is money.
Title: Re: Proposed Europa Missions
Post by: the_other_Doug on 04/03/2016 03:14 am
On the lander, I would have thought that even a few days of seismic data would be extremely valuable in characterizing the thickness of the ice crust.  With Jovian tides, I imagine there would be a lot of seismic activity going on in the crust.

Is it just a difficulty in getting a long enough surface lifetime for meaningful data, or more of a deployment issue?
Title: Re: Proposed Europa Missions
Post by: Ashley.Baldwin on 04/03/2016 12:08 pm
Thanks everyone for the insights into interplanetary mission planning and costs. I'm a huge fan of the Falcon Heavy and in sure one day it will pay a big role , thought not till SpaceX use their ISS and commercial crew public money to first get the launcher as expendable and heap as possible to consolidate their core business of LEO comes satellites and GEO DoD whatevers. Whilst avoiding any confrontation with principal paymasters Nasa over SLS for as long as possible , though that will come.

They are perfecting the boosted workhorse engine in the Merlin v1.2 for reusable boosters and are developing the Raptor which will be available in different sizes and arrays as part of central core , both first and second stage . Full reuseaability and low price first then bigger targets later. More powerful boosters , two stage raptor core configurations and cross feed with total expendibility enables full lifting power without holding any reserve to return bits to Earth. Why not a Rapto based booster even ? Who knows . Not even SpaceX yet I suspect. They just know the general direction to head and the eventual destination - Mars via the MCT. Forget price for any full power version though still likely less than SLS still though as the Raptor progresses even interplanetary versions become at least partially reusable . The Falcon Heavy is not a rocket , it is a family of rockets which will ultimately , if Musk gets his way, evolve into the almighty MCT.
That said , even the basic version hasn't launched because of the reusability target whilst safe public money is there to back them up whilst the cost of development is picked up. No way will it be used on interplanetary missions till it has heritage . And a decent Explorer upper stage, though a two engined Centaur might do the job short term if there is any priority.

The Next ion engine for Saturn was explored in a 2007 paper. It can indeed speed up transfer dramatically , it's a question of power. With 3 thrusters at 25 KW , and an Earth flyby it can get 3.5-4 tonnes or more to Saturn in less than 5.5 years. That's dependent on a big solar array that provides adequate power out to 3.5 AU then gets ejected . Conventional propellant will be required for SOI of course hence need for big mass carriage though retaining some of solar array might provide adequate power for ion engine in system use . NEXT likely available from New Frontiers 4 with a radioactive power source too . Whether  it extends to high power use with large solar arrays is another matter altogether  ! But it can be done .

All things being equal though . Europa Flyby , SLS and even a clever little lander based on proven Pathfinder. Even if the flybys can achieve landing site certification  , perhaps while the lander sits in some "stand off" orbit for 3 years or so , where does the $3.5 billion funding come from ? I agree that 80% of something is better than 100 % nothing but even $2.2 billion is a lot for even the flyby alone.

 Is there high politics at play here? Delay till new more mission friendly President gets in and assists at last ,  unencumbered as much over the critical mission years by JWST overspend. Is there a Flyby only compromise or does there need to be cuts and if so what ? If so what ? Neither NASA or ESA can really afford their proposed Mars Rovers so is the reach out to the ESA over a lander a suggestion for a Mars Rover merger ? The U.S. One is proven through Curiosity so a less risky choice , especially with sky crane landing heritage . Two landers there too whose cash could be redirected ( as from same fund ) to offset SLS, assuming cancellation of expensive "Insight" and use of its launcher for a combined Mars mission . May be too advanced for that , but it illustrates the sort of drastic things that would need to be done unless the  President comes to rescue . "Tactical" mission cuts at least rather than much more damaging " strategic" programme cuts .
Title: Re: Proposed Europa Missions
Post by: Ashley.Baldwin on 04/03/2016 12:22 pm
As to the inclusion of a seismic element to a Europa Lander I couldn't agree more. The only problem is the instrument itself. It was the SEIS seismic tool leakage that delayed the Mars Insight mission . It's obviously a difficult piece of technology .
Title: Re: Proposed Europa Missions
Post by: vjkane on 04/03/2016 02:16 pm
On the lander, I would have thought that even a few days of seismic data would be extremely valuable in characterizing the thickness of the ice crust.  With Jovian tides, I imagine there would be a lot of seismic activity going on in the crust.

Is it just a difficulty in getting a long enough surface lifetime for meaningful data, or more of a deployment issue?
I watched the Europa presentation at the meeting.  Another slide showed a geophone as part of the baseline (desired, attempt to include) rather than the threshold (don't fly without these) instrument suites.
Title: Re: Proposed Europa Missions
Post by: vjkane on 04/03/2016 02:17 pm
As to the inclusion of a seismic element to a Europa Lander I couldn't agree more. The only problem is the instrument itself. It was the SEIS seismic tool leakage that delayed the Mars Insight mission . It's obviously a difficult piece of technology .
The SEIS instrument apparently worked fine.  It would the containing vessel that has vacuum leaks.  This isn't likely to be a problem at Europa since its surface has a high grade vacuum. 
Title: Re: Proposed Europa Missions
Post by: vjkane on 04/03/2016 02:19 pm
Thanks everyone for the insights into interplanetary mission planning and costs. I'm a huge fan of the Falcon Heavy and in sure one day it will pay a big role , thought not till SpaceX use their ISS and commercial crew public money to first get the launcher as expendable and heap as possible to consolidate their core business of LEO comes satellites and GEO DoD whatevers. Whilst avoiding any confrontation with principal paymasters Nasa over SLS for as long as possible , though that will come.
At the meeting, the Europa project manager said that they expect to evaluate the Falcon Heavy, but can't do so until the design and the resulting specifications are complete.  He said that the performance would be similar to that of a Delta IV heavy.
Title: Re: Proposed Europa Missions
Post by: vjkane on 04/03/2016 02:23 pm
Is there high politics at play here? Delay till new more mission friendly President gets in and assists at last ,  unencumbered as much over the critical mission years by JWST overspend. Is there a Flyby only compromise or does there need to be cuts and if so what ? If so what ? Neither NASA or ESA can really afford their proposed Mars Rovers so is the reach out to the ESA over a lander a suggestion for a Mars Rover merger ? The U.S. One is proven through Curiosity so a less risky choice , especially with sky crane landing heritage . Two landers there too whose cash could be redirected ( as from same fund ) to offset SLS, assuming cancellation of expensive "Insight" and use of its launcher for a combined Mars mission . May be too advanced for that , but it illustrates the sort of drastic things that would need to be done unless the  President comes to rescue . "Tactical" mission cuts at least rather than much more damaging " strategic" programme cuts .
OMB clearly doesn't want to see the Europa mission fly.  Stating in the most recent proposed budget that the mission may fly as early as the late 2020s is the same as saying never.  That's at least two Presidents and several Congresses from now, and you could never keep a design team together for that long.

My belief is that OMB doesn't want any more large Flagship planetary missions that aren't tied to the goal of getting humans to Mars.

I don't understand your comment about NASA not being able to afford the Mars 2020 mission.  It is being fully funded and by all reports is on track.
Title: Re: Proposed Europa Missions
Post by: Ashley.Baldwin on 04/03/2016 03:15 pm
A fair point . Though I get the impression that the rover missions are stretching both agencies.  I accept that NASA may have committed to this . One way or another  Europa has to be funded as things stand though , unless things change a lot in the elections . I'm throwing up the sort of options that might apply , ugly as they may be , ideally the least problematic . My choice would be to have the lot if I had the funds.

As to the Falcon Heavy , it's a family not an individual rocket. The first version we see by necessity will emphasise reusability and cost to impress SpaceX current and potential  customers with all power to reusability. Just with the enhanced Merlin engine . It will bear little resemblance to later versions that could even be bespoke. The Merlin as your work horse and reusable , the Raptor for power ( and ultimately reusable too) and cross feed. Any combination of the above , possibly with varying numbers of Raptors too. A family and an evolving family probably creating the MCT at some point .
We won't see real power till the Raptor , and there isn't a big interplanetary market yet anyway for big "throwing power " options. Maybe if enough Pu238 power sources are available to offer them on Discovery missions too as well as ion thrusters then there will be a market. That said you can easily increase power simply by going entirely expendable the more so the better the engine. I'm no rocket scientist but cross feed could help too. At a cost though .
Title: Re: Proposed Europa Missions
Post by: Blackstar on 04/03/2016 05:46 pm
There are many other threads where we can wax rhapsodic over the wonders of the Falcon Heavy, inhaling its hallucinogenic vapors, giddy on all things SpaceX.

I think this thread is about Europa missions.
Title: Re: Proposed Europa Missions
Post by: redliox on 04/03/2016 07:11 pm
The new slides are impressive to look at.

So the lander will be separate and a plume probe is nixed; I suspect daughter craft with the 'Clipper will be out of the question in general; had some hopes for the Io mini-flyer but then again Europa is the priority so you have to admire the tenacity and focus the team is keeping toward that end.

So if anything else is added, a laser altimeter?  Most if its benefits were tied to the orbiter concept as opposed to fly-by; how useful could it be during flybys?
Title: Re: Proposed Europa Missions
Post by: vjkane on 04/03/2016 09:24 pm
The new slides are impressive to look at.

So the lander will be separate and a plume probe is nixed; I suspect daughter craft with the 'Clipper will be out of the question in general; had some hopes for the Io mini-flyer but then again Europa is the priority so you have to admire the tenacity and focus the team is keeping toward that end.

So if anything else is added, a laser altimeter?  Most if its benefits were tied to the orbiter concept as opposed to fly-by; how useful could it be during flybys?
I would still like to see cubesats as an option, but they haven't been mentioned in awhile.

The laser altimeter is a recommendation from the gravity science work group and would measure the tidal flex in the ice shell as another constraint on shell thickness.
Title: Re: Proposed Europa Missions
Post by: redliox on 04/03/2016 10:15 pm
Thanks everyone for the insights into interplanetary mission planning and costs. I'm a huge fan of the Falcon Heavy and in sure one day it will pay a big role

Setting your giant speech aside, I'll get to the part where Falcon Heavy and Europa meet and what your favorite rocket (not that I'm unenthusiastic to see it fly myself) can do that's directly relevant to this thread...

If you thumb the thread back to page 64 of the thread I dug into the application of FH + Europa.  I'll repost that here:
A question about using the Falcon Heavy for the Europa mission. Will the transit time to Europa be less than the baseline EELV?

I pondered about the same thing too.  I actually dug into the Falcon Heavy threads and found this (not to mention posted it within this thread too), courtesy of Hyperion5:
Quote
Rocket   Falcon Heavy
PLF Mass   4,000 kg
PLF separation   231 seconds
Payload to LEO (185 km x 185 km x 28 deg)   60,539 kg
Payload to GTO (-1800 m/s (18 degrees))   24,236 kg
Payload to GTO (-1500 m/s (18 degrees))   21,141 kg
Payload to GSO   10,968 kg
Payload to Moon (TLI)   17,692 kg
Payload to Mars   14,419 kg
Payload to Venus   15,135 kg
Payload to Jupiter (direct)   3,090 kg
Payload to Mercury   5,353 kg

Considering the Europa mission is going to weigh ~5,000 kg that means the FH can deliver 2/3 of the mass directly to Jupiter.  It is only going to need a modest push to get it finally to Jupiter, so most likely 1 Earth flyby just like Juno.  As for timeline, vjkane mentioned Elachi here:

Elachi: SLS will get spacecraft to Jupiter in 2-2.5 yrs instead of 6-7. If lander is really heavy cld do 1 Earth flyby & get there in 4 yrs

The FH specs Hyperion5 mentioned are just under a year old, more than likely still relevant.  The FH would make a fine alternative to SLS.  But, to answer your question, YES.  ;)

Now, considering Blackstar and Star One pointed out how it's less likely SLS will offer a "freebie" ride, the FH option would be appealing although more thought has probably been given to the Atlas option.  JPL and the Europa mission members probably won't bite for FH until they see it physically fly.
Title: Re: Proposed Europa Missions
Post by: AegeanBlue on 04/04/2016 02:31 am
I just wish we could avoid the SpaceX panegyrics in the Science section. SpaceX is a launch provider, nothing more, that has proven a bit but needs to prove quite a bit more. They are not the Messiah!

That being said, any attempt to add immature technologies such as a high power ion engine will lead to the Europa mission the way of JIMO. For once we have a relatively mature mission intended for Europa. Then again CRAF also reached this stage and got cancelled. I watched Jim Green's presentation at LPSC and my understanding is that the Planetary Division wants to use SLS in order to send more missions to the gas giants. They understand that it won't be for free but if they are charged a price similar to an Atlas V 551 they are willing to help with the cadence. On the other hand they are afraid of a new Space Shuttle debacle.

If the November elections lead to a flipping of both houses of Congress, we might see the Europa mission on Falcon Heavy. That of course assumes that Falcon Heavy will have had one launch by then. From the Von Karman lecture my understanding is that the Europa mission could potentially run into a weight issue, meaning it could turn out to be heavier than the maximum payload of Atlas V. Solar Probe Plus solved this by switching to Delta IV Heavy. Then again other posters here have more insider information than me the outside observer.
Title: Re: Proposed Europa Missions
Post by: Malderi on 04/04/2016 02:38 am
I suppose you're not going to see rovers on places like Europa until autonomous technology is far more advanced because of the communication delays.
I don't think so, a daily cycle as used for Mars rovers should work fine. The reason you won't see a Europa rover any time soon is money.
More than that. Rovers take a lot of power, and a lot of bandwidth, just to move around safely. That+actual science, at Europa, would get very big very fast. Money solves most mass problems but that's a big one.
Title: Re: Proposed Europa Missions
Post by: vjkane on 04/04/2016 04:53 am
I suppose you're not going to see rovers on places like Europa until autonomous technology is far more advanced because of the communication delays.
I don't think so, a daily cycle as used for Mars rovers should work fine. The reason you won't see a Europa rover any time soon is money.
More than that. Rovers take a lot of power, and a lot of bandwidth, just to move around safely. That+actual science, at Europa, would get very big very fast. Money solves most mass problems but that's a big one.
Based on our current understanding of interesting places on Europa scientifically, they are chaotic regions full of large ice blocks and cliffs.  A spider walker would be more useful than a rover.
Title: Re: Proposed Europa Missions
Post by: hop on 04/04/2016 06:25 am
Based on our current understanding of interesting places on Europa scientifically, they are chaotic regions full of large ice blocks and cliffs.  A spider walker would be more useful than a rover.
Which actually raises a bigger issue: To know what instruments make sense and what capabilities are required, you really want much better data than we have now. Trying to design a rover (or walker) mission now would be very expensive and high risk. Imagine trying to design MSL based on Mariner data.

A very basic lander on the first mission may make sense, but anything big and sophisticated will be a much better value if it's informed by the data from the missions currently under development.
Title: Re: Proposed Europa Missions
Post by: savuporo on 04/04/2016 06:34 am
Imagine trying to design MSL based on Mariner data.
A very basic lander on the first mission may make sense
Anything beyond Huygens-level capabilities would be stretching it.
Title: Re: Proposed Europa Missions
Post by: redliox on 04/04/2016 09:38 am
I'm amused trajectory 3 opens on my birthday  ;D

Am glad there's an alternative in case SLS is no longer an option or if JPL, ect wishes to do better than an Atlas V (or in case more 'fun' with Russian engines occurs).
Title: Re: Proposed Europa Missions
Post by: NovaSilisko on 04/04/2016 11:40 pm
Is the shell around the lander an actual structure or some bounding box sort of thing? It's a little hard to tell, it looks like the lander stack slots into the doughnut-shaped carrier and pops out the top before dumping the shell?

Will be interested in seeing if more LV studies are done as Falcon Heavy and Vulcan show up (but that's all I'm saying on this, I don't want to start another Thing about FH)
Title: Re: Proposed Europa Missions
Post by: Don2 on 04/05/2016 07:27 am
I don't see why people are discussing a rover that would be dead from radiation damage before it ever got off the lander.

I also don't think that NASA should be talking about the lander doing 'astrobiology' . Europa has an ice shell 1-30 km thick, the surface may be covered with sulfuric acid and is subject to intense radiation. None of that is promising for biology. What a lander can realistically do is to measure surface chemistry and isotope ratios. Isotope ratios could tell you something about the formation history of the moon. It should also have a small drill experiment to measure the mechanical properties of the ice so that future drilling schemes can be constrained by data.

A basic lander might have a Chemcam type instrument to measure elemental compositions and a Raman to measure mineralogy and organics content (if any). Those instruments can fire their lasers at spots on the surface within a few meters of the lander. A small heated tube could be pushed into the surface to vaporize ice and the vapors fed to a GCMS for measurement of the H and O isotope ratios.

A more advanced lander might have a small radar sounding payload to detect liquids within 10-100m of the surface. If you could find a site which had liquids within 10m of the surface then you would have a great target for a future astrobiology lander.

Of course NASA doesn't have the money for a lander. If NASA did have the money they would probably spend it on something else, and the science-political support isn't there because the decadal survey didn't mention a lander mission.
Title: Re: Proposed Europa Missions
Post by: redliox on 04/05/2016 08:14 am
I don't see why people are discussing a rover that would be dead from radiation damage before it ever got off the lander.

Have to agree with you there; a rover is way too premature and, obviously, certainly something like Sojournor might die within hours.  Also, in the coming era we might find better ways to be mobile both on Mars and Europa; in Europa's case some kind of rocket hopper might be possible.

I also don't think that NASA should be talking about the lander doing 'astrobiology' . Europa has an ice shell 1-30 km thick, the surface may be covered with sulfuric acid and is subject to intense radiation. None of that is promising for biology. What a lander can realistically do is to measure surface chemistry and isotope ratios. Isotope ratios could tell you something about the formation history of the moon. It should also have a small drill experiment to measure the mechanical properties of the ice so that future drilling schemes can be constrained by data.

Would 'cryo-paleontology' sound better?  The probe would be looking for promising signs of chemistry and microscopic fossils in the ice - both endeavors are reasonably possible even with a simple lander.  The key is 'Clipper (or whatever it may be named) finding a spot akin to Europa what Gale Crater or Meridiani were to Mars.

Of course NASA doesn't have the money for a lander. If NASA did have the money they would probably spend it on something else, and the science-political support isn't there because the decadal survey didn't mention a lander mission.

There is a ball rolling for a lander at least thanks to Congress.  It will be a stretch at the least.  However it would be the next logical step after a successful Europa mapping project; the next decadal survey may make mention of that.
Title: Re: Proposed Europa Missions
Post by: redliox on 04/05/2016 09:35 am
Is the shell around the lander an actual structure or some bounding box sort of thing? It's a little hard to tell, it looks like the lander stack slots into the doughnut-shaped carrier and pops out the top before dumping the shell?

That looks like the case.  I'm wondering about the carrier itself; it has some thought put into it but I'm wondering what it will be doing, more so if it is going to double for a relay platform later.  It's not as elaborated upon as the lander or its descent packaging.  Should we assume it enters orbit chemically or would SEP be an option despite weak sunlight?
Title: Re: Proposed Europa Missions
Post by: A8-3 on 04/13/2016 01:55 pm
I haven't seen this before. Is it new? Similar to the StarChip Nanocrafts proposed by the Starshot project.

http://aviationweek.com/space/smallsat-concept-could-change-game-europa
Title: Re: Proposed Europa Missions
Post by: Star One on 04/19/2016 07:18 pm
Jeff Foust –  ‏@jeff_foust

Culberson: NASA number should be a good one overall, in particular Europa mission [a personal favorite of his]
9:31 a.m. - 19 Apr 2016

https://mobile.twitter.com/jeff_foust/status/722462619903397888
Title: Re: Proposed Europa Missions
Post by: Blackstar on 04/20/2016 03:58 pm
http://www.bbc.com/news/science-environment-36079069

Title: Re: Proposed Europa Missions
Post by: Dalhousie on 04/20/2016 11:39 pm
There are similar issues with Mars sample return. Every time I see somebody suggest that they should add ISRU to the Mars sample return architecture I cringe. That's adding unproven and complicated technology to something that is already difficult to do, and it does not actually improve the result, it only adds risk (a good rule of thumb is that if you are going to add risk, you should also have a good benefit to the mission for doing so).

OT comment by me, but adding operational ISRU allows increasing the returned sample mass by about an order of magnitude.  Despite the advances in analytical techniques, sample size and diversity is still very important.  I quite agree with the point of added complexity but I'll match your cringe with my eye roll over the greatly reduced return any day.  OK, back to the scheduled program. :)
Title: Re: Proposed Europa Missions
Post by: Blackstar on 04/21/2016 12:26 am
OT comment by me, but adding operational ISRU allows increasing the returned sample mass by about an order of magnitude.  Despite the advances in analytical techniques, sample size and diversity is still very important.  I quite agree with the point of added complexity but I'll match your cringe with my eye roll over the greatly reduced return any day.  OK, back to the scheduled program. :)

I fully agree with you that untested, unproven, theoretical technologies that are high risk have far greater performance than tested, proven, existing technologies. Absolutely true. On Mars. On Europa. Everywhere.
Title: Re: Proposed Europa Missions
Post by: okan170 on 04/21/2016 05:36 pm
New NASA/JPL render of the current Clipper configuration.  (this would've really helped me last week!)

http://www.nasa.gov/image-feature/jpl/pia20025/europa-mission-spacecraft-artists-rendering
Title: Re: Proposed Europa Missions
Post by: Blackstar on 05/03/2016 01:03 am
Europa mission.
Title: Re: Proposed Europa Missions
Post by: rocx on 05/03/2016 07:18 am
I really like this part in the pdf about Europa Missions:

Quote
–Lander
  •Science!!!

From a Kerbal point of view I completely agree that landing on a planet will give a lot more science than orbiting.
Title: Re: Proposed Europa Missions
Post by: Dalhousie on 05/04/2016 03:41 am
OT comment by me, but adding operational ISRU allows increasing the returned sample mass by about an order of magnitude.  Despite the advances in analytical techniques, sample size and diversity is still very important.  I quite agree with the point of added complexity but I'll match your cringe with my eye roll over the greatly reduced return any day.  OK, back to the scheduled program. :)

I fully agree with you that untested, unproven, theoretical technologies that are high risk have far greater performance than tested, proven, existing technologies. Absolutely true. On Mars. On Europa. Everywhere.

Nothing theoretical, untested, or unproven about ISRU. TRL varies between 3 and 6 depending on type under discussion. 
Title: Re: Proposed Europa Missions
Post by: baldusi on 05/04/2016 04:27 am
OT comment by me, but adding operational ISRU allows increasing the returned sample mass by about an order of magnitude.  Despite the advances in analytical techniques, sample size and diversity is still very important.  I quite agree with the point of added complexity but I'll match your cringe with my eye roll over the greatly reduced return any day.  OK, back to the scheduled program. :)

I fully agree with you that untested, unproven, theoretical technologies that are high risk have far greater performance than tested, proven, existing technologies. Absolutely true. On Mars. On Europa. Everywhere.

Nothing theoretical, untested, or unproven about ISRU. TRL varies between 3 and 6 depending on type under discussion.
I believe that you have to read again the very definition of TRL.
Title: Re: Proposed Europa Missions
Post by: savuporo on 05/04/2016 04:41 am
Nothing theoretical, untested, or unproven about ISRU. TRL varies between 3 and 6 depending on type under discussion. 
Not to sidetrack, but i'm aware of multiple projects that have gone to TRL 4/5, but not legitimately at 6 - i.e. mostly flight weight/volume prototype that meets the performance goals, tested in analog environment.
Title: Re: Proposed Europa Missions
Post by: Star One on 05/04/2016 06:42 am
So the lander will be using another Skycrane, I suppose that's logical as by then similar devices should have been used twice to land on Mars.
Title: Proposed Europa Missions
Post by: Star One on 05/17/2016 08:13 pm
Looks like the politicians are trying to force NASA's hand this.

Quote
The House bill also specified that, of the $5.6 billion allocated for NASA’s science programs, $260 million go towards a mission to Europa. NASA requested less than $50 million for the Europa mission, while the Senate’s bill did not specify an amount for that proposed mission.

The additional Europa funding is not surprising, as Rep. John Culberson (R-Texas), chairman of the CJS subcommittee, has been a leading advocate for a Europa mission for several years, adding funding well above any NASA request for a spacecraft to help determine if the icy moon can support life.

http://spacenews.com/house-bill-offers-19-5-billion-for-nasa-in-2017/
Title: Re: Proposed Europa Missions
Post by: Blackstar on 05/17/2016 08:34 pm
Looks like the politicians are trying to force NASA's hand this.

Quote
The House bill also specified that, of the $5.6 billion allocated for NASA’s science programs, $260 million go towards a mission to Europa. NASA requested less than $50 million for the Europa mission, while the Senate’s bill did not specify an amount for that proposed mission.

The additional Europa funding is not surprising, as Rep. John Culberson (R-Texas), chairman of the CJS subcommittee, has been a leading advocate for a Europa mission for several years, adding funding well above any NASA request for a spacecraft to help determine if the icy moon can support life.

http://spacenews.com/house-bill-offers-19-5-billion-for-nasa-in-2017/

It's not forcing NASA's hand. It's forcing the OMB/Obama administration's hand. And this has been going on for a number of years now. There are people at NASA who would love if the administration asked for sufficient money to fund a Europa mission. But the administration is not doing that, so Congressman Culberson is forcing it on them.

There is the civics lessons they teach you in school and then there is how government really works, and understanding the latter is really tough. I got a Ph.D. in it and I still learn stuff all the time.
Title: Re: Proposed Europa Missions
Post by: redliox on 05/17/2016 09:09 pm
It's not forcing NASA's hand. It's forcing the OMB/Obama administration's hand. And this has been going on for a number of years now. There are people at NASA who would love if the administration asked for sufficient money to fund a Europa mission. But the administration is not doing that, so Congressman Culberson is forcing it on them.

Obama's administration definitely had zero interest in NASA, that's proven obvious by now; even (Bill) Clinton and George (W) Bush before him showed at least slightly more interest.  Not terribly surprised NASA's the Cinderella of the situation, although at least the Planetary Science program is fairing vastly better than it was in the 1980s.

Steering back to the proper topic though, it is still heartwarming to know Europa hasn't been forgotten.  Clearly it will be funded and become the next flagship after Mars 2020.  The real fun part will be seeing IF it flies aboard SLS or not, which is also part of the funding fun.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 05/17/2016 09:25 pm
Obama's administration definitely had zero interest in NASA, that's proven obvious by now; even (Bill) Clinton and George (W) Bush before him showed at least slightly more interest.  Not terribly surprised NASA's the Cinderella of the situation, although at least the Planetary Science program is fairing vastly better than it was in the 1980s.

Steering back to the proper topic though, it is still heartwarming to know Europa hasn't been forgotten.  Clearly it will be funded and become the next flagship after Mars 2020.  The real fun part will be seeing IF it flies aboard SLS or not, which is also part of the funding fun.

I don't want to get too far into this, but I disagree with your first statement. Obama did not cut NASA in any serious way. The administration wanted to use it to serve their larger agendas, which included monitoring climate change and STEM issues. I think that when it came to human exploration, they tried to redirect the train, but were surprised that when they turned the wheel on it really hard it came off the tracks. Then they walked away from it. This was not unusual--both the first and second Bush administrations tried to redirect NASA, saw their efforts blow up in their face, and then walked away. It's a problem with how the executive branch views NASA: they pay attention to it for a short period of time, think that they can simply point it in a new direction and say "Go!" and then they don't need to do anything else. That's not the way stuff works--continued monitoring and engagement and funding is necessary--but they don't care enough about NASA to do all that work, and so they quit.

Planetary science is not doing as well as it was under Bush. Earth science is doing better.

And yes, you are right about Europa. It will indeed be interesting to see what happens.
Title: Re: Proposed Europa Missions
Post by: Star One on 05/17/2016 09:41 pm
Will it be able to reach completion as a project if there is a repeated stance of indifference by the next adminstration?
Title: Re: Proposed Europa Missions
Post by: Blackstar on 05/18/2016 12:54 am
Will it be able to reach completion as a project if there is a repeated stance of indifference by the next adminstration?

I don't know. From a project management standpoint this is a horrible way to run a program. The people who run it (HQ, JPL) have to know how much money they will have for the next several years so that they can start buying stuff. But they don't. In fact, it's worse than that--OMB tells them how much money to plan to have, and then when Congress gets done, they have more money, so they either scramble to spend it, or leave some of it unspent. And what happens if the Republicans lose the Senate or even the House next year? Then Congress will stop adding in the money for a Europa mission.

It is a helluva way to run a railroad.
Title: Re: Proposed Europa Missions
Post by: wbianco on 05/18/2016 03:22 am

And yes, you are right about Europa. It will indeed be interesting to see what happens.

As per the House budget proposal today, the "plan" is to launch Clipper in 2022 on an SLS, with a second SLS used to launch a lander in 2024.  Which is a nonstarter unless somebody subsidizes SMD for the launches....do you see any hands being raised?  Didn't think so.     

Which is to say - Clipper sounds cool and there is support, but lots of cool things have fallen by the wayside given far smaller cost pressures.  Blackstar's right - it's a hell of a way to run a railroad.
Title: Re: Proposed Europa Missions
Post by: savuporo on 05/18/2016 07:17 pm
The people who run it (HQ, JPL) have to know how much money they will have for the next several years so that they can start buying stuff. ..

Imagine if we actually had orbital infrastructure and staging options, like Lockheed Jupiter/Exoliner. With the excess $200 million thrown at this, you could promptly buy a cargo launch full of hydrazine and park it on orbit, waiting for the spacecraft itself - yet to be designed.
Title: Re: Proposed Europa Missions
Post by: wbianco on 05/18/2016 08:45 pm
Blackstar - so the implicit deal is, give us the $ for 2 x SLS and we can do Clipper and a lander in sequence?  Would make Shelby, Brooks et al happy, as well as the entire HEOMD division, as they get to fund their SLS standing army.  Put another way, if you are going to build some SLSs, you might as well build a couple more.  I could see that working, the only cost is the extra two boosters, which in a real sense is no cost at all.
Title: Re: Proposed Europa Missions
Post by: redliox on 05/18/2016 09:47 pm
Wishes. Horses. Unicorns.

*facepalms* Blackstar if you say unicorn again I will swear you surely are a space brony...

I think Clipper will happen (although not by that name). I knew about the plan to separate the lander from the Clipper mission. NASA was telegraphing that many months ago and the question was if they would convince Culberson it was the way to go (and it really is a very bad idea to put the flyby mission and the lander on the same launch, for lots and lots of reasons). A few months back I heard that some wise people had convinced Culberson of the wisdom of separating them. So it was only a question of when that became public.

Now the lander... That's going to slip. It will be an expensive spacecraft to design and it will take some time. You really want to do it right, not half-assed. So 2 years after the flyby mission is not a good phasing for that. But baby steps. Baby steps.

As for the SLS, it's a complex budget issue and I don't understand it (well, I just haven't asked the right people to explain it to me). But an extra SLS will cost more money to NASA, no matter whether it comes out of the SMD budget or the HEOMD budget. It will probably be added on top of the NASA budget, and book-kept in HEOMD or SMD or somewhere. But the key thing is that it's going to cost more money.

Glad they convinced Culberson to tone the ambition down by 10%.  Baby steps are overrated, but I do think pinpointing a landing site warrants a 2 to 6 year break between launches to give the flyby-orbiter and its team to time to properly search.  Keep most of the focus on the flyby-orbiter but allow the lander to decently simmer on the back burner.

It'll be interesting to see what becomes of SLS; but if they want to prove the launcher is more than Orion's workhorse, sending a probe out is probably the best near-term bet.  They still have the embarrassment of not having any payloads to prove their worth...so after the EM-1 mission flies I wouldn't be surprised if they scramble and beg for something to do, regardless of where the money comes from.  However I say just launch the orbiter on it but not the lander, and certainly not both at once.
Title: Re: Proposed Europa Missions
Post by: savuporo on 05/19/2016 02:05 am
And the example proposed above, launching propellant into orbit with nothing for it to do based upon the idea that eventually you might build a payload that could use it, is an imaginary idea. It's a really nonsensical way to do something, like going out and buying 200 gallons of gas and storing it in your garage in case someday you may buy a car. Nobody does that.

February 3rd, 1978 is the first time these kinds of ideas were put to practice, and they have been holding up pretty well - i wouldn't call it 'imaginary'.
And, a few in-space infrastructure bits have gone up before they have seen their final use like TDRS, comm relay capabilities on Martian orbiters or even things like Zarya & Unity which definitely haven't yet seen their final use.

And how many unicorns, angels and tinkerbells can actually dance on top of all these HLVs that never actually seem to take off, anyway ?
Title: Re: Proposed Europa Missions
Post by: Sesquipedalian on 05/19/2016 02:35 am
I think that if Congress is going to mandate that NASA fly robotic payloads on SLS, then Congress (or a new White House) is going to have to add in more money for the additional SLS rockets.

If it happens, I hope it happens that way.  I worry the budget will remain flat and Shelby will say, "Okay, 50% of your planetary science funds are now earmarked for your SLS launch."
Title: Re: Proposed Europa Missions
Post by: NovaSilisko on 05/19/2016 04:18 am
Maybe a topic for another thread if the answer gets too long, but how were interplanetary payloads for the Shuttle handled from a funding standpoint? Is there any similarity with that and how things are proceeding with Clipper on SLS?
Title: Re: Proposed Europa Missions
Post by: savuporo on 05/19/2016 02:00 pm
And you were proposing launching propellant into space long before there is a spacecraft built that can use it. That's nonsensical.

About as nonsensical as collecting samples on Mars before there is even a token plan of getting these back home
Title: Re: Proposed Europa Missions
Post by: Blackstar on 05/19/2016 02:06 pm
And you were proposing launching propellant into space long before there is a spacecraft built that can use it. That's nonsensical.

About as nonsensical as collecting samples on Mars before there is even a token plan of getting these back home


Not by a long shot. For starters, Mars 2020 has other science equipment and will conduct very useful science besides the collection of samples. And it is also envisioned as the first step in sample return.

But you don't buy 200 gallons of gas and store it before you buy a car, even if gas is cheap.
Title: Re: Proposed Europa Missions
Post by: Archibald on 05/19/2016 04:03 pm
Gosh, I had missed the two SLS news. So the deal is now,  one SLS for the orbiter, one other SLS for the lander ?
Quote
It is a helluva way to run a railroad.


Sure it is. Who gonna pay for the uber-expensive twin SLS flights ? 

How good are relations between Culbertson (Mr Europa) and Shelby (Mr SLS) ? do they work hand by hand to provide SLS payloads - desperately needed since HSF can't fund anything else than Orion, not even a lander to any place ?
Title: Re: Proposed Europa Missions
Post by: Arcas on 05/19/2016 04:07 pm
Gosh, I had missed the two SLS news. So the deal is now,  one SLS for the orbiter, one other SLS for the lander ?
Quote
It is a helluva way to run a railroad.


Sure it is. Who gonna pay for the uber-expensive twin SLS flights ?
With the way the senate has been throwing money at SLS, I doubt we'll have trouble funding it. We managed to launch the shuttle multiple times a year, and this is basically the same.
Title: Re: Proposed Europa Missions
Post by: Star One on 05/19/2016 07:25 pm
House tells NASA to stop messing around, start planning two Europa missions

Provide a realistic funding profile next time, Congress tells the White House.

Quote
"We have increased funding for planetary programs and made sure we are going to complete the incredibly important mission to Europa that the planetary decadal survey mapped out because of the very high likelihood that life will be discovered in those oceans," Culberson said during a hearing Tuesday. "This will be a transformative moment in the history of humanity and the country."

In its documents about the Europa mission, NASA has not formally approved a lander, and it says only that the flyby mission will launch "sometime in the 2020s." The House bill is much more specific, calling for an orbiter launch no later than 2022 and a lander launch no later than 2024. Senior officials at the Jet Propulsion Laboratory have told Culberson that those dates are attainable. Additionally, the bill specifies that NASA's next budget, for fiscal year 2018, includes a five-year funding profile to support those two launches.

http://arstechnica.com/science/2016/05/house-budget-provides-260-million-for-two-life-tracking-europa-missions/
Title: Re: Proposed Europa Missions
Post by: Blackstar on 05/20/2016 12:00 am
http://arstechnica.com/science/2016/05/house-budget-provides-260-million-for-two-life-tracking-europa-missions/
Title: Re: Proposed Europa Missions
Post by: Don2 on 05/20/2016 01:41 am
This looks like it is growing into a $6bn megaproject. To my eye, the orbiter and its instruments looks more like a $4bn mission than a $2bn mission. As for the lander, who knows? I'll open the bidding at $3bn. The use of the skycrane landing system suggests a large and complex mission like Curiosity, which cost $2.4bn To drive the cost up, there is the fact that the surface of Europa requires a large delta-v, and the radiation environment is much more demanding than at Mars. The thermal environment will be distinctly chilly during the Europan night, which will probably require an RTG unless the surface mission is very short.

Then there is the cost of the SLS launches. The real cost of an SLS launch at a flight rate of 1/year could easily be over $1bn when all the overheads are included. Charging those costs to the science budget gives SLS an opportunity to loot science in order to pay their own bills. 

I think there is a way for everybody to agree on a Europa orbiter if everyone agrees to keep the costs down to $2bn or so. That means no lander of course. If Congress wants to add money to the planetary science budget they need to show where it will come from. More money for planetary would be very welcome, but realistic cost estimates for the lander and a fixed price for the SLS launches are still needed.

However much money is on offer, NASA should not promise an astrobiology lander. There isn't enough data on the surface of Europa to design such a beast, and what little is known is not at all promising for the survival of surface organics. All that can be done is a basic exploration of the surface chemistry and composition, and the collection of engineering data needed to design something more ambitious.
Title: Proposed Europa Missions
Post by: Star One on 05/20/2016 06:21 am
This looks like it is growing into a $6bn megaproject. To my eye, the orbiter and its instruments looks more like a $4bn mission than a $2bn mission. As for the lander, who knows? I'll open the bidding at $3bn. The use of the skycrane landing system suggests a large and complex mission like Curiosity, which cost $2.4bn To drive the cost up, there is the fact that the surface of Europa requires a large delta-v, and the radiation environment is much more demanding than at Mars. The thermal environment will be distinctly chilly during the Europan night, which will probably require an RTG unless the surface mission is very short.

Then there is the cost of the SLS launches. The real cost of an SLS launch at a flight rate of 1/year could easily be over $1bn when all the overheads are included. Charging those costs to the science budget gives SLS an opportunity to loot science in order to pay their own bills. 

I think there is a way for everybody to agree on a Europa orbiter if everyone agrees to keep the costs down to $2bn or so. That means no lander of course. If Congress wants to add money to the planetary science budget they need to show where it will come from. More money for planetary would be very welcome, but realistic cost estimates for the lander and a fixed price for the SLS launches are still needed.

However much money is on offer, NASA should not promise an astrobiology lander. There isn't enough data on the surface of Europa to design such a beast, and what little is known is not at all promising for the survival of surface organics. All that can be done is a basic exploration of the surface chemistry and composition, and the collection of engineering data needed to design something more ambitious.

Not quite sure why you're assuming the lander is just going to examine the surface alone. Such a project would be rather limited unless it was put down somewhere where it could also access one of the numerous cracks on Europa's surface and therefore conduct some subsurface science as well.
Title: Re: Proposed Europa Missions
Post by: Proponent on 05/20/2016 07:05 am
How good are relations between Culbertson (Mr Europa) ....

By the way that's Culberson, without a 't'.  Culbertson, with a 't', is the former astronaut who now works for Orbital ATK.

I kept getting them confused, so I came up with a mnemonic:  Culbertson is the guy who works for Orbital ATK.  Although it doesn't help that Culberson is a representative from Texas, just remember that's only a single T against Orbital ATK's two.

EDIT:  [groan]You could say Culbertson fits Orbital ATK to a tee[/groan].
Title: Re: Proposed Europa Missions
Post by: Archibald on 05/20/2016 04:23 pm
My bad for Culberson. About CulberTsons, there was a couple of them in NASA history - manager Philip http://www.astronautix.com/astros/culhilip.htm
and astronaut Frank (that you mentionned). Always wondered if they were related in any way.
Title: Re: Proposed Europa Missions
Post by: hop on 05/21/2016 06:14 am
Not quite sure why you're assuming the lander is just going to examine the surface alone. Such a project would be rather limited unless it was put down somewhere where it could also access one of the numerous cracks on Europa's surface and therefore conduct some subsurface science as well.
Without data from the orbiter, that's very speculative. We know the cracks are young (in geological terms) and somehow relate to interior activity, but that doesn't necessarily mean landing in these areas would tell us much about the interior.

We also don't know what capabilities are required to land there. Without better data, the lander either has to be designed for worst case scenarios (very expensive), or run a high risk of not being able to land safely in those regions.

Similar issues apply to the science payload.

A lander designed after the data from the first orbiter have been analyzed will be much lower risk, more cost effective and have better science return.
Title: Re: Proposed Europa Missions
Post by: Star One on 05/21/2016 08:19 am
Not quite sure why you're assuming the lander is just going to examine the surface alone. Such a project would be rather limited unless it was put down somewhere where it could also access one of the numerous cracks on Europa's surface and therefore conduct some subsurface science as well.
Without data from the orbiter, that's very speculative. We know the cracks are young (in geological terms) and somehow relate to interior activity, but that doesn't necessarily mean landing in these areas would tell us much about the interior.

We also don't know what capabilities are required to land there. Without better data, the lander either has to be designed for worst case scenarios (very expensive), or run a high risk of not being able to land safely in those regions.

Similar issues apply to the science payload.

A lander designed after the data from the first orbiter have been analyzed will be much lower risk, more cost effective and have better science return.

That's what I was assuming that it would arrive after the orbiter has done its work.
Title: Re: Proposed Europa Missions
Post by: redliox on 05/21/2016 09:00 am
Maybe a topic for another thread if the answer gets too long, but how were interplanetary payloads for the Shuttle handled from a funding standpoint? Is there any similarity with that and how things are proceeding with Clipper on SLS?

Well the main difficulty with the shuttle days was how the managers heavily insisted for planetary missions to use it, which was the case for Galileo, Magellan, and Ulysses.  The shuttle requirement forced the probes to be redesigned, especially for Galileo, to accommodate it.  However, after Challenger they couldn't use the planned Centaur booster and improvised with solid rocket stages instead.  Cassini and CRAFT had been briefly considered for the shuttle but (because of Challenger again) fortunately got switched over to a Titan launcher instead.

While the SLS is unflown for now, the plus side for using it is, unlike the shuttle, it can operate more easily for crewless missions.  The shuttle was essentially weighed down by the orbiter itself, or else it might have made a fairly useful heavy lift vehicle; by comparison the SLS doesn't have this limitation - all you do is essentially change "the topper" i.e. payload to whatever's required.

Cost is probably the true issue for flying via SLS.  For the Europa mission (either the orbiter or lander), it would be wonderful to get directly to Jupiter; bad news is it may cost a lot, which coupled with safety was also a reason satellite providers rapidly abandoned the space shuttle.  I'd like to see the flyby-orbiter fly with it, but I wouldn't want to do that with the lander since developing that will be enough of a future expense as is.
Title: Re: Proposed Europa Missions
Post by: vjkane on 05/21/2016 03:27 pm
Cost is probably the true issue for flying via SLS.  For the Europa mission (either the orbiter or lander), it would be wonderful to get directly to Jupiter; bad news is it may cost a lot, which coupled with safety was also a reason satellite providers rapidly abandoned the space shuttle.  I'd like to see the flyby-orbiter fly with it, but I wouldn't want to do that with the lander since developing that will be enough of a future expense as is.
I've worked with enough finance people to know that there is a lot of leeway on how costs are accounted for.  NASA will have large fixed costs for maintaining the capability of launching SLS missions.  Then there will be the marginal costs associated with building an individual booster, transporting it, fueling it, launching it, etc.  The key will be whether the science division (I suspect there are some great telescope observatories that SLS could launch in addition to planetary missions) is charged only the marginal cost or a substantial portion of the fixed costs.

I strongly suspect that NASA will design planetary missions so they can also be launched on commercial systems.  SLS may not work.  Political support may dry up (when will Shelby retire?).  There could be a launch failure and the whole system stands down for a couple of years.  Backups are good.

In the case of the Europa multiflyby mission, a key decision will be whether to expand the fuel tanks or not and/or design the spacecraft for the heat of Venus gravity assists.  The former would allow a deep space maneuver that would shorten the flight to 4.7 years with a Delta IV Heavy.  The latter would allow an EVEEGA trajectory and a 7.4 year flight.  How much insurance will NASA buy?
Title: Re: Proposed Europa Missions
Post by: savuporo on 05/21/2016 09:35 pm
While the SLS is unflown for now...
And that's the crazy part .. This will predictably become a multi-billion dollar mission. It will be trusted to a launcher that will have scored one or two flights maybe ? Whatever happened to launcher certification and all that.
Title: Re: Proposed Europa Missions
Post by: ugordan on 05/21/2016 11:18 pm
While the SLS is unflown for now...
And that's the crazy part .. This will predictably become a multi-billion dollar mission. It will be trusted to a launcher that will have scored one or two flights maybe ? Whatever happened to launcher certification and all that.

Well, wasn't Cassini launched on only the 2nd Titan IVB vehicle flown? Yeah, it wasn't a completely new vehicle, but still it puts things into some context.
Title: Re: Proposed Europa Missions
Post by: redliox on 05/21/2016 11:44 pm
Well, wasn't Cassini launched on only the 2nd Titan IVB vehicle flown? Yeah, it wasn't a completely new vehicle, but still it puts things into some context.

Right.  The SLS will certainly fly at least once with Orion aboard before a chance comes up before Europa's turn.
Title: Re: Proposed Europa Missions
Post by: Star One on 05/22/2016 07:37 am
Well, wasn't Cassini launched on only the 2nd Titan IVB vehicle flown? Yeah, it wasn't a completely new vehicle, but still it puts things into some context.

Right.  The SLS will certainly fly at least once with Orion aboard before a chance comes up before Europa's turn.
But how similar will the configuration be. Isn't there a chance the Europa mission could be the first to use EUS.
Title: Re: Proposed Europa Missions
Post by: savuporo on 05/22/2016 08:10 am
Well, wasn't Cassini launched on only the 2nd Titan IVB vehicle flown? Yeah, it wasn't a completely new vehicle, but still it puts things into some context.

Very fair point (http://commons.erau.edu/cgi/viewcontent.cgi?article=1347&context=space-congress-proceedings). Wonder if these "lessons learned" are lessons remembered ..
Title: Re: Proposed Europa Missions
Post by: Blackstar on 05/23/2016 01:13 am
In the case of the Europa multiflyby mission, a key decision will be whether to expand the fuel tanks or not and/or design the spacecraft for the heat of Venus gravity assists.  The former would allow a deep space maneuver that would shorten the flight to 4.7 years with a Delta IV Heavy.  The latter would allow an EVEEGA trajectory and a 7.4 year flight.  How much insurance will NASA buy?

I heard someone say that they're designing it for the thermal effects of a Venus flyby no matter what. I don't know why, but myabe the margins opened up and they figured it is better to just plan for that no matter what.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 06/06/2016 12:05 pm
New paper by Ralph Lorenz just published showing that the retropropulsion on a Europa Lander will likely alter a region about 10m in radius; if using conventional hydrazine, the ammonia-rich exhaust will likely frustrate assays of nitrogen-bearing compounds which would be very important for any Europan life.



Abstract
"Soft-landings on large worlds such as Europa or our Moon require near-surface retropropulsion, which leads to impingement of the rocket plume on the surface. Surface modification by such plumes was documented on Apollo and Surveyor, and on Mars by Viking, Curiosity and especially Phoenix. The low temperatures of the Europan regolith may lead to efficient trapping of ammonia, a principal component of the exhaust from monopropellant hydrazine thrusters. Deposited ammonia may react with any trace organics, and may overwhelm the chemical and isotopic signatures of any endogenous nitrogen compounds, which are likely rare on Europa. An empirical correlation of the photometrically-altered regions (‘blast zones’) around prior lunar and Mars landings is made, indicating A=0.02T1.5, where A is the area in m2 and W is the lander weight (thus, ~thrust) at landing in N: this suggests surface alteration will occur out to a distance of ~9 m from a 200 kg lander on Europa."

Keywords
Europa; Astrobiology; Nitrogen; Thruster exhaust




http://www.sciencedirect.com/science/article/pii/S0032063316300484

Title: Re: Proposed Europa Missions
Post by: vjkane on 06/06/2016 01:12 pm
I heard someone say that they're designing it for the thermal effects of a Venus flyby no matter what. I don't know why, but myabe the margins opened up and they figured it is better to just plan for that no matter what.
The lowest launch energy solutions for getting to Jupiter, as I understand it, require Venus gravity assists.  Designing for Venus is insurance against either increases in spacecraft mass or the eventual need to use a smaller launch vehicle.
Title: Re: Proposed Europa Missions
Post by: Sesquipedalian on 06/06/2016 02:56 pm
New paper by Ralph Lorenz just published showing that the retropropulsion on a Europa Lander will likely alter a region about 10m in radius; if using conventional hydrazine, the ammonia-rich exhaust will likely frustrate assays of nitrogen-bearing compounds which would be very important for any Europan life.

Could a Europa lander use airbags?  Or is the retrofire still too close to the surface for that to matter?
Title: Re: Proposed Europa Missions
Post by: slavvy on 06/06/2016 03:13 pm
New paper by Ralph Lorenz just published showing that the retropropulsion on a Europa Lander will likely alter a region about 10m in radius; if using conventional hydrazine, the ammonia-rich exhaust will likely frustrate assays of nitrogen-bearing compounds which would be very important for any Europan life.

Could a Europa lander use airbags?  Or is the retrofire still too close to the surface for that to matter?

What about using hydrogen peroxide as mono-propellant?

http://www.esa.int/gsp/ACT/doc/PRO/ACT-RPR-PRO-JPC2006-HP%20Rockets%202006-5239.pdf (http://www.esa.int/gsp/ACT/doc/PRO/ACT-RPR-PRO-JPC2006-HP%20Rockets%202006-5239.pdf)
Title: Re: Proposed Europa Missions
Post by: ncb1397 on 06/06/2016 07:52 pm
New paper by Ralph Lorenz just published showing that the retropropulsion on a Europa Lander will likely alter a region about 10m in radius; if using conventional hydrazine, the ammonia-rich exhaust will likely frustrate assays of nitrogen-bearing compounds which would be very important for any Europan life.

Could a Europa lander use airbags?  Or is the retrofire still too close to the surface for that to matter?

skycrane strikes back!
Title: Re: Proposed Europa Missions
Post by: Star One on 06/06/2016 08:10 pm
New paper by Ralph Lorenz just published showing that the retropropulsion on a Europa Lander will likely alter a region about 10m in radius; if using conventional hydrazine, the ammonia-rich exhaust will likely frustrate assays of nitrogen-bearing compounds which would be very important for any Europan life.

Could a Europa lander use airbags?  Or is the retrofire still too close to the surface for that to matter?

skycrane strikes back!

Isn't that what they were proposing to use on this anyway?
Title: Re: Proposed Europa Missions
Post by: redliox on 07/31/2016 10:13 pm
Later this month there's a meeting of the OPAG which will include discussion on both 'Clipper and the Lander for Europa.  The agenda here:
http://www.lpi.usra.edu/opag/meetings/aug2016/agenda.pdf (http://www.lpi.usra.edu/opag/meetings/aug2016/agenda.pdf)
Title: Proposed Europa Missions
Post by: Star One on 08/11/2016 08:05 pm
Quote
Jeff Foust –  ‏@jeff_foust

NASA’s Curt Niebur, at OPAG meeting, on Europa Clipper: strong support for mission from Congress now shared by administration  and NASA.

https://mobile.twitter.com/jeff_foust/status/763784667082260480

Quote
Jeff Foust –  ‏@jeff_foust

Niebur: studied several “enhancements” to Clipper, like probes for plumes, add’l astrobiology payloads; decided to pursue them.

https://mobile.twitter.com/jeff_foust/status/763786003878326274

Quote
Jeff Foust –  ‏@jeff_foust

Niebur: for lander, definition of mission success is that, at end of 23-day mission, hold a press conference to announce finding life.

https://mobile.twitter.com/jeff_foust/status/763786565235580929
Title: Re: Proposed Europa Missions
Post by: JH on 08/12/2016 03:11 am
Quote
Jeff Foust –  ‏@jeff_foust

Niebur: for lander, definition of mission success is that, at end of 23-day mission, hold a press conference to announce finding life.

Yeah, I did a double take when Curt said this. I was not the only one.

Kevin Hand, who gave info about the lander SDT later in the day, was more restrained:

Quote
Julie Rathbun –  ‏@lokivolcano

Hand: Europa Lander SDT has planetary scientists, microbiologists, and geochemists, some folks not part of outer planets community

Hand: SDT science goals: search biomarkers & life, assess habitability via in situ techniques, characterize surface properties

Hand: lander separate launch, target 2024, carries own communication, battery powered, 20-day life, 35 kg science payload

Hand: draft science trace matrix: search for evidence of life: detect organic, morphological, & inorganic indicators
Determine where sample came from, determine if living organisms persist in sample (not threshold)

Hand: 2. Assess Habitability of Europa: composition, proximity to liquid water, activity

Hand: 3. characterize surface properties at lander scale: biosignature preservation potential, surface dynamics, material properties

https://twitter.com/LokiVolcano/status/763856287805300736 (This link is only for the first tweet, as I combined a number of them in the quote.)
Title: Proposed Europa Missions
Post by: Star One on 08/12/2016 06:27 am
I should have said that I found that last Tweet I quoted to be rather surprising as it could be considered both a hostage to fortune hopefully not with budgetary consequences in the event of failure or non-detection and less seriously liable to excite the CTs online.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 08/12/2016 12:49 pm
He was joking. Scientists don't define mission success as "finding life." There are just too many problems with that (starting with how do you define "life"?).

Title: Re: Proposed Europa Missions
Post by: as58 on 08/12/2016 12:58 pm
Joking scientists are always dangerous... No matter how obvious a joke may seem to them, it still often is reported as a serious comment in the media.
Title: Re: Proposed Europa Missions
Post by: Star One on 08/12/2016 02:02 pm
Joking scientists are always dangerous... No matter how obvious a joke may seem to them, it still often is reported as a serious comment in the media.

Especially when jokes don't always translate well in Tweeted reporting.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 08/12/2016 02:04 pm
Joking scientists are always dangerous... No matter how obvious a joke may seem to them, it still often is reported as a serious comment in the media.

Especially when jokes don't always translate well in Tweeted reporting.

"Tweeted reporting" is a contradiction in terms.

Title: Re: Proposed Europa Missions
Post by: vjkane on 08/12/2016 02:44 pm
There was a serious intent behind his statement (I was listening). He wants instruments that can determine if life is present (or more likely on the surface, unequivocally detect dead microbes).
Title: Re: Proposed Europa Missions
Post by: Star One on 08/12/2016 03:05 pm
There was a serious intent behind his statement (I was listening). He wants instruments that can determine if life is present (or more likely on the surface, unequivocally detect dead microbes).

What kind of instrumentation will have for assessing beneath the surface of Europa. I know the orbiter will have ice penetrating radar.
Title: Re: Proposed Europa Missions
Post by: vjkane on 08/12/2016 03:36 pm
There was a serious intent behind his statement (I was listening). He wants instruments that can determine if life is present (or more likely on the surface, unequivocally detect dead microbes).

What kind of instrumentation will have for assessing beneath the surface of Europa. I know the orbiter will have ice penetrating radar.
I believe that the assumption is that they will find a landing site with material recently delivered from the subsurface ocean.  So the equivalent of finding the remains of microbes from a platform on the top of the arctic ice sheet.
Title: Re: Proposed Europa Missions
Post by: Star One on 08/12/2016 03:52 pm
There was a serious intent behind his statement (I was listening). He wants instruments that can determine if life is present (or more likely on the surface, unequivocally detect dead microbes).

What kind of instrumentation will have for assessing beneath the surface of Europa. I know the orbiter will have ice penetrating radar.
I believe that the assumption is that they will find a landing site with material recently delivered from the subsurface ocean.  So the equivalent of finding the remains of microbes from a platform on the top of the arctic ice sheet.

Seems to suggest that a staggered launch of orbiter and lander would be the best solution rather launching them together.
Title: Re: Proposed Europa Missions
Post by: vjkane on 08/12/2016 04:04 pm
Seems to suggest that a staggered launch of orbiter and lander would be the best solution rather launching them together.
That is now assumed.  Both a funding stream and a mass driven split (as well as it is good to complete the orbital reconnaissance first).
Title: Re: Proposed Europa Missions
Post by: RonM on 08/12/2016 05:09 pm
Two missions will result in two launches for SLS. That should help the SLS program. NASA needs to launch one SLS per year and they need payloads for that.
Title: Proposed Europa Missions
Post by: Star One on 08/12/2016 05:12 pm
Is there any idea on the weight of the lander, are we talking about something in the Curiosity class if they are intending to use Sky Crane technology?
Title: Re: Proposed Europa Missions
Post by: vjkane on 08/12/2016 06:00 pm
Is there any idea on the weight of the lander, are we talking about something in the Curiosity class if they are intending to use Sky Crane technology?
Check out  http://futureplanets.blogspot.com/2016/04/defining-missions-for-ocean-worlds.html
Title: Re: Proposed Europa Missions
Post by: redliox on 08/12/2016 06:53 pm
Two missions will result in two launches for SLS. That should help the SLS program. NASA needs to launch one SLS per year and they need payloads for that.

Not necessarily. If it is going to take time to sort through the orbiter's maps you may as well slow-boat the lander. Put it on maybe a FH at most and put it on a flyby route. The SLS is good but expensive, so I think use it for the orbiter once since it is needed more heavily than the lander. It's naive to expect 2 freebie SLSs when 1 is enough of a miracle.
Title: Re: Proposed Europa Missions
Post by: RonM on 08/12/2016 07:27 pm
Two missions will result in two launches for SLS. That should help the SLS program. NASA needs to launch one SLS per year and they need payloads for that.

Not necessarily. If it is going to take time to sort through the orbiter's maps you may as well slow-boat the lander. Put it on maybe a FH at most and put it on a flyby route. The SLS is good but expensive, so I think use it for the orbiter once since it is needed more heavily than the lander. It's naive to expect 2 freebie SLSs when 1 is enough of a miracle.

The thing about SLS freebies is that NASA needs to maintain the SLS production line with one flight per year and currently doesn't have enough payloads. Now if more payloads for manned flights are selected, then there wouldn't be SLS launches available for planetary sciences.

If SpaceX can get the MCT flying, then SLS could be cancelled. Too many variables at the moment to say what is going to happen. The Europa missions might never fly.
Title: Re: Proposed Europa Missions
Post by: JH on 08/12/2016 08:27 pm
He was joking. Scientists don't define mission success as "finding life." There are just too many problems with that (starting with how do you define "life"?).

Obviously. The reason that it was surprising is that a joke like that is super easy to take at face value for someone who doesn't know better.
Title: Re: Proposed Europa Missions
Post by: redliox on 08/13/2016 06:01 pm
Two missions will result in two launches for SLS. That should help the SLS program. NASA needs to launch one SLS per year and they need payloads for that.

Not necessarily. If it is going to take time to sort through the orbiter's maps you may as well slow-boat the lander. Put it on maybe a FH at most and put it on a flyby route. The SLS is good but expensive, so I think use it for the orbiter once since it is needed more heavily than the lander. It's naive to expect 2 freebie SLSs when 1 is enough of a miracle.

The thing about SLS freebies is that NASA needs to maintain the SLS production line with one flight per year and currently doesn't have enough payloads. Now if more payloads for manned flights are selected, then there wouldn't be SLS launches available for planetary sciences.

If SpaceX can get the MCT flying, then SLS could be cancelled. Too many variables at the moment to say what is going to happen. The Europa missions might never fly.

A) Maintaining the production line isn't enough justification for using it twice for Jupiter.  If you're going to use it again in the name of planetary exploration, reserve it for an Ice Giant expedition, Mars Sample Return, or a new giant telescope as examples; especially for the Ice Giant mission, these are the missions that truly could use the SLS lift and fairing size.  Like I said, using it for the 'Clipper itself will be enough of a miracle.

B) Don't turn this into a SpaceX thread (granted I'm the one that brought up Falcon 9/HV).  I only mentioned Falcon HV because, outside of SLS, it is the largest.  MCT is a pipe dream for the moment so best to leave it out of probe discussions.
Title: Re: Proposed Europa Missions
Post by: redliox on 08/17/2016 07:00 pm
Updates are starting to come in from the OPAG meeting.  Their page now includes a posters section here:
http://www.lpi.usra.edu/opag/meetings/aug2016/posters/index.shtml (http://www.lpi.usra.edu/opag/meetings/aug2016/posters/index.shtml)

It looks like a mix of good and bad news for 'Clipper (or whatever it should be called). 

Good news: Sources from spacenews.com state the choice of launcher still has SLS as first choice, but second choices include both the Delta 4 and Falcon Heavy; the 'standard' for probes of late,Atlas V, isn't on their list anymore.  So, obviously, they're trying to favor launchers than can shorten the trip as much as possible.

Bad news: Congress, while still supportive of the mission, can't collectively decide how much to fund the mission at steadily.  The 'Clipper team says they expect a funding crunch during '17 and are trying to plan around it as best as possible.  Another problem relates to power; they're debating on whether to have each of the 2 solar arrays to have 4 or 5 panels, with a push toward 4 if possible.  Between these 2 factors, this may force a descope to prevent options like a laser altimeter from being added.

As for the lander, not much is mentioned aside from making surviving 23 days a priority.  One of the posters mentions an idea to use a form of chemical(?) energy at Europa as an alternative power source, which might be interesting to pursue: http://www.lpi.usra.edu/opag/meetings/aug2016/posters/A-Fire-On-Europa.jpg (http://www.lpi.usra.edu/opag/meetings/aug2016/posters/A-Fire-On-Europa.jpg)
Title: Re: Proposed Europa Missions
Post by: Star One on 08/17/2016 07:03 pm
Updates are starting to come in from the OPAG meeting.  Their page now includes a posters section here:
http://www.lpi.usra.edu/opag/meetings/aug2016/posters/index.shtml (http://www.lpi.usra.edu/opag/meetings/aug2016/posters/index.shtml)

It looks like a mix of good and bad news for 'Clipper (or whatever it should be called). 

Good news: Sources from spacenews.com state the choice of launcher still has SLS as first choice, but second choices include both the Delta 4 and Falcon Heavy; the 'standard' for probes of late,Atlas V, isn't on their list anymore.  So, obviously, they're trying to favor launchers than can shorten the trip as much as possible.

Bad news: Congress, while still supportive of the mission, can't collectively decide how much to fund the mission at steadily.  The 'Clipper team says they expect a funding crunch during '17 and are trying to plan around it as best as possible.  Another problem relates to power; they're debating on whether to have each of the 2 solar arrays to have 4 or 5 panels, with a push toward 4 if possible.  Between these 2 factors, this may force a descope to prevent options like a laser altimeter from being added.

As for the lander, not much is mentioned aside from making surviving 23 days a priority.  One of the posters mentions an idea to use a form of chemical(?) energy at Europa as an alternative power source, which might be interesting to pursue: http://www.lpi.usra.edu/opag/meetings/aug2016/posters/A-Fire-On-Europa.jpg (http://www.lpi.usra.edu/opag/meetings/aug2016/posters/A-Fire-On-Europa.jpg)

So Congress were the ones throwing money at NASA in the first place for Clipper to get started ASAP and now when NASA decides to push forward with it seriously the money starts becoming uncertain. Typical politicians.
Title: Re: Proposed Europa Missions
Post by: redliox on 08/17/2016 07:21 pm
So Congress were the ones throwing money at NASA in the first place for Clipper to get started ASAP and now when NASA decides to push forward with it seriously the money starts becoming uncertain. Typical politicians.

Unfortunately yes, but granted it is an election year which makes them all skittish on long-term decisions.  The lander is the real wild card since its evaluation isn't complete just yet.  'Clipper will somehow persevere I believe, and its team is planning to weather both politics and radiation.
Title: Re: Proposed Europa Missions
Post by: Bob Shaw on 08/17/2016 08:00 pm

As for the lander, not much is mentioned aside from making surviving 23 days a priority.  One of the posters mentions an idea to use a form of chemical(?) energy at Europa as an alternative power source, which might be interesting to pursue: http://www.lpi.usra.edu/opag/meetings/aug2016/posters/A-Fire-On-Europa.jpg (http://www.lpi.usra.edu/opag/meetings/aug2016/posters/A-Fire-On-Europa.jpg)

The 'heat battery' idea is very interesting, and not just for power and not just for Europa.

On Europa, it might be used as part of a drill system using hot water to melt down to non-irradiated ice in search of biochemical traces.

Ditto on Mars, and in the permanently shadowed Lunar polar craters.

On the manned front, this technology might keep a Lunar outpost ticking over during the night, or act as a 'get-me-home' emergency power source.

I wonder whether the battery can be recharged like crystallisation types of hand warmer? They generate heat through the exothermic crystallisation of supersaturated solution of food-grade sodium acetate.

Title: Re: Proposed Europa Missions
Post by: redliox on 08/17/2016 08:39 pm

As for the lander, not much is mentioned aside from making surviving 23 days a priority.  One of the posters mentions an idea to use a form of chemical(?) energy at Europa as an alternative power source, which might be interesting to pursue: http://www.lpi.usra.edu/opag/meetings/aug2016/posters/A-Fire-On-Europa.jpg (http://www.lpi.usra.edu/opag/meetings/aug2016/posters/A-Fire-On-Europa.jpg)

The 'heat battery' idea is very interesting, and not just for power and not just for Europa.

On Europa, it might be used as part of a drill system using hot water to melt down to non-irradiated ice in search of biochemical traces.

Ditto on Mars, and in the permanently shadowed Lunar polar craters.

On the manned front, this technology might keep a Lunar outpost ticking over during the night, or act as a 'get-me-home' emergency power source.

I wonder whether the battery can be recharged like crystallisation types of hand warmer? They generate heat through the exothermic crystallisation of supersaturated solution of food-grade sodium acetate.

Indeed, it could be used in any cold environment in the solar system, moon included like you suggested!

You have a point regarding recharging, although I'd assume not for this tech.  Even so, you'd need something to put energy back into it - on the Moon this'd be the sun during Lunar day, so easy fix there.  On Europa or the Lunar poles though, the Sun wouldn't be a viable option is the problem.
Title: Re: Proposed Europa Missions
Post by: Star One on 08/17/2016 08:45 pm
Europa mission planning for possible budget cuts in 2017

http://spacenews.com/europa-mission-planning-for-possible-budget-cuts-in-2017/
Title: Re: Proposed Europa Missions
Post by: Blackstar on 08/17/2016 09:31 pm
So Congress were the ones throwing money at NASA in the first place for Clipper to get started ASAP and now when NASA decides to push forward with it seriously the money starts becoming uncertain. Typical politicians.

You misunderstand. This is a complex and subtle issue, but it goes to the core of how the government works and how projects get funded. The ideal way for things to work is for the president to request money to start a program and issue a proposed budget outline for the program, and then for Congress to fund that program at the requested level over all those years.

That never happens.

Instead, what usually happens is that the president requests money to start a program and proposes a budget outline for the program, and then Congress provides most, but not all of the money over the course of the program. This requires the agency (in this case NASA) to defer some things each year because there is not enough money in the budget to fund them. That stretches out a program and ultimately leads to higher costs overall (but lower annual costs).

That's not what is happening here.

Instead, what is happening here is that the president (and actually, we're talking about the appointed and career civil servant people at the Office of Management and Budget) never wanted to fund a Europa mission. So they never put in a request or developed a budget profile. Then Congress--really congressman Culberson--said "Well, this is an important mission, and if you are not going to request the money, I'm going to put it in the budget anyway." Culberson was powerful enough to do that. And he kept doing that despite the fact that OMB/White House opposed the mission. With no overall spending profile for the Europa mission, it was not possible to develop a good cost estimate for the entire thing, or a good budget profile.

Eventually, OMB got the message and realized that unless they started requesting the money themselves, and unless they produced their own budget profile, Culberson was going to keep doing that. And OMB was going to be stuck behind the cart getting dragged instead of being out in front of the cart, pulling it (reluctantly).

But, guess what? We're going into an election. Elections are somewhat like event horizons and nobody can see beyond them. NASA is not really allowed to make budget predictions beyond elections unless they're very sure that a project is going to continue (for instance, if development is nearly complete). So they cannot predict with any certainty if the money is going to be there for the Europa mission in two years. What happens if the Republicans lose the Senate? Or the House? If they lose the House, Culberson loses his chairmanship and he can no longer stuff money into the NASA budget for Europa, and presumably people at OMB would open up the champagne.

You can assign blame if you want, but it's not very useful to do so. If you're in favor of a Europa mission, you might assign most of the blame to faceless people in OMB. If you are neutral about it, you might just shrug your shoulders and accept that government policy making in a democracy is complicated and messy.
Title: Proposed Europa Missions
Post by: Star One on 08/17/2016 10:20 pm
So Congress were the ones throwing money at NASA in the first place for Clipper to get started ASAP and now when NASA decides to push forward with it seriously the money starts becoming uncertain. Typical politicians.

You misunderstand. This is a complex and subtle issue, but it goes to the core of how the government works and how projects get funded. The ideal way for things to work is for the president to request money to start a program and issue a proposed budget outline for the program, and then for Congress to fund that program at the requested level over all those years.

That never happens.

Instead, what usually happens is that the president requests money to start a program and proposes a budget outline for the program, and then Congress provides most, but not all of the money over the course of the program. This requires the agency (in this case NASA) to defer some things each year because there is not enough money in the budget to fund them. That stretches out a program and ultimately leads to higher costs overall (but lower annual costs).

That's not what is happening here.

Instead, what is happening here is that the president (and actually, we're talking about the appointed and career civil servant people at the Office of Management and Budget) never wanted to fund a Europa mission. So they never put in a request or developed a budget profile. Then Congress--really congressman Culberson--said "Well, this is an important mission, and if you are not going to request the money, I'm going to put it in the budget anyway." Culberson was powerful enough to do that. And he kept doing that despite the fact that OMB/White House opposed the mission. With no overall spending profile for the Europa mission, it was not possible to develop a good cost estimate for the entire thing, or a good budget profile.

Eventually, OMB got the message and realized that unless they started requesting the money themselves, and unless they produced their own budget profile, Culberson was going to keep doing that. And OMB was going to be stuck behind the cart getting dragged instead of being out in front of the cart, pulling it (reluctantly).

But, guess what? We're going into an election. Elections are somewhat like event horizons and nobody can see beyond them. NASA is not really allowed to make budget predictions beyond elections unless they're very sure that a project is going to continue (for instance, if development is nearly complete). So they cannot predict with any certainty if the money is going to be there for the Europa mission in two years. What happens if the Republicans lose the Senate? Or the House? If they lose the House, Culberson loses his chairmanship and he can no longer stuff money into the NASA budget for Europa, and presumably people at OMB would open up the champagne.

You can assign blame if you want, but it's not very useful to do so. If you're in favor of a Europa mission, you might assign most of the blame to faceless people in OMB. If you are neutral about it, you might just shrug your shoulders and accept that government policy making in a democracy is complicated and messy.

I will stick to blaming the OMB then as from my interpretation of what you and others have posted over time on here really don't have a clue here. The fact that they are still effectively passively resisting this says a lot about their shortsightness or intransigence take your pick.
Title: Re: Proposed Europa Missions
Post by: Star One on 08/18/2016 09:45 am
I will stick to blaming the OMB then as from my interpretation of what you and others have posted over time on here really don't have a clue here. The fact that they are still effectively passively resisting this says a lot about their shortsightness or intransigence take your pick.

A space policy guru who has substantial NASA experience explained the basic operating rules for OMB to me. If I remember correctly it goes like this:

-oppose big programs
-oppose multi-part programs (meaning ones where the first step commits you to a second step, and so on)
-oppose international cooperative programs

OMB wants flexibility in budgeting, meaning the ability to shift money around from project to project to cover shortfalls. Any of those things above, and particularly when they are in combination, restrict their freedom of movement. A really big multi-billion dollar project, like an international Mars sample return mission, ties them up for a long time and they cannot shift money out of it. So they don't want those kinds of things to start.

And right now they have both a Mars 2020 rover and a Europa mission starting, and they look at the out-year expenditures and they shudder, because they imagine lots of cash getting stuck in those programs and they cannot shift them out of those budgets to cover shortfalls elsewhere.

It's logical from their point of view.

And that's where leadership is required. "Leadership" gets bandied around a lot, but here I use it to refer to a senior official who provides clear direction (i.e. "do this, by this timetable") and who also follows up and makes sure things happen (as opposed to giving an order and then walking away, which is very common in Washington). Right now there is no advocate within the executive branch for a Europa mission. There's nobody in the White House who really wants it to happen and who has the clout to tell people to make it happen. Absent that advocate, asserting leadership, the people at OMB revert to their internal guidelines that I listed above. And so they're bucking up against a member of Congress who has some power to make things happen, but can only do so much without similar advocates in the executive branch.

So does that mean that the Europa mission is doomed to go nowhere and the money already spent on it wasted if there is determination amongst the OMB to kill it.
Title: Re: Proposed Europa Missions
Post by: Star One on 08/18/2016 02:36 pm
So does that mean that the Europa mission is doomed to go nowhere and the money already spent on it wasted if there is determination amongst the OMB to kill it.

No.

What's the best way forward in your view?
Title: Re: Proposed Europa Missions
Post by: vjkane on 08/18/2016 04:47 pm
And I'll add an aside: when you go to school they teach you about the three branches of government. If you go to college, you may learn a bit more about government, like the bureaucracy and the budgeting process. But the actual implementation of laws and policies is really hard to discover and understand. A lot of government activity involves the little everyday decisions and interactions between the various branches and bureaucrats and individuals. I still find it really difficult to figure out what is going on.
If I remember correctly, Blackstar, you have a PhD in public policy.  So if you have problems understanding the system, then the rest of us are screwed...  :)

I worked for a large technology firm for many years.  After awhile, possibly my greatest asset was that I had the accumulated background on all the ways decisions had really been made based on the informal system and the knowledge of how to use that system.  I suspect the federal government works much the same way.
Title: Re: Proposed Europa Missions
Post by: Lar on 08/18/2016 05:13 pm
Thanks for your insight, Blackstar. I think we all benefit when you explain about how things work, even when we disagree about goals. This not being the space policy section we can skip talking about how they *should* work. But this was very valuable insight. (worth noting more than just a like would note)
Title: Re: Proposed Europa Missions
Post by: redliox on 08/18/2016 07:11 pm
Further updates on the Europa mission!
'Clipper here: http://www.lpi.usra.edu/opag/meetings/aug2016/presentations/day-1/Pappalardo.pdf (http://www.lpi.usra.edu/opag/meetings/aug2016/presentations/day-1/Pappalardo.pdf)
Lander here: http://www.lpi.usra.edu/opag/meetings/aug2016/presentations/day-1/LanderUpdate.pdf (http://www.lpi.usra.edu/opag/meetings/aug2016/presentations/day-1/LanderUpdate.pdf)

The more significant updates (or at least one with more visuals) relate to the lander out of these 2.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 08/18/2016 08:56 pm
All of that said, NASA got some greater clarity this year on Europa. Even though they are being forced to plan for a Europa lander mission that almost nobody had really thought about, they did secure from Congress permission to separate that from the orbiter. So they can focus on the orbiter and continue defining the lander. That's more logical than closely linking the two missions at this stage.

Title: Re: Proposed Europa Missions
Post by: Star One on 08/18/2016 09:14 pm
And I'll add an aside: when you go to school they teach you about the three branches of government. If you go to college, you may learn a bit more about government, like the bureaucracy and the budgeting process. But the actual implementation of laws and policies is really hard to discover and understand. A lot of government activity involves the little everyday decisions and interactions between the various branches and bureaucrats and individuals. I still find it really difficult to figure out what is going on.
If I remember correctly, Blackstar, you have a PhD in public policy.  So if you have problems understanding the system, then the rest of us are screwed...  :)


Yeah, Ph.D. in political science, focusing on space policy and national security policy. But here's the thing: a lot of this stuff is not in textbooks or academic journals. You really have to see it in action in order to understand how it works. I think that part of that is that there is a blurry line between the rules and regulations and the tactics that people and institutions use to get what they want.

So, we all know the saying that the president proposes and the Congress disposes. Officially, Congress produces the budget and the president signs it. But we also know that in practice, the starting point is the president's budget. If a new project is not in the president's budget, it is really hard for Congress to initiate that project on their own, and it is very very hard for them to sustain it (except when we're talking about simply buying more of something that is already in production, like tanks or airplanes). And because the agencies like NASA are all in the executive branch, they take their marching orders from the White House, even if Congress is putting money into a project that the people in that agency support.

Getting back to the Europa mission, in the past few years what was happening was that Congress (Culberson) was pushing money into the budget, but NASA did not have an approved blueprint from OMB on how to spend it, even though they were required to spend it. Now NASA got lucky because there was a way for them to spend a big chunk of that money: they could buy instruments for the spacecraft. That would spend up a lot of the cash sitting around. But of course Culberson was going to shove more money into the budget after NASA spent the initial batch on the instruments, trying to force OMB to approve a formal development plan for the Europa mission. Everybody knew this. This was a tactic.

I mentioned earlier the analogy of putting the horse before the cart and it really works fairly well as an analogy. OMB--and really, the White House--wants to be leading the decisions and the program development. They want to be steering. But they were like a horse that wanted to go in a different direction (i.e. not a Europa mission), and the cart was pulling them in a direction for several years. Finally, OMB approved the Europa "new start," but at a lower level of funding. Think of it like the horse trying to keep the cart from moving too fast.

And where is NASA in all of this? NASA is an executive branch agency, so of course it has to abide by what the White House says NASA should do. Certainly there are people at NASA (and definitely at JPL!) who want a Europa mission. But they also want full funding for such a mission, and a clear budget outline. They're not getting that, and so they're stuck in the middle of this clash between the White House and Congress. And all that uncertainty gets magnified when there's an election coming up. They literally cannot plan for future budgets for a Europa mission. They can sketch the outlines (meaning penciling-in procuring item X in 2018 and item Y in 2019 and so on), but the uncertainty factor is very high.

But like I've said, this kind of stuff happens all the time. Pick a non-space subject and you can find similar fights.

Considering how far this has now got isn't it rather counterproductive and also likely to lead to higher costs longer term by the OMB still dragging their feet?
Title: Re: Proposed Europa Missions
Post by: vjkane on 08/18/2016 11:23 pm
We also need to remember that we are talking about total dollar amounts that are a gnat upon a gnat in terms of the federal budget.  If the peak funding for Clipper turns out to be $500M in a given year, that is equivalent to an expense of $12.66 to a family that spends $100K a year.  How hard to you try to optimize spending for that small of an amount?  Most spending is done on autopilot -- this year's spending looks much like last year's spending and next year's spending.

To add to what Blackstar stated, the cost overruns on large projects likely has made OMB very gun shy about anything that costs >$1B in total mission costs.  In addition, adding Clipper to the budget breaks the autopilot rule -- either other programs in planetary will have to be cut to pay for this or the planetary budget will have to go up.

Title: Re: Proposed Europa Missions
Post by: Blackstar on 08/19/2016 02:54 am
From the slide presentation.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 08/19/2016 03:01 am
We also need to remember that we are talking about total dollar amounts that are a gnat upon a gnat in terms of the federal budget.  If the peak funding for Clipper turns out to be $500M in a given year, that is equivalent to an expense of $12.66 to a family that spends $100K a year.  How hard to you try to optimize spending for that small of an amount?  Most spending is done on autopilot -- this year's spending looks much like last year's spending and next year's spending.


The problem is that while it is small relative to the overall federal budget, there's nobody in government who deals with the entire budget. Everybody deals with their own relatively small fraction of it, and that's where even millions can be big money. For instance, $500 million out of NASA's $18+ billion is a big chunk of change. And the congressional committees that deal with budgets deal with certain agencies, and generally cannot play with the entire pie, only slices of it (for instance, they cannot cut federal salaries).

This is one of the reasons why OMB has the attitude that it does. They like smaller projects more than larger ones, for instance, because they can move that money around more easily.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 08/19/2016 03:30 am
Title: Re: Proposed Europa Missions
Post by: Blackstar on 08/19/2016 03:32 am
One thing that I see in the lander presentation that I don't think was there earlier was a communications relay orbiter. They cannot plan for having Clipper still be alive to serve as a relay.
Title: Re: Proposed Europa Missions
Post by: sdsds on 08/19/2016 03:52 am
One thing that I see in the lander presentation that I don't think was there earlier was a communications relay orbiter. They cannot plan for having Clipper still be alive to serve as a relay.

Would it be right to characterize that as being a direct consequence of launching independently? Also is there a chance the lander's relay orbiter could provide a redundant relay channel for Clipper data transmission back to Earth?
Title: Re: Proposed Europa Missions
Post by: vjkane on 08/19/2016 01:14 pm
One thing that I see in the lander presentation that I don't think was there earlier was a communications relay orbiter. They cannot plan for having Clipper still be alive to serve as a relay.
The relay, as I recall, was previously included but not emphasized.  There's a European discussion that ESA might provide the relay, which would later orbit Europa to provide high fidelity gravity and magnetic studies.  Such a craft could essentially be all vault with solar panels, a radio antenna, and a magnetometer sticking out.  I don't think it would have to last long in orbit to significantly improve on the Europa Clipper measurements, but don't know that for sure.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 08/19/2016 02:07 pm
One thing that I see in the lander presentation that I don't think was there earlier was a communications relay orbiter. They cannot plan for having Clipper still be alive to serve as a relay.

Would it be right to characterize that as being a direct consequence of launching independently? Also is there a chance the lander's relay orbiter could provide a redundant relay channel for Clipper data transmission back to Earth?

It was never really possible to put the Clipper and the lander together anyway. The only other option is to operate both missions simultaneously, and that's not really possible either because of budgets and a whole bunch of other reasons.

If the lander happens (and that's a big "if), it will be years after the Clipper. And that's really the best way to do it anyway. You want to process the Clipper data to figure out the best possible landing site and the best kind of science observations at Europa.
Title: Re: Proposed Europa Missions
Post by: Star One on 08/19/2016 07:30 pm
The Blue Spectres of Abyssal Europa

Quote
Claudio Flores Martinez has just finished an MSc at the European Molecular Biology Laboratory (EMBL) in Heidelberg, Germany and is now enroute to a PhD in theoretical biology. He currently serves as a research assistant at the Developmental Biology Unit of EMBL and the University of Heidelberg’s Centre for Organismal Studies. With three papers in Acta Astronautica under his belt, Claudio is already deep into theoretical evolutionary biology, and in particular the contingency vs. convergence debate. In the paper below, he discusses how these issues couple with the possible emergence and development of life on Europa and the potential biosignatures by which we might find it, a journey that takes us deep into the nature of living systems. Just what might we encounter under that Europan ice?

http://www.centauri-dreams.org/?p=36142
Title: Re: Proposed Europa Missions
Post by: TakeOff on 08/20/2016 07:44 am
50 tons payload to Europa orbit and surface! 2x25 tons with two SLS.



Wow, I haven't understood before, that it is a completely new kind of super mega flagship mission. Several times larger than all previous missions to the outer Solar System combined. 20 times the dry mass of Cassini-Huygens. About as much mass as all of the Apollo Lunar Modules combined. That's enough for drilling several kilometers deep and return samples to Earth, land a global network of seismometers and bring huge solar panels to power a ground penetrating radar and whatever is on the wishlist. Why not a several meter diameter mirror to get some good resolution images?


Listen 21:20 into this FISO teleconference from August 3rd, 2016. The guys who are building the SLS say that their Block Ib will be able to deliver 25 tons payload to Europa in 4-5 years trip time by using an Earth flyby gravity assist.
http://spirit.as.utexas.edu/~fiso/telecon/Sanders-Fuller-DaLee_8-3-16/ (http://spirit.as.utexas.edu/~fiso/telecon/Sanders-Fuller-DaLee_8-3-16/)


Why is this not reflected in the spacecraft design now under consideration?
Title: Re: Proposed Europa Missions
Post by: vjkane on 08/20/2016 01:37 pm
50 tons payload to Europa orbit and surface! 2x25 tons with two SLS.

Why is this not reflected in the spacecraft design now under consideration?
Because NASA has nowhere near the funding needed to build 50 tons of planetary spacecraft.  There's a rough linear relationship between spacecraft cost and its mass.  If you want 50 tons of operating spacecraft at Jupiter, you need to come up with billions more in funding.
Title: Re: Proposed Europa Missions
Post by: TakeOff on 08/20/2016 02:35 pm
50 tons payload to Europa orbit and surface! 2x25 tons with two SLS.

Why is this not reflected in the spacecraft design now under consideration?
Because NASA has nowhere near the funding needed to build 50 tons of planetary spacecraft.  There's a rough linear relationship between spacecraft cost and its mass.  If you want 50 tons of operating spacecraft at Jupiter, you need to come up with billions more in funding.

But one could build a spacecraft cheaper if one doesn't have to care so much about the mass of the components. You could use off the shelf stuff and redundancy to compensate for their quality. Kind of the Russian philosophy.

But with two SLS launches given away, and $260,000,000 suggested by Congress next year, allows for starting building a pretty good spacecraft science payload. Two SLS launches is already a great investment. It'd be suboptimal to not give these two missions to Europa Flagship status. Other things will have to wait. If Mars and Europa are the priorities, then finally there's a focus, a plan, for NASA. Getting something done.

The public's interest in the alien life myth needs to be answered soundly once and for all. Proving that no one is living inside any moon. Then, in the 2030s when we've finally gotten that popular distraction out of the way, NASA could start doing serious astronomy again. I think that NASA, as a tax payer funded organization, if it wants to continue to exist, needs to deal with the wish of the public, and the Congress, to look for life inside Europa. And real science will be done too. There are as many icy moons as there are planets. They are a rational science priority as much as they are popular and politically prioritized. It's like a conjuncture of everything on the night sky, but NASA does not notice it.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 08/20/2016 03:55 pm
But one could build a spacecraft cheaper if one doesn't have to care so much about the mass of the components. You could use off the shelf stuff and redundancy to compensate for their quality. Kind of the Russian philosophy.


Yeah, up to a point. In fact, the cost of Juno and the cost of Clipper is lower because they use commercial grade chips, not rad-hardened. Juno relies upon a vault to protect the electronics.

But whereas it is true that a lot of money has been spent shaving a few kilograms off a spacecraft, there is no clear existence proof that having very wide mass margins allows you to save a lot of money. In fact, one could argue that the huge amounts spent on shaving kilograms off of spacecraft were a symptom of poor design and management--they should not have gotten themselves into that position in the first place where it required them to spend a lot of money.

Although cost scales with mass, cost also scales with a lot of other things too, like complexity. So open up the mass margins really wide and you might encourage the spacecraft designers to add instruments and make a much more complex spacecraft, and then you don't save any money.

Title: Re: Proposed Europa Missions
Post by: baldusi on 08/20/2016 06:48 pm
I believe that the mass is used with the only "cheap" thing in space industies: propellant. Orbit insertion and landing is very delta-v demanding.
Title: Re: Proposed Europa Missions
Post by: Don2 on 08/21/2016 07:14 pm
Thank goodness OMB is trying to bring some discipline to this. They seem to be the only adults in the room right now.

NASA already has a good process for selecting and flying missions. Scientists attempt to identify the most promising science targets in the Decadal Survey. The last decadal survey identified Mars Sample Return as a priority over a Europa orbiter. Previous decadals went for a Europa orbiter, but a lander was never seriously considered.

In the Discovery and New Frontiers programs, NASA has a good process for executing missions. Scientists and engineers put their heads together and come up with proposals for specific missions. These proposals are studied and reviewed, and then the best are selected for implementation. The open question is what to do about compelling science objectives that don't fit into a New Frontiers budget. There is probably a need for a cost capped program with a $2 billion pot of money. Old fashioned 'flagship' programs like Cassini and Viking were undisciplined orgies of spending that ate the entire budget and killed off everything else. We don't want to go back to that.

There really is no need for non experts in the White House or on Capitol Hill to be selecting missions themselves. High level leaders clearly need to provide the cost and spending discipline which the science and engineering community needs. There is also a discussion to be had about the degree of diversification in the program. However, mission selection is best left to the experts.

Enter Culberson. The best thing he could do would be to fund the existing process. However he prefers Europa to Mars. There is already a good science case for a Europa mission, so it isn't that hard to steer things toward Europa if that mission can fit into a $2bn box. OMB goes along with that. Now Culberson, whose background is a Houston lawyer, decides for himself that NASA's next priority should be a Europa LANDER !!!!? Where was the scientific community input into that decision??? Culberson claims that he will add new money to pay for the Europa orbiter and lander, but I don't believe that he can provide the stable long term funding profile needed to get those built without killing off other things. Where is the money going to come from exactly? Perhaps Culberson thinks he can take it away from Earth Science, but a Democrat president will never go along with that. His Republican colleagues will never go along with increasing the budget deficit, cutting defense or killing SLS in order to pay for Europa. In the end, Europa funding will come from halting the New Frontiers, Discovery and Mars programs. Culberson will throw out the decadal survey priorities and replace them with his own. In my opinion, that is what OMB is trying to prevent.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 08/21/2016 07:24 pm
OMB goes along with that.

Er... no. That's not really what happened.

OMB opposed Mars 2020 and opposed any Europa mission.

Big missions don't happen unless they have champions. Culberson is the champion for Europa Clipper, and for the lander too. You gotta take what you get, or you get nothing.
Title: Re: Proposed Europa Missions
Post by: ccdengr on 08/21/2016 07:28 pm
Yeah, up to a point. In fact, the cost of Juno and the cost of Clipper is lower because they use commercial grade chips, not rad-hardened. Juno relies upon a vault to protect the electronics.
No, Juno in general uses standard rad-hard components that are good to something like 50 to 100 krads.  It needs the vault because the environment would be much higher than that otherwise.

Clipper's dose is something like 10x higher than Juno's.  It needs megarad-hard components even with a vault, which is pretty constraining.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 08/21/2016 08:04 pm
I heard one of the Europa program managers say months ago that they had lowered their cost by switching to components that were not rad-hardened. Maybe it was "less rad-hardened," but I heard him say it.
Title: Re: Proposed Europa Missions
Post by: Don2 on 08/22/2016 09:35 pm

Don2, you may want to go re-read the Decadal Survey.  It makes clear that both a Mars caching rover and a Europa mission were nearly equally ranked priority Flagship missions.  Congress has decided to increase the funding for the planetary science budget to fly both of the missions that were top ranked by the scientific community.


There is no mention of a Europa lander in the Decadal Survey. In fact it says:

"the costs of the recommended Flagship missions must not be allowed to grow above the values quoted in this report.  Central to accomplishing this is avoiding “requirements creep.”  The CATE process does not account for a lack of discipline that allows a mission to become too ambitious.  In order to preserve programmatic balance, then, the scope of each of the recommended Flagship missions cannot be permitted to increase significantly beyond what was assumed during the committee’s cost estimation process."

The Recommended Program was:

"• Discovery program funded at the current level adjusted for inflation;
• Mars Trace Gas Orbiter conducted jointly with ESA;
• New Frontiers Missions 4 and 5;
• MAX-C (descoped to $2.5 billion);
•Jupiter Europa Orbiter (descoped);
•Uranus Orbiter and Probe  "

The Cost Constrained Program was:

"• Discovery program funded at the current level adjusted for inflation;
• Mars Trace Gas Orbiter conducted jointly with ESA;
• New Frontiers Mission 4 and 5;
• MAX-C (descoped to $2.5 billion);
• Uranus Orbiter and Probe "

Note that a Europa mission does not appear on the Cost Constrained list, so arguably it is the fifth or sixth priority. You can make a case that the Decadal viewed a $4.7 billion Europa mission as too expensive, but would have ranked a $2 billion mission much higher. However, the survey clearly comes out against the kind of requirements creep represented by the lander.

It also explicitly states that :

"If cuts to the program are necessary, the first approach should be descoping or delaying Flagship missions.  Changes to the New Frontiers or Discovery programs should be considered only if adjustments to Flagship missions cannot solve the problem."

Given how few Discovery and New Frontiers missions have been flown recently, it seems to me that restoring those programs should be given a higher priority.
Title: Re: Proposed Europa Missions
Post by: vjkane on 08/22/2016 10:40 pm
Given how few Discovery and New Frontiers missions have been flown recently, it seems to me that restoring those programs should be given a higher priority.
Congressional action has led to the Discovery and New Frontiers getting back on track.  Green says he expects to select 5 Discovery missions and two New Frontiers missions a decade going forward, which is the Decadal recommended pace. 

Larry Soderblum (sp?) just presented a recap of the last Decadal at the just completed OPAG mission.  He emphasized that it was a very tight race between Mars and Europa as the top Flagship mission.  Green says he expects to select NF 5 before the end of the Decadal period.  Much of the restored funding for these programs have come through Culberson's efforts as I understand it.

I agree that a Europa lander is not on the Decadal list, and I also doubt that it will survive long once the full cost is understood.  While Culberson could build off of solid community support for the multi-flyby mission, pushing the lander through will be more like pushing on a rope if the costs are what I expect they will be.  The Europa multi-flyby mission meets the rescoped Europa goal, and architecting the descoped mission was explicitly called for in the Survey.

Title: Proposed Europa Missions
Post by: Star One on 08/22/2016 10:44 pm

Don2, you may want to go re-read the Decadal Survey.  It makes clear that both a Mars caching rover and a Europa mission were nearly equally ranked priority Flagship missions.  Congress has decided to increase the funding for the planetary science budget to fly both of the missions that were top ranked by the scientific community.


There is no mention of a Europa lander in the Decadal Survey. In fact it says:

"the costs of the recommended Flagship missions must not be allowed to grow above the values quoted in this report.  Central to accomplishing this is avoiding “requirements creep.”  The CATE process does not account for a lack of discipline that allows a mission to become too ambitious.  In order to preserve programmatic balance, then, the scope of each of the recommended Flagship missions cannot be permitted to increase significantly beyond what was assumed during the committee’s cost estimation process."

The Recommended Program was:

"• Discovery program funded at the current level adjusted for inflation;
• Mars Trace Gas Orbiter conducted jointly with ESA;
• New Frontiers Missions 4 and 5;
• MAX-C (descoped to $2.5 billion);
•Jupiter Europa Orbiter (descoped);
•Uranus Orbiter and Probe  "

The Cost Constrained Program was:

"• Discovery program funded at the current level adjusted for inflation;
• Mars Trace Gas Orbiter conducted jointly with ESA;
• New Frontiers Mission 4 and 5;
• MAX-C (descoped to $2.5 billion);
• Uranus Orbiter and Probe "

Note that a Europa mission does not appear on the Cost Constrained list, so arguably it is the fifth or sixth priority. You can make a case that the Decadal viewed a $4.7 billion Europa mission as too expensive, but would have ranked a $2 billion mission much higher. However, the survey clearly comes out against the kind of requirements creep represented by the lander.

It also explicitly states that :

"If cuts to the program are necessary, the first approach should be descoping or delaying Flagship missions.  Changes to the New Frontiers or Discovery programs should be considered only if adjustments to Flagship missions cannot solve the problem."

Given how few Discovery and New Frontiers missions have been flown recently, it seems to me that restoring those programs should be given a higher priority.

Hmm some nice highly selective quoting there that says more about your very, very obvious biases than the actual current situation.
Title: Re: Proposed Europa Missions
Post by: Don2 on 08/23/2016 01:27 am
@vjkane:
I agree there would be solid support for a $2 billion class Europa multi-flyby mission. However, that is not where things are going right now. The lander is a symptom of out of control requirements growth, which is probably also affecting the orbiter.

The lander now requires a communications relay orbiter, a 23 day surface life, and is thinking seriously about astrobiology. They mention 3 samples from a depth of 10cm, so there is some sort of a drilling requirement. 4.4t of dry mass is not going to be cheap.

JPL doesn't seem to be worried that there is no guarantee that a lander will be able to access material from the underlying ocean. People seem to have forgotten what high radiation does to organics, not to mention the sulfuric acid and peroxides which are also mentioned as possible surface materials. We know very little about the chemical environments on Europa, and can only speculate about how that might interact with potential instruments.

This is rapidly heading in the direction of a $6 billion class program like Cassini. Culberson has stated in the past that a  Europa mission should be the biggest and best outer planets mission ever flown, and JPL seems happy to oblige.

@Star One
If by bias you mean that I think that Discovery and New Horizons produce better returns on investment than flagships then you would be right. Or if you mean that I don't think the surface of Europa is a very promising environment for life then you would be also be right. We know very little, but what we do know isn't very promising.
Title: Re: Proposed Europa Missions
Post by: vjkane on 08/23/2016 03:03 am
@vjkane:
I agree there would be solid support for a $2 billion class Europa multi-flyby mission. However, that is not where things are going right now. The lander is a symptom of out of control requirements growth, which is probably also affecting the orbiter.

The lander now requires a communications relay orbiter, a 23 day surface life, and is thinking seriously about astrobiology. They mention 3 samples from a depth of 10cm, so there is some sort of a drilling requirement. 4.4t of dry mass is not going to be cheap.

JPL doesn't seem to be worried that there is no guarantee that a lander will be able to access material from the underlying ocean. People seem to have forgotten what high radiation does to organics, not to mention the sulfuric acid and peroxides which are also mentioned as possible surface materials. We know very little about the chemical environments on Europa, and can only speculate about how that might interact with potential instruments.

This is rapidly heading in the direction of a $6 billion class program like Cassini. Culberson has stated in the past that a  Europa mission should be the biggest and best outer planets mission ever flown, and JPL seems happy to oblige.
I think there is a reasonable amount of political maneuvering going on.  Culberson, under House Repbulican rules, must give us his chairmanship somewhere around 2022.  So he is trying to push a the program forward while he still has the political power. 

The earliest speculations on the cost of a lander, as I recall, were that one might add $500M-$1B to the total mission.  That would be around a 25% to 50% increase in mission cost.  That early optimism turned out to be unviable.  To say that JPL isn't concerned about whether useful samples can be obtained is premature in my opinion.  The scientific requirements are still in definition as is the lander concept  Neibur said, I think more than once, at the OPAG meeting that the new concept for a lander mission will go forward if it proves to be "viable."  I think that the costs will prove to be quite large and the technologies not ready.  Any lander will become an issue for the next Decadal. 

If my speculation proves to be right and Culberson doubles down, then I will agree with you on his actions regarding the lander.  However, he gave in quickly when the engineers told him that the initial cheap option was viable and went with the separate later launch.  We shall see.
Title: Re: Proposed Europa Missions
Post by: Star One on 08/23/2016 06:45 am
@vjkane:
I agree there would be solid support for a $2 billion class Europa multi-flyby mission. However, that is not where things are going right now. The lander is a symptom of out of control requirements growth, which is probably also affecting the orbiter.

The lander now requires a communications relay orbiter, a 23 day surface life, and is thinking seriously about astrobiology. They mention 3 samples from a depth of 10cm, so there is some sort of a drilling requirement. 4.4t of dry mass is not going to be cheap.

JPL doesn't seem to be worried that there is no guarantee that a lander will be able to access material from the underlying ocean. People seem to have forgotten what high radiation does to organics, not to mention the sulfuric acid and peroxides which are also mentioned as possible surface materials. We know very little about the chemical environments on Europa, and can only speculate about how that might interact with potential instruments.

This is rapidly heading in the direction of a $6 billion class program like Cassini. Culberson has stated in the past that a  Europa mission should be the biggest and best outer planets mission ever flown, and JPL seems happy to oblige.

@Star One
If by bias you mean that I think that Discovery and New Horizons produce better returns on investment than flagships then you would be right. Or if you mean that I don't think the surface of Europa is a very promising environment for life then you would be also be right. We know very little, but what we do know isn't very promising.

Why would assume at this stage that any investigation of Europa would be just limited to the surface. Again your bias seems to be showing. I cannot really give your posts that much weight as you already seem to have made your mind up your mind on these matters.
Title: Re: Proposed Europa Missions
Post by: Don2 on 08/23/2016 05:43 pm
@vjkane...I'm not sure why anybody would have thought that a Europa lander would be doable for $500 million. Europa is not Titan, where you can brake with an aeroshell, pop out a parachute and drift gently down to the surface. I think Huygens cost about $500 million.  Europa requires rockets all the way to the surface, and the delta-v is large. It is a tough radiation environment. The night-side temperatures are going to be very chilly. It is farther from Earth than Mars, so it will require a bigger comms system and more power to run it. I don't think there has ever been a powered landing on a icy body before, so the surface will be unfamiliar. Phoenix showed that collecting samples from icy surfaces can be hard.

If you compare Mars and Jupiter missions it is apparent that everything in the outer solar system costs more.  A basic , stripped down orbiter like Mars Odyssey cost $300 million. A basic Jupiter orbiter like Juno cost $1 billion.  So Jupiter is around 3 times as much. If you remember that Phoenix at Mars cost $750 million, then something over $2 billion is a sensible guess for a simple Europa lander. Of course it could be more.

The lander already seems to be suffering cost growth. They have selected a skycrane landing system, which is the most complex and expensive choice. The only way that Europa is easier than Mars is that the surface gravity is 0.13g versus 0.37g, but they aren't taking advantage of that to simplify the landing system. They want 23 days of operation, versus a few hours for Huygens. They need a comms relay spacecraft. That will add an extra $1bn or so. They want to do astrobiology. The whole thing is out of control.
Title: Re: Proposed Europa Missions
Post by: vjkane on 08/23/2016 07:33 pm
If you compare Mars and Jupiter missions it is apparent that everything in the outer solar system costs more.  A basic , stripped down orbiter like Mars Odyssey cost $300 million. A basic Jupiter orbiter like Juno cost $1 billion.  So Jupiter is around 3 times as much. If you remember that Phoenix at Mars cost $750 million, then something over $2 billion is a sensible guess for a simple Europa lander. Of course it could be more.
Probably a fairer comparison in terms of spacecraft capability and instrument complexity is the Mars Reconnaissance Orbiter, which cost $720M in 2005 and inflated to today (3% inflation per year) is $996M.  Juno has an advanced set of instruments; it's hard to find anything that lists their final total mass, but one paper I saw from pre launch listed their mass as 174 kg..  (If anyone reading this knows the answer to this, I'd appreciate hearing the actual number.)  MRO's instruments are 139 kg.

But I agree with you that a Europa lander that is more than a penetrator or simple hard lander is going to get into Flagship mission costs.
Title: Re: Proposed Europa Missions
Post by: Star One on 08/23/2016 08:52 pm
If you compare Mars and Jupiter missions it is apparent that everything in the outer solar system costs more.  A basic , stripped down orbiter like Mars Odyssey cost $300 million. A basic Jupiter orbiter like Juno cost $1 billion.  So Jupiter is around 3 times as much. If you remember that Phoenix at Mars cost $750 million, then something over $2 billion is a sensible guess for a simple Europa lander. Of course it could be more.
Probably a fairer comparison in terms of spacecraft capability and instrument complexity is the Mars Reconnaissance Orbiter, which cost $720M in 2005 and inflated to today (3% inflation per year) is $996M.  Juno has an advanced set of instruments; it's hard to find anything that lists their final total mass, but one paper I saw from pre launch listed their mass as 174 kg..  (If anyone reading this knows the answer to this, I'd appreciate hearing the actual number.)  MRO's instruments are 139 kg.

But I agree with you that a Europa lander that is more than a penetrator or simple hard lander is going to get into Flagship mission costs.
Well surely that's what they are proposing effectively two flagship missions.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 08/23/2016 09:01 pm
I think there's a lot of misunderstanding of the political maneuvering here. The only mission that is being actively developed is the Clipper. The lander mission is still in the early study phase. And it is likely to stay in that stage for several years. As long as the money spent on studying the lander is not huge, what's the harm in studying it? In fact, studying lander concepts helps refine the Clipper, because it enables the people working on the Clipper to think about the best science and operations to support a future lander mission, whether it happens in 22, 26, or 30.
Title: Re: Proposed Europa Missions
Post by: TakeOff on 08/24/2016 11:26 am
A couple of things I don't understand here.


1) Difficulty of reaching
Europa has an orbital speed of 13.7 km/s. That's alot. Add Jupiter's orbital speed of 13 km/s to that and you have a great speed range, relative to Earth, to choose from. This should allow for matching an arriving spacecraft's speed with its speed much better than for example a mission from Earth to the Moon. I'd think it is one of the easiest objects in the Solar System to orbit or land on. Also given its low surface gravity and lack of atmosphere and the huge gravity well of Jupiter. If it is difficult anyway, compared to for example Mars, I'd like to learn what makes it so difficult.


2) SLS for free
Why would it be more expensive to use the SLS to send probes to Europa, than to use them to something else? Such as a non-scientific asteroid boulder technology demonstration mission. If Congress gives away two SLS to the planetary science program, why not accept the gift most graciously? SLS obviously has a huge political support and will fly a few times at any cost to save face. Otherwise this poorly designed but potent thing wouldn't have gotten this far. And it's built on proven legacy technology so it should be quite reliable.


Politically and in public opinion (you know, the poor guys who are taxed to pay for these space toys) are all in on the alien life myth. Everyone, I mean everyone, understands that it is important to find out whether we have what would be perceived as company, or are alone. Mars and icy moons are at the top of their wish list. I think our sister planet Venus is in great need of further exploration to understand Earth and exoplanetary atmospheres, but that won't happen much because Venus is as dead an burried as a doornail can get. This crazy myth about alien life inside of moons must be embraced in order to explore the outer Solar System. Icy moons are very interesting even if they are sterile.
Title: Re: Proposed Europa Missions
Post by: the_other_Doug on 08/24/2016 02:43 pm
,,,I'd think (Europa) is one of the easiest objects in the Solar System to orbit or land on. Also given its low surface gravity and lack of atmosphere and the huge gravity well of Jupiter. If it is difficult anyway, compared to for example Mars, I'd like to learn what makes it so difficult.

From a trajectory perspective, it's not all that difficult (though targeting to land on any moon of a gas giant is not trivial, either.)  The biggest challenge in landing on, or orbiting, Europa is the radiation environment.

Europa lies within one of the belts of trapped charged particles that are created and maintained by Jupiter's magnetic field -- very similar, though far stronger, than Earth's van Allen belts.  The inner Galilean moons orbit within a very high radiation environment.  Not only is the radiation level high, but there is a strong electrical flux throughout this region.  Note that the Galileo orbiter had to spend most of its time orbiting outside of the high radiation belts, and did suffer damage and glitches when it flew threw them.  Juno flies above and below the highest radiation regions due to its polar orbit, and though it does, of course, have to traverse some of the high radiation regimes, it does so as quickly as possible by arranging its perijove to occur below the worst areas and traversing from above and below, rather than entering the high radiation belts along Jupiter's rotational plane.

One reason why a Europa orbiter really won't work is that an orbiter in that environment will die rather quickly.  I've seen a lot of discussion of Clipper trajectories, and they include many repeated close flyby passes of Europa, but also keep the orbit out past the main radiation zones most of the time.  Heck, one of the earliest proposals for a Europa probe actually put the spacecraft in orbit around Ganymede, and did all of its Europa observations with long-range sensors from that more benign vantage point.

That was a good idea for trying to maximize the lifetime of a Jupiter-system orbiter which was tasked for specific observations in re Europa, but it didn't give you the options for laser altimetry or ice-penetrating radar sensors, as are being proposed for the current incarnation of Clipper.  So, in order to do the things necessary to prepare for a lander, Clipper will have to spend at least some time quite close to Europa.  Which means either a ridiculous amount of parallel capability or extreme rad-hardening of its electronics and sensors.

And the lander is even more of a challenge, since from the moment it starts operating on the Europan surface, it's being irradiated at a very high rate.  Electronics and sensors will either need to be able to sink under the ice via melting down a few meters, or likely result in a short lifetime for such a lander.  Note, current concepts call for a lander lifetime of around 21 days -- that's not because they're cheaping out on the power source for the lander, it's because it's hard to design something to operate in that radiation environment for much longer than that.

Any lander that is tasked with actually drilling or melting a hole down into the liquid ocean below (assuming its presence is confirmed, since as of now it is inferred, albeit strongly, from things like magnetic field responses) is likely going to need to bury most of itself under a few meters of ice to provide the radiation shielding required for any kind of long-life operations.  It will have to leave enough of an antenna structure above the ice to retain contact with a relay spacecraft, but most of the thing will likely need to pull up a bit of the ice shell over itself, like a rabbit shivering in its warren during the winter...
Title: Re: Proposed Europa Missions
Post by: vjkane on 08/24/2016 03:08 pm
And the lander is even more of a challenge, since from the moment it starts operating on the Europan surface, it's being irradiated at a very high rate.  Electronics and sensors will either need to be able to sink under the ice via melting down a few meters, or likely result in a short lifetime for such a lander.  Note, current concepts call for a lander lifetime of around 21 days -- that's not because they're cheaping out on the power source for the lander, it's because it's hard to design something to operate in that radiation environment for much longer than that.

Any lander that is tasked with actually drilling or melting a hole down into the liquid ocean below (assuming its presence is confirmed, since as of now it is inferred, albeit strongly, from things like magnetic field responses) is likely going to need to bury most of itself under a few meters of ice to provide the radiation shielding required for any kind of long-life operations.  It will have to leave enough of an antenna structure above the ice to retain contact with a relay spacecraft, but most of the thing will likely need to pull up a bit of the ice shell over itself, like a rabbit shivering in its warren during the winter...
One "trick" to extending the life of any lander is to land on the leading hemisphere of the moon.  Since the radiation particles slam into the trailing hemisphere, the body of the moon acts as a very large radiation shield.  There's a map of radiation levels contrasting the two hemispheres around half way down on this blog post (double click for an enlarged image).  The contrast is very dramatic.

I heard that one of the key issues with going for a longer lived lander, which would require solar panels or radioisotope power, is weight.  NASA is also looking at this lander concept as a generic icy moons lander design, so Europa's environment is not the only concern.  It also turns out that the batteries make good radiation shielding (landing on the leading hemisphere only partially helps).

For this lander, the goal is at least three samples from 10 cm below the surface, so no real drilling.  Anything that tried to drill to the ocean likely would need to be buried as Doug suggests.
Title: Re: Proposed Europa Missions
Post by: Don2 on 08/24/2016 09:38 pm
If you compare Mars and Jupiter missions it is apparent that everything in the outer solar system costs more.  A basic , stripped down orbiter like Mars Odyssey cost $300 million. A basic Jupiter orbiter like Juno cost $1 billion.  So Jupiter is around 3 times as much. If you remember that Phoenix at Mars cost $750 million, then something over $2 billion is a sensible guess for a simple Europa lander. Of course it could be more.
Probably a fairer comparison in terms of spacecraft capability and instrument complexity is the Mars Reconnaissance Orbiter, which cost $720M in 2005 and inflated to today (3% inflation per year) is $996M.  Juno has an advanced set of instruments; it's hard to find anything that lists their final total mass, but one paper I saw from pre launch listed their mass as 174 kg..  (If anyone reading this knows the answer to this, I'd appreciate hearing the actual number.)  MRO's instruments are 139 kg.


MRO is vastly more capable than Juno. For instance, MRO has 2kW of power, Juno has 400W. That is a factor of 5 difference.  MRO can achieve a data rate to earth of 6Mb/s, Juno can achieve no more than 18kb/s. That is a factor of 333 difference.  Juno is spin stabilized which is much less convenient for cameras that the 3-axis stabilized MRO. Juno is built around one heavy, expensive instrument, the microwave radiometer, with a bunch of small add-ons. MRO has multiple heavy, expensive, data intensive instruments.

If you think about the physics it is easy to understand why Jupiter is much more expensive. The energy needed to send a bit of data will increase with the square of the distance from earth. Sunlight decreases with the square of the distance from the sun, so the cost of energy will increase with the square of the distance, until you switch over to RTGs. So you need more energy to send data home and that energy gets more costly. Things get worse if you need to divert energy to thermal control as sunlight gets weaker.

The cost of electricity for the instruments also goes up steeply until you switch to RTGs. Even after that point, you need more delta-v to go farther out, so the cost of the RTG mass and energy will increase with distance.

For Juno we should also add the 200kg of radiation vault to the discussion. That adds 12.5% to the dry mass of the probe.
Title: Re: Proposed Europa Missions
Post by: Don2 on 08/24/2016 09:59 pm
... but most of the thing will likely need to pull up a bit of the ice shell over itself, like a rabbit shivering in its warren during the winter...

You make it all sound so cozy. It might work too, if the ice was very pure. You could heat the ice under the lander, and encourage the vapor that sublimes to condense on top, giving a nice layer of radiation shielding.

Of course, if there is a little silicate dust or elemental sulfur mixed into the ice, that won't sublime. It will collect under the lander until there is enough to block further progress.

What other impurities might there be in the ice? The scientists are talking about sulfuric acid and hydrogen peroxide. Sulfuric acid ices will tend to collect underneath the lander, while the hydrogen peroxide will tend to go with the water. It goes without saying that a mix like that will destroy any organics, but it also has a good chance of dissolving the lander. Aerospace projects are not usually built out of highly corrosion resistant materials.

One thing's for sure. The creature from Alien will be right at home in that highly acidic environment. Your lander, not so much.
Title: Re: Proposed Europa Missions
Post by: the_other_Doug on 08/25/2016 01:01 am
... but most of the thing will likely need to pull up a bit of the ice shell over itself, like a rabbit shivering in its warren during the winter...

You make it all sound so cozy. It might work too, if the ice was very pure. You could heat the ice under the lander, and encourage the vapor that sublimes to condense on top, giving a nice layer of radiation shielding.

Of course, if there is a little silicate dust or elemental sulfur mixed into the ice, that won't sublime. It will collect under the lander until there is enough to block further progress.

What other impurities might there be in the ice? The scientists are talking about sulfuric acid and hydrogen peroxide. Sulfuric acid ices will tend to collect underneath the lander, while the hydrogen peroxide will tend to go with the water. It goes without saying that a mix like that will destroy any organics, but it also has a good chance of dissolving the lander. Aerospace projects are not usually built out of highly corrosion resistant materials.

One thing's for sure. The creature from Alien will be right at home in that highly acidic environment. Your lander, not so much.

Oh, for sure.  I was talking at a much higher level than these concerns -- and, of course, yes, they can be show-stoppers.

The chemistry of the outer ice shell is indeed a concern when it comes to melting your way down (which is the one obvious strategy to achieve penetration through the ice shell and into the ocean).  But what we have now is hints and theories.  That's why it becomes obvious you need Clipper first before any lander, to get more detailed small-scale surface information.  Including chemistry.  I've yet to see a completely homogeneous world, so I'd bet you that there are some locations on the Europan surface that don't feature either sulfuric acid nor hydrogen peroxide.  Clipper ought to be able to constrain that concern a lot better than the data we have right now.

Of course, I wasn't suggesting that the first Europa surface lander could even begin to have the capability of melting through tens, much less hundreds, of meters of ice shell.  The whole concept of melting a deep drill hole is for follow-on landers with an order of magnitude greater set of capabilities.

The purity of the ice in any icy moon will be a generic problem for any melt-drilling process; I've been tossing that issue around in my head for years, now.  Some means of maintaining Earthlike pressures and temperatures in the drill hole, and of mechanically removing silicates and metals from your drill hole, may have to be devised to deal with these issues.  That implies sinking an insulated, sealed drill shaft, and that has always seemed to me to be so energy- and mass-intensive as to be prohibitive...
Title: Re: Proposed Europa Missions
Post by: Jim on 08/25/2016 03:08 am
A couple of things I don't understand here.


1) Difficulty of reaching
Europa has an orbital speed of 13.7 km/s. That's alot. Add Jupiter's orbital speed of 13 km/s to that and you have a great speed range, relative to Earth, to choose from. This should allow for matching an arriving spacecraft's speed with its speed much better than for example a mission from Earth to the Moon. I'd think it is one of the easiest objects in the Solar System to orbit or land on. Also given its low surface gravity and lack of atmosphere and the huge gravity well of Jupiter. If it is difficult anyway, compared to for example Mars, I'd like to learn what makes it so difficult.


2) SLS for free
Why would it be more expensive to use the SLS to send probes to Europa, than to use them to something else?

3. Such as a non-scientific asteroid boulder technology demonstration mission. If Congress gives away two SLS to the planetary science program, why not accept the gift most graciously? SLS obviously has a huge political support and will fly a few times at any cost to save face. Otherwise this poorly designed but potent thing wouldn't have gotten this far.

4. And it's built on proven legacy technology so it should be quite reliable.



1. It is difficult because of the velocity of the spacecraft approaching Europa.   It is has to be dissipated.  It is higher than one going to the moon or mars. 

2.  Because the spacecraft would be too large and expensive.

3.  The asteroid mission is a scientific one.  The mission is to collect samples from the asteroid.  The asteroid is capture by a spacecraft flown on nonSLS launch vehicles.

4.  Not true.  It would fly too infrequently to "quite reliable"
Title: Re: Proposed Europa Missions
Post by: vjkane on 08/25/2016 02:41 pm
MRO is vastly more capable than Juno. For instance, MRO has 2kW of power, Juno has 400W. That is a factor of 5 difference.  MRO can achieve a data rate to earth of 6Mb/s, Juno can achieve no more than 18kb/s. That is a factor of 333 difference.  Juno is spin stabilized which is much less convenient for cameras that the 3-axis stabilized MRO. Juno is built around one heavy, expensive instrument, the microwave radiometer, with a bunch of small add-ons. MRO has multiple heavy, expensive, data intensive instruments.

If you think about the physics it is easy to understand why Jupiter is much more expensive. The energy needed to send a bit of data will increase with the square of the distance from earth. Sunlight decreases with the square of the distance from the sun, so the cost of energy will increase with the square of the distance, until you switch over to RTGs. So you need more energy to send data home and that energy gets more costly. Things get worse if you need to divert energy to thermal control as sunlight gets weaker.

The cost of electricity for the instruments also goes up steeply until you switch to RTGs. Even after that point, you need more delta-v to go farther out, so the cost of the RTG mass and energy will increase with distance.

For Juno we should also add the 200kg of radiation vault to the discussion. That adds 12.5% to the dry mass of the probe.
Don2, you clearly know much more about this than I do, so could I pick your brains a bit since this is a question I've wondered about?

As the first order magnitude measure of a mission's capability, I've looked at the mass of the instruments.  You appear to be arguing that radio transmitter power is a better basic measure.

As a thought experiment, imagine sending MRO to orbit Callisto (low radiation levels, so special electronics and vaults likely not needed based on what I understand of the JUICE design).  Even if the solar panels were increased to have the same level of power so that the transmitter still had the same amount of power out, the data return would be much less (at perihelion, Mars is 1.38 AU, Jupiter 4.9 AU, can't get around the inverse square law).  So any mission to Jupiter or further out will be on a much more severe data diet than a similarly capable Mars orbiter. 

In reality, I suspect that the solar arrays can't be increased to match the power at Mars, so there will be less power, and hence still lower transmitter power. 

Once you accept the lower data return, what else would drive up the cost of MRO at Callisto other than the longer cruise time?  In other words, what is it about being at 5 AU in a low radiation environment that simply makes spacecraft that much more expensive?  (One partial answer I know is that low light, low temperature arrays cost more as do RTGs.  Other things?)

Appreciate your time answering a question that has puzzled me.
Title: Proposed Europa Missions
Post by: Star One on 08/25/2016 03:06 pm
I think there's a lot of misunderstanding of the political maneuvering here. The only mission that is being actively developed is the Clipper. The lander mission is still in the early study phase. And it is likely to stay in that stage for several years. As long as the money spent on studying the lander is not huge, what's the harm in studying it? In fact, studying lander concepts helps refine the Clipper, because it enables the people working on the Clipper to think about the best science and operations to support a future lander mission, whether it happens in 22, 26, or 30.

Some posters appear to be deliberately kicking up a lot of fuss about the lander, even though as you say it's actually at a very early stage, just in an effort to discredit the whole Europa enterprise because it doesn't suit how they think things should be done.
Title: Re: Proposed Europa Missions
Post by: Don2 on 08/25/2016 09:17 pm
@vjkane...I'm not sure I do know more about this than you, and I'm sure I know less than some of the other posters here, but I will have a go at the problem.

As you go further out the cost of power and data rate explodes. The other thing to mention is that mission operations costs go up because the missions become longer.

So at Mars perihelion MRO will generate 2000W of power.  At Jupiter at perihelion the same spacecraft will generate 155W. At apihelion that goes down to 128W. The big problem here is that you need a certain amount of overhead just to run computers, attitude and thermal control, and a radio receiver. The Decadal Survey did a number of design studies and from those you can figure out that the minimum survival power is about 100-200W for a probe. So MRO would be using all its power just to survive at Callisto and would have almost nothing for instruments or data return.

You can't just hang an extra solar panel on the spacecraft without triggering a whole cascade of other design changes. An extra panel means more weight, so you need bigger reaction wheels and rocket engines. To preserve the same delta-v capability you need larger fuel tanks and more fuel. All that extra mass needs a larger structure. Pretty soon you are talking about a substantially bigger and more expensive spacecraft.

How much does the cost of a spacecraft influence the cost of a project? Again, I use the Decadal survey studies to get a sense of how the costs stack up. Simplifying and combining some of the NASA items I end up with this breakdown for the Jupiter Europa orbiter:

Instruments 27%, Spacecraft 41%, Launch 9%, Operations 22%

For the Trojan Tour I get:

Instruments 20%, Spacecraft 39%, Launch 29%, Operations 12%
Title: Re: Proposed Europa Missions
Post by: Star One on 08/25/2016 09:35 pm
@vjkane...I'm not sure I do know more about this than you, and I'm sure I know less than some of the other posters here, but I will have a go at the problem.

As you go further out the cost of power and data rate explodes. The other thing to mention is that mission operations costs go up because the missions become longer.

So at Mars perihelion MRO will generate 2000W of power.  At Jupiter at perihelion the same spacecraft will generate 155W. At apihelion that goes down to 128W. The big problem here is that you need a certain amount of overhead just to run computers, attitude and thermal control, and a radio receiver. The Decadal Survey did a number of design studies and from those you can figure out that the minimum survival power is about 100-200W for a probe. So MRO would be using all its power just to survive at Callisto and would have almost nothing for instruments or data return.

You can't just hang an extra solar panel on the spacecraft without triggering a whole cascade of other design changes. An extra panel means more weight, so you need bigger reaction wheels and rocket engines. To preserve the same delta-v capability you need larger fuel tanks and more fuel. All that extra mass needs a larger structure. Pretty soon you are talking about a substantially bigger and more expensive spacecraft.

How much does the cost of a spacecraft influence the cost of a project? Again, I use the Decadal survey studies to get a sense of how the costs stack up. Simplifying and combining some of the NASA items I end up with this breakdown for the Jupiter Europa orbiter:

Instruments 27%, Spacecraft 41%, Launch 9%, Operations 22%

For the Trojan Tour I get:

Instruments 20%, Spacecraft 39%, Launch 29%, Operations 12%
I am increasingly of the view that you have some kind of political axe to grind regarding this whole Europa project, if this is the case I wish you would just come out and say it.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 08/25/2016 11:28 pm
I think there's a lot of misunderstanding of the political maneuvering here. The only mission that is being actively developed is the Clipper. The lander mission is still in the early study phase. And it is likely to stay in that stage for several years. As long as the money spent on studying the lander is not huge, what's the harm in studying it? In fact, studying lander concepts helps refine the Clipper, because it enables the people working on the Clipper to think about the best science and operations to support a future lander mission, whether it happens in 22, 26, or 30.

Some posters appear to be deliberately kicking up a lot of fuss about the lander, even though as you say it's actually at a very early stage, just in an effort to discredit the whole Europa enterprise because it doesn't suit how they think things should be done.

But I totally understand that. The lander is the point where the needle scratches off the record album and everything starts to get strange. It's not in the decadal, for example.

But... well look: I've run one decadal survey (not by myself) and I work with the guy who has run both of them and also worked the pre-decadals that did much the same thing. And as he points out, every major project has a convoluted and sometimes messy political origin. It's not simple and pristine. They have always required people to come in and advocate for them and for china to get smashed. That's normal.

And if you look at what is going on now from that perspective, it is also normal. It may seem really oddball to us because we're up too close to it, but if you take a broader historical view, it's not unusual. And nobody should be making straight-line extrapolations to conclusions. You should not look at what is happening right now and conclude that both Europa Clipper and the lander will get built, or will launch in the same manner. They may not. Lots of things will change. So getting all caught up in things like "the lander is not in the decadal survey and is going to totally wreck the bank" at this very early stage is pointless, because Things Change.
Title: Re: Proposed Europa Missions
Post by: ncb1397 on 08/26/2016 12:21 am
The decadel survey only looks at the goals of one interest group (the planetary science community). NASA programs usually aren't justified by these measures alone. Economic growth, technology spin-offs, national soft power,national prestige, employment, and even national defense are all factors used to justify the expense. If astrobiology didn't have any ramifications for those factors I just listed, there probably wouldn't be a Europa mission funded by a national government. Of course, scientists and people that are curious about what is out there could fund their own mission. Try looking at a lander through those prisms as well as the pure science and maybe the logic will be more apparent. Just as an example: the technology that allows a robotic lander to work on the surface of Europa could potentially be used for disaster relief (i.e. the robots Japan has sent in to the Fukushima Daichi nuclear plant have been killed by the radiation).
Title: Re: Proposed Europa Missions
Post by: ccdengr on 08/26/2016 01:07 am
MRO can achieve a data rate to earth of 6Mb/s, Juno can achieve no more than 18kb/s.
Actually Juno can do 120 kb/s to a 70m antenna and 22 kb/s to a 34m antenna.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 08/26/2016 02:45 am
The decadel survey only looks at the goals of one interest group (the planetary science community). NASA programs usually aren't justified by these measures alone. Economic growth, technology spin-offs, national soft power,national prestige, employment, and even national defense are all factors used to justify the expense. If astrobiology didn't have any ramifications for those factors I just listed, there probably wouldn't be a Europa mission funded by a national government. Of course, scientists and people that are curious about what is out there could fund their own mission. Try looking at a lander through those prisms as well as the pure science and maybe the logic will be more apparent. Just as an example: the technology that allows a robotic lander to work on the surface of Europa could potentially be used for disaster relief (i.e. the robots Japan has sent in to the Fukushima Daichi nuclear plant have been killed by the radiation).



Das ist nicht nur nicht richtig, es ist nicht einmal falsch!

Title: Re: Proposed Europa Missions
Post by: Don2 on 08/26/2016 06:53 pm
I am increasingly of the view that you have some kind of political axe to grind regarding this whole Europa project, if this is the case I wish you would just come out and say it.

I have no problem with the orbiter if it stays under $2.5bn. Europa is like nowhere else in the Solar System, and the orbiter will address questions that have been out there for nearly 20 years. The Galileo mission was partly a failure, and a return to the moons of Jupiter with a fully functioning spacecraft is long overdue. The Jupiter system has a very rich set of scientific phenomena, and there are plenty of other things to see besides Europa.
Title: Re: Proposed Europa Missions
Post by: vjkane on 08/26/2016 07:04 pm
I am increasingly of the view that you have some kind of political axe to grind regarding this whole Europa project, if this is the case I wish you would just come out and say it.

I have no problem with the orbiter if it stays under $2.5bn. Europa is like nowhere else in the Solar System, and the orbiter will address questions that have been out there for nearly 20 years. The Galileo mission was partly a failure, and a return to the moons of Jupiter with a fully functioning spacecraft is long overdue. The Jupiter system has a very rich set of scientific phenomena, and there are plenty of other things to see besides Europa.

ESA's JUICE will spend a lot of its time looking at all the other wonders of the Jupiter system.  Per the Europa mission's project manager, they haven't spent any time looking at studies of additional bodies.  I did see one orbital study for the mission that included several flybys of Ganymede and Callisto.  Right now the plan to dispose of Clipper is to crash it on Ganymede; the project manager says his dream is to see it do a couple of flybys of Io first before crashing it on that moon.

But JUICE has instruments better suited to studying Jupiter and the magnetosphere than the Clipper.

Together the two missions will do an awesome job, especially if they operate at the same time.

In my fantasy world, a Discovery Io flyby mission would also operate at the same time, but it would have to be selected in the next competition for that to happen.
Title: Re: Proposed Europa Missions
Post by: Star One on 08/26/2016 07:35 pm
I am increasingly of the view that you have some kind of political axe to grind regarding this whole Europa project, if this is the case I wish you would just come out and say it.

I have no problem with the orbiter if it stays under $2.5bn. Europa is like nowhere else in the Solar System, and the orbiter will address questions that have been out there for nearly 20 years. The Galileo mission was partly a failure, and a return to the moons of Jupiter with a fully functioning spacecraft is long overdue. The Jupiter system has a very rich set of scientific phenomena, and there are plenty of other things to see besides Europa.

Thank you. For me I felt like you jumped straight into your paper so to speak without putting the abstract first.
Title: Re: Proposed Europa Missions
Post by: Don2 on 08/26/2016 07:51 pm
@vjkane....Europa may be driving the design, and that's OK, but I have a feeling the science team will find excuses to point the probe at other targets.

If they use the Hirise camera that will get them no better than 250m/pixel on Io from Europa orbit. However, an extended mission to Io is a very obvious possibility, and HiRise can collect data very quickly during a flyby. The limitation would be on returning it back to earth. For the disk of Io you could get 50m2/px in color back in 28 days at 40kb/s. You  need a 12 GB data store for that.

What you really want for Io is a very long orbit so you have plenty of time to transmit the flyby data back to Earth. 3 flybys would give good coverage of the equatorial regions. I can see that happening at the end of the mission with a little luck.

@Star One...You're welcome!
Title: Re: Proposed Europa Missions
Post by: vjkane on 08/26/2016 07:56 pm
@vjkane....Europa may be driving the design, and that's OK, but I have a feeling the science team will find excuses to point the probe at other targets.
At the talk by the project manager, it was clear from his language that they expect to look at other targets (and certainly will keep the field and particles instruments collecting data throughout the orbits); they just hadn't put time into considering what yet.

The repetitive nature of the measurements and the need to spend the bulk of the orbit transmitting data back to Earth may limit time to point elsewhere.  I can't remember how many hours a day they plan to downlink.  When they aren't downlinking, they could study other objects assuming the instruments can point to them while the solar arrays can still gather power.
Title: Re: Proposed Europa Missions
Post by: Star One on 08/26/2016 07:58 pm
@vjkane....Europa may be driving the design, and that's OK, but I have a feeling the science team will find excuses to point the probe at other targets.

If they use the Hirise camera that will get them no better than 250m/pixel on Io from Europa orbit. However, an extended mission to Io is a very obvious possibility, and HiRise can collect data very quickly during a flyby. The limitation would be on returning it back to earth. For the disk of Io you could get 50m2/px in color back in 28 days at 40kb/s. You  need a 12 GB data store for that.

What you really want for Io is a very long orbit so you have plenty of time to transmit the flyby data back to Earth. 3 flybys would give good coverage of the equatorial regions. I can see that happening at the end of the mission with a little luck.

@Star One...You're welcome!

I am not as smart as some of you in these technical aspects so I need an 'abstract' to use as a starting point to follow your argument.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 09/15/2016 09:53 pm
Title: Re: Proposed Europa Missions
Post by: redliox on 09/16/2016 09:01 am
ESA's JUICE will spend a lot of its time looking at all the other wonders of the Jupiter system.  Per the Europa mission's project manager, they haven't spent any time looking at studies of additional bodies.  I did see one orbital study for the mission that included several flybys of Ganymede and Callisto.  Right now the plan to dispose of Clipper is to crash it on Ganymede; the project manager says his dream is to see it do a couple of flybys of Io first before crashing it on that moon.

Unlike JUICE, the (formerly known as) 'Clipper has superior radiation protection, so between the 2 it has the best potential for examining Io.  Also unlike JUICE, 'Clipper isn't planned to end up bound to one satellite; it can visit the others readily with a gravitational assist and approval from management.  Galileo, despite its poor state (largely the antenna among other factors), was granted 2 mission extensions that added 6 years onto the primary's 2; I'd confidently bet 'Clipper could endure into at least 1 extension.

I hope the project manager sees his dream with Io fulfilled.  Considering it is, aside from Europa, the most scientifically intriguing satellite of Jupiter, any visit to it is worthwhile; more so, Galileo's visits proved that since Voyager's the moon significantly changed...meaning every visit will surely reveal surprises.  Also, considering it's a volcanic, fiery, and radioactive rock that only Venus and the Sun exceed in inhospitality, good place to dispose a used spacecraft if you fear contaminating its neighbors.

Aside from Io, personally I'd like to see a visit to at least one of the tiny inner or outer moons.  I'd prioritize Io over them, but we've seen Amalthea's group distantly and Himalia is the only outer satellite remotely examined (in the vaguest of senses).  These are, more than likely, part of the same family as the Trojans, which themselves may be a collection of random junk Jupiter's been adding to since its formation.  Unless the 'Clipper is given a hard boost outward from the Galileans prior to death on the inbound return, I doubt the outer moons can be visited (at least Saturn's Phoebe got very lucky with Cassini); so a more likely scenario would be, prior to a Jupiter disposal, Amalthea or perhaps Thebe receive a proper flyby.

But JUICE has instruments better suited to studying Jupiter and the magnetosphere than the Clipper.

Together the two missions will do an awesome job, especially if they operate at the same time.

In my fantasy world, a Discovery Io flyby mission would also operate at the same time, but it would have to be selected in the next competition for that to happen.

Oh I have the same hopes as you; between the two of them they'll bring the Galilean moons to the same level as Mars in terms of resolution and maps.  As I said, I'm sure 'Clipper will get a mission extension just as grandpa Galileo did.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 09/17/2016 08:53 pm
Unlike JUICE, the (formerly known as) 'Clipper has superior radiation protection, so between the 2 it has the best potential for examining Io.  Also unlike JUICE, 'Clipper isn't planned to end up bound to one satellite; it can visit the others readily with a gravitational assist and approval from management.  Galileo, despite its poor state (largely the antenna among other factors), was granted 2 mission extensions that added 6 years onto the primary's 2; I'd confidently bet 'Clipper could endure into at least 1 extension.

I hope the project manager sees his dream with Io fulfilled.  Considering it is, aside from Europa, the most scientifically intriguing satellite of Jupiter, any visit to it is worthwhile; more so, Galileo's visits proved that since Voyager's the moon significantly changed...meaning every visit will surely reveal surprises.  Also, considering it's a volcanic, fiery, and radioactive rock that only Venus and the Sun exceed in inhospitality, good place to dispose a used spacecraft if you fear contaminating its neighbors.

I think that one thing that could affect extended mission planning for Clipper is the desire to keep it around to support a lander mission.

As for Io, I'd love to see more study of Io. But my understanding is that its surface is not exactly "fiery"--despite all the volcanic activity, the surface is actually rather cold. (There was a recent published paper on this, I believe.) I wonder if anybody has tried to model a heat map? I imagine that anything coming out of a volcano hot is going to cool very quickly.
Title: Re: Proposed Europa Missions
Post by: redliox on 09/18/2016 12:15 am
I think that one thing that could affect extended mission planning for Clipper is the desire to keep it around to support a lander mission.

True, barring the next Congress being stingier but we'll see.  In any case, if it's still functional with or without a lander its use ought to be continued, just like with Cassini, LRO, Opportunity...which collectively are another example of why an extension could be favored.  If it still has fuel and the electronics haven't been fried, keep it going a lil longer.

As for Io, I'd love to see more study of Io. But my understanding is that its surface is not exactly "fiery"--despite all the volcanic activity, the surface is actually rather cold. (There was a recent published paper on this, I believe.) I wonder if anybody has tried to model a heat map? I imagine that anything coming out of a volcano hot is going to cool very quickly.

I'm sure there is a huge variance in heat with Io.  I was under the impression one reason it is so surprisingly colorful is because sulfur (and presumably its compounds) change depending on the temperature, going from black-hot to white-cold with all those shades of red and yellow in between.  A thermal map would be good, especially since some scientists were noticing its volcanoes are appearing in regions where models suggest they shouldn't form.  There could be some odd situation where the tides are heating the mantle and crust more than the core, causing unanticipated anomalies.

Hopefully as the mission develops, the Europa team will mention what else may be studied on the side in addition to Europa.  Io hopefully will be one of these.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 09/18/2016 03:29 am
I think that one thing that could affect extended mission planning for Clipper is the desire to keep it around to support a lander mission.

True, barring the next Congress being stingier but we'll see.  In any case, if it's still functional with or without a lander its use ought to be continued, just like with Cassini, LRO, Opportunity...which collectively are another example of why an extension could be favored.  If it still has fuel and the electronics haven't been fried, keep it going a lil longer.

There is one difference for missions around Jupiter--they have to "fail safe" from a planetary protection standpoint. That means that the policy is not to simply run them until they fail and die. Instead, when it becomes highly likely that they will die, they have to be crashed into a safe body, like Jupiter or a dead moon.

If we were all going to bet on this, the safe money is that Clipper gets delayed a bit, but still flies, and the lander gets delayed a lot, or canceled. That could mean that any lander would arrive many years after Clipper. So the odds of Clipper still being alive to support a lander are slim.
Title: Re: Proposed Europa Missions
Post by: Star One on 09/18/2016 08:27 am
I think that one thing that could affect extended mission planning for Clipper is the desire to keep it around to support a lander mission.

True, barring the next Congress being stingier but we'll see.  In any case, if it's still functional with or without a lander its use ought to be continued, just like with Cassini, LRO, Opportunity...which collectively are another example of why an extension could be favored.  If it still has fuel and the electronics haven't been fried, keep it going a lil longer.

There is one difference for missions around Jupiter--they have to "fail safe" from a planetary protection standpoint. That means that the policy is not to simply run them until they fail and die. Instead, when it becomes highly likely that they will die, they have to be crashed into a safe body, like Jupiter or a dead moon.

If we were all going to bet on this, the safe money is that Clipper gets delayed a bit, but still flies, and the lander gets delayed a lot, or canceled. That could mean that any lander would arrive many years after Clipper. So the odds of Clipper still being alive to support a lander are slim.

In that case would there be any possibility to move it to Saturn after it has finished at Jupiter, surly Enceladus would be ideal for study with the exact same set of instruments?
Title: Re: Proposed Europa Missions
Post by: Jim on 09/18/2016 11:57 am
I think that one thing that could affect extended mission planning for Clipper is the desire to keep it around to support a lander mission.

True, barring the next Congress being stingier but we'll see.  In any case, if it's still functional with or without a lander its use ought to be continued, just like with Cassini, LRO, Opportunity...which collectively are another example of why an extension could be favored.  If it still has fuel and the electronics haven't been fried, keep it going a lil longer.

There is one difference for missions around Jupiter--they have to "fail safe" from a planetary protection standpoint. That means that the policy is not to simply run them until they fail and die. Instead, when it becomes highly likely that they will die, they have to be crashed into a safe body, like Jupiter or a dead moon.

If we were all going to bet on this, the safe money is that Clipper gets delayed a bit, but still flies, and the lander gets delayed a lot, or canceled. That could mean that any lander would arrive many years after Clipper. So the odds of Clipper still being alive to support a lander are slim.

In that case would there be any possibility to move it to Saturn after it has finished at Jupiter, surly Enceladus would be ideal for study with the exact same set of instruments?

No, too much delta V would be required
Title: Re: Proposed Europa Missions
Post by: ncb1397 on 09/18/2016 06:13 pm
I think that one thing that could affect extended mission planning for Clipper is the desire to keep it around to support a lander mission.

True, barring the next Congress being stingier but we'll see.  In any case, if it's still functional with or without a lander its use ought to be continued, just like with Cassini, LRO, Opportunity...which collectively are another example of why an extension could be favored.  If it still has fuel and the electronics haven't been fried, keep it going a lil longer.

There is one difference for missions around Jupiter--they have to "fail safe" from a planetary protection standpoint. That means that the policy is not to simply run them until they fail and die. Instead, when it becomes highly likely that they will die, they have to be crashed into a safe body, like Jupiter or a dead moon.

If we were all going to bet on this, the safe money is that Clipper gets delayed a bit, but still flies, and the lander gets delayed a lot, or canceled. That could mean that any lander would arrive many years after Clipper. So the odds of Clipper still being alive to support a lander are slim.

In that case would there be any possibility to move it to Saturn after it has finished at Jupiter, surly Enceladus would be ideal for study with the exact same set of instruments?

No, too much delta V would be required

This study seems to think capture into Saturn orbit could be possible. Europa Clipper can always add mass by doing one earth gravity assist instead of doing a direct flight that adds a year or 2. The real problem is power, not Delta-V. The study below assumes Radio-isotope and so wouldn't be affected as much by distance from the Sun.

Quote
Many additional potential spacecraft disposal
options exist that avoid collision with Europa,
including (but not limited to) the following:
 Jovian system impacting trajectories:
– Jupiter (via short- or long-period
orbits, the latter using solar perturbations)

– Io, Ganymede, or Callisto
 Long-term Jupiter-centered orbits:
– Circular orbit between Ganymede
and Callisto
– Eccentric orbit outside of Callisto
 Jupiter system escape:
– Heliocentric orbit
– Saturn flyby, impactor, or potentially
even capture

– Icy-giant flyby or impactor
– Trojan asteroid flyby or impactor
http://www.lpi.usra.edu/opag/europa2012/ES%202012%20Report%20C%20Flyby%20-%20Final%20-%2020120501.pdf
Title: Re: Proposed Europa Missions
Post by: savuporo on 09/18/2016 06:36 pm
In that case would there be any possibility to move it to Saturn after it has finished at Jupiter, surly Enceladus would be ideal for study with the exact same set of instruments?
Maybe just build two copies from the get go, like MER
Title: Re: Proposed Europa Missions
Post by: as58 on 09/18/2016 07:47 pm
In that case would there be any possibility to move it to Saturn after it has finished at Jupiter, surly Enceladus would be ideal for study with the exact same set of instruments?
Maybe just build two copies from the get go, like MER

I doubt solar power would work at Saturn (at least without huge changes), and getting good enough data rates would probably need some changes to communications. And if you're going to change all that, you'll probably also want to rethink the instrument set...
Title: Re: Proposed Europa Missions
Post by: redliox on 09/18/2016 08:43 pm
I doubt solar power would work at Saturn (at least without huge changes), and getting good enough data rates would probably need some changes to communications. And if you're going to change all that, you'll probably also want to rethink the instrument set...

Right.  Jupiter is roughly 5-4 percent as much sunlight as Earth, but Saturn is not even 1 percent, which means power production is quartered already.  A Europa mission isn't going to be useful any farther out than Jupiter...

No, too much delta V would be required

This study seems to think capture into Saturn orbit could be possible. Europa Clipper can always add mass by doing one earth gravity assist instead of doing a direct flight that adds a year or 2. The real problem is power, not Delta-V. The study below assumes Radio-isotope and so wouldn't be affected as much by distance from the Sun.

Quote
Many additional potential spacecraft disposal
options exist that avoid collision with Europa,
including (but not limited to) the following:
 Jovian system impacting trajectories:
– Jupiter (via short- or long-period
orbits, the latter using solar perturbations)

– Io, Ganymede, or Callisto
 Long-term Jupiter-centered orbits:
– Circular orbit between Ganymede
and Callisto
– Eccentric orbit outside of Callisto
 Jupiter system escape:
– Heliocentric orbit
– Saturn flyby, impactor, or potentially
even capture

– Icy-giant flyby or impactor
– Trojan asteroid flyby or impactor
http://www.lpi.usra.edu/opag/europa2012/ES%202012%20Report%20C%20Flyby%20-%20Final%20-%2020120501.pdf

Bear in mind the study you reference is about 4 years old now.  Secondly, because of solar power you can instantly cross out Saturn and the Ice Giants not to mention the transfer time would be too long.  However, there hypothetically could be more options...

Io is definitely a good possibility, in part because it's unlikely we'll see another rad-armored probe (which JUICE is not for example) capable of visiting it.  Also because it isn't icy at all, unlike the other Galileans, it would be an excellent body to crash the probe into after a few flybys.  Also, for gravity assists, Io is great to utilize (sparingly of course due to radiation).

Ganymede and Callisto, apart from the primary mission, may be ignored because JUICE is going to study them in greater detail than the Europa mission could.  Callisto could merit some attention since even JUICE won't examine it as extensively as Ganymede.  Either way, they will be visited simply because of their gravity assist use.

If you're interested in leaving Jupiter as a whole, I'd say the best bets would be visiting (at least one of) Jupiter's outermost moons and the Trojans.  Because these bodies are at the same distance as Jupiter, these at least would allow the Europa probe to operate normally and, since the probe is optimized to technically do flybys of Europa, flybys (albeit at larger velocities) outside of Jupiter is a possibility.

So if you're talking exotic extensions, I'd say expect either Io visits or Trojan ones at most.
Title: Re: Proposed Europa Missions
Post by: Jim on 09/18/2016 09:18 pm
I think that one thing that could affect extended mission planning for Clipper is the desire to keep it around to support a lander mission.

True, barring the next Congress being stingier but we'll see.  In any case, if it's still functional with or without a lander its use ought to be continued, just like with Cassini, LRO, Opportunity...which collectively are another example of why an extension could be favored.  If it still has fuel and the electronics haven't been fried, keep it going a lil longer.

There is one difference for missions around Jupiter--they have to "fail safe" from a planetary protection standpoint. That means that the policy is not to simply run them until they fail and die. Instead, when it becomes highly likely that they will die, they have to be crashed into a safe body, like Jupiter or a dead moon.

If we were all going to bet on this, the safe money is that Clipper gets delayed a bit, but still flies, and the lander gets delayed a lot, or canceled. That could mean that any lander would arrive many years after Clipper. So the odds of Clipper still being alive to support a lander are slim.

In that case would there be any possibility to move it to Saturn after it has finished at Jupiter, surly Enceladus would be ideal for study with the exact same set of instruments?

No, too much delta V would be required

This study seems to think capture into Saturn orbit could be possible. Europa Clipper can always add mass by doing one earth gravity assist instead of doing a direct flight that adds a year or 2. The real problem is power, not Delta-V. The study below assumes Radio-isotope and so wouldn't be affected as much by distance from the Sun.

Quote
Many additional potential spacecraft disposal
options exist that avoid collision with Europa,
including (but not limited to) the following:
 Jovian system impacting trajectories:
– Jupiter (via short- or long-period
orbits, the latter using solar perturbations)

– Io, Ganymede, or Callisto
 Long-term Jupiter-centered orbits:
– Circular orbit between Ganymede
and Callisto
– Eccentric orbit outside of Callisto
 Jupiter system escape:
– Heliocentric orbit
– Saturn flyby, impactor, or potentially
even capture

– Icy-giant flyby or impactor
– Trojan asteroid flyby or impactor
http://www.lpi.usra.edu/opag/europa2012/ES%202012%20Report%20C%20Flyby%20-%20Final%20-%2020120501.pdf

He was talking about a probe  going from Jupiter orbit to Saturn orbit. 
Title: Re: Proposed Europa Missions
Post by: redliox on 11/29/2016 06:33 am
Here's a proposal for a daughter craft I hadn't heard of before: http://www.hou.usra.edu/meetings/lpsc2016/pdf/2602.pdf (http://www.hou.usra.edu/meetings/lpsc2016/pdf/2602.pdf)

Biosignature Explorer for Europa (BEE)

I know the likelihood of a daughter spacecraft is unlikely, especially since a Europa Lander is (at least mostly) officially tagged to follow, but this particular proposal is from 2016 with some decent details.

It's payload would consist of 3 cameras covering UV, visible, and IR (nothing mentioned about if these are spectrometers or not; I'd assume if it's simplicity they're after, presumably cameras with lenses), a mass spectrometer, and a gas chromatograph.  In Deep Impact/LCROSS-esque fashion (minus the impact), it would use specifically the UV camera to zero in on a plume and fly through with an active propulsion system adjusting course.  The craft would be battery powered and under the 250kg limit.

Not a bad idea itself, just unsure how likely it would be.  The Europa Clipper Flyby Orbiter could easily do the same job during a mission extension, and the required funding better put toward either improving the Orbiter's instruments or developing the upcoming lander.

Anybody heard about this BEE buzzing?
Title: Re: Proposed Europa Missions
Post by: vjkane on 11/29/2016 07:14 am
Here's a proposal for a daughter craft I hadn't heard of before: http://www.hou.usra.edu/meetings/lpsc2016/pdf/2602.pdf (http://www.hou.usra.edu/meetings/lpsc2016/pdf/2602.pdf)

Biosignature Explorer for Europa (BEE)

Anybody heard about this BEE buzzing?
I believe that NASA is no longer considering this.
Title: Re: Proposed Europa Missions
Post by: redliox on 11/29/2016 07:48 am
Here's a proposal for a daughter craft I hadn't heard of before: http://www.hou.usra.edu/meetings/lpsc2016/pdf/2602.pdf (http://www.hou.usra.edu/meetings/lpsc2016/pdf/2602.pdf)

Biosignature Explorer for Europa (BEE)

Anybody heard about this BEE buzzing?
I believe that NASA is no longer considering this.

I wanted to confirm that; I heard of a few daughter craft incarnations but never saw one in detail like this.  I'm pretty sure the lander inclusion killed their chances.  All the same was curious who heard of this.  Blackstar would be perfect, although I suspect he'll just verify what you said.
Title: Re: Proposed Europa Missions
Post by: vjkane on 11/29/2016 07:52 am
Here's a proposal for a daughter craft I hadn't heard of before: http://www.hou.usra.edu/meetings/lpsc2016/pdf/2602.pdf (http://www.hou.usra.edu/meetings/lpsc2016/pdf/2602.pdf)

Biosignature Explorer for Europa (BEE)

Anybody heard about this BEE buzzing?
I believe that NASA is no longer considering this.

I wanted to confirm that; I heard of a few daughter craft incarnations but never saw one in detail like this.  I'm pretty sure the lander inclusion killed their chances.  All the same was curious who heard of this.  Blackstar would be perfect, although I suspect he'll just verify what you said.
My understanding is that this was proposed by a team led by APL.  NASA management decided against daughter craft for cost, mass, and complexity reasons.  I have heard of one other daughter craft, much smaller, that may still be under consideration.  Will check it out.
Title: Proposed Europa Missions
Post by: Star One on 02/03/2017 07:21 pm
To Get to Europa, Think Like MacGyver

A look at the idea lab where scientists are preparing for a fly-by mission to one of Jupiter’s icy moons.

Quote
In a separate, earlier project, the team experimented with which kind of drills or cutters might work best to bore through Europa’s ice, even tooling around with some of the standard drills you can find in your local hardware store. That research led to a prototype that’s now informing the development of future robotic arms at JPL.

“Those kinds of higher-end experiments would never be possible without first doing the kind of scientific and engineering rapid prototyping to answer the basic question first,” Hand says.

In answering these basic questions, they get closer to their ultimate goal. “The big-picture motivation [of this lab] is to advance our capability to seek out and understand signs of life on ocean worlds beyond Earth,” says Hand.

Quote
Scientists are hoping to gather clues about whether or not Europa could support life in the upcoming fly-by NASA mission. The spacecraft (it has no official name yet) is slated to launch as soon as 2022, and could potentially arrive at the satellite as early as 2026.

The spacecraft will be equipped with nine main instruments, including spectrometers, magnetometers, cameras, and a radar. The plan is for the spacecraft to orbit Jupiter and use its gravity, and that of the Galilean moons, to do multiple fly-bys of Europa, all in about 3.5 years.

Mission scientists are also preparing for the possibility of launching some kind of lander soon after sending off the probe, so that researchers can more quickly apply the information being projected back.

If the spacecraft were to detect a hotspot of geological activity, for instance, or a region with evidence of organic materials, “then that might be the place that we want to send a future lander,” says Pappalardo. “But we’ll see how that plays out.”

https://www.youtube.com/watch?v=HK5qnpDClRI

http://www.sciencefriday.com/articles/to-get-to-europa-think-like-macgyver/
Title: Re: Proposed Europa Missions
Post by: redliox on 02/04/2017 04:57 am
In about 20 days we should finally get some news on Europa and the Outer Planets via the next OPAG meeting:
http://www.lpi.usra.edu/opag/meetings/feb2017/agenda.pdf (http://www.lpi.usra.edu/opag/meetings/feb2017/agenda.pdf)
Title: Re: Proposed Europa Missions
Post by: Blackstar on 02/08/2017 08:30 pm
Europa Lander study report:

http://solarsystem.nasa.gov/docs/Europa_Lander_SDT_Report_2016.pdf

Warning: it's a 40 megabyte file.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 02/08/2017 09:11 pm
From page 210: "The lander would be enclosed in a biobarrier and would undergo a system-level DHMR bioburden reduction process prior to launch. As a backup, some lander hardware may undergo penetrating iraidation microbial reduction and then be aseptically assembled. Batteries would be irradiated instead of DHMR to achieve Planetary Protection requirements. Finally, an incendiary device design option is being explored for the vault. This device would potentially be triggered just prior to the end of the lander surface phase so as to further sterilize the space craft."

Title: Re: Proposed Europa Missions
Post by: Vultur on 02/09/2017 02:35 am
Isn't the ice crust supposed to be something like 20 km thick? How are bacteria supposed to get through that anyway?

(Yeah I know there have been suggestions that there are 'break throughs' or some other occasional surface-ocean interaction... but it seems like bacteria would have to get down there really fast due to the crazy radiation levels. I know lots of bacteria are insanely radiation resistant by our standards, but still, there are limits, especially without active metabolism to repair DNA.)
Title: Re: Proposed Europa Missions
Post by: redliox on 02/09/2017 04:14 am
The design surprises me a little, although still overall practical.  Instead of a pyramid it looks like they're sending a box with legs, eyes, and a robot arm.  The antenna/cameras will become an obvious anthropomorphic head if NASA tries to show this off to Space Camp tikes.

They definitely went straight to the point of using SLS 1B for delivering this to Jupiter, although apparently even it will require a gravity-assist along the way; so the Lander will take 5 years versus the 'Clipper's ~2 year jaunt despite using the same rocket.  They'll certainly have plenty of time to chose a landing site.

Could they have used a simpler carrier for the job?  Granted, especially with the 5 year flight, there is a larger chance the 'Clipper wouldn't be available for relay duty.  Although I doubt they'd plan to instrument the carrier, it would be an opportunity other agencies would merrily take interest in.
Title: Re: Proposed Europa Missions
Post by: baldusi on 02/09/2017 12:06 pm
Well, those extra years are critical to analyze the data of the flybys.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 02/09/2017 02:51 pm
The design surprises me a little, although still overall practical.  Instead of a pyramid it looks like they're sending a box with legs, eyes, and a robot arm.

Note that this is still "pre-Phase A." That's a very preliminary design. The actual hardware could change quite a bit.

I've heard that from an engineering standpoint, the margins on this vehicle are really huge. They don't know much about the surface of Europa, so how can you accurately design a vehicle that will land there? How would the lander look if the surface were rolling smooth ice mounds as opposed to 1-meter tall ice spikes? So I suspect that one of the next steps would be to model several widely different types of surfaces and then drop a model vehicle on them and see what happens (this could all happen as a computer simulation, but some physical modeling might be necessary).

I think that there's a lot of uncertainty about this program overall. From a normal program management sense, it is better to wait for good data on Europa before trying to design a lander. But they have somebody who wants to fund it right now, so it's not like the cart is in front of the horse, the horse is on top of the cart...
Title: Re: Proposed Europa Missions
Post by: Nomadd on 02/09/2017 03:06 pm


Note that this is still "pre-Phase A." That's a very preliminary design. The actual hardware could change quite a bit.

I've heard that from an engineering standpoint, the margins on this vehicle are really huge. They don't know much about the surface of Europa, so how can you accurately design a vehicle that will land there? How would the lander look if the surface were rolling smooth ice mounds as opposed to 1-meter tall ice spikes? So I suspect that one of the next steps would be to model several widely different types of surfaces and then drop a model vehicle on them and see what happens (this could all happen as a computer simulation, but some physical modeling might be necessary).

I think that there's a lot of uncertainty about this program overall. From a normal program management sense, it is better to wait for good data on Europa before trying to design a lander. But they have somebody who wants to fund it right now, so it's not like the cart is in front of the horse, the horse is on top of the cart...
It seems strange that the carrier/relay would have no science payload. You'd think even the ability to record detailed surface changes over time would be major. Maybe they just aren't at that point in the design yet?
Title: Re: Proposed Europa Missions
Post by: Blackstar on 02/09/2017 03:32 pm
To provide a little bit of context: there was no Europa lander in the 2011 decadal survey. However, it was mentioned as a possible "future mission" in the 2001 decadal survey on page 132.

https://www.nap.edu/catalog/10432/new-frontiers-in-the-solar-system-an-integrated-exploration-strategy

I will post the excerpt next.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 02/09/2017 03:34 pm
From the 2001 decadal survey, page 132:

Europa Pathfinder Lander
The panel considered two levels of potential landed science at Europa. The Europa Pathfinder concept
involves a small (~10- to 20-kg) payload delivered to the surface from an orbiting spacecraft using a retropropulsion system and airbags to achieve landing. Total system mass is in the vicinity of ~200 kg, including the retro-propulsion and airbag landing systems. A key feature of the mission studied to date is a compact lander body capable of operating from an arbitrary landed attitude.

Proposed instrumentation could include a sophisticated geophysical station with seismic/acoustic sensors, a
magnetometer, and possibly a tilt meter, combined with surface elemental and phase composition measurements
of the immediate vicinity of the lander using some combination of optical, infrared, Raman spectrometer, and
Laser Induced Breakdown Spectroscopy (LIBS) techniques. No subsurface sampling, sample handling, or preparation
systems are envisioned for the Europa Pathfinder. In addition to data relayed from the lander to the orbiter,
complementary orbital science is assumed, with the details to be determined by results of the Europa Geophysical
Explorer mission. Technology needs include airbag and landing systems for the Europa environment.

Europa Astrobiology Lander

A more ambitious Europa mission concept involves a study of organic chemistry and possible biosignatures
from a landed station. The science rationale and some of the experiment concepts for such a mission have
developed recently in a series of workshops sponsored by the Europa Focus Group of the NASA Astrobiology
Institute, and are complementary to objectives developed by the 1999 NASA Campaign Science Working Group
for Prebiotic Chemistry in the Outer Solar System, but no complete system/mission studies of the concept have
been performed.

The key elements that distinguish this candidate mission (which could also carry some of the same payload as
that on the Europa Pathfinder Lander) are the inclusion of subsurface sampling capability to obtain material that is
less processed by radiation (at depths greater than approximately 10 cm) and sample handling and sample preparation for a sophisticated chemical analysis suite, including a gas chromatograph/mass spectrometer and the coring instrument. This greatly extends the compositional capability, and particularly the characterization of organic materials, from that envisioned for the Europa Pathfinder, but with a significant increase in complexity and cost (unquantified at present).

As does the Pathfinder, this concept assumes either prior Europa Geophysical Explorer data for global context
and/or orbital science on its own supporting orbiter delivery spacecraft. In addition to radiation-hard electronics,
this class of mission requires significant technology development in the experimental areas of highly compact and
sophisticated chemical analysis systems.
Title: Re: Proposed Europa Missions
Post by: vjkane on 02/09/2017 03:53 pm
It seems strange that the carrier/relay would have no science payload. You'd think even the ability to record detailed surface changes over time would be major. Maybe they just aren't at that point in the design yet?
I think that they are simply so early in the process that they haven't thought about an orbiter.  Similarly, the Europa multiple-flyby mission team hasn't spent time thinking about all the great science they could do for the rest of the Jovian system with the flybys of Callisto and Ganymede, for Jupiter, and for the magnetosphere.

If this lander mission occurs, the highest priority measurements, which are best done from orbit, would likely be:

Gravity measurements using the radio system
Magnetometer measurements to test the salinity and bulk of the ocean
LiDAR or radar measurements to measure surface tides

Everything else will will be been done pretty will with the multiple-flyby mission.  The latter will make the measurements listed above, but they will all be limited in their resolution by the brief time and limited spatial location of each encounter.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 02/09/2017 04:26 pm
I think that they are simply so early in the process that they haven't thought about an orbiter. 

Yes, but I think there might be another thing going on as well. I got info from another channel that implies that the mission is only possible with an SLS, and even then, it's marginal. I think that they may have ended up a bit surprised that there wasn't a lot of room to do other stuff on this mission.

That said, they have to iterate this stuff. They'll go back and refine the trajectories, refine the instruments, and maybe they'll find more margin in places they did not expect. Or--as I think this stuff usually goes--they'll discover that they are holding margin in some places that they don't need to hold and they can then allocate it to something else. So they might discover that if they tweak the orbit and slide some of their parameters around a bit, it gives them another 10kg to play with, and maybe they can add an instrument or something. (Then again, it can also go in the opposite direction too and they can discover that they need to take stuff away.)



Title: Re: Proposed Europa Missions
Post by: vjkane on 02/09/2017 07:58 pm
I think that they are simply so early in the process that they haven't thought about an orbiter. 

Yes, but I think there might be another thing going on as well. I got info from another channel that implies that the mission is only possible with an SLS, and even then, it's marginal. I think that they may have ended up a bit surprised that there wasn't a lot of room to do other stuff on this mission.
The two highest priority measurements for an orbiter vs a flyby mission, as I understand it, is the gravity measurements that require just an ultra stable oscillator for the radio system, and the magnetic field measurements that require a magnetometer and a simple plasma instrument.  I have hope that these could be included.

A radar or lidar instrument would be a big jump in mass and data.
Title: Re: Proposed Europa Missions
Post by: notsorandom on 02/09/2017 08:36 pm
Interesting that the carrier and relay craft is an orbiter. I thought that doing an orbiter was quite a bit more expensive than a multiple flyby trajectory. The lander would have a limited time on the surface due to power constraints and radiation exposure. So it makes sense to optimize to get the most out of that. Do the relay requirements preclude a multiple flyby trajectory and make an orbiter necessary? If that is the case it doesn't look like the Europa Mission even if it is still alive then would be helpful to this mission as a relay.
Title: Proposed Europa Missions
Post by: Star One on 02/10/2017 07:44 pm
Here's an article based on the above report.

Quote
In 2015, NASA revealed its plans to send a spacecraft to conduct several close flybys of Europa sometime in the 2020s. Now, the space agency has detailed — in a Science Definition Team (SDT) report — a mission to send a lander to the icy moon.

The 264-page report, which can be accessed here, lists out three key science goals for a future lander mission — searching for life on the moon, assessing its habitability by analyzing material from the surface, and characterizing Europa’s surface and subsurface to support future robotic missions.

http://www.ibtimes.com/life-europa-nasa-details-plan-send-lander-jovian-moon-look-biological-signatures-2489567
Title: Re: Proposed Europa Missions
Post by: smfarmer11 on 02/14/2017 05:40 pm
It doesn't really surprise me that the mass requirements are large for this mission. Mostly due to Europa not having any significant atmosphere means it would require an entirely propulsive descent. Also since it would be an orbiter that would drastically lower the dV requirements of any lander it deploys compared to one being deployed from a fly-by.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 02/18/2017 01:58 am
The Europa mission went through some kind of confirmation review on Wednesday. I forget the details. I'll have to check. I was also told that its official name is now "Europa Clipper," but I won't believe that until I see it officially confirmed.
Title: Re: Proposed Europa Missions
Post by: JH on 02/20/2017 02:36 pm
The Europa mission went through some kind of confirmation review on Wednesday. I forget the details. I'll have to check. I was also told that its official name is now "Europa Clipper," but I won't believe that until I see it officially confirmed.

I just heard it will be called Europa Clipper from Jim Green.
Title: Proposed Europa Missions
Post by: Star One on 02/20/2017 03:41 pm
The Europa mission went through some kind of confirmation review on Wednesday. I forget the details. I'll have to check. I was also told that its official name is now "Europa Clipper," but I won't believe that until I see it officially confirmed.

I just heard it will be called Clipper from Jim Green.

Without the Europa, just Clipper?
Title: Re: Proposed Europa Missions
Post by: Blackstar on 02/21/2017 05:22 pm
OPAG is meeting Wednesday. You can get an update on Europa there. Also, MEPAG is meeting Wednesday as well. I included that agenda for comparison.
Title: Re: Proposed Europa Missions
Post by: vjkane on 02/21/2017 05:35 pm
OPAG is meeting Wednesday. You can get an update on Europa there. Also, MEPAG is meeting Wednesday as well. I included that agenda for comparison.
I'm on a plane during the Europa Clipper session, and so would appreciate anyone who can grab some screen shots.  Appreciate slides from the other sessions, too; darn that day job!  Thanks.
Title: Re: Proposed Europa Missions
Post by: redliox on 02/21/2017 05:57 pm
OPAG is meeting Wednesday. You can get an update on Europa there. Also, MEPAG is meeting Wednesday as well. I included that agenda for comparison.
OPAG is meeting Wednesday. You can get an update on Europa there. Also, MEPAG is meeting Wednesday as well. I included that agenda for comparison.
I'm on a plane during the Europa Clipper session, and so would appreciate anyone who can grab some screen shots.  Appreciate slides from the other sessions, too; darn that day job!  Thanks.

Go forth and bring us joyous news of the Outer Planets
Title: Re: Proposed Europa Missions
Post by: Star One on 02/21/2017 06:50 pm
OPAG is meeting Wednesday. You can get an update on Europa there. Also, MEPAG is meeting Wednesday as well. I included that agenda for comparison.
I'm on a plane during the Europa Clipper session, and so would appreciate anyone who can grab some screen shots.  Appreciate slides from the other sessions, too; darn that day job!  Thanks.

Hope it doesn't get completely buried under the TRAPPIST-1 announcement.
Title: Re: Proposed Europa Missions
Post by: Star One on 02/21/2017 07:04 pm
Hope it doesn't get completely buried under the TRAPPIST-1 announcement.

It's an AG meeting, not a public announcement. People continue to do their jobs despite press announcements.

Won't there be any public information release afterwards?
Title: Re: Proposed Europa Missions
Post by: Star One on 02/21/2017 07:38 pm
Hope it doesn't get completely buried under the TRAPPIST-1 announcement.

It's an AG meeting, not a public announcement. People continue to do their jobs despite press announcements.

Won't there be any public information release afterwards?

From an AG meeting? No. It's a workshop meeting of scientists to share information. You can listen in over the web. But it's a meeting, not a press announcement.

Thanks for the info about being able to listen in.
Title: Proposed Europa Missions
Post by: Star One on 02/21/2017 09:23 pm
NASA's audacious Europa missions are getting closer to reality

Quote
NASA officials say the Clipper mission is still on track for a mid-2022 launch.

Using a powerful boost from NASA's new heavy lift rocket, the Space Launch System, the Clipper would fly directly to Jupiter and arrive in 2025. Without SLS, the journey would take five years longer, and require flybys of Venus and Earth to reach the right trajectory.

Flying past Venus means flying closer to the Sun. Flying closer to the Sun means extra heat shielding. And extra heat shielding means a heavier spacecraft. Though Congress has ordered NASA to use SLS for both the Clipper and lander missions, the agency is still keeping the extra heat shielding in the Clipper's design for now—just in case anything derails development of the yet-to-be-flown rocket.

Without SLS, the lander as currently designed might not be able to fly at all, according to the SDT report. That's because the spacecraft will be heavy. In addition to the lander itself, there are three other components: a carrier and relay stage, a de-orbit stage, and a descent stage. Officials aren't publicly saying how heavy the entire package might be, but it would currently require a deep space thruster burn and Earth gravity assist to put it on the correct path to Jupiter—even with the added boost from SLS. The earliest the lander would launch is 2024 or 2025, putting it at Jupiter around 2030.

Once in orbit around Jupiter, the lander spacecraft would spend 18 months slowly spiraling inward to Europa, swinging past Callisto and Ganymede on the way. At Europa, the carrier and relay orbiter would separate and act as a data relay satellite. The Clipper, ideally still operating in an extended mission, would be used as a backup relay. The lander would not have the capability to talk to Earth on its own.

Remember the Curiosity spacecraft's seven minutes of terror, during which it plunged to the Martian surface in a harrowing process known as entry, descent and landing, or EDL? Since Europa has no atmosphere, and the descent begins in orbit, a new acronym is in play: DDL, which stands for de-orbit, descent and landing.

First, the de-orbit stage will pull the descent stage and lander out of orbit. As the thruster-powered descent stage approaches the surface, it will perform the same skycrane maneuver that deposited Curiosity onto Mars, where a tether lowers the lander. The descent stage then cuts loose and flys away for an intentional crash-landing.

Once the lander is safely on the surface, scientists will have to work fast to gather their data. The spacecraft is powered only by a 45-kilowatt-hour battery designed to last between 20 to 40 days. Why not find a way to stay longer? Because the carrier relay orbiter, which will be bathed in Jupiter's radiation, is expected to fail in just a single a month.

http://www.planetary.org/blogs/jason-davis/2017/nasas-audacious-europa.html
Title: Re: Proposed Europa Missions
Post by: JH on 02/22/2017 12:23 am
I'm on a plane during the Europa Clipper session, and so would appreciate anyone who can grab some screen shots.  Appreciate slides from the other sessions, too; darn that day job!  Thanks.

I'll post if there is anything particularly interesting.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 02/22/2017 02:37 pm
Mission got through KDP-B:

http://www.spacedaily.com/reports/Europa_Flyby_Mission_Moves_into_Design_Phase_999.html

Title: Re: Proposed Europa Missions
Post by: as58 on 02/24/2017 07:09 pm
Is there any official cost estimate for Europa Clipper? Isn't some sort of estimate usually given by the time a mission goes to phase B?
Title: Re: Proposed Europa Missions
Post by: Blackstar on 02/24/2017 09:17 pm
Is there any official cost estimate for Europa Clipper? Isn't some sort of estimate usually given by the time a mission goes to phase B?

KDP-C, which is the "confirmation" review, is when they produce a cost estimate. There are still a lot of possible changes between B and C.

Note that in the attached graphic, the Preliminary Design Review occurs right before KDP-C. Then the cost estimate is conducted after KDP-C (not shown, but that's when it happens). The way to think of this is that PDR is when the engineering team presents their design and says that it is ready and will not change substantially beyond that point. KDP-C then looks at the engineering and (I think) other factors, and they say "It is confirmed as ready to be developed." Then the cost estimate is performed, and at that point headquarters looks at the cost estimate and decides whether to proceed or to delay or to send things back to the drawing boards.

There are a lot of other major decisions during all of this. For instance, I assume (don't know) that around KDP-C the program managers have been soliciting bids from contractors. You need a star sensor, well, you contact a company that builds star sensors and you ask them to give you a price. And that price is then fed into the cost estimate.
Title: Re: Proposed Europa Missions
Post by: vjkane on 02/26/2017 06:03 pm
Is there any official cost estimate for Europa Clipper? Isn't some sort of estimate usually given by the time a mission goes to phase B?
They are reportedly still managing the project to target ~$2B.  Not clear if that includes launch; I suspect not.  See Blackstar's other post on when official cost estimate is set.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 02/26/2017 09:30 pm
They are reportedly still managing the project to target ~$2B.  Not clear if that includes launch; I suspect not.  See Blackstar's other post on when official cost estimate is set.

I think that the number is more like $2.5 billion, but it is still under $3 billion.

The presentation about the mission at OPAG was interesting because of what it revealed about instrument development. I assumed that since the contracts were awarded two years ago, the instruments would all be into full hardware production by now. Apparently not. They're doing a number of refinements to the instrument designs even now. For example, the imager is getting color, whereas previously it was panchromatic. What all that indicated to me is that there is still the possibility of the instruments going over budget.

I don't know how all this works (independent cost estimating at KDP-C, that is), but I think that awarding instrument contracts long before KDP-B is reached is unusual, so that is going to affect how the cost estimates shake out. On the one hand, I would assume that the instruments will be sufficiently mature by KDP-C that their costs would be known and that would help the accuracy of the cost estimate. However, on the other hand, I've heard some rumblings about how they may have too many instruments for the actual spacecraft, and that could force design changes that could actually increase the cost. So they might gain in some ways and lose in others.

But that's also the nature of these designs--it's like pushing on a balloon where you press on one side and something pops out elsewhere.

Title: Re: Proposed Europa Missions
Post by: JH on 03/07/2017 06:50 pm
And there you go:

Quote

verified NASA Europa Mission account
@NASAEuropa

It's official! @NASA's mission to explore an ocean world orbiting Jupiter will be called #Europa Clipper. https://www.nasa.gov/europa


https://twitter.com/NASAEuropa/status/839190352871350273
Title: Re: Proposed Europa Missions
Post by: JH on 03/07/2017 09:17 pm
I was talking to some people attached to the mission at JPL recently and the consensus was that Pappalardo thought of the separate names as a sort of version control. In his mind, Europa Clipper is the 2013 concept and the current mission has evolved away from it enough (moving to solar, for one thing) that a new name was needed in order to distinguish it. I think you're right as far as OMB's reasoning, though.
Title: Re: Proposed Europa Missions
Post by: redliox on 03/07/2017 11:36 pm
I was talking to some people attached to the mission at JPL recently and the consensus was that Pappalardo thought of the separate names as a sort of version control. In his mind, Europa Clipper is the 2013 concept and the current mission has evolved away from it enough (moving to solar, for one thing) that a new name was needed in order to distinguish it. I think you're right as far as OMB's reasoning, though.

There might have been a logic that they used at JPL. But the pressure to not use "Clipper" came from OMB.

Does this mean we should create an official "Europa Clipper" thread now?  ;D
Title: Re: Proposed Europa Missions
Post by: Blackstar on 03/16/2017 06:18 pm
https://www.whitehouse.gov/sites/whitehouse.gov/files/omb/budget/fy2018/2018_blueprint.pdf

The President’s 2018 Budget:

• Reinvigorates robotic exploration of the Solar System by providing $1.9 billion for the Planetary
Science program, including funding for a mission to repeatedly fly by Jupiter’s icy ocean moon
Europa and a Mars rover that would launch in 2020.  To preserve the balance of NASA’s science
portfolio and maintain flexibility to conduct missions that were determined to be more important
by the science community, the Budget provides no funding for a multi-billion-dollar mission to
land on Europa.  The Budget also supports initiatives that use smaller, less expensive satellites
to advance science in a cost-effective manner.



NASA budget is on pages 43-44 of the attached document.
Title: Re: Proposed Europa Missions
Post by: redliox on 03/17/2017 02:36 am
Apparently Clipper is approved but the lander is being cut.   A pity, but in many ways the lander was a force-fed concept.  Regardless, it can probably afford to wait since it depends on Clipper's data to find an appropriate landing site first anyway.  I also expect Congress to fight a bit over it or at least keep it going as a back burner study, not unlike how Clipper was for many years.
Title: Re: Proposed Europa Missions
Post by: JH on 03/17/2017 05:17 am
Yeah... Culberson is probably going to be Chairman of the House Appropriations CJS Subcommittee for another 4 years. I think he is more likely to shiv Trump than let him can the Europa lander.
Title: Re: Proposed Europa Missions
Post by: Star One on 03/17/2017 05:58 am
Yeah... Culberson is probably going to be Chairman of the House Appropriations CJS Subcommittee for another 4 years. I think he is more likely to shiv Trump than let him can the Europa lander.

The lander I expect will be reinstated by Culberson.
Title: Re: Proposed Europa Missions
Post by: vjkane on 03/19/2017 08:56 am
Yeah... Culberson is probably going to be Chairman of the House Appropriations CJS Subcommittee for another 4 years. I think he is more likely to shiv Trump than let him can the Europa lander.

The lander I expect will be reinstated by Culberson.
I'm not sure what re-instatement would mean at this point.  As I understand it, a relatively small team is conducting concept studies.  So far as we know there is no official estimate of what the mission would cost (but I'm betting it will be substantially more than Clipper, whose last cost estimate I saw from Eric Berger was $2.7B, although I don't know if that includes the launch vehicle). 

I believe that OMB is telling Culberson that it won't support the ramp up in spending that would come in a couple to a few years if the mission were to be approved to enter Phase A.
Title: Re: Proposed Europa Missions
Post by: Star One on 03/19/2017 03:02 pm
Yeah... Culberson is probably going to be Chairman of the House Appropriations CJS Subcommittee for another 4 years. I think he is more likely to shiv Trump than let him can the Europa lander.

The lander I expect will be reinstated by Culberson.
I'm not sure what re-instatement would mean at this point.  As I understand it, a relatively small team is conducting concept studies.  So far as we know there is no official estimate of what the mission would cost (but I'm betting it will be substantially more than Clipper, whose last cost estimate I saw from Eric Berger was $2.7B, although I don't know if that includes the launch vehicle). 

I believe that OMB is telling Culberson that it won't support the ramp up in spending that would come in a couple to a few years if the mission were to be approved to enter Phase A.

All the commentary I've read seems to imply if they are trying to send him signals he isn't likely to heed them.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 03/20/2017 02:34 am
Yeah, both vjkane and Star One are right, but...

It is very hard to see how both projects could be afforded simultaneously. There's not enough budget to pay for them. I don't know when Mars 2020 finally starts ramping down, but that has to get out of the way before Europa Clipper can really ramp up, and even if EC and the lander cost the same amount, there's not enough in the budget--and my rough guestimate is that the lander is going to cost twice what Europa Clipper costs, if not more.

Title: Re: Proposed Europa Missions
Post by: Archibald on 03/20/2017 04:34 pm
With a little luck D. J. T won't be re-elected in 2020 (which doesn't mean NASA future would be better)

Mars 2020 is a very important mission so I'm not really shocked to see the uber-expensive Europe lander pushed after it. It makes some sense.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 03/20/2017 05:51 pm
Mars 2020 is a very important mission so I'm not really shocked to see the uber-expensive Europe lander pushed after it. It makes some sense.

Mars 2020 is in the 2011 planetary science decadal survey.

A Europa orbiter is in the 2011 planetary science decadal survey.

Title: Re: Proposed Europa Missions
Post by: vjkane on 03/20/2017 09:28 pm
Mars 2020 is a very important mission so I'm not really shocked to see the uber-expensive Europe lander pushed after it. It makes some sense.
The two missions may end up having costs within a few hundred million of each other; but caveat, I don't know if the budget numbers I'm hearing include any launch costs.  The Clipper costs certainly don't include the full cost of an SLS launch, but it's uncertain how much of an SLS cost will be charged to SMD
Title: Re: Proposed Europa Missions
Post by: vjkane on 03/20/2017 09:30 pm
Yeah, both vjkane and Star One are right, but...

It is very hard to see how both projects could be afforded simultaneously. There's not enough budget to pay for them. I don't know when Mars 2020 finally starts ramping down, but that has to get out of the way before Europa Clipper can really ramp up, and even if EC and the lander cost the same amount, there's not enough in the budget--and my rough guestimate is that the lander is going to cost twice what Europa Clipper costs, if not more.
I believe, but haven't looked at the spreadsheets for months, that 2018 is the peak year of funding for Mars 2020
Title: Re: Proposed Europa Missions
Post by: jgoldader on 03/20/2017 11:55 pm
A good argument could be made for delaying the lander until surface conditions are understood.  Having the lander die by being impaled on ice spikes during terminal descent would be double-plus ungood. But if delaying the lander, hopefully there'd be funding for instrument development and landing strategy studies, so some some of that risk can be bought down in the early, less expensive stages of such an ambitious project.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 03/21/2017 02:29 am
A good argument could be made for delaying the lander until surface conditions are understood.  Having the lander die by being impaled on ice spikes during terminal descent would be double-plus ungood. But if delaying the lander, hopefully there'd be funding for instrument development and landing strategy studies, so some some of that risk can be bought down in the early, less expensive stages of such an ambitious project.

I think there are a lot of hidden risks that are not readily apparent--and by "risk" I don't mean simply "the spacecraft crashes" but more like "the spacecraft fails to perform the mission." What I've heard is that some of the instruments might be pretty difficult to design to return the data that you really want. So as you note, it might make sense to delay this stuff a bit to build better instruments.

Also, reread my previous post.
Title: Re: Proposed Europa Missions
Post by: as58 on 03/29/2017 11:06 pm
Jeff Foust's tweets (https://twitter.com/jeff_foust) about Barry Goldstein's talk at National Academies Space Science Week contain some new info:

some picks:

- earliest launch window for Clipper is June 2022
- lander launch NET late 2025
- lander mission total mass 16 metric tons (Clipper is 6 tons). There are also pictures; the lander itself is a lot bigger than I had thought
- lander uses thermite-based incinerator for planetary protection at the end of the mission
Title: Re: Proposed Europa Missions
Post by: Blackstar on 03/30/2017 02:13 am
Title: Re: Proposed Europa Missions
Post by: Archibald on 03/30/2017 06:08 am
Quote
- lander mission total mass 16 metric tons (Clipper is 6 tons). There are also pictures; the lander itself is a lot bigger than I had thought

Well, that's the mass of a Lunar Module. Then again, landing on Europa probably takes a helluva lots of propellants.
Title: Re: Proposed Europa Missions
Post by: Zed_Noir on 03/30/2017 07:06 pm
Quote
- lander mission total mass 16 metric tons (Clipper is 6 tons). There are also pictures; the lander itself is a lot bigger than I had thought

Well, that's the mass of a Lunar Module. Then again, landing on Europa probably takes a helluva lots of propellants.

What are they proposing for lander propulsion?
Title: Re: Proposed Europa Missions
Post by: Blackstar on 04/04/2017 04:46 pm
http://www.thespacereview.com/article/3208/1

Title: Re: Proposed Europa Missions
Post by: Archibald on 04/04/2017 06:41 pm
Must be hypergolic.
Title: Re: Proposed Europa Missions
Post by: AegeanBlue on 04/04/2017 11:26 pm
One question I am having about Europa Clipper: As far I know the heaviest mission launched to date (or I should say that made it to the launchpad) is Mars 96, which is still slightly heavier than Cassini. Would Europa Clipper break that record and become the heaviest planetary probe ever?
Title: Re: Proposed Europa Missions
Post by: redliox on 04/05/2017 12:24 am
Must be hypergolic.

Pretty much everything sent beyond the Moon's orbit operates with hypergolic because it's easy to store and well understood.  I'm almost tempted to wonder how well SEP would function at braking into Jupiter's orbit although I suspect 'not well' as a default answer due to weak sunlight and power-hungry systems.
Title: Re: Proposed Europa Missions
Post by: plutogno on 04/05/2017 06:46 pm
One question I am having about Europa Clipper: As far I know the heaviest mission launched to date (or I should say that made it to the launchpad) is Mars 96, which is still slightly heavier than Cassini.

Fobos Grunt was reported at 13,535 kg at launch, as it had to carry the engine for escaping Earth and for orbit insertion, Chinese probe and adapter. hard to beat that
Title: Re: Proposed Europa Missions
Post by: AegeanBlue on 04/06/2017 06:25 pm
One question I am having about Europa Clipper: As far I know the heaviest mission launched to date (or I should say that made it to the launchpad) is Mars 96, which is still slightly heavier than Cassini.

Fobos Grunt was reported at 13,535 kg at launch, as it had to carry the engine for escaping Earth and for orbit insertion, Chinese probe and adapter. hard to beat that

Apparently the Europa Lander in its current iteration would. Let's see if it does go forward, I would prefer a Uranus or Neptune orbiter to the current iteration of Europa Lander.
Title: Re: Proposed Europa Missions
Post by: shooter6947 on 04/06/2017 06:41 pm
I'm almost tempted to wonder how well SEP would function at braking into Jupiter's orbit although I suspect 'not well' as a default answer due to weak sunlight and power-hungry systems.

Badly.  (1) not enough sunlight to generate power, as you mention; (2) thrust too low, which means; (3) no Oberth effect advantage.
Title: Re: Proposed Europa Missions
Post by: ChrisGebhardt on 04/10/2017 05:52 pm
NASA to Reveal New Discoveries in News Conference on Oceans Beyond Earth

NASA will discuss new results about ocean worlds in our solar system from the agency’s Cassini spacecraft and the Hubble Space Telescope during a news briefing 2 p.m. EDT on Thursday, April 13. The event, to be held at the James Webb Auditorium at NASA Headquarters in Washington, will include remote participation from experts across the country.

The briefing will be broadcast live on NASA Television and the agency's website.

These new discoveries will help inform future ocean world exploration -- including NASA’s upcoming Europa Clipper mission planned for launch in the 2020s -- and the broader search for life beyond Earth.

The news briefing participants will be:
Thomas Zurbuchen, associate administrator, Science Mission Directorate at NASA Headquarters in Washington
Jim Green, director, Planetary Science Division at NASA Headquarters

Mary Voytek, astrobiology senior scientist at NASA Headquarters

Linda Spilker, Cassini project scientist at NASA’s Jet Propulsion Laboratory in Pasadena, California
Hunter Waite, Cassini Ion and Neutral Mass Spectrometer team lead at the Southwest Research Institute (SwRI) in San Antonio

Chris Glein, Cassini INMS team associate at SwRI
William Sparks, astronomer with the Space Telescope Science Institute in Baltimore
A question-and-answer session will take place during the event with reporters on site and by phone. Members of the public also can ask questions during the briefing using #AskNASA.

To participate by phone, reporters must contact Dwayne Brown at 202-358-1726 or [email protected] and provide their media affiliation no later than noon April 13.
Title: Proposed Europa Missions
Post by: Star One on 04/13/2017 06:51 am
Quote
NASA Watch‏ @NASAWatch

Watch @NewsHour tonight for a story on #Europa and #NASA space policy with @milesobrien @Alienoceans
@CongCulberson & Robert Walker

https://mobile.twitter.com/NASAWatch/status/852281281392107520
Title: Proposed Europa Missions
Post by: Star One on 04/13/2017 06:28 pm
Cross posting from the Cassini thread as more evidence of Europa plumes.

NASA press release 

https://www.nasa.gov/press-release/nasa-missions-provide-new-insights-into-ocean-worlds-in-our-solar-system
Title: Re: Proposed Europa Missions
Post by: Alpha_Centauri on 04/13/2017 06:28 pm
New Europa plume paper;

http://imgsrc.hubblesite.org/hvi/uploads/science_paper/file_attachment/233/plumes2_revised_submitted.pdf
Title: Re: Proposed Europa Missions
Post by: Alpha_Centauri on 04/13/2017 07:14 pm
Interesting post on Mike Brown's blog regarding verifying if the proposed hotspot is real, looks like it might be;

http://www.mikebrownsplanets.com/2017/04/europa-is-hot.html
Title: Proposed Europa Missions
Post by: Star One on 04/13/2017 07:23 pm
Interesting post on Mike Brown's blog regarding verifying if the proposed hotspot is real, looks like it might be;

http://www.mikebrownsplanets.com/2017/04/europa-is-hot.html

So is that where the lander mission should go, dependent on further data from Europa Clipper?

Seems about the right time to post this with narration written and spoken by Carl Sagan.

https://www.youtube.com/watch?v=YH3c1QZzRK4
Title: Re: Proposed Europa Missions
Post by: Alpha_Centauri on 04/13/2017 07:53 pm
I'd imagine the lander would land in the safest place possible, the Europan surface can be very rough.
Title: Re: Proposed Europa Missions
Post by: Star One on 04/13/2017 07:56 pm
I'd imagine the lander would land in the safest place possible, the Europan surface can be very rough.

I am sure I read today that once the lander has finished its mission it will incinerate itself?
Title: Re: Proposed Europa Missions
Post by: redliox on 04/13/2017 08:19 pm
Interesting post on Mike Brown's blog regarding verifying if the proposed hotspot is real, looks like it might be;

http://www.mikebrownsplanets.com/2017/04/europa-is-hot.html

Read it just now.  Apparently the hot spot is in the vicinity of, if not itself, Pwyll Crater (https://en.wikipedia.org/wiki/Pwyll_(crater)).  I recalled a moment from the 2010 movie when the Soviet probe was visiting Europa and Dr. Floyd says "There there!  It's down in that crater there."  Apparently now we know that crater was Pwyll!

It makes some sense to me: it's a geologically young impact that is visibly shallow, implying post-impact that an ocean refilled and refroze.  I just find it surprising one of the few features I can both name and identify on a Europa image might be prominent in searching for life there.
Title: Re: Proposed Europa Missions
Post by: Sam Ho on 04/13/2017 08:34 pm
I'd imagine the lander would land in the safest place possible, the Europan surface can be very rough.

I am sure I read today that once the lander has finished its mission it will incinerate itself?

Yes, from Section 10.5.2 of the Science Definition Team report:
Quote
Finally, an incendiary device design option is being explored for the vault. This device would potentially be triggered just prior to the end of the lander surface phase so as to further sterilize the space craft.
https://solarsystem.nasa.gov/docs/Europa_Lander_SDT_Report_2016.pdf
Title: Re: Proposed Europa Missions
Post by: Star One on 04/13/2017 09:43 pm
I'd imagine the lander would land in the safest place possible, the Europan surface can be very rough.

I am sure I read today that once the lander has finished its mission it will incinerate itself?

Yes, from Section 10.5.2 of the Science Definition Team report:
Quote
Finally, an incendiary device design option is being explored for the vault. This device would potentially be triggered just prior to the end of the lander surface phase so as to further sterilize the space craft.
https://solarsystem.nasa.gov/docs/Europa_Lander_SDT_Report_2016.pdf

Thanks. Sounds a sensible precaution.
Title: Re: Proposed Europa Missions
Post by: yg1968 on 04/14/2017 04:29 am
Archived video of the press conference:

https://www.youtube.com/watch?v=3n-0CSCcJuQ

See above.
Title: Re: Proposed Europa Missions
Post by: Dalhousie on 04/17/2017 06:07 am
I'd imagine the lander would land in the safest place possible, the Europan surface can be very rough.

I am sure I read today that once the lander has finished its mission it will incinerate itself?

Yes, from Section 10.5.2 of the Science Definition Team report:
Quote
Finally, an incendiary device design option is being explored for the vault. This device would potentially be triggered just prior to the end of the lander surface phase so as to further sterilize the space craft.
https://solarsystem.nasa.gov/docs/Europa_Lander_SDT_Report_2016.pdf

Thanks. Sounds a sensible precaution.

Seems excessive to me. The surface of Europa gets over 5 Sv per day of radiation.
Title: Re: Proposed Europa Missions
Post by: JH on 04/17/2017 07:56 am
Which Deinococcus radiodurans could survive for over 15 years...

Page 86, http://www.springer.com/us/book/9783319423296
Title: Re: Proposed Europa Missions
Post by: Welsh Dragon on 04/17/2017 07:58 am
^ Beat me to it. That's going to be unlikely to be on the probe though. But the point is, there are very few conditions for which there isn't some extremophile that'll thrive in them.
Title: Re: Proposed Europa Missions
Post by: JH on 04/17/2017 08:13 am
A likely candidate being tardigrades (water bears) which have an LD50 of 5000 to 6000 Sv and are everywhere.
Title: Re: Proposed Europa Missions
Post by: Star One on 04/25/2017 05:01 pm
NASA and ESA join forces to build life-seeking Europa lander

https://www.newscientist.com/article/2128751-nasa-and-esa-join-forces-to-build-life-seeking-europa-lander/
Title: Re: Proposed Europa Missions
Post by: Blackstar on 04/25/2017 05:25 pm
NASA and ESA join forces to build life-seeking Europa lander

https://www.newscientist.com/article/2128751-nasa-and-esa-join-forces-to-build-life-seeking-europa-lander/

The headline is misleading. It states that NASA and ESA have already done this. But the article indicates that this was a proposal at a science meeting.

Title: Re: Proposed Europa Missions
Post by: as58 on 04/25/2017 06:09 pm
They seem to be discussing JEM, one of the M5 proposals. I don't know in what sense the plan was unveiled now; there are already some links to JEM presentations and meeting abstracts in the ESA M5 call thread: http://forum.nasaspaceflight.com/index.php?topic=41991.0

Maybe this confirms that JEM passed the technical downselection?
Title: Re: Proposed Europa Missions
Post by: vjkane on 04/25/2017 09:18 pm
They seem to be discussing JEM, one of the M5 proposals. I don't know in what sense the plan was unveiled now; there are already some links to JEM presentations and meeting abstracts in the ESA M5 call thread: http://forum.nasaspaceflight.com/index.php?topic=41991.0

Maybe this confirms that JEM passed the technical downselection?

JEM seems to be a solid idea for how NASA and ESA could collaborate on a Europa lander and orbiter mission.  I can't see the European contribution being done on a Medium-class budget
Title: Re: Proposed Europa Missions
Post by: Blackstar on 04/25/2017 09:45 pm
According to a colleague, this JEM mission proposal has been around awhile and is not going anywhere. See the attached abstract that describes it.
Title: Re: Proposed Europa Missions
Post by: redliox on 04/26/2017 01:15 am
According to a colleague, this JEM mission proposal has been around awhile and is not going anywhere. See the attached abstract that describes it.

All the same hopefully it can happen.  Hard to predict the president but Congress seems to be supportive of Europa and NASA as a positive.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 04/26/2017 03:47 am
According to a colleague, this JEM mission proposal has been around awhile and is not going anywhere. See the attached abstract that describes it.

All the same hopefully it can happen.  Hard to predict the president but Congress seems to be supportive of Europa and NASA as a positive.

I think you're misunderstanding. This is a specific proposal that is going nowhere. It has apparently been kicking around awhile and has gained no traction.

If a joint Europa mission is to occur, it has to come from a different vector than this.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 04/26/2017 03:48 am
New Scientist runs a horrible headline and a mediocre article and soon the story is spinning out of control:

https://futurism.com/its-official-in-2025-nasa-and-the-esa-will-land-on-europa-to-look-for-alien-life/

No, it's not "official."

The story is so inaccurate it's not even wrong...
Title: Re: Proposed Europa Missions
Post by: vjkane on 04/26/2017 01:48 pm

I think you're misunderstanding. This is a specific proposal that is going nowhere. It has apparently been kicking around awhile and has gained no traction.

If a joint Europa mission is to occur, it has to come from a different vector than this.
This idea came out of a set of studies of possible ESA contributions to NASA's Clipper mission when it appeared that the latter could carry a European sub-satellite.  I suspect that it's still being promoted to keep the idea of a joint ESA/NASA mission to Europa alive should NASA go ahead with a lander mission.  At this point, all Europa missions past the Clipper mission are concept studies.  There's some good ideas in the JEM proposal.  Should the ESA and NASA funding streams and interest align in time, I'd like to see them pursued.  But there's a lot of ifs in that stream.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 04/26/2017 04:43 pm
My point was that this is really a bottom-up proposal. But for a joint mission, which will involve a LOT of money, it really has to be top down.
Title: Re: Proposed Europa Missions
Post by: Star One on 04/26/2017 04:53 pm
NASA and ESA join forces to build life-seeking Europa lander

https://www.newscientist.com/article/2128751-nasa-and-esa-join-forces-to-build-life-seeking-europa-lander/

The headline is misleading. It states that NASA and ESA have already done this. But the article indicates that this was a proposal at a science meeting.

Why don't you take that up with SN as they are the people linking to the article where I got it from.

http://spacenews.com/scientists-want-nasa-and-esa-to-work-together-on-a-europa-lander-mission/
Title: Re: Proposed Europa Missions
Post by: Blackstar on 04/26/2017 06:33 pm
NASA and ESA join forces to build life-seeking Europa lander

https://www.newscientist.com/article/2128751-nasa-and-esa-join-forces-to-build-life-seeking-europa-lander/

The headline is misleading. It states that NASA and ESA have already done this. But the article indicates that this was a proposal at a science meeting.

Why don't you take that up with SN as they are the people linking to the article where I got it from.

http://spacenews.com/scientists-want-nasa-and-esa-to-work-together-on-a-europa-lander-mission/

Space News has a correct headline: "Scientists want NASA and ESA to work together on a Europa lander mission." That is accurate.

This New Scientist headline is inaccurate: "NASA and ESA join forces to build life-seeking Europa lander."

This Futurism headline is truly horrible: "It’s Official. In 2025, NASA and the ESA Will Land on Europa to Look For Alien Life"

The Space News short blurb is by Jeff Foust. I've known Jeff for about 15 years now. Jeff has a Ph.D. in planetary sciences from MIT. His writing is almost always very accurate. And he is very careful with interpreting his sources.
Title: Re: Proposed Europa Missions
Post by: Star One on 04/26/2017 06:43 pm
NASA and ESA join forces to build life-seeking Europa lander

https://www.newscientist.com/article/2128751-nasa-and-esa-join-forces-to-build-life-seeking-europa-lander/

The headline is misleading. It states that NASA and ESA have already done this. But the article indicates that this was a proposal at a science meeting.

Why don't you take that up with SN as they are the people linking to the article where I got it from.

http://spacenews.com/scientists-want-nasa-and-esa-to-work-together-on-a-europa-lander-mission/

Space News has a correct headline: "Scientists want NASA and ESA to work together on a Europa lander mission." That is accurate.

This New Scientist headline is inaccurate: "NASA and ESA join forces to build life-seeking Europa lander."

This Futurism headline is truly horrible: "It’s Official. In 2025, NASA and the ESA Will Land on Europa to Look For Alien Life"

The Space News short blurb is by Jeff Foust. I've known Jeff for about 15 years now. Jeff has a Ph.D. in planetary sciences from MIT. His writing is almost always very accurate. And he is very careful with interpreting his sources.

I am sure SN is fine but my point is they linked to the article & therefore promoted it to their readership.
Title: Re: Proposed Europa Missions
Post by: as58 on 04/26/2017 06:47 pm
This Futurism headline is truly horrible: "It’s Official. In 2025, NASA and the ESA Will Land on Europa to Look For Alien Life"

I like the headline. It's so unashamed in its beyond-wrongness.
Title: Re: Proposed Europa Missions
Post by: Alpha_Centauri on 04/26/2017 09:31 pm
It's almost like the job of the media is to sell, not be truthful or accurate.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 04/26/2017 11:20 pm
It's almost like the job of the media is to sell, not be truthful or accurate.

Well, we expect greater accuracy from the trade press. Why is New Scientist so sloppy?
Title: Re: Proposed Europa Missions
Post by: vjkane on 04/26/2017 11:41 pm
It's almost like the job of the media is to sell, not be truthful or accurate.

Well, we expect greater accuracy from the trade press. Why is New Scientist so sloppy?
In my experience, New Scientist generally is pretty solid although they tend towards solid coverage of somewhat more sensational stories.  In some cases the reporting is sloppy.  My guess is that someone with no understanding of how missions actually get approved was handed a press release or the equivalent.
Title: Re: Proposed Europa Missions
Post by: as58 on 04/27/2017 05:58 am
It's almost like the job of the media is to sell, not be truthful or accurate.

Well, we expect greater accuracy from the trade press. Why is New Scientist so sloppy?
In my experience, New Scientist generally is pretty solid although they tend towards solid coverage of somewhat more sensational stories.  In some cases the reporting is sloppy.  My guess is that someone with no understanding of how missions actually get approved was handed a press release or the equivalent.

New Scientist is fond of stories about very speculative theories. To their credit, they usually at least include a sceptical comment from some expert who is not directly involved in the work. Even in their news article they like to emphasise the sensational part  (there's always a miracle cure found or some impeding catastrophe is threatening), though they don't usually get things as clearly wrong as in this case.

New Scientist was really bad a few years ago, but they've maybe toned down their sensationalism a bit lately.
Title: Re: Proposed Europa Missions
Post by: Star One on 04/27/2017 08:50 am
It's almost like the job of the media is to sell, not be truthful or accurate.

Well, we expect greater accuracy from the trade press. Why is New Scientist so sloppy?
In my experience, New Scientist generally is pretty solid although they tend towards solid coverage of somewhat more sensational stories.  In some cases the reporting is sloppy.  My guess is that someone with no understanding of how missions actually get approved was handed a press release or the equivalent.

New Scientist is fond of stories about very speculative theories. To their credit, they usually at least include a sceptical comment from some expert who is not directly involved in the work. Even in their news article they like to emphasise the sensational part  (there's always a miracle cure found or some impeding catastrophe is threatening), though they don't usually get things as clearly wrong as in this case.

New Scientist was really bad a few years ago, but they've maybe toned down their sensationalism a bit lately.

I am a regular reader and find that news pieces usually include a counter view to a varying extent. Not sure what happened with that headline as that was below their usual standards. Hopefully someone will flag it up in their letters page where you often get things like this that they are pulled up on.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 04/27/2017 12:14 pm
Another example of a clickbait headline. You can read it in the url:

http://www.independent.co.uk/news/science/cassini-spacecraft-nasa-loses-contact-dive-through-saturns-rings-grand-finale-a7703616.html

Title: Proposed Europa Missions
Post by: Star One on 04/27/2017 12:38 pm
Another example of a clickbait headline. You can read it in the url:

http://www.independent.co.uk/news/science/cassini-spacecraft-nasa-loses-contact-dive-through-saturns-rings-grand-finale-a7703616.html

You can find loads of examples of such things online, so I am not sure what kind of point you're trying to prove here?
Title: Re: Proposed Europa Missions
Post by: Star One on 05/02/2017 05:15 pm
Here's the relevant section.

NASA receives more than $19.6 billion in 2017 omnibus spending bill

Quote
That planetary science funding also includes $275 million for Europa missions, both the Europa Clipper multiple flyby spacecraft and a proposed lander. Language in the bill requires NASA to launch Europa Clipper no later than 2022 and the lander no later than 2024, although NASA officials have recently said they don’t expect the lander mission to be ready for launch until at least 2025. The Trump administration’s 2018 budget blueprint supported Europa Clipper but included no funding for a Europa lander.

http://spacenews.com/nasa-receives-more-than-19-6-billion-in-2017-omnibus-spending-bill/#sthash.YUSbvZyG.dpuf
Title: Re: Proposed Europa Missions
Post by: Star One on 05/11/2017 03:40 pm
The sounds of Europa

Quote
Although there are no plans at present to send a lander to Europa, we continue to work on the prospects, asking what kind of operations would be possible there. NASA is, for example, now funding a miniature seismometer no more than 10 centimeters to the side, working with the University of Arizona on a project called Seismometers for Exploring the Subsurface of Europa (SESE). Is it possible our first task on Europa’s surface will just be to listen?

The prospect is exciting because what we’d like to do is find a way to penetrate the surface ice to reach the deep saltwater ocean beneath or, barring that, any lakes that may occur within the upper regions of the ice shell. The ASU seismometer would give us considerable insights by using the movements of the ice crust to tell us how thick it is, and whether and where ocean water that rises to the surface can be sampled by future landers.

Quote
Seismometers would help us detect ongoing activity in the shell. ASU envisions a seismometer mounted on each leg of a lander — four to six seismometers in all, depending on lander design. These would be driven deep into the ground, avoiding the kind of loose surface materials that would isolate the instruments from seismic waves passing through the shell. And that calls for the kind of rugged instrument ASU is building. Able to operate at any angle, the prototype can survive landings hard enough to ensure deep penetration for each seismometer.

http://www.centauri-dreams.org/?p=37673
Title: Re: Proposed Europa Missions
Post by: Star One on 05/19/2017 10:21 am
As noted by another poster.

Nasa seeks experiment ideas for Europa lander

http://www.bbc.co.uk/news/science-environment-39964904
Title: Re: Proposed Europa Missions
Post by: Star One on 05/23/2017 04:43 pm
Budget Questions Hang Over NASA’s Europa Lander

Aerospace Daily & Defense Report
HOUSTON—There may or may not be funding for a multibillion dollar lander to seek evidence of life on the surface of Jupiter’s ice-covered moon Europa in the Trump administration’s upcoming budget request. But the space agency is telling those interested in providing instruments for the mission not to lose ...

http://m.aviationweek.com/space/budget-questions-hang-over-nasa-s-europa-lander
Title: Re: Proposed Europa Missions
Post by: Blackstar on 05/23/2017 05:24 pm
You can find the Europa program in the NASA budget proposal. Somebody with more energy than I can cut it down to only the relevant parts and post them here.
Title: Re: Proposed Europa Missions
Post by: Star One on 05/24/2017 07:31 pm
Quote
Mike Brown @plutokiller

LOOK! fresh-from-the-satellite-link HST spectral slices of  Europa. Mmmmmm. Time to get to work!

More info on the link below.

https://mobile.twitter.com/plutokiller/status/867423347046350852
Title: Re: Proposed Europa Missions
Post by: GClark on 05/26/2017 08:52 am
You can find the Europa program in the NASA budget proposal. Somebody with more energy than I can cut it down to only the relevant parts and post them here.

Here are the parts that jumped out at me:

pg. PS-60:  "Costs and schedule for the current Europa Clipper mission design are not baselined, as the mission
                   is still in formulation and NASA does not commit to costs and schedules until KDP-C, however the
                   notional outyear profile in the Budget supports a launch in the mid-to-late-2020s."

pg. PS-61:  "The budget provides no funding for a multi-billion-dollar mission to land on Europa that was not in
                   the last Decadal Survey and would send another flagship mission to Europa before analysis of the
                   Europa Clipper data is completed."

pg. PS-62:  "Per Public Law 114-113, Division B, Title III, the following table provides rough estimates for the
                   current mission design, including launch vehicle, assuming launch in 2022. NASA does not
                   recommend acceleration of the launch to 2022, given potential impacts to the rest of the Science
                   portfolio. The Administration supports a balanced science program, as recommended in the
                   Decadal Survey.

                                               FY18    FY19   FY20   FY21   FY22
                   Europa 2022 ($M)  425.0  580.0  665.0  485.0  327.0

                   Note:  The Europa profile above assumes an Evolved Expendable Launch Vehicle, as the cost of an
                   SLS flight is not yet known."

For comparison, the Requested budget profile (pg. PS-60) is:

     FY18    FY19   FY20   FY21    FY22
     425.0  303.0  215.7  432.4  253.6


Also on pg. PS-62, the project schedule:

PDR      Aug 2018
KDP-C   Sep 2018
CDR      Nov 2019
SIR       Sep 2020
KDP-D   Dec 2020
Launch   TBD


Last but not least, from pg. PS-63 comes this tidbit:

Estimated Life Cycle Cost Range ($M)     3,100 - 4,000
Title: Re: Proposed Europa Missions
Post by: Star One on 05/26/2017 09:58 am
The bit about the lander is likely to be over-ridden by the politicians that's pretty clear by now.
Title: Re: Proposed Europa Missions
Post by: vjkane on 05/26/2017 04:45 pm
The bit about the lander is likely to be over-ridden by the politicians that's pretty clear by now.
The politicians may make noise, but unless they increase the planetary budget by something on the order of $200M/year to keep the Clipper on a 2022 launch and then by several hundred million more a year for the lander, it is all noise.
Title: Re: Proposed Europa Missions
Post by: Star One on 05/26/2017 04:53 pm
The bit about the lander is likely to be over-ridden by the politicians that's pretty clear by now.
The politicians may make noise, but unless they increase the planetary budget by something on the order of $200M/year to keep the Clipper on a 2022 launch and then by several hundred million more a year for the lander, it is all noise.

Only time will tell on that.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 06/20/2017 09:14 pm
http://www.leonarddavid.com/a-human-touch-on-the-icy-moons-of-jupiter-saturn/

Title: Re: Proposed Europa Missions
Post by: gosnold on 06/20/2017 09:28 pm
http://www.leonarddavid.com/a-human-touch-on-the-icy-moons-of-jupiter-saturn/

That's not how any of this works.  :)
Title: Re: Proposed Europa Missions
Post by: sevenperforce on 06/27/2017 05:11 pm
Does anyone know what propellant will be used for Europa Clipper's thrusters? Is it ion, mono, or biprop?
Title: Re: Proposed Europa Missions
Post by: redliox on 06/27/2017 05:59 pm
Does anyone know what propellant will be used for Europa Clipper's thrusters? Is it ion, mono, or biprop?

Pretty sure it's bipropellant; NTO/MMT combo with the later doing double-duty for small maneuvers and attitude.  Pretty much similar to what Cassini or MRO used.  NASA may debate on which fuel to use for a human mission, but with probes they stick with known mono propellants or a bi-setup when big orbit insertions unavoidable.
Title: Re: Proposed Europa Missions
Post by: sevenperforce on 06/27/2017 06:01 pm
Does anyone know what propellant will be used for Europa Clipper's thrusters? Is it ion, mono, or biprop?

Pretty sure it's bipropellant; NTO/MMT combo with the later doing double-duty for small maneuvers and attitude.  Pretty much similar to what Cassini or MRO used.  NASA may debate on which fuel to use for a human mission, but with probes they stick with known mono propellants or a bi-setup when big orbit insertions unavoidable.

Thanks. Planning a KSP clone and wanted to be as accurate as possible.
Title: Re: Proposed Europa Missions
Post by: Jim on 06/27/2017 06:32 pm
Does anyone know what propellant will be used for Europa Clipper's thrusters? Is it ion, mono, or biprop?

Pretty sure it's bipropellant; NTO/MMT combo with the later doing double-duty for small maneuvers and attitude.  Pretty much similar to what Cassini or MRO used.  NASA may debate on which fuel to use for a human mission, but with probes they stick with known mono propellants or a bi-setup when big orbit insertions unavoidable.

FYI. MRO was monoprop.
Title: Re: Proposed Europa Missions
Post by: redliox on 06/27/2017 10:21 pm
Does anyone know what propellant will be used for Europa Clipper's thrusters? Is it ion, mono, or biprop?

Pretty sure it's bipropellant; NTO/MMT combo with the later doing double-duty for small maneuvers and attitude.  Pretty much similar to what Cassini or MRO used.  NASA may debate on which fuel to use for a human mission, but with probes they stick with known mono propellants or a bi-setup when big orbit insertions unavoidable.

FYI. MRO was monoprop.

My mistake.  It does show how NASA prefers to work with simple i.e. monopropellants whenever possible, and biprop when something bigger required.  MRO was able to reach Mars w/o biprop in its case.
Title: Re: Proposed Europa Missions
Post by: FutureSpaceTourist on 07/10/2017 06:44 pm
Quote
Europa Clipper Update Planned for 2017 Mars Society Convention
 
The Mars Society is pleased to announce that Dr. Robert Pappalardo, a Project Scientist in JPL’s Planetary Science Division, will provide an update about NASA’s Europa Clipper mission during the 20th Annual International Mars Society Convention, scheduled for September 7-10, 2017 at the University of California Irvine.
 
Due for launch in the 2020’s, the Europa Clipper mission will place a spacecraft in orbit around Jupiter in order to perform a detailed investigation of the giant planet's moon Europa - a world that shows strong evidence for an ocean of liquid water beneath its icy crust and which could host conditions favorable for life.
 
Dr. Pappalardo’s research focuses on processes that have shaped the icy satellite moons of the outer solar system, especially Europa, the nature, origin and evolution of bright grooved terrain on Jupiter’s moon Ganymede and the geological implications of geyser-like activity on Saturn’s moon Enceladus. Prior to joining JPL in 2006, Dr. Pappalardo served as an Assistant Professor of Planetary Science at the University of Colorado Boulder’s Astrophysical & Planetary Science Department.
 
For more details about the 2017 Mars Society Convention, including registration information for the four-day convention and evening banquet, please visit our web site (www.marssociety.org). The full 2017 speaker schedule will be posted online in the near future.

http://mailchi.mp/marssociety/utdd0ujaqz-1101873 (http://mailchi.mp/marssociety/utdd0ujaqz-1101873)
Title: Proposed Europa Missions
Post by: Star One on 07/12/2017 07:32 pm
Space Subcommittee Hearing- Planetary Flagship Missions: Mars Rover 2020 and Europa Clipper

Quote
Witnesses
Dr. Jim Green

Director, Planetary Science Division, Science Mission Directorate, NASA

Dr. Kenneth Farley

Mars Rover 2020 Project Scientist; Professor of Geochemistry, California Institute of Technology

Dr. Robert Pappalardo

Europa Clipper Project Scientist, Jet Propulsion Laboratory, California Institute of Technology

Dr. Linda T. Elkins-Tanton

Director and Foundation Professor, School of Earth and Space Exploration, Arizona State University; Principal Investigator, NASA Psyche Mission

Dr. William B. McKinnon

Co-Chair, National Academy of Sciences, Committee on Astrobiology and Planetary Science; Professor of Earth and Planetary Sciences, Washington University in St. Louis

https://science.house.gov/legislation/hearings/space-subcommittee-hearing-planetary-flagship-missions-mars-rover-2020-and
Title: Re: Proposed Europa Missions
Post by: zubenelgenubi on 07/12/2017 10:04 pm
U.S. House of Representatives
Date: Tuesday, July 18, 2017 - 10:00am
Location: 2318 Rayburn House Office Building
Subcommittees: Subcommittee on Space (115th Congress)

Space Subcommittee Hearing- Planetary Flagship Missions: Mars Rover 2020 and Europa Clipper

Quote
Witnesses
Dr. Jim Green

Director, Planetary Science Division, Science Mission Directorate, NASA

Dr. Kenneth Farley

Mars Rover 2020 Project Scientist; Professor of Geochemistry, California Institute of Technology

Dr. Robert Pappalardo

Europa Clipper Project Scientist, Jet Propulsion Laboratory, California Institute of Technology

Dr. Linda T. Elkins-Tanton

Director and Foundation Professor, School of Earth and Space Exploration, Arizona State University; Principal Investigator, NASA Psyche Mission

Dr. William B. McKinnon

Co-Chair, National Academy of Sciences, Committee on Astrobiology and Planetary Science; Professor of Earth and Planetary Sciences, Washington University in St. Louis

https://science.house.gov/legislation/hearings/space-subcommittee-hearing-planetary-flagship-missions-mars-rover-2020-and
Title: Re: Proposed Europa Missions
Post by: zubenelgenubi on 07/18/2017 06:20 pm
Surprised that no one had posted this, or their commentary, yet...

Hearing opens about 25 minutes into the file.

https://www.youtube.com/watch?v=PLJ5QrR_zj8
Title: Re: Proposed Europa Missions
Post by: Star One on 07/18/2017 07:11 pm
JPL moves ahead with Mars and Europa missions despite funding uncertainty

http://spacenews.com/jpl-moves-ahead-with-mars-and-europa-missions-despite-funding-uncertainty/
Title: Re: Proposed Europa Missions
Post by: Star One on 08/29/2017 07:38 pm
ALMA Thermal Observations of a Proposed Plume Source Region on Europa

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We present a daytime thermal image of Europa taken with the Atacama Large Millimeter Array. The imaged region includes the area northwest of Pwyll Crater, which is associated with a nighttime thermal excess seen by the Galileo Photopolarimeter Radiometer and with two potential plume detections. We develop a global thermal model of Europa and simulate both the daytime and nighttime thermal emission to determine if the nighttime thermal anomaly is caused by excess endogenic heat flow, as might be expected from a plume source region. We find that the nighttime and daytime brightness temperatures near Pwyll Crater cannot be matched by including excess heat flow at that location. Rather, we can successfully model both measurements by increasing the local thermal inertia of the surface.

https://arxiv.org/abs/1708.07922
Title: Re: Proposed Europa Missions
Post by: zubenelgenubi on 08/31/2017 05:08 pm
NASA studies mission to return samples from Mars by end of 2020s (https://spaceflightnow.com/2017/08/28/nasa-studies-mission-to-return-samples-from-mars-by-end-of-2020s/), dated August 28

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Proceeding with development of a Mars Ascent Vehicle and fetch rover for a launch in 2026 will strain NASA’s planetary science budget.

The multibillion-dollar Europa Clipper mission is scheduled for launch in the early 2020s to make dozens of low-altitude flybys of Jupiter’s ice-covered moon, and NASA is also studying a Europa lander that could launch later in the decade. Europa Clipper is an approved mission, while the lander is still awaiting a go-ahead from NASA Headquarters.
Title: Proposed Europa Missions
Post by: Star One on 09/06/2017 08:06 pm
Quote
Jeff Foust @jeff_foust
Niebur: concerned about growth in resources for payloads on Europa Clipper. Reporting plan in place to monitor instruments in development.

https://mobile.twitter.com/jeff_foust/status/905459292106575873

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Jeff Foust @jeff_foust
Niebur: Europa Lander had mission concept review in June; still evaluating different options for mission, so premature for instrument AO.

https://mobile.twitter.com/jeff_foust/status/905459905502613504


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Jeff Foust @jeff_foust
Bob Pappalardo, JPL, at OPAG meeting: Europa Clipper spacecraft now up to 4.5 solar panels per wing for add’l power for instruments.

https://mobile.twitter.com/jeff_foust/status/905489471432515584

Image on the above link.

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Jeff Foust @jeff_foust
Pappalardo: already started preliminary design reviews for subsystems of Europa Clipper. Full project PDR in August 2018.

https://mobile.twitter.com/jeff_foust/status/905490000837529601

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Jeff Foust @jeff_foust
Niebur reiterates that NASA is “reconsidering the trade space” for Europa Lander, which take some time. “Science is on the table.”
7:59 pm · 6 Sep 2017

https://mobile.twitter.com/jeff_foust/status/905505650616266753

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Jeff Foust @jeff_foust
Q: cost estimate for Europa Lander?
Niebur: estimates in progress, not yet briefed to HQ. Prefer they hear it from us first, not Twitter.
8:03 pm · 6 Sep 2017

https://mobile.twitter.com/jeff_foust/status/905506782734426112

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Jeff Foust @jeff_foust
Replying to @jabe8
SLS is currently the only launch vehicle under consideration for launching Europa Lander.

https://mobile.twitter.com/jeff_foust/status/905509735495028738
Title: Proposed Europa Missions
Post by: Star One on 09/07/2017 04:31 pm
Further to the above here is the related article.

NASA studying less expensive options for Europa lander mission

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WASHINGTON — NASA is continuing to examine various, potentially less expensive options for a mission to land on Jupiter’s moon Europa even after completing a recent review, postponing a call for instruments for the spacecraft.

At a meeting of the Outer Planets Assessment Group (OPAG) Sept. 6 in La Jolla, California, Curt Niebur, a program scientist in the planetary science division at NASA Headquarters, said mission planners are continuing to examine several factors, including mission cost and science return, as they evaluate the design of the mission.

The lander mission, he said, successfully passed an early-stage review called a mission concept review in June. However, he said the agency had not settled on a specific, single concept for the mission.

“As a result of that mission concept review, what we want to do is essentially continue exploring the different options we have for a Europa lander mission,” he said. “We want to continue balancing the trade amongst risk, cost and science return.”

Quote
Progress is going well on Europa Clipper, Niebur and others said at the OPAG meeting. The mission passed a major project milestone called Key Decision Point B in February, allowing it to enter a preliminary design phase. Robert Pappalardo, project scientist for the mission, said at the OPAG meeting that the mission is on schedule to complete a series of preliminary design reviews by next August.

One issue with Europa Clipper that Niebur raised is the growth in resources in the spacecraft’s instrument payload. “It wasn’t so much that the resources grew, but it was the amount that they grew,” he said. The mission, he said, has put into place a “resource monitoring plan” to track that growth, and understand what instruments are having issues as early as possible.

Power demands from those instruments, though, have led to a design change in the spacecraft. The spacecraft’s two solar arrays now consist of four and a half panels each, up from four panels from earlier designs. “We needed to increase the total size of the arrays slightly in order to accommodate the energy demands of the payload,” Pappalardo said.

http://spacenews.com/nasa-studying-less-expensive-options-for-europa-lander-mission/
Title: Re: Proposed Europa Missions
Post by: redliox on 09/07/2017 06:16 pm
Further to the above here is the related article.

NASA studying less expensive options for Europa lander mission

I can already hear Blackstar laughing out loud...

The article does make a point although, as we all know (and Blackstar moreso via expertise), Europa (and the rest of the Outer Planets) don't come cheap.

The only thought that comes to mind on how to, somewhat effectively, reduce cost would be by reducing mass (which no doubt is debatable).  Both this lander and the 'Clipper will be hauling a ton of propellant, and handling it in turn amps up complexity.  You could try cutting out the 'carrier,' although there are numerous complexities (which, as I'm sure Blackstar will testify) result in why some engineers opt for making a second craft instead of a slightly-insane lander.  On top of that (and a simpler route), would be doing as many Galilean gravity assists possible to lower the lander's velocity to make a smoother landing; I have a feeling the engineers have already calculated this part heavily.  Regarding this, the best you could do with the least rads would be to get the lander to closely match Ganymede's orbit via GAs prior to rendezvousing with Europa for a final few GAs there and descent.

Cutting those instruments will send the scientists into a bloodbath of competition.  Personally I'd suggest cameras and seisometers, but I can see how microscopes and chemistry labs would make the trip worthwhile (*coughsettlelifequestionfastercough*).  The 20 day limit (coupled with whatever rad exposure from the possible GAs beforehand) will further restrict science.  No easy choices.
Title: Re: Proposed Europa Missions
Post by: Star One on 09/07/2017 06:43 pm
Would it be better to send a heavier lander but on a slower gravity assisted route even if you used the same launcher?
Title: Re: Proposed Europa Missions
Post by: Star One on 10/25/2017 08:07 pm
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Hill, discussing SLS use for Europa Clipper: launch date drifting later into the 2020s, but Congress could add $ to move it up. #VonBraun

https://mobile.twitter.com/jeff_foust/status/923202544100413441
Title: Re: Proposed Europa Missions
Post by: Blackstar on 10/25/2017 09:13 pm
I knew this woman who wanted to have a
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Hill, discussing SLS use for Europa Clipper: launch date drifting later into the 2020s, but Congress could add $ to move it up. #VonBraun

https://mobile.twitter.com/jeff_foust/status/923202544100413441

I knew this woman who wanted a baby, but didn't want to wait 9 months for it to arrive, so she got eight of her friends together and the nine women were able to have a baby in one month...
Title: Re: Proposed Europa Missions
Post by: redliox on 10/25/2017 11:54 pm
I knew this woman who wanted to have a
Quote
Hill, discussing SLS use for Europa Clipper: launch date drifting later into the 2020s, but Congress could add $ to move it up. #VonBraun

https://mobile.twitter.com/jeff_foust/status/923202544100413441

I knew this woman who wanted a baby, but didn't want to wait 9 months for it to arrive, so she got eight of her friends together and the nine women were able to have a baby in one month...

That reminds me of the mythical birth of Heimdall; he had nine mothers.

I do however see you point about doing a "rush job" on a mission as important as Europa Clipper.  I would think being given full funding between now and its earliest tentative launch date of 2022 could get things done in the ~5 year space, emphasis on "if" being key.  My concerns are less with the probe itself and more with SLS, especially since it will be the first mission to ride a EUS (and I imagine JPL is less-than-happy about playing Guinea Pig).

In your professional opinion Blackstar, how much time would be best to spend maturing a flagship mission once it's into Phase B onward?
Title: Re: Proposed Europa Missions
Post by: redliox on 10/26/2017 03:24 am
I do however see you point about doing a "rush job" on a mission as important as Europa Clipper.  I would think being given full funding between now and its earliest tentative launch date of 2022 could get things done in the ~5 year space, emphasis on "if" being key.  My concerns are less with the probe itself and more with SLS, especially since it will be the first mission to ride a EUS (and I imagine JPL is less-than-happy about playing Guinea Pig).

In your professional opinion Blackstar, how much time would be best to spend maturing a flagship mission once it's into Phase B onward?

EC has some issues that they are working through. At least one of them could be a major problem, or it could go away suddenly (because it's based upon a model, not actual data, and the model is currently showing something rather bad).

One of the things that has been plaguing them for a while now has been that they committed to a set of instruments rather early, and now they're trying to fit them to a spacecraft. Usually that is more of an iterative process, but because they had the money early, they settled on the instruments early, and it's proving hard to design a spacecraft that can accommodate all of them.

The decision point for SLS happens in 2018. That's when they have to have a vehicle approved.

I would think the radar instrument, REASON, would be especially problematic.  That and the decision to add a further half-a-panel to the solar arrays.  However the JUICE mission is going to have 2 further instruments than 'Clipper and I can't say I've heard any troubles on their side; is there any way to compare the development problems 'Clipper has versus JUICE?  Both missions are very similar in their science approach.

The lander is a different issue entirely. We'll see what happens there (cue mysterious, slightly ominous music...)

The lander was a force-fed cluster of a kerfuckle, as exciting as directly visiting Europa could be.  They might have to downsize the affair into something that focuses on one aspect, such as an astrobiology package versus a seismology package.  Other than just landing the thing it's the trouble of relaying the data.

An alternative that could be cool to see would be a sample-return flyby of the plumes; I'd only suggest this after 'Clipper firmly confirms their presence.
Title: Re: Proposed Europa Missions
Post by: vjkane on 10/26/2017 05:10 am
In public presentations, the team has made it clear that their are issues, but the word choice has suggested that they are not beyond what is normal for a design as it progresses.  Reviews of the progress reportedly have been very positive.  Blackstar, though, may have additional information.

From what has been publicly said, a key issue has been power.  In many missions, the key power driver is the communications system.  Ralph Lorenz published a paper showing the power needed to push the data back to Earth is the largest consumer of power on many planetary spacecraft.  If this is true for Clipper, then returning less data per flyby might be one option. 

Mass has been another problem because the project wants to keep non-SLS launch options available.  If the project goes with SLS, I believe that the mass problems go away, but we are likely looking at a mid-2020s launch based on that vehicle's progress or lack thereof. 

Title: Re: Proposed Europa Missions
Post by: redliox on 10/26/2017 05:30 am
Mass has been another problem because the project wants to keep non-SLS launch options available.  If the project goes with SLS, I believe that the mass problems go away, but we are likely looking at a mid-2020s launch based on that vehicle's progress or lack thereof.

I'm going to guess we'll see SLS EM-1 liftoff either in '19 or '20.  Although this subject is more accurate for an SLS thread, is there any word on the progress of EUS?  I don't expect them to be at the point of bending metal just yet but if anything specific with SLS is going to affect 'Clipper it'll be the EUS and overall transition to Block 1B.

Thus far, it'll look like 'Clipper could launch somewhere between '22 and '25 with emphasis on the later date?
Title: Re: Proposed Europa Missions
Post by: Zed_Noir on 10/27/2017 03:51 am
....
....
Thus far, it'll look like 'Clipper could launch somewhere between '22 and '25 with emphasis on the later date?

If the 'Clipper is launched beyond 2023. Then there will be more launch vehicle options available if the various development programs have flying hardware in the next few years. IMO no decision regarding the launch vehicle selection for the 'Clipper should be make until after the next US Presidential election. Funding & launcher availability should be more clear.
Title: Re: Proposed Europa Missions
Post by: vjkane on 10/27/2017 05:18 am
If the 'Clipper is launched beyond 2023. Then there will be more launch vehicle options available if the various development programs have flying hardware in the next few years. IMO no decision regarding the launch vehicle selection for the 'Clipper should be make until after the next US Presidential election. Funding & launcher availability should be more clear.
I believe that the mission has to settle on a launch vehicle soon so they can design the spacecraft to the specific requirements of the vehicle and resulting flight plan (for example, does the spacecraft have to be designed for the heat environment of a Venus flyby?).
Title: Re: Proposed Europa Missions
Post by: Star One on 10/27/2017 05:51 am
If the 'Clipper is launched beyond 2023. Then there will be more launch vehicle options available if the various development programs have flying hardware in the next few years. IMO no decision regarding the launch vehicle selection for the 'Clipper should be make until after the next US Presidential election. Funding & launcher availability should be more clear.
I believe that the mission has to settle on a launch vehicle soon so they can design the spacecraft to the specific requirements of the vehicle and resulting flight plan (for example, does the spacecraft have to be designed for the heat environment of a Venus flyby?).

I am sure it’s next year they have to pick a launch vehicle.
Title: Re: Proposed Europa Missions
Post by: Jim on 10/27/2017 02:53 pm
If the 'Clipper is launched beyond 2023. Then there will be more launch vehicle options available if the various development programs have flying hardware in the next few years. IMO no decision regarding the launch vehicle selection for the 'Clipper should be make until after the next US Presidential election. Funding & launcher availability should be more clear.
I believe that the mission has to settle on a launch vehicle soon so they can design the spacecraft to the specific requirements of the vehicle and resulting flight plan (for example, does the spacecraft have to be designed for the heat environment of a Venus flyby?).

Not really, it can still wait a few years
Title: Re: Proposed Europa Missions
Post by: redliox on 10/27/2017 03:18 pm
I really, really hope they can bypass needing a Venus flyby.  With the Galileo that need forced them to add a lot of insulation.  Earth flybys are easier to handle, and I hope at worst that's all 'Clipper could need for a Juno-esque route.

What would be available by 2023?  I would assume Delta IV and Atlas V might be preparing to retire not long after, and I wouldn't expect Blue Origins to have a matured vehicle (flown perhaps).
Title: Re: Proposed Europa Missions
Post by: LouScheffer on 10/27/2017 08:11 pm
From what has been publicly said, a key issue has been power.  In many missions, the key power driver is the communications system.  Ralph Lorenz published a paper showing the power needed to push the data back to Earth is the largest consumer of power on many planetary spacecraft.

In some hypothetical rational world, NASA would gain a lot more bang for the buck by spending some of those bucks on substantially improving the DSN.  One mission's worth of money spent on the DSN could improve all other missions by a factor of 5 or so.  (Worst case, you could add 10 new 35-meter dishes to each DSN station for $1B.  Currently they are about $40M each, but I'm sure you could get a deal if you ordered 30 of them.  And almost surely you could do better with arrays of smaller dishes.)

This would make *every* mission easier to design, higher data return, or some combination, including those already designed or launched. It would especially help outer planet missions, where fewer missions would need RTGs.   All missions would save mass from smaller solar panels and power systems.   Direct to earth from landers and probes becomes much more practical.  No design changes to the RF systems are needed, other than lower power amplifiers - the current transponders already support higher data rates which cannot be used since the S/N is not good enough.

Such a plan has no hard (and therefore expensive) deadlines and it's used when the spacecraft arrives, not when it's launched, allowing for additional years of technical improvement.  It can use less antique technology since it's on the ground where it can be fixed.   It has an excellent fallback strategy - if you get to Europa and only 8 of the 10 dishes are finished, you just get 80% of the data.  (and since the situation is known in advance, the scientists can pick which 80%, making the loss even less.)

On the other hand, it's really hard to see NASA spending a billion on infrastructure instead of a new mission.  DSN is treated as an expense to be minimized, and not an opportunity for investment.    Each individual investigator would prefer one mission more, even with 1/5 the data, since that mission might well be theirs.  Infrastructure is not sexy, either to investigators, the public, congress, or the NASA administrator, who wants to announce new and exciting missions.  Sp I don't see this situation changing, unfortunately.
Title: Re: Proposed Europa Missions
Post by: Proponent on 11/29/2017 02:23 pm
Why is it that the Europa spacecraft's electronics vault is made of aluminum rather than some other material?
Title: Re: Proposed Europa Missions
Post by: JH on 11/29/2017 08:40 pm
Low atomic weight and won't release volatiles.
Title: Re: Proposed Europa Missions
Post by: Star One on 12/05/2017 08:10 pm
Research bolsters possibility of plate tectonics on Europa

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Subduction--the sliding of one tectonic plate beneath another--is possible on the ice shell of Jupiter's moon Europa, a new study shows. The process could supply chemical food for life to a subsurface ocean.

https://news.brown.edu/articles/2017/11/europa
Title: Re: Proposed Europa Missions
Post by: UltraViolet9 on 12/22/2017 04:18 pm

Quote
Rep. Culberson’s Seat in Jeopardy?

One of the Republican seats that may be in jeopardy according to the Times belongs to Rep. John Culberson, chairman of the House Appropriations Subcommittee on Commerce-Justice-Science (CJS) that funds NASA and NOAA...

Using the power of his chairmanship, he has compelled NASA to build and launch a probe to Jupiter’s moon Europa because he is convinced life exists in the ocean that some scientists believe exists under its icy shell...

https://spacepolicyonline.com/news/today-tidbits-december-21-2017/ (https://spacepolicyonline.com/news/today-tidbits-december-21-2017/)

Title: Re: Proposed Europa Missions
Post by: AegeanBlue on 02/05/2018 07:23 am
I am under the impression that these 4 lectures from the Keck Institute for Space Science have not been shared in this thread:

https://www.youtube.com/watch?v=SrEYbHNETe8

https://www.youtube.com/watch?v=YsiA35gqHZ8

https://www.youtube.com/watch?v=4RrKuqdozOY

https://www.youtube.com/watch?v=Rk-nxZAUaXE
Title: Re: Proposed Europa Missions
Post by: CitabriaFlyer on 02/07/2018 01:21 pm
In the afterglow of yesterday's F9H flight I think it is worth spending some time on launch options again.  From a taxpayer's standpoint I am not sure I want to keep SLS going just for this mission.  I have a much higher degree of confidence that BFR will obviate the rationale by 2030.  We have waited half a century for sustainable interplanetary transport I have no problem cancelling SLS and waiting at most an extra 5 years to get into cis lunar space.

Realize F9H stage 2 not optimized for beyond GTO but can F9H do this mission with only Earth flybys?
Title: Re: Proposed Europa Missions
Post by: CitabriaFlyer on 02/07/2018 01:25 pm
And since 39A had cryo capability for J2 and SSME why not F9H/Centaur/EC.  Certainly I would think the option to integrate those two vehicles could be done for less expense than the SLS black hole.  Moderators, please move this thread if it belongs in another category but my thoughts were primarily re the EC mission.
Title: Re: Proposed Europa Missions
Post by: CitabriaFlyer on 02/07/2018 02:25 pm
Might be more difficult than I thought.  F9H fairing is 43 feet tall.  Both Centaur and DCSS would both occupy most of that length leaving little room for spacecraft.  Extended fairing or placing the 3rd cryo stage between stage 2 and fairing would probably cause more engineering work than SpaceX cares to expend on the F9 at this point.
Title: Re: Proposed Europa Missions
Post by: Zed_Noir on 02/08/2018 01:28 am
Might be more difficult than I thought.  F9H fairing is 43 feet tall.  Both Centaur and DCSS would both occupy most of that length leaving little room for spacecraft.  Extended fairing or placing the 3rd cryo stage between stage 2 and fairing would probably cause more engineering work than SpaceX cares to expend on the F9 at this point.

Just use the RUAG 26.5m height PLF instead of the 13.1m height SX PLF.

There is issues raised by @jim about the lack of vertical payload integration and access to the payload while the LV is vertical with the FH on other threads.

Also there might not be Hydrogen handling GSE available at LC-39A right now.
Title: Re: Proposed Europa Missions
Post by: UltraViolet9 on 02/08/2018 02:06 am
Might be more difficult than I thought.  F9H fairing is 43 feet tall.  Both Centaur and DCSS would both occupy most of that length leaving little room for spacecraft.  Extended fairing or placing the 3rd cryo stage between stage 2 and fairing would probably cause more engineering work than SpaceX cares to expend on the F9 at this point.

https://en.wikipedia.org/wiki/Raptor_prototype_upper-stage_engine

https://en.wikipedia.org/wiki/Raptor_(rocket_engine_family)
Title: Re: Proposed Europa Missions
Post by: redliox on 02/08/2018 12:30 pm
In the afterglow of yesterday's F9H flight I think it is worth spending some time on launch options again.  From a taxpayer's standpoint I am not sure I want to keep SLS going just for this mission.  I have a much higher degree of confidence that BFR will obviate the rationale by 2030.  We have waited half a century for sustainable interplanetary transport I have no problem cancelling SLS and waiting at most an extra 5 years to get into cis lunar space.

Realize F9H stage 2 not optimized for beyond GTO but can F9H do this mission with only Earth flybys?

I asked this question before, and the answer was yes.  A single Earth flyby coupled with the FH would yield a trajectory akin to what Juno went through.  Don't turn this into a SpaceX thread though.  A Europa mission will be able to chose from a variety of rockets, and any (especially new) rocket won't initially be trusted with a payload like a flagship right away.
Title: Re: Proposed Europa Missions
Post by: Zed_Noir on 02/08/2018 09:12 pm
....
A Europa mission will be able to chose from a variety of rockets, and any (especially new) rocket won't initially be trusted with a payload like a flagship right away.

So sending the Europa Clipper with the first SLS Block 1B is a good idea?  ::)
Title: Re: Proposed Europa Missions
Post by: redliox on 02/09/2018 12:15 am
....
A Europa mission will be able to chose from a variety of rockets, and any (especially new) rocket won't initially be trusted with a payload like a flagship right away.

So sending the Europa Clipper with the first SLS Block 1B is a good idea?  ::)

Don't be a SpaceX troll  ;)

Also, if you invoke the name of either FH or SLS too much the 'Clipper might be jinxed to fly on Atlas V so watch yourself!

Seriously though guys, YES, Falcon Heavy could be an option.  Even a good option.  However don't turn this into a SpaceX fandom.  Besides, wait for the Outer Planet Assessment Group meeting due this month; perhaps in light of the launch the 'Clipper team might give a public update on their options.  Let them speak about the matter themselves.
Title: Re: Proposed Europa Missions
Post by: Zed_Noir on 02/09/2018 01:17 am
....
A Europa mission will be able to chose from a variety of rockets, and any (especially new) rocket won't initially be trusted with a payload like a flagship right away.

So sending the Europa Clipper with the first SLS Block 1B is a good idea?  ::)

Don't be a SpaceX troll  ;)

Also, if you invoke the name of either FH or SLS too much the 'Clipper might be jinxed to fly on Atlas V so watch yourself!

Seriously though guys, YES, Falcon Heavy could be an option.  Even a good option.  However don't turn this into a SpaceX fandom.  Besides, wait for the Outer Planet Assessment Group meeting due this month; perhaps in light of the launch the 'Clipper team might give a public update on their options.  Let them speak about the matter themselves.

Only pointing out the obvious fallacy in your argument in your previous post.  ;)
Title: Re: Proposed Europa Missions
Post by: redliox on 02/09/2018 02:38 am
Only pointing out the obvious fallacy in your argument in your previous post.  ;)

SPACE TROLL!  *starts firing the laser guns*
Title: Re: Proposed Europa Missions
Post by: redliox on 02/12/2018 07:20 pm
Although the The Outer Planets Assessment Group (OPAG) isn't due to have its meeting for over another week, they released a draft of their collective goals: https://www.lpi.usra.edu/opag/goals-02-12-18.pdf (https://www.lpi.usra.edu/opag/goals-02-12-18.pdf)

Ganymede, Europa, and Io are listed as individual science objectives, which bears relevance to the Europa Clipper.

Hopefully we hear even more news from the OPAG's meeting soon!
Title: Re: Proposed Europa Missions
Post by: psloss on 02/14/2018 02:10 pm
In the FY 2019 PBR details released sometime in the last 12 hours or so:
Quote
This budget enables a Europa Clipper launch readiness date in 2025. The Administration proposes to
launch the Clipper on a commercial launch vehicle, which would be several hundreds of millions of
dollars cheaper than an SLS flight and would not impact the availability of SLS rockets to support human
exploration. The Administration recognizes the benefits of using an SLS vehicle, including a shorter
cruise to Europa and a more direct trajectory (enabling a simpler thermal design and earlier science return
to inform future outer planet missions), but makes this proposal primarily due to budget considerations.

Reference:
https://www.nasa.gov/sites/default/files/atoms/files/fy19_nasa_budget_estimates.pdf

(PS-77, page 433 of the PDF)

Edit: a bit more two pages later (PS-79), after reiterating much of the same:
Quote
Consistent with Public Law 115-31, NASA is currently maintaining the capability to launch the Clipper on an SLS rocket.

PS-80 excerpt:
Quote
The profile assumes $432 million for a commercial launch vehicle, which may be reduced as commercial
offerings and pricing continue to evolve. It is not possible to launch the Clipper on an SLS earlier than
2024 without disrupting current NASA human exploration plans.

PS-83 excerpt:
Quote
If the Congress were to support the Administration’s position, NASA could move forward this year with securing a commercial launch vehicle.
Title: Re: Proposed Europa Missions
Post by: Jim on 02/14/2018 04:06 pm
In the FY 2019 PBR details released sometime in the last 12 hours or so:
Quote
This budget enables a Europa Clipper launch readiness date in 2025. The Administration proposes to
launch the Clipper on a commercial launch vehicle, which would be several hundreds of millions of
dollars cheaper than an SLS flight and would not impact the availability of SLS rockets to support human
exploration. The Administration recognizes the benefits of using an SLS vehicle, including a shorter
cruise to Europa and a more direct trajectory (enabling a simpler thermal design and earlier science return
to inform future outer planet missions), but makes this proposal primarily due to budget considerations.

Reference:
https://www.nasa.gov/sites/default/files/atoms/files/fy19_nasa_budget_estimates.pdf

(PS-77, page 433 of the PDF)


Yea
Title: Re: Proposed Europa Missions
Post by: Bubbinski on 02/14/2018 05:26 pm
Which commercial vehicles/variants would be capable of launching Europa Clipper?

-which versions of Atlas?
-would Vulcan be considered?
-Delta 4 Heavy?
- New Glenn?
- F9/FH?
-NGLV/Antares?
-Ariane 5/6?
Title: Re: Proposed Europa Missions
Post by: Demidrol on 02/14/2018 05:40 pm
Which commercial vehicles/variants would be capable of launching Europa Clipper?

-which versions of Atlas?
-would Vulcan be considered?
-Delta 4 Heavy?
- New Glenn?
- F9/FH?
-NGLV/Antares?
-Ariane 5/6?
Quote
Pappalardo said the mission is continuing to study the use of Delta 4 Heavy and Falcon Heavy as alternatives, but those would require the use of gravity assists that increase the mission’s flight time. The use of the Atlas 5 has been “closed off,” he said.
http://spacenews.com/europa-mission-planning-for-possible-budget-cuts-in-2017/
Title: Re: Proposed Europa Missions
Post by: zubenelgenubi on 02/14/2018 07:34 pm
Quote
Pappalardo said the mission is continuing to study the use of Delta 4 Heavy and Falcon Heavy as alternatives, but those would require the use of gravity assists that increase the mission’s flight time. The use of the Atlas 5 has been “closed off,” he said.
http://spacenews.com/europa-mission-planning-for-possible-budget-cuts-in-2017/

Article was dated August 17, 2016.  A door closed 1.5 years ago or more could be re-opened?

Also, this article quote doesn't appear to preclude use of Vulcan/Centaur.
Title: Re: Proposed Europa Missions
Post by: psloss on 02/14/2018 08:02 pm
Attached a composite graphic from the detailed FY19 PBR release showing the PBR funding ramp for the mission targeting a 2025 launch vs. what would be required for a 2022 launch (numbers required to be provided by law) .

(This is likely to come up during the congressional oversight and/or budget process.)
Title: Re: Proposed Europa Missions
Post by: AegeanBlue on 02/23/2018 06:13 pm
I am surprised that this article has not been shared yet:

http://spacenews.com/nasa-budget-proposal-continues-debate-on-when-and-how-to-launch-europa-clipper/

Per the article they do not consider Falcon Heavy because they doubt that it will be certified for Class A missions at launch time.
Title: Re: Proposed Europa Missions
Post by: Star One on 02/23/2018 08:17 pm
I am surprised that this article has not been shared yet:

http://spacenews.com/nasa-budget-proposal-continues-debate-on-when-and-how-to-launch-europa-clipper/

Per the article they do not consider Falcon Heavy because they doubt that it will be certified for Class A missions at launch time.

One wonders how SLS is supposed to be certified by then.
Title: Re: Proposed Europa Missions
Post by: AegeanBlue on 02/23/2018 08:27 pm
I am surprised that this article has not been shared yet:

http://spacenews.com/nasa-budget-proposal-continues-debate-on-when-and-how-to-launch-europa-clipper/

Per the article they do not consider Falcon Heavy because they doubt that it will be certified for Class A missions at launch time.

One wonders how SLS is supposed to be certified by then.

More like trying to spread the cost of an SLS flight with other directorates
Title: Re: Proposed Europa Missions
Post by: speedevil on 02/23/2018 08:29 pm
I am surprised that this article has not been shared yet:

http://spacenews.com/nasa-budget-proposal-continues-debate-on-when-and-how-to-launch-europa-clipper/

Per the article they do not consider Falcon Heavy because they doubt that it will be certified for Class A missions at launch time.

I do not see the words 'Class A' in the article, and am I missing this, or has it changed.
Title: Re: Proposed Europa Missions
Post by: Star One on 02/23/2018 08:36 pm
I am surprised that this article has not been shared yet:

http://spacenews.com/nasa-budget-proposal-continues-debate-on-when-and-how-to-launch-europa-clipper/

Per the article they do not consider Falcon Heavy because they doubt that it will be certified for Class A missions at launch time.

I do not see the words 'Class A' in the article, and am I missing this, or has it changed.

Isn’t there some odd situation where Europa Clipper is classed as a class b mission at the moment?
Title: Re: Proposed Europa Missions
Post by: zubenelgenubi on 02/23/2018 10:17 pm
re: Is Europa Clipper a "Class A" mission.

See p.10 of the attached document: If it walks like a duck, quacks like a duck...

A direct reference that Europa Clipper is Class A would be appreciated.
Title: Re: Proposed Europa Missions
Post by: zubenelgenubi on 02/23/2018 10:24 pm
Re: use of Atlas V 551

Quote
Pappalardo said the mission is continuing to study the use of Delta 4 Heavy and Falcon Heavy as alternatives, but those would require the use of gravity assists that increase the mission’s flight time. The use of the Atlas 5 has been “closed off,” he said.
http://spacenews.com/europa-mission-planning-for-possible-budget-cuts-in-2017/

Article was dated August 17, 2016.  A door closed 1.5 years ago or more could be re-opened?

Also, this article quote doesn't appear to preclude use of Vulcan/Centaur.

NASA budget proposal continues debate on when and how to launch Europa Clipper (http://spacenews.com/nasa-budget-proposal-continues-debate-on-when-and-how-to-launch-europa-clipper/), dated February 22, 2018
Quote
NASA has studied launching Europa Clipper on both SLS and on the most powerful variant of the United Launch Alliance Atlas 5. SLS offers the ability to fly a fast, direct route to Jupiter, with the spacecraft arriving at the planet less than three years after launch. The Atlas 5 would take more than six years to get Europa Clipper to Jupiter, and require flybys of both Venus and Earth to do so.

No mention in the article of Delta IV-Heavy as an option.
Title: Re: Proposed Europa Missions
Post by: UltraViolet9 on 02/24/2018 05:52 am
Isn’t there some odd situation where Europa Clipper is classed as a class b mission at the moment?

You're thinking of the controversial Class B designation for WFIRST:

Quote
The independent review also raised questions about the risk classification of the mission. WFIRST is considered a “Class B” risk mission by NASA, which means it is high priority but only medium to high cost and with a medium mission lifetime. That is less stringent than the Class A assignments usually given to “strategically important missions with comparable levels of investment and risks,” Zurbuchen wrote.

The review, the memo noted, suggested NASA add more engineering development and spare hardware, as well as additional analysis, “to provide a more robust program” than its existing Class B risk classification.

http://spacenews.com/nasa-seeks-cost-cutting-changes-in-design-of-wfirst-mission/ (http://spacenews.com/nasa-seeks-cost-cutting-changes-in-design-of-wfirst-mission/)
Title: Re: Proposed Europa Missions
Post by: Star One on 02/24/2018 08:30 am
Isn’t there some odd situation where Europa Clipper is classed as a class b mission at the moment?

You're thinking of the controversial Class B designation for WFIRST:

Quote
The independent review also raised questions about the risk classification of the mission. WFIRST is considered a “Class B” risk mission by NASA, which means it is high priority but only medium to high cost and with a medium mission lifetime. That is less stringent than the Class A assignments usually given to “strategically important missions with comparable levels of investment and risks,” Zurbuchen wrote.

The review, the memo noted, suggested NASA add more engineering development and spare hardware, as well as additional analysis, “to provide a more robust program” than its existing Class B risk classification.

http://spacenews.com/nasa-seeks-cost-cutting-changes-in-design-of-wfirst-mission/ (http://spacenews.com/nasa-seeks-cost-cutting-changes-in-design-of-wfirst-mission/)

Thanks. After I posted the above I started thinking it might be another mission, but couldn’t think which one it was.
Title: Re: Proposed Europa Missions
Post by: Don2 on 02/24/2018 07:40 pm
It would be nice to get to Jupiter faster, but the problem I can see is that Clipper will never be a priority for SLS and it may get kicked off the launcher if it gets in the way of the manned missions. The other issue is that the reliability of SLS is questionable given the low flight rate. The current schedule has Clipper flying 2 and a half years after the first SLS, which is too long a gap between flights IMO.

In the end, I think Clipper rides another vehicle.
Title: Re: Proposed Europa Missions
Post by: clongton on 02/24/2018 09:01 pm
It would be nice to get to Jupiter faster, but the problem I can see is that Clipper will never be a priority for SLS and it may get kicked off the launcher if it gets in the way of the manned missions. The other issue is that the reliability of SLS is questionable given the low flight rate. The current schedule has Clipper flying 2 and a half years after the first SLS, which is too long a gap between flights IMO.

In the end, I think Clipper rides another vehicle.

The sooner that decision is made the better.
Title: Re: Proposed Europa Missions
Post by: Star One on 02/25/2018 08:20 am
It would be nice to get to Jupiter faster, but the problem I can see is that Clipper will never be a priority for SLS and it may get kicked off the launcher if it gets in the way of the manned missions. The other issue is that the reliability of SLS is questionable given the low flight rate. The current schedule has Clipper flying 2 and a half years after the first SLS, which is too long a gap between flights IMO.

In the end, I think Clipper rides another vehicle.

The sooner that decision is made the better.

One of the biggest impediments to the program moving forward at the moment is SLS. Once they can move it elsewhere the better.
Title: Re: Proposed Europa Missions
Post by: Jim on 02/26/2018 01:00 pm

One wonders how SLS is supposed to be certified by then.

SLS is not subject to certification. Certification is not applicable to NASA managed vehicles.
Title: Re: Proposed Europa Missions
Post by: redliox on 02/28/2018 04:41 am
Fresh updates thanks to the recent OPAG meeting on 'Clipper:
https://www.lpi.usra.edu/opag/meetings/feb2018/presentations/Pappalardo.pdf (https://www.lpi.usra.edu/opag/meetings/feb2018/presentations/Pappalardo.pdf)
Title: Re: Proposed Europa Missions
Post by: arezn on 03/08/2018 06:27 am
From another topic:

MATTBLACK:
Yes - things would certainly look good for lunar missions, doing 'distributed launch' of the spacecraft and the Earth Departure Stage (EDS). A Falcon 9 could place a 20 ton Lander or Command Module type vehicle into orbit first. A Falcon Heavy places it's upper stage as an EDS into orbit next, where it's only payload is propellant (65-70 tons?) and a docking mechanism. The spacecraft docks with this and the EDS burns for TLI.

Why not use the scheme for Europa Clipper?
Can Atlas 401/F9 and F9H provide direct flight to Jupiter?
Title: Re: Proposed Europa Missions
Post by: redliox on 03/08/2018 12:51 pm
From another topic:

MATTBLACK:
Yes - things would certainly look good for lunar missions, doing 'distributed launch' of the spacecraft and the Earth Departure Stage (EDS). A Falcon 9 could place a 20 ton Lander or Command Module type vehicle into orbit first. A Falcon Heavy places it's upper stage as an EDS into orbit next, where it's only payload is propellant (65-70 tons?) and a docking mechanism. The spacecraft docks with this and the EDS burns for TLI.

Why not use the scheme for Europa Clipper?
Can Atlas 401/F9 and F9H provide direct flight to Jupiter?

There's already an answer if you scroll back a few pages.  Otherwise email the Clipper team and directly ask them.
Title: Re: Proposed Europa Missions
Post by: Star One on 03/29/2018 03:56 pm
Twenty days on the surface doesn’t seem all that much for the time and money invested.

Europa lander concept redesigned to lower cost and complexity

Quote
In a presentation at a meeting of the Committee on Astrobiology and Planetary Science of the National Academies March 28, Kevin Hand of the Jet Propulsion Laboratory said that feedback from a mission concept review for the proposed lander last June led to changes in the design to reduce its cost.

“The technology and science were well received. The marching orders that we got out of that review were to see if we could simplify the architecture to reduce complexity and cost,” he said. While there’s been little discussion of the lander’s cost, Hand said there was a “desire” to reduce its cost to below $3 billion.

The concept for the mission presented at that review involved the launch of the lander on a Space Launch System rocket no earlier than late 2025. The spacecraft would enter orbit around Jupiter in 2030 with a landing on Europa to follow no earlier than December 2031. The battery-powered lander would operate on the surface for at least 20 days, relying on a communications relay spacecraft in orbit to return data to Earth.

http://spacenews.com/europa-lander-concept-redesigned-to-lower-cost-and-complexity/
Title: Re: Proposed Europa Missions
Post by: redliox on 03/29/2018 10:34 pm
Excellent update Blackstar; obviously depicts how they're trying to improve the antenna.

So is the main part of the redesign to ditch the orbiting relay setup, leaving basically the descent module and the lander?
Title: Re: Proposed Europa Missions
Post by: redliox on 03/29/2018 10:52 pm
Twenty days on the surface doesn’t seem all that much for the time and money invested.

Overall I agree; the more time the better but in that radiation environment good idea to be conservative and it might not be impossible.

Quote
Another factor that enables the change in design, he said, is a shift in the science requirements for the lander. A report by a science definition team last year had included, as one of the mission’s priorities, the ability of the lander’s instruments to directly detect any life that might exist in the moon’s icy surface.

“That’s a very high bar,” Hand said. “That bar runs the risk of setting expectations too high, perhaps, and also potentially cannibalizing some of the other science that the community sees as very valuable.”

Instead, the mission team looked at what the “sweet spot” for science from the lander mission might be. Hand said that looking for biosignatures of past or present life would simplify the science requirements for the mission, including reducing the amount of data needed to be transmitted back to Earth.

This would be the part I'd worry on: reducing the science for such an expensive mission.  Searching for life by sifting samples under a microscope isn't bad, but including 1 or 2 supplemental experiments (the seisometer as one example) should be allowed.  I'd understand if 75% of the payload is devoted to one objective (like biosignatures).
Title: Re: Proposed Europa Missions
Post by: Blackstar on 03/29/2018 11:10 pm
So is the main part of the redesign to ditch the orbiting relay setup, leaving basically the descent module and the lander?

The briefing was at one of our meetings that just ended today. The Europa lander is going through a lot of redesign. The big change was to get rid of the orbiter, but they've also changed the science focus a lot. The goal is to both get the cost down and to broaden the mission because the focus on finding life was considered too narrow. There are some interesting animations as well. The lack of data about the surface makes landing really challenging, so one of their goals is to develop a very smart landing system that can choose the best landing site in real time.
Title: Re: Proposed Europa Missions
Post by: Archibald on 03/30/2018 08:30 am
Nice to see possible collaboration between JUICE and Clipper, NASA and ESA. Makes some sense.
Title: Proposed Europa Missions
Post by: Star One on 03/30/2018 08:44 am
So is the main part of the redesign to ditch the orbiting relay setup, leaving basically the descent module and the lander?

The briefing was at one of our meetings that just ended today. The Europa lander is going through a lot of redesign. The big change was to get rid of the orbiter, but they've also changed the science focus a lot. The goal is to both get the cost down and to broaden the mission because the focus on finding life was considered too narrow. There are some interesting animations as well. The lack of data about the surface makes landing really challenging, so one of their goals is to develop a very smart landing system that can choose the best landing site in real time.

It’s a shame that time & cost no doubt preclude  the inclusion of something like a very simple probe that could have been put on Clipper to be dropped onto the surface to gain data to help with the lander development. But I suspect the cost of sterilisation alone for planetary protection would have made it prohibitively expensive for something like this.
Title: Re: Proposed Europa Missions
Post by: TakeOff on 03/30/2018 02:22 pm
Impactors have been crashed into asteroids to create a temporary plume of material from just under the surface. A, plume the composition of which could be identified by spectroscopy. Could this also be done on the largest airless bodies, like Europa, or is the surface gravity too strong? (I suppose collecting orbiting ejecta for sample return is way too acrobatic).
Title: Re: Proposed Europa Missions
Post by: ncb1397 on 03/30/2018 05:43 pm
Impactors have been crashed into asteroids to create a temporary plume of material from just under the surface. A, plume the composition of which could be identified by spectroscopy. Could this also be done on the largest airless bodies, like Europa, or is the surface gravity too strong? (I suppose collecting orbiting ejecta for sample return is way too acrobatic).

Europa is about the mass and size of our moon and impactors have been done on the Moon. Feedback goes the other way as well. The same technology for this lander could be used for a human scale lander if scaled.


See:
https://en.wikipedia.org/wiki/LCROSS
Title: Re: Proposed Europa Missions
Post by: Star One on 05/02/2018 08:04 pm
https://twitter.com/NASAOIG/status/991738510171426816

Quote
OIG announces an audit to assess NASA’s management of its mission to Europa, a moon of Jupiter.
Title: Re: Proposed Europa Missions
Post by: redliox on 08/02/2018 10:31 pm
An agenda has been posted for the next OPAG in September: https://www.lpi.usra.edu/opag/meetings/sep2018/agenda.pdf (https://www.lpi.usra.edu/opag/meetings/sep2018/agenda.pdf)
There'll be an update regarding 'Clipper alongside a general science update it appears.
Title: Re: Proposed Europa Missions
Post by: jbenton on 08/30/2018 10:33 pm
Hello Everyone, a few weeks ago, I decided to take a few days to read through this thread. The story of how the Europa Clipper probe came together (and is coming together) is quite interesting, and I was hoping since 2013 at least that it would be able to fly at least as early as 2025. Anyways I read through because I felt that when it does, it'd be nice for me to have some more historical perspective. Given that there has been so much discussion about the possibility of flying on SLS - as well as the requirement to fly on SLS - such as these relatively recent posts:

It would be nice to get to Jupiter faster, but the problem I can see is that Clipper will never be a priority for SLS and it may get kicked off the launcher if it gets in the way of the manned missions. The other issue is that the reliability of SLS is questionable given the low flight rate. The current schedule has Clipper flying 2 and a half years after the first SLS, which is too long a gap between flights IMO.

In the end, I think Clipper rides another vehicle.

The sooner that decision is made the better.

One of the biggest impediments to the program moving forward at the moment is SLS. Once they can move it elsewhere the better.

I was a little surprised to see no mention of this development:

https://www.nasaspaceflight.com/2018/05/sls-block-1-revival-plans-getting-mobile-launcher-money/
https://www.nasaspaceflight.com/2018/04/nasas-dual-ml-plan-extra-sls-block-1-missions/

The availability of two mobile launchers (and the ability of the Block I SLS to support this mission, which was in doubt early on) removes the concern that the Europa Clipper may interfere with Crewed exploration missions and vice-versa. However there remains the LV reliability concerns as well as well as the possibility that SLS may be cancelled by 2022-2025
Title: Re: Proposed Europa Missions
Post by: jbenton on 08/30/2018 10:34 pm
SLS is the baseline, but it looks like EC is already designed to be launcher-agnostic:

Thanks for the response. In reference to the launcher decision... I imagine that "if" the SLS could cut the transit time in half, that would certainly alter how they architect the systems? Or no?

Absolutely. First of all, if EC does not have to do the Venus flybys, then they can take off the thermal protection. So how long do they keep designing the vehicle with thermal protection and without it? That's two designs, more money, etc.

Also, a much shorter trip time may affect how much they have to test the spacecraft. But that could be a tricky issue. I'll provide a caveat that I'm not an expert on any of that stuff (remember, I'm a policy wonk), but generally a lot of testing is for lifetime. So they test something to see how long it will last. And if they can test it for a shorter lifetime that costs less.

Cost is probably the true issue for flying via SLS.  For the Europa mission (either the orbiter or lander), it would be wonderful to get directly to Jupiter; bad news is it may cost a lot, which coupled with safety was also a reason satellite providers rapidly abandoned the space shuttle.  I'd like to see the flyby-orbiter fly with it, but I wouldn't want to do that with the lander since developing that will be enough of a future expense as is.
I've worked with enough finance people to know that there is a lot of leeway on how costs are accounted for.  NASA will have large fixed costs for maintaining the capability of launching SLS missions.  Then there will be the marginal costs associated with building an individual booster, transporting it, fueling it, launching it, etc.  The key will be whether the science division (I suspect there are some great telescope observatories that SLS could launch in addition to planetary missions) is charged only the marginal cost or a substantial portion of the fixed costs.

I strongly suspect that NASA will design planetary missions so they can also be launched on commercial systems.  SLS may not work.  Political support may dry up (when will Shelby retire?).  There could be a launch failure and the whole system stands down for a couple of years.  Backups are good.
In the case of the Europa multiflyby mission, a key decision will be whether to expand the fuel tanks or not and/or design the spacecraft for the heat of Venus gravity assists.  The former would allow a deep space maneuver that would shorten the flight to 4.7 years with a Delta IV Heavy.  The latter would allow an EVEEGA trajectory and a 7.4 year flight.  How much insurance will NASA buy?

I heard someone say that they're designing it for the thermal effects of a Venus flyby no matter what. I don't know why, but myabe the margins opened up and they figured it is better to just plan for that no matter what.

It makes perfect sense to have a backup plan in the design of the spacecraft itself (to avoid the cost of duplicity of design), but much has changed since 2016, so I must ask: Are they still designing with TPS for the EVEEGA trajectory?

It would seem to make more sense to me remove the TPS from the design and plan on expanding the fuel tanks with the idea of using the Heavy EELV-launched EGA trajectory for the following reasons:

1) The plan is to launch in 2022, 2023, 2024 or 2025; Atlas V 551 will no longer exist during that time frame. The Falcon 9 Full Thrust Block 5 is the only comparable LV that may be available in that time. Though comparable, performance decreases over time, if I'm not mistaken. According to SpaceX' website, The Falcon 9 does 22,800kg to LEO, 8,300 to GTO and 4,020 trans-Martian Injection; whereas the Atlas V 551 - according to ULA Rocket Builder - does 18,856 to LEO, 8,899 to GTO, and 6,109 to Earth Escape (though MSL, launch mass of 3,839kg, used an Atlas V 541 to Mars which RB says isn't needed until 4,943kg - I take it that some extra propellant is required after Earth-escape for a Mars or Jupiter injection-burn, but I don't know how much)
https://www.spacex.com/about/capabilities
https://www.rocketbuilder.com/start/configure

2) In the 2022-2025 there may be as many as four or five affordable American HEELV launchers: Delta-IV Heavy, Falcon Heavy, Vulcan 562, New Glenn and maybe even OmegA Heavy. This seems to be a more reliable back-up plan.

3) 4.7 years is less than 7.4 years. 'nuf said

4) The TPS is all dead weight, if there is no Venus encounter, whereas the extra fuel can be used for mission extensions.

None of my arguments are valid if SLS has insufficient mass-margin to handle the extra fuel on the 2.7 year Jupiter direct route.
Title: Re: Proposed Europa Missions
Post by: jbenton on 08/30/2018 10:34 pm
On the other hand, I was not surprised that no one mentioned this. We all knew by then that the Europa Clipper was being designed to investigate any plumes that it may encounter - only now we have more confidence that there will actually be plumes to investigate:

https://www.nasaspaceflight.com/2018/05/nasa-galileo-flew-europa-plumes-excitement-europa-clipper-mission/

I find it interesting that when Galileo visited Europa, they notices strange perturbations in Jupiter's magnetosphere around Europa, but had no way to account for them. Now, after Cassini's one score and three years in the Saturn system, they now know that Enceladus' plumes have a similar effect on Saturn's magnetosphere. So someone on the Galileo team sifted through old data to see if the perturbations would correspond with some of the plume data that Hubble was watching less than five years ago, and sure enough, it did. It's just amazing how these discoveries can come together from such different science missions originally intended to examine such different things. "Expect the unexpected"

Anyways, that's also part of the story of this mission coming together, thought I'd post it (though anyone who has been following this thread in real-time surely already knows about this)
Title: Re: Proposed Europa Missions
Post by: jbenton on 08/30/2018 10:34 pm
https://spacepolicyonline.com/news/today-tidbits-december-21-2017/ (https://spacepolicyonline.com/news/today-tidbits-december-21-2017/)

Quote
Rep. Culberson’s Seat in Jeopardy?

One of the Republican seats that may be in jeopardy according to the Times belongs to Rep. John Culberson, chairman of the House Appropriations Subcommittee on Commerce-Justice-Science (CJS) that funds NASA and NOAA...

Using the power of his chairmanship, he has compelled NASA to build and launch a probe to Jupiter’s moon Europa because he is convinced life exists in the ocean that some scientists believe exists under its icy shell...


Direct link: http://www.rollcall.com/news/gonzales/ratings-change-culbersons-texas-seat-creeps-closer-toss
For anyone who's interested in digging a little deeper into this:

I'm a huge political junkie and my favorite site for this kind of stuff is FiveThirtyEight. They just opened a feature projecting a statistical model giving the odds of which party will win each seat in the House:

https://projects.fivethirtyeight.com/2018-midterm-election-forecast/house/

They have three different models "Lite", which appears identical to the "polls-only" model they had for 2016, "Classic" - the default option, which appears identical to the "polls-plus" model they had for 2016, and "Deluxe" which is completely new. Polls-plus is polls only, but with certain "fundamentals" - such as demographic data -  worked in. Polls-Plus was more accurate in previous elections, but in 2016 polls-only was more accurate. "Deluxe" is polls-plus but also with "expert opinions baked in.

They have a cartogram-map of the whole country where each hexagon represents one district. On the default "Classic" map, Rep. Culberson's 7th District is the Pale Blue Dot in the middle of the fourth row from the bottom of what is obviously Texas (even with the distortion) the "Lite" setting turns his hex dark pink.
"Lite" gives him a 75.7% chance of winning, and he's forecast to win 53.5% of the vote (plus or minus ~6.5%)
"Classic" gives him a 51.5% chance of winning, and he's forecast to win 50.2% (+ or - 5.2%)
"Deluxe" gives him a 50.7% chance, and he's forecast to carry 50.1% (+ or - 5.1%)
In short, Rep. Culberson has a slightly better chance of winning than losing, but his seat is nowhere near "safe". If he wins then he'll stay "Chairman" under a GOP majority or he'll probably be "Ranking Member" (if I'm not mistaken) under the Dems. Either way, he'll have more than enough power to push Europa Clipper (if not also the Lander) through and possibly even under his aggressive time-scale.

Not that I would be too worried that Europa Clipper would be in trouble, even if he loses. Planetary Science in general and JPL in particular have strong defenders on the Left:

http://www.planetary.org/blogs/casey-dreier/2013/20130515-nasa-steals-back-money-from-planetary-science.html

Quote
Despite Congress rejecting cuts to NASA's Planetary Science Division in March, NASA plans to raid the restored funds for use in other projects for the remainder of this year. This is a stunning rebuke to Congress and a very rare move by NASA that continues to undercut this popular and productive program.

... [snip]

This is an entirely separate issue from the proposed 2014 budget, which continues cuts to this program next year.

Key people in Congress will be very upset about this, especially Adam Schiff, Dianne Feinstein, and John Culberson, who wrote an open letter to the NASA Administrator just last month warning them to not defy congressional will on the importance of planetary science.

(Rep. Schiff, for anyone who doesn't know represents the district containing JPL. As a Democrat representing an urban/suburban district in California and further as a known Trump-critic, his seat is probably very safe. 538 gives him ">99%" chance of winning under all models.
Title: Re: Proposed Europa Missions
Post by: jbenton on 08/30/2018 10:34 pm
Why is it that the Europa spacecraft's electronics vault is made of aluminum rather than some other material?
Low atomic weight and won't release volatiles.

...and Juno is using 1cm of titanium:

https://en.wikipedia.org/wiki/Juno_(spacecraft)#Orbit_and_environment

Quote
The orbits were carefully planned in order to minimize contact with Jupiter's dense radiation belts, which can damage spacecraft electronics and solar panels, by exploiting a gap in the radiation envelope near the planet, passing through a region of minimal radiation. The "Juno Radiation Vault", with 1-centimeter-thick titanium walls, also aids in protecting Juno's electronics. Despite the intense radiation, JunoCam and the Jovian Infrared Auroral Mapper (JIRAM) are expected to endure at least eight orbits, while the Microwave Radiometer (MWR) should endure at least eleven orbits. Juno will receive much lower levels of radiation in its polar orbit than the Galileo orbiter received in its equatorial orbit. Galileo's subsystems were damaged by radiation during its mission, including an LED in its data recording system.

"Juno Radiation Vault" blue-links into an entire article dedicated to just that subject.

I'm wondering what the comparative advantages between Ti and Al are. I assume they both do the job of radiation shielding (without radiation spalling) quite well.

However, I assume that titanium is more mass-efficient and volume-efficient, but Al is much cheaper. I further assume that, for Juno, which didn't need as much, Ti was more cost-effective, but for 'Clipper - which needs much more - Al will be better because you can just keep piling more of it on, more cheaply.

Anyone have anything better than assumptions?
Title: Re: Proposed Europa Missions
Post by: jbenton on 08/30/2018 10:35 pm
...Europa is like nowhere else in the Solar System, and the orbiter will address questions that have been out there for nearly 20 years. The Galileo mission was partly a failure, and a return to the moons of Jupiter with a fully functioning spacecraft is long overdue. The Jupiter system has a very rich set of scientific phenomena, and there are plenty of other things to see besides Europa.

ESA's JUICE will spend a lot of its time looking at all the other wonders of the Jupiter system.  Per the Europa mission's project manager, they haven't spent any time looking at studies of additional bodies.  I did see one orbital study for the mission that included several flybys of Ganymede and Callisto.  Right now the plan to dispose of Clipper is to crash it on Ganymede; the project manager says his dream is to see it do a couple of flybys of Io first before crashing it on that moon.

But JUICE has instruments better suited to studying Jupiter and the magnetosphere than the Clipper.

Together the two missions will do an awesome job, especially if they operate at the same time.

In my fantasy world, a Discovery Io flyby mission would also operate at the same time, but it would have to be selected in the next competition for that to happen.

I would like to ask about extended missions; What are the risks and benefits of:

1) More Europa flybys - Someone posted here on one of the earlier threads that the Solar wings can handle more than 200 flybys, whereas the primary mission only involves 45. How many can the other components handle? Is there fuel enough to match?

2) Callisto flybys - If 'Clipper can use a gravity assist to circularize it's orbit at apojove, then it could put itself in a less radioactive environment to investigate Ganymede and Callisto. Callisto is more important because she receives less attention from JUICE (that and the radiation is tolerable for humans over there)

3) The Io flybys are most exciting to me. IIRC, Io Observer baselines 6 flybys. How many could ol' 'Clipper handle after its primary mission at Europa?

4) Could some mix of the 3 be at all possible? (I was thinking extra Europa flybys, followed by a few years of Callisto flybys as a second extended mission to take a break from all that radiation and lastly a "grand finale" mission for Io, kinda like Cassini got multiple extended missions)

Also: Why does it need to crash into Ganymede or Io? Why can't they send it hurtling through Jupiter's atmosphere like Cassini?
Title: Re: Proposed Europa Missions
Post by: TripleSeven on 08/30/2018 10:43 pm
https://spacepolicyonline.com/news/today-tidbits-december-21-2017/ (https://spacepolicyonline.com/news/today-tidbits-december-21-2017/)

Quote
Rep. Culberson’s Seat in Jeopardy?

One of the Republican seats that may be in jeopardy according to the Times belongs to Rep. John Culberson, chairman of the House Appropriations Subcommittee on Commerce-Justice-Science (CJS) that funds NASA and NOAA...

Using the power of his chairmanship, he has compelled NASA to build and launch a probe to Jupiter’s moon Europa because he is convinced life exists in the ocean that some scientists believe exists under its icy shell...


Direct link: http://www.rollcall.com/news/gonzales/ratings-change-culbersons-texas-seat-creeps-closer-toss
For anyone who's interested in digging a little deeper into this:

I'm a huge political junkie and my favorite site for this kind of stuff is FiveThirtyEight. They just opened a feature projecting a statistical model giving the odds of which party will win each seat in the House:

https://projects.fivethirtyeight.com/2018-midterm-election-forecast/house/

They have three different models "Lite", which appears identical to the "polls-only" model they had for 2016, "Classic" - the default option, which appears identical to the "polls-plus" model they had for 2016, and "Deluxe" which is completely new. Polls-plus is polls only, but with certain "fundamentals" - such as demographic data -  worked in. Polls-Plus was more accurate in previous elections, but in 2016 polls-only was more accurate. "Deluxe" is polls-plus but also with "expert opinions baked in.

They have a cartogram-map of the whole country where each hexagon represents one district. On the default "Classic" map, Rep. Culberson's 7th District is the Pale Blue Dot in the middle of the fourth row from the bottom of what is obviously Texas (even with the distortion) the "Lite" setting turns his hex dark pink.
"Lite" gives him a 75.7% chance of winning, and he's forecast to win 53.5% of the vote (plus or minus ~6.5%)
"Classic" gives him a 51.5% chance of winning, and he's forecast to win 50.2% (+ or - 5.2%)
"Deluxe" gives him a 50.7% chance, and he's forecast to carry 50.1% (+ or - 5.1%)
In short, Rep. Culberson has a slightly better chance of winning than losing, but his seat is nowhere near "safe". If he wins then he'll stay "Chairman" under a GOP majority or he'll probably be "Ranking Member" (if I'm not mistaken) under the Dems. Either way, he'll have more than enough power to push Europa Clipper (if not also the Lander) through and possibly even under his aggressive time-scale.

Not that I would be too worried that Europa Clipper would be in trouble, even if he loses. Planetary Science in general and JPL in particular have strong defenders on the Left:

http://www.planetary.org/blogs/casey-dreier/2013/20130515-nasa-steals-back-money-from-planetary-science.html

Quote
Despite Congress rejecting cuts to NASA's Planetary Science Division in March, NASA plans to raid the restored funds for use in other projects for the remainder of this year. This is a stunning rebuke to Congress and a very rare move by NASA that continues to undercut this popular and productive program.

... [snip]

This is an entirely separate issue from the proposed 2014 budget, which continues cuts to this program next year.

Key people in Congress will be very upset about this, especially Adam Schiff, Dianne Feinstein, and John Culberson, who wrote an open letter to the NASA Administrator just last month warning them to not defy congressional will on the importance of planetary science.

(Rep. Schiff, for anyone who doesn't know represents the district containing JPL. As a Democrat representing an urban/suburban district in California and further as a known Trump-critic, his seat is probably very safe. 538 gives him ">99%" chance of winning under all models.

nice comments.  I was suprised to see when I read that article on 538 that TX 22 was moved from safe.
Title: Re: Proposed Europa Missions
Post by: vjkane on 08/30/2018 11:04 pm
1) More Europa flybys - Someone posted here on one of the earlier threads that the Solar wings can handle more than 200 flybys, whereas the primary mission only involves 45. How many can the other components handle? Is there fuel enough to match?

2) Callisto flybys - If 'Clipper can use a gravity assist to circularize it's orbit at apojove, then it could put itself in a less radioactive environment to investigate Ganymede and Callisto. Callisto is more important because she receives less attention from JUICE (that and the radiation is tolerable for humans over there)

3) The Io flybys are most exciting to me. IIRC, Io Observer baselines 6 flybys. How many could ol' 'Clipper handle after its primary mission at Europa?

4) Could some mix of the 3 be at all possible? (I was thinking extra Europa flybys, followed by a few years of Callisto flybys as a second extended mission to take a break from all that radiation and lastly a "grand finale" mission for Io, kinda like Cassini got multiple extended missions)

Also: Why does it need to crash into Ganymede or Io? Why can't they send it hurtling through Jupiter's atmosphere like Cassini?
In presentations, the mission team has said that the spacecraft and instruments likely could survive many more encounters with Europa than the planned 45.

As for studying Ganymede and Callisto, there will be several early flybys used as gravity assists to pump down the orbit for the final Europa-focused orbits.  In addition, ESA's JUICE spacecraft will orbit Ganymede and perform a number of Callisto flybys (along with a couple of Europa flybys).  There's probably not a whole lot more science that EC could do at those moons that isn't already planned.  On the other hand, more flybys of Europa will provide more high resolution imaging coverage and improve the models of the gravity field and the interaction of the magnetosphere with the interior ocean.  The greater the number of Europa flybys, the more the coverage comes to become equivalent to that from a spacecraft orbiting that moon.
Title: Re: Proposed Europa Missions
Post by: LouScheffer on 08/31/2018 02:29 am
SLS is the baseline, but it looks like EC is already designed to be launcher-agnostic:


Absolutely. First of all, if EC does not have to do the Venus flybys, then they can take off the thermal protection. So how long do they keep designing the vehicle with thermal protection and without it? That's two designs, more money, etc.

Also, a much shorter trip time may affect how much they have to test the spacecraft. But that could be a tricky issue. I'll provide a caveat that I'm not an expert on any of that stuff (remember, I'm a policy wonk), but generally a lot of testing is for lifetime. So they test something to see how long it will last. And if they can test it for a shorter lifetime that costs less.


I strongly suspect that NASA will design planetary missions so they can also be launched on commercial systems.  SLS may not work.  Political support may dry up (when will Shelby retire?).  There could be a launch failure and the whole system stands down for a couple of years.  Backups are good.
In the case of the Europa multiflyby mission, a key decision will be whether to expand the fuel tanks or not and/or design the spacecraft for the heat of Venus gravity assists.  The former would allow a deep space maneuver that would shorten the flight to 4.7 years with a Delta IV Heavy.  The latter would allow an EVEEGA trajectory and a 7.4 year flight.  How much insurance will NASA buy?

I heard someone say that they're designing it for the thermal effects of a Venus flyby no matter what. I don't know why, but myabe the margins opened up and they figured it is better to just plan for that no matter what.

It makes perfect sense to have a backup plan in the design of the spacecraft itself (to avoid the cost of duplicity of design), but much has changed since 2016, so I must ask: Are they still designing with TPS for the EVEEGA trajectory?

It would seem to make more sense to me remove the TPS from the design and plan on expanding the fuel tanks with the idea of using the Heavy EELV-launched EGA trajectory for the following reasons:
Looking at recent  NASA launch vehicle specs for high energy trajectories (https://forum.nasaspaceflight.com/index.php?topic=43025.msg1849465#msg1849465), and assuming Europa Clipper stays at 6000 kg, it would appear that Delta-4 Heavy would still require a Venus assist, but Falcon Heavy could do it with a deep space maneuver, saving several years and the need for thermal shielding.  Here is the thinking:

Juno, for example, had a C3 of about 30 km^2/sec^2, then used about 775 m/s of deep space maneuver followed by one Earth assist.   Assuming an ISP of 320 for the DSM engine, that implies a mass ratio of about 1.28, or an initial mass of 7800 kg if the Jupiter arrival mass is to be kept at 6000 kg.  The Falcon Heavy can put about 8000 kg to a C3 of 30, so this works. 

Delta-4 heavy looks like it can put about 6000 kg to a C3 of 30.  This is more than enough to send EC to Venus (which requires only a C3 of 15, even in the worst windows), and hence to Jupiter.  But it's not enough to do this with a single deep space maneuver, as Juno did.  So you would still need the high-temp shielding.
Title: Re: Proposed Europa Missions
Post by: jbenton on 08/31/2018 03:48 am
nice comments.  I was surprised to see when I read that article on 538 that TX 22 was moved from safe.

I just checked their map. TX 22 is listed as "solid R" under their polls-only model, and as "likely R" under their other two models. Just to bring Culberson back into focus, another one of their articles was pointing out a few places where one of their models disagreed with other expert analyses, and they compared the 7th district (Culberson's) with the 25th. They said that their "Lite" and "Classic" model considered the 25th to be much safer R than the experts' who considered it just as worrisome (for the Republicans) as the 7th. I find it kind of interesting that these ballot-watchers (who aren't necessarily space geeks) consider Culberson a go-to "generic Republican who should be more worried than usual".

(Another interesting note, though was the campaign finance site they had linked: One of the things that people have been saying about Culberson is that he hasn't been fundraising enough, and it is true that he has raised less funds than his opponent, but she has spent just enough the he now has more "cash-on-hand" than she does. I'm not sure if he can or will use that to his advantage, but I mention it because it is interesting.)

I honestly don't know much about this guy outside of his work with NASA, but I really like how has been pushing to make this mission happen, and has also been able to increase NASA's top line budget to make it happen. Other programs have been on 'Clipper's "coattails" to use the political term. I'm not sure how I feel about the lander; it seems too early, and it may get in the way of sample return. In any case, whether he wins or loses, I hope he or his successor as chairperson of CJS' Space Subcommittee will make 'Clipper launches and be mindful of NASA's other priorities.
Title: Re: Proposed Europa Missions
Post by: jbenton on 08/31/2018 03:49 am
In presentations, the mission team has said that the spacecraft and instruments likely could survive many more encounters with Europa than the planned 45.

As for studying Ganymede and Callisto, there will be several early flybys used as gravity assists to pump down the orbit for the final Europa-focused orbits.  In addition, ESA's JUICE spacecraft will orbit Ganymede and perform a number of Callisto flybys (along with a couple of Europa flybys).  There's probably not a whole lot more science that EC could do at those moons that isn't already planned.  On the other hand, more flybys of Europa will provide more high resolution imaging coverage and improve the models of the gravity field and the interaction of the magnetosphere with the interior ocean.  The greater the number of Europa flybys, the more the coverage comes to become equivalent to that from a spacecraft orbiting that moon.

Glad to hear that it can do a Europa-focused extended mission! I was always just assuming that there'd be more than 45 Europa flybys. Until reading the talk here about Io flybys, I just off-hand assumed that any extended missions would be just as Europa-focused as the prime mission.

I guess they're already going to know Callisto pretty well by the time JUICE starts orbiting Ganymede (and EC completes its prime mission). I was just thinking if Callisto turns out to be more interesting than mission planners thought it would be. Also, I just like the idea of have a complete map for as many worlds as possible, and between the three of them (Europa, Ganymede and Callisto) I think Callisto is the most beautiful. Being outside of the intense radiation belt is also nice.
Title: Re: Proposed Europa Missions
Post by: jbenton on 08/31/2018 03:49 am
Looking at recent  NASA launch vehicle specs for high energy trajectories (https://forum.nasaspaceflight.com/index.php?topic=43025.msg1849465#msg1849465), and assuming Europa Clipper stays at 6000 kg, it would appear that Delta-4 Heavy would still require a Venus assist, but Falcon Heavy could do it with a deep space maneuver, saving several years and the need for thermal shielding.  Here is the thinking:

Juno, for example, had a C3 of about 30 km^2/sec^2, then used about 775 m/s of deep space maneuver followed by one Earth assist.   Assuming an ISP of 320 for the DSM engine, that implies a mass ratio of about 1.28, or an initial mass of 7800 kg if the Jupiter arrival mass is to be kept at 6000 kg.  The Falcon Heavy can put about 8000 kg to a C3 of 30, so this works. 

Delta-4 heavy looks like it can put about 6000 kg to a C3 of 30.  This is more than enough to send EC to Venus (which requires only a C3 of 15, even in the worst windows), and hence to Jupiter.  But it's not enough to do this with a single deep space maneuver, as Juno did.  So you would still need the high-temp shielding.

Huh, weird...

They've been saying for years that the Delta IV trajectory would be 4.7 years and with no Venus flybys. I guess that was the whole point of the extra propellant. Clipper would have to be its own kick stage! There's really no point in spending the extra money for Delta Heavy if it can't skip the Venus flyby. Delta IV is over-kill for that. At that point you may as well go for the exspendable Falcon Heavy, save some money and do the same mission slightly better, i.e. with margin.

It's too bad that the chart you linked didn't have a trajectory for the Falcon 9 Block 5. I wanted to see if it could match the performance of Atlas V 551.
(Wait, I answer my own question: It looks like re-used Falcon Heavy matches the performance of an Atlas V 551 for this mission; therefore it stands to reason that the single-core Falcon 9 Block 5 would perform worse for this mission)
Title: Re: Proposed Europa Missions
Post by: JH on 08/31/2018 05:46 am
I'm wondering what the comparative advantages between Ti and Al are. I assume they both do the job of radiation shielding (without radiation spalling) quite well. However, I assume that titanium is more mass-efficient and volume-efficient, but Al is much cheaper. I further assume that, for Juno, which didn't need as much, Ti was more cost-effective, but for 'Clipper - which needs much more - Al will be better because you can just keep piling more of it on, more cheaply.

I'm not certain about the exact reasons for Ti vs. Al — probably related to expected radiation spectra in different regions of Jupiter's magnetosphere, combined with anticipated mission lifetimes (calculating dosimetry in the Jovian magnetosphere is complex) — but I can tell you that it didn't have anything to do with cost.
Title: Re: Proposed Europa Missions
Post by: Star One on 08/31/2018 06:28 am
Looking at recent  NASA launch vehicle specs for high energy trajectories (https://forum.nasaspaceflight.com/index.php?topic=43025.msg1849465#msg1849465), and assuming Europa Clipper stays at 6000 kg, it would appear that Delta-4 Heavy would still require a Venus assist, but Falcon Heavy could do it with a deep space maneuver, saving several years and the need for thermal shielding.  Here is the thinking:

Juno, for example, had a C3 of about 30 km^2/sec^2, then used about 775 m/s of deep space maneuver followed by one Earth assist.   Assuming an ISP of 320 for the DSM engine, that implies a mass ratio of about 1.28, or an initial mass of 7800 kg if the Jupiter arrival mass is to be kept at 6000 kg.  The Falcon Heavy can put about 8000 kg to a C3 of 30, so this works. 

Delta-4 heavy looks like it can put about 6000 kg to a C3 of 30.  This is more than enough to send EC to Venus (which requires only a C3 of 15, even in the worst windows), and hence to Jupiter.  But it's not enough to do this with a single deep space maneuver, as Juno did.  So you would still need the high-temp shielding.

Huh, weird...

They've been saying for years that the Delta IV trajectory would be 4.7 years and with no Venus flybys. I guess that was the whole point of the extra propellant. Clipper would have to be its own kick stage! There's really no point in spending the extra money for Delta Heavy if it can't skip the Venus flyby. Delta IV is over-kill for that. At that point you may as well go for the exspendable Falcon Heavy, save some money and do the same mission slightly better, i.e. with margin.

It's too bad that the chart you linked didn't have a trajectory for the Falcon 9 Block 5. I wanted to see if it could match the performance of Atlas V 551.
(Wait, I answer my own question: It looks like re-used Falcon Heavy matches the performance of an Atlas V 551 for this mission; therefore it stands to reason that the single-core Falcon 9 Block 5 would perform worse for this mission)

Would Falcon Heavy be certified to fly this kind of mission as so far it seems to have a relatively low flight rate.
Title: Re: Proposed Europa Missions
Post by: LouScheffer on 08/31/2018 12:40 pm

Huh, weird...

They've been saying for years that the Delta IV trajectory would be 4.7 years and with no Venus flybys. I guess that was the whole point of the extra propellant. Clipper would have to be its own kick stage! There's really no point in spending the extra money for Delta Heavy if it can't skip the Venus flyby. Delta IV is over-kill for that. At that point you may as well go for the exspendable Falcon Heavy, save some money and do the same mission slightly better, i.e. with margin.

It's too bad that the chart you linked didn't have a trajectory for the Falcon 9 Block 5. I wanted to see if it could match the performance of Atlas V 551.
(Wait, I answer my own question: It looks like re-used Falcon Heavy matches the performance of an Atlas V 551 for this mission; therefore it stands to reason that the single-core Falcon 9 Block 5 would perform worse for this mission)

Perhaps the 6000 kg launch mass already includes the extra fuel for the Deep Space Maneuver , so the Jupiter arrival mass is about 4600 kg?  Since the Delta IV can place 6000 kg to a C3 of 30, that would allow D4H with no Venus flyby.  FH can do this trajectory as well, with somewhat better margins.

In this case both the D4H and FH could do the mission with the deep space maneuver.   But neither of them can put 4600 kg to a C3 of 80, which would be needed for a direct course to Jupiter.

An Atlas 551 can put about 4600 kg to Venus, so that could be the backup-backup-backup plan with a still longer trajectory (if the SLS, D4H, and FH plans fall through).   But at some point it makes sense to stop planning for a Venus flyby.
Title: Re: Proposed Europa Missions
Post by: MATTBLAK on 08/31/2018 01:00 pm
I've been wondering what kind of Europa mission Falcon Heavy could do with 'simple' upper stage upgrades done - I'm not talking about a Raptor-powered upper stage. But an upper stage widened to match the 5.2 meter payload fairing, to give increased propellant loads and a further upgraded Merlin 1D Vacuum? Or if the stage widening is too difficult/costly: keeping the same 3.7 meter diameter but stretching it's tankage another couple meters?

We already know what to expect in terms of specific impulse, thrust classes and increased masses, gravity losses etc; because of our relative familiarity with the Falcon hardware. But has anyone ever done some specific, sober analysis into FH upper stage upgrades on NSF? Even improving FH's Earth Escape capability by 3 or 4 metric tons - or more - would be a big win.

And then, even landing missions on Mercury and Ceres start to look pretty decent. And what about the other Jovian moons, such as Callisto, Ganymede etc? What about missions to the surface of Titan..?
Title: Re: Proposed Europa Missions
Post by: ugordan on 08/31/2018 01:30 pm
Even improving FH's Earth Escape capability by 3 or 4 metric tons - or more - would be a big win.

What would be the business case for that? A heavy interplanetary mission that happens *maybe* once in a decade and you'd do that significant upgrade and lose all flight reliability history of the base vehicle, all the while FH is slated to be retired in favor of BFR anyway.

I don't see it ever happening.
Title: Re: Proposed Europa Missions
Post by: vjkane on 08/31/2018 01:53 pm
Even improving FH's Earth Escape capability by 3 or 4 metric tons - or more - would be a big win.

What would be the business case for that? A heavy interplanetary mission that happens *maybe* once in a decade and you'd do that significant upgrade and lose all flight reliability history of the base vehicle, all the while FH is slated to be retired in favor of BFR anyway.

I don't see it ever happening.
Anyone who suggests that a flagship planetary mission should plan on using a non-qualified launcher should review the search for a launch vehicle for the Galileo mission and review the length of time it took/will take for FH/SLS to reach its first launch much less its still to come qualification for launching key missions.  Rocket development is hard, takes a long time, and almost always takes much longer than planned.

The Clipper program has been silent in its public presentations about launch options for several years now.  I suspect that they are trying to meet the legal mandate to launch on SLS (see paragraph above) while holding a backup option.  One problem is that they probably need to decide soon -- you don't just go down to the local hardware store and pick up a Delta IV Heavy.
Title: Re: Proposed Europa Missions
Post by: MATTBLAK on 08/31/2018 02:01 pm
Probably not a 'business case' so to speak, ugordon. It is a relevant point, though barely; because further solar system exploration 'Flagship' missions are hardly a sure thing anymore. Some folk have said there's no business case for more RD-180 engines for more Atlas V's - yet more engines are coming. How many extensions have there been now?! Look: when it comes to the long range planning for these missions, choosing a launcher for them is an integral part of mission planning. It all needs to be looked at - how big is the spacecraft? What launchers are available and at what cost? Delta IV-H? Ariane V or 6? Proton? Falcon Heavy? SLS? Atlas V-551 or 552, Vulcan or New Glenn..? It all matters. We're just going to have to see what happens in the coming few years. The more successes Falcon Heavy has, the more attractive it might start to look.

Especially since upgrade possibilities for it haven't really been looked at in any depth, expect in discussions like this one, driven in part by amateur Space Geeks like me. Upgrades for traditional EELV's have been looked at for many years, by the companies that build them. Many pdf and Powerpoint papers have gone into those prospects. Spacecraft design and mission architectures can be frozen once the mission designers and managers know what's going to be around. A lot of people keep writing off Falcon Heavy because they have a blind faith the BFR/BFS is all going to go swimmingly and on schedule. I bloody well hope it does - because I'm a T-shirt wearing, SpaceX fan and cheerleader. But I've been around too long now to lock in any one approach as being the only way to do things. And it's only all over when they call 'wheels stop' or splashdown...
Title: Re: Proposed Europa Missions
Post by: TripleSeven on 08/31/2018 02:29 pm
nice comments.  I was surprised to see when I read that article on 538 that TX 22 was moved from safe.

I just checked their map. TX 22 is listed as "solid R" under their polls-only model, and as "likely R" under their other two models. Just to bring Culberson back into focus, another one of their articles was pointing out a few places where one of their models disagreed with other expert analyses, and they compared the 7th district (Culberson's) with the 25th. They said that their "Lite" and "Classic" model considered the 25th to be much safer R than the experts' who considered it just as worrisome (for the Republicans) as the 7th. I find it kind of interesting that these ballot-watchers (who aren't necessarily space geeks) consider Culberson a go-to "generic Republican who should be more worried than usual".

(Another interesting note, though was the campaign finance site they had linked: One of the things that people have been saying about Culberson is that he hasn't been fundraising enough, and it is true that he has raised less funds than his opponent, but she has spent just enough the he now has more "cash-on-hand" than she does. I'm not sure if he can or will use that to his advantage, but I mention it because it is interesting.)

I honestly don't know much about this guy outside of his work with NASA, but I really like how has been pushing to make this mission happen, and has also been able to increase NASA's top line budget to make it happen. Other programs have been on 'Clipper's "coattails" to use the political term. I'm not sure how I feel about the lander; it seems too early, and it may get in the way of sample return. In any case, whether he wins or loses, I hope he or his successor as chairperson of CJS' Space Subcommittee will make 'Clipper launches and be mindful of NASA's other priorities.

Exactly.  Its the first time I have seen old Pete campaigning since he was elected.  I didn't even know his opponents name. Lol

I dont care to much for the mission.  The science while good will be to primitive to take any advantage of...we should spend the money on finding water on the moon.
Title: Re: Proposed Europa Missions
Post by: LouScheffer on 08/31/2018 02:34 pm
Would Falcon Heavy be certified to fly this kind of mission as so far it seems to have a relatively low flight rate.
If the FH can launch twice a year, by 2022 it will have as many launches as Delta-4 Heavy does now - Parker Solar Probe was the 10th mission of the D4H.  All of these bigger rockets have quite low flight rates - there are not many payloads that need their services.
Title: Re: Proposed Europa Missions
Post by: Star One on 08/31/2018 02:49 pm
Would Falcon Heavy be certified to fly this kind of mission as so far it seems to have a relatively low flight rate.
If the FH can launch twice a year, by 2022 it will have as many launches as Delta-4 Heavy does now - Parker Solar Probe was the 10th mission of the D4H.  All of these bigger rockets have quite low flight rates - there are not many payloads that need their services.

That’s might come true but at the moment the first flight wouldn’t count for NASA as that wasn’t using the block 5 configuration and the first flight with this appears to be drifting out of 2018.
Title: Re: Proposed Europa Missions
Post by: vjkane on 08/31/2018 03:17 pm
If the FH can launch twice a year, by 2022 it will have as many launches as Delta-4 Heavy does now - Parker Solar Probe was the 10th mission of the D4H.  All of these bigger rockets have quite low flight rates - there are not many payloads that need their services.
*IF*.  Do you want to bet your $3B flagship mission on there being no development hiccups (first flight went great; will the second and third?) or SpaceX deciding it really doesn't need the FH with the BFH coming on line or there just turning out not to be enough customers to make it viable?

I lived through the Galileo search for a launch.  You don't want your booster development to be in your critical path.  I think it is idiocy to tie Clipper to the SLS for this reason.
Title: Re: Proposed Europa Missions
Post by: TripleSeven on 08/31/2018 04:00 pm
Anyone who suggests that a flagship planetary mission should plan on using a non-qualified launcher should review the search for a launch vehicle for the Galileo mission and review the length of time it took/will take for FH/SLS to reach its first launch much less its still to come qualification for launching key missions.  Rocket development is hard, takes a long time, and almost always takes much longer than planned.

Shhhh!!! Don't interrupt the kids while they're role-playing...

Can the heavy do the launch without modifications?
Title: Re: Proposed Europa Missions
Post by: TripleSeven on 08/31/2018 04:02 pm
If the FH can launch twice a year, by 2022 it will have as many launches as Delta-4 Heavy does now - Parker Solar Probe was the 10th mission of the D4H.  All of these bigger rockets have quite low flight rates - there are not many payloads that need their services.
*IF*.  Do you want to bet your $3B flagship mission on there being no development hiccups (first flight went great; will the second and third?) or SpaceX deciding it really doesn't need the FH with the BFH coming on line or there just turning out not to be enough customers to make it viable?

I lived through the Galileo search for a launch.  You don't want your booster development to be in your critical path.  I think it is idiocy to tie Clipper to the SLS for this reason.

I was more or less a child then lol..assuming challenger had not happen.  What is your opinion of if the centaur g would have flown?
Title: Re: Proposed Europa Missions
Post by: ugordan on 08/31/2018 04:07 pm
Can the heavy do the launch without modifications?

IMHO if Clipper doesn't go up on SLS, the only launch provider that'll launch it is ULA, whether it being Vulcan or D-IVH. It's just too valuable of a payload to risk anything, especially Musk's whims and changes of plans.
Title: Re: Proposed Europa Missions
Post by: su27k on 08/31/2018 04:10 pm
Would Falcon Heavy be certified to fly this kind of mission as so far it seems to have a relatively low flight rate.
If the FH can launch twice a year, by 2022 it will have as many launches as Delta-4 Heavy does now - Parker Solar Probe was the 10th mission of the D4H.  All of these bigger rockets have quite low flight rates - there are not many payloads that need their services.

That’s might come true but at the moment the first flight wouldn’t count for NASA as that wasn’t using the block 5 configuration and the first flight with this appears to be drifting out of 2018.

A FH was already sold to USAF under EELV Phase 1A, which would require FH to be certified by USAF by 2020 for EELV missions. NASA LSP certification would be similar to USAF certification.
Title: Proposed Europa Missions
Post by: Star One on 08/31/2018 04:18 pm
Can the heavy do the launch without modifications?

IMHO if Clipper doesn't go up on SLS, the only launch provider that'll launch it is ULA, whether it being Vulcan or D-IVH. It's just too valuable of a payload to risk anything, especially Musk's whims and changes of plans.

Would Vulcan be certified by the point that they have to make a decision on the launcher?
Title: Re: Proposed Europa Missions
Post by: TripleSeven on 08/31/2018 04:24 pm
Can the heavy do the launch without modifications?

IMHO if Clipper doesn't go up on SLS, the only launch provider that'll launch it is ULA, whether it being Vulcan or D-IVH. It's just too valuable of a payload to risk anything, especially Musk's whims and changes of plans.

"Whims" :)

If its not SLS or Falcon H it would have to be DIVH because I don't think Vulcan well its big on my list of vaporware rockets.. 

But in my view ..if Musk got the contract..and I assume it would be a fully expendable rocket..he would eagerly want it, would make sure it flew. And it would probably work.  Or put it another way it would have as good odds as the DIVH.  He wants nd needs the FH business .  I assume the FH fully expendable could do it ?
Title: Re: Proposed Europa Missions
Post by: ugordan on 08/31/2018 04:25 pm
Would Vulcan be certified by the point that they have to make a decision on the launcher?

Depends on when it becomes operational. While it's not an apples-to-apples comparison, remember that Cassini-Huygens launched on only the 2nd Titan IV-B.
Title: Re: Proposed Europa Missions
Post by: clongton on 08/31/2018 04:27 pm
It's just too valuable of a payload to risk anything, especially Musk's whims and changes of plans.

I'm not clear about what whims and changes of plan Musk might initiate that would cost the Clipper its ride. NASA would never select SpaceX to be the ride without guarantees as to what specific LV would be the ride on launch day. Any launch contract with NASA will be fulfilled by SpaceX as written. SpaceX would never risk losing NASA support by doing anything untoward with Clipper's contracted LV.
Title: Re: Proposed Europa Missions
Post by: LouScheffer on 08/31/2018 05:21 pm
If the FH can launch twice a year, by 2022 it will have as many launches as Delta-4 Heavy does now - Parker Solar Probe was the 10th mission of the D4H.  All of these bigger rockets have quite low flight rates - there are not many payloads that need their services.
*IF*.  Do you want to bet your $3B flagship mission on there being no development hiccups (first flight went great; will the second and third?) or SpaceX deciding it really doesn't need the FH with the BFH coming on line or there just turning out not to be enough customers to make it viable?
Well, the military has already made this bet: (https://www.forbes.com/sites/bridaineparnell/2018/06/22/spacex-bags-130m-military-contract-after-just-one-falcon-heavy-test-flight/#5599ae9d1e37) So the main risk is technical, not supply and demand.  And on the technical side, the FH cores have several technical advantages over Delta-IV cores - (a) more flight experience, (b) teardown and examination of flown cores, (c) human-rating, which implies very extensive analysis.  Plus the FH has more margin to cover any performance shortfall.  It's still a risk, but I'm not sure the risk is greater than relying on the Delta-IV.
Quote
I lived through the Galileo search for a launch. 
Galileo was particularly bad because of the RTGs.  There is a big difference (in public perception, and in the paperwork required) between risking a $3B mission on a rocket otherwise certified only for lesser missions, and OMG, you want launch a DEADLY, NUCLEAR POWERED mission on an UNQUALIFIED ROCKET, where an accident might KILL US ALL!!!
Quote
You don't want your booster development to be in your critical path.  I think it is idiocy to tie Clipper to the SLS for this reason.
This I agree with 100%.  But the FH,though new, seems a much safer bet.  It has flown successfully, has both commercial and military contracts, is expected to be certified, and is built from parts with an extensive and current technology base.  I'd be willing to bet my career that FH will be around and available in 2022.   That's a bet I would not take for SLS.

If I was the Europa Clipper manager, I'd insist on a design that was compatible with the D4H, the smallest of the proposed launchers.  Then I'd wait as long as possible, watching all three potential launchers intently, before deciding.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 08/31/2018 06:12 pm
Okay, can we now end the never-ending which rocket is bestest debate that belongs on another thread and get back to the actual subject of this thread?
Title: Re: Proposed Europa Missions
Post by: ncb1397 on 08/31/2018 06:20 pm
Okay, can we now end the never-ending which rocket is bestest debate that belongs on another thread and get back to the actual subject of this thread?

Aye, Aye, Captain.

The May 2018 issue of the Europa Clipper newsletter had this to chart:

(https://i.imgur.com/caqoCxA.png)

Anyone know where they are?

Title: Re: Proposed Europa Missions
Post by: redliox on 08/31/2018 06:30 pm
Okay, can we now end the never-ending which rocket is bestest debate that belongs on another thread and get back to the actual subject of this thread?

I agree with ya, not to mention it was debated and sorted way back in the thread with a conclusion like this:

-SLS can do direct to Jupiter (for Clipper, Lander not so much)
-Delta 4 or Falcon Heavy could do a single EGA route
-Atlas 5 would require the multiple GA route

End of line
Title: Re: Proposed Europa Missions
Post by: redliox on 08/31/2018 06:34 pm
Okay, can we now end the never-ending which rocket is bestest debate that belongs on another thread and get back to the actual subject of this thread?

Aye, Aye, Captain.

The May 2018 issue of the Europa Clipper newsletter had this to chart:

So the chart would imply most of the project has undergone PDR with the solar wings getting a final look over currently.

As far as where or when, I would presume the upcoming OPAG meeting on the 11th will mention something about the 'Clipper's status.  I can only hope the design is mostly sorted by now.  Until the meeting all else I'd regard as hearsay, not to mention we'll hear something from the source soon enough.
Title: Re: Proposed Europa Missions
Post by: psloss on 08/31/2018 06:48 pm
Another slide from Mr. Pappalardo as presented to the last OPAG in February, other slides and PDF link here:
https://forum.nasaspaceflight.com/index.php?topic=27871.msg1794242#msg1794242
Title: Re: Proposed Europa Missions
Post by: redliox on 08/31/2018 07:04 pm
Thanks psloss!

So Clipper's moving from Preliminary to Critical, at least by November if not the original October goal.
Title: Re: Proposed Europa Missions
Post by: Star One on 08/31/2018 07:40 pm
Okay, can we now end the never-ending which rocket is bestest debate that belongs on another thread and get back to the actual subject of this thread?

The choice of launcher is hardly irrelevant unless you intend to use a trampoline to get it into space, as once suggested by a certain Russian official.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 08/31/2018 08:49 pm
So Clipper's moving from Preliminary to Critical, at least by November if not the original October goal.

There is currently an IG audit of the project underway (prompted by the JWST problems). That may have led to some slowdown in achieving certain milestones. But I have heard from people involved in the review process that there are no major problems at the moment.
Title: Re: Proposed Europa Missions
Post by: MATTBLAK on 09/03/2018 02:18 am
I'd like to see a breakdown or even a good paper on the various other launcher options (not SLS) for Europa Clipper and how it might effect the size, capability and trajectory of the probe. If only one Earth gravity assist is required to get a good-sized probe to Jupiter when launched on a Delta IV-Heavy or Falcon Heavy; I think that's a tolerable requirement. Would the FH have to be fully expendable to do the mission, or core expended and 2x boosters droneship landed, far out at sea? Can D-IVH do it with minimal mods and no additional STAR kickstage needed? Building a one-time version of D-IVH with aluminum/lithium structures and sub-cooled propellants should get another 2 or 3 metric tons to Earth escape without a major redesign of the booster. I think a D-IVH with added 4x GEM-60 solid boosters could probably do a direct flight to Jupiter without EGA. 6x added GEMS definitely a direct flight (?)
Title: Re: Proposed Europa Missions
Post by: jbenton on 09/03/2018 03:34 am
Can the heavy do the launch without modifications?

I'd like to see a breakdown or even a good paper on the various other launcher options (not SLS) for Europa Clipper and how it might effect the size, capability and trajectory of the probe.

I think I have what you both are looking for; as LouScheffer said, there was a fancy chart posted in the Falcon Heavy Discusion thread: https://forum.nasaspaceflight.com/index.php?topic=43025.msg1849643#msg1849643

One of the commentators there said you could probably complete the chart by having a Falcon Heavy with exspendable side-boosters, but recovered core matching Delta-IV's payload at C3=20, and Atlas V 551 matching the partly recovered Falcon Heavy at C3=60

(https://forum.nasaspaceflight.com/index.php?action=dlattach;topic=43025.0;attach=1506797;image)

Lou's comment about this was:
Juno, for example, had a C3 of about 30 km^2/sec^2, then used about 775 m/s of deep space maneuver followed by one Earth assist.   Assuming an ISP of 320 for the DSM engine, that implies a mass ratio of about 1.28, or an initial mass of 7800 kg if the Jupiter arrival mass is to be kept at 6000 kg.  The Falcon Heavy can put about 8000 kg to a C3 of 30, so this works. 

Delta-4 heavy looks like it can put about 6000 kg to a C3 of 30.  This is more than enough to send EC to Venus (which requires only a C3 of 15, even in the worst windows), and hence to Jupiter.  But it's not enough to do this with a single deep space maneuver, as Juno did.  So you would still need the high-temp shielding.

Considering that this information is correct:


...it was debated and sorted way back in the thread with a conclusion like this:

-SLS can do direct to Jupiter (for Clipper, Lander not so much)
-Delta 4 or Falcon Heavy could do a single EGA route
-Atlas 5 would require the multiple GA route

End of line

I think Lou's numbers here are also correct:


Huh, weird...

They've been saying for years that the Delta IV trajectory would be 4.7 years and with no Venus flybys. I guess that was the whole point of the extra propellant. Clipper would have to be its own kick stage! There's really no point in spending the extra money for Delta Heavy if it can't skip the Venus flyby. Delta IV is over-kill for that. At that point you may as well go for the expendable Falcon Heavy, save some money and do the same mission slightly better, i.e. with margin.


Perhaps the 6000 kg launch mass already includes the extra fuel for the Deep Space Maneuver , so the Jupiter arrival mass is about 4600 kg?  Since the Delta IV can place 6000 kg to a C3 of 30, that would allow D4H with no Venus flyby.  FH can do this trajectory as well, with somewhat better margins.

In this case both the D4H and FH could do the mission with the deep space maneuver.   But neither of them can put 4600 kg to a C3 of 80, which would be needed for a direct course to Jupiter.

An Atlas 551 can put about 4600 kg to Venus, so that could be the backup-backup-backup plan with a still longer trajectory (if the SLS, D4H, and FH plans fall through).

This would follow logically from the information (without numbers) that the project team has been giving us since 2012. The 1400 kg would account for the fuel that Delta-IV Heavy would apparently need to perform a single EGA, and the fuel wouldn't be there in the case of Atlas V 551. Although I'm not sure if the 6000 kg is supposed to have the extra fuel or not.

If only one Earth gravity assist is required to get a good-sized probe to Jupiter when launched on a Delta IV-Heavy or Falcon Heavy; I think that's a tolerable requirement.
Apparently, the Clipper team don't consider this as a requirement as they originally baselined Atlas V 551 to do the mission. Cassini-Huygens did the long EVEEGA cruise, JUICE is doing the full ~7 years, this isn't uncommon. I however would like to see the mission happen with the shorter cruise (however the more overlap there is between Clipper's stay at Jupiter and JUICE at Jupiter, the more collaborative science they could do together)
Title: Re: Proposed Europa Missions
Post by: jbenton on 09/03/2018 04:06 am
I've been wondering what kind of Europa mission Falcon Heavy could do with 'simple' upper stage upgrades done - I'm not talking about a Raptor-powered upper stage. But an upper stage widened to match the 5.2 meter payload fairing, to give increased propellant loads and a further upgraded Merlin 1D Vacuum? Or if the stage widening is too difficult/costly: keeping the same 3.7 meter diameter but stretching it's tankage another couple meters?

I think that any discussion about modified Falcon Heavies belong in some other thread. Not that we shouldn't discuss it all, we should - as in the spirit of this thread:

Fly Me to the Moon on a SLS Block II (https://forum.nasaspaceflight.com/index.php?topic=38069.msg1406530#msg1406530[b)
But I don't think it belongs in this particular thread.

I should note, however that the FH already has a payload to LEO that is 11 tonnes more than originally promised (I remember that they originally said it'd be 53 tonnes; they also said it'd be ready by 2013)
The only enhancement I think they'd ever consider, though would be going back to having propellant cross-feed between the cores (though I admit, that I have no idea how difficult or expensive that is.

Would Falcon Heavy be certified to fly this kind of mission as so far it seems to have a relatively low flight rate.
If the FH can launch twice a year, by 2022 it will have as many launches as Delta-4 Heavy does now - Parker Solar Probe was the 10th mission of the D4H.  All of these bigger rockets have quite low flight rates - there are not many payloads that need their services.

That'll be the day!

By the way what is the requirement to be certified for Class A launches 3 clean flights in the same variant and configuration? 5?

Okay, can we now end the never-ending which rocket is bestest debate that belongs on another thread and get back to the actual subject of this thread?

For the record, the post I made that started the rocket talk was not about rockets per se, but the modifications to the spacecraft itself needed to enable it to launch on any rocket. (also for the record, I don't have any horse in this race, when it comes to Atlas, Delta, and Falcon, I don't have a preference: I like all of them!) Specifically I was asking the following questions:

1) Are they still planning to keep the TPS in the design, no matter what?
2) Did they ever decide to put in the extra fuel for DIVH?
3) How expensive, would it be to change either of those?
Further discussion brought forth a further question in my mind:
4) What exactly was Clipper supposed to do with that fuel anyhow? Was it part of the GA? Was it for a Deep Space Maneuver to enable a GA?

IMO, the safest bet would be to have both the TPS and the extra fuel, if that fits within SLS' mass margin. The best bet however, again IMO - I could be wrong - would be to have the extra fuel, but not the TPS. Of the five rockets considered (Atlas, Delta, Falcon, Vulcan, and SLS) Atlas is the most demonstrably reliable, but also the least like to exist, partially for cost but mostly for geopolitical reasons.
Title: Re: Proposed Europa Missions
Post by: redliox on 09/03/2018 06:32 am
Outer Planet Assessment Group meeting t-minus 8 days now...

One of the earliest agenda items worthy of note is that ESA's going to speak on their Ice Giant study.  Further down the line on the same day will be a joint talk between the Small Body and Outer Planet groups regarding the Kuiper Belt Objects; in light of the heavy thread talk on the Ice Giant thread that seemed worth mentioning.  And, naturally, there'll be plenty of talk on Europa Clipper, JUICE, and the potential Europa Lander.
Title: Re: Proposed Europa Missions
Post by: LouScheffer on 09/03/2018 02:19 pm

IMO, the safest bet would be to have both the TPS and the extra fuel, if that fits within SLS' mass margin. The best bet however, again IMO - I could be wrong - would be to have the extra fuel, but not the TPS. Of the five rockets considered (Atlas, Delta, Falcon, Vulcan, and SLS) ...

On the one hand, it's nice to have options for launch.

On the other hand, this is clearly adding lots of additional complexity to the design process.  Since the probe costs billions of dollars and won't be repeated for decades, everyone wants to make the best choice possible.  This involves studying every option in a fair amount of detail.  In the limiting case, this is equivalent to designing 5 probes, but only launching one.  In the opposite case, the launcher is known, and all effort goes into optimization for that launcher.

Time-to-launch-window is one of the most valuable engineering resources.  Time used to analyze multiple launch options could otherwise be used to optimize other aspects of the probe.  So there is actually a big opportunity cost associated with multiple launchers, as well as large potential benefits. For Europa Clipper, for example, time being spent on designing thermal protection for a Venus is not being spent on radiation protection for Jupiter orbit.

You see negative consequences from extra choice all the time in real life.  People will drive kilometers out of their way to get to a gas (petrol) station that is slightly cheaper.  This optimizes out-of-pocket expenses, but when you include the cost-per-km of the car you find that overall, the cheaper station both took more time and cost more money.   So more choice, which seems good in principle, in this case leads to a worse outcome - if there was no choice, they would have made a better decision.
Title: Re: Proposed Europa Missions
Post by: Zed_Noir on 09/03/2018 04:13 pm
...

I agree with ya, not to mention it was debated and sorted way back in the thread with a conclusion like this:

-SLS can do direct to Jupiter (for Clipper, Lander not so much)
-Delta 4 or Falcon Heavy could do a single EGA route
-Atlas 5 would require the multiple GA route

End of line

Which variant of the SLS? Did't they planned for the Clipper to be the Guinea Pig to ushered into service the SLS Block-1B.
Title: Re: Proposed Europa Missions
Post by: jbenton on 09/03/2018 04:58 pm
...

I agree with ya, not to mention it was debated and sorted way back in the thread with a conclusion like this:

-SLS can do direct to Jupiter (for Clipper, Lander not so much)
-Delta 4 or Falcon Heavy could do a single EGA route
-Atlas 5 would require the multiple GA route

End of line

Which variant of the SLS? Did't they planned for the Clipper to be the Guinea Pig to ushered into service the SLS Block-1B?

They planned on that, but EUS was running late, so Congress put up the funds to build another Mobile Launcher that would be EUS-specific:

https://www.nasaspaceflight.com/2018/05/sls-block-1-revival-plans-getting-mobile-launcher-money/
https://www.nasaspaceflight.com/2018/04/nasas-dual-ml-plan-extra-sls-block-1-missions/

IIRC, there was some question as to whether SLS Block-1A could do it, so they were considering doing Block-1B, but they were saying for years that 1A could only do 70 tonnes to LEO, that figure has since been raised to 95 tonnes. The concern about 1A may have been due to underestimation of SLS. I could of course be mis-remembering.

IIRC, I think they were originally touting a shorter direct-to-Jupiter cruise than the 2.7yrs; that could've been thinking in terms of SLS Block-IB or an earlier version of Clipper that would be lighter, but again, I could be mis-remembering.

Short answer: they will use Block-1A if they use SLS at all.
Title: Re: Proposed Europa Missions
Post by: Jim on 09/04/2018 03:33 pm

Well, the military has already made this bet: (https://www.forbes.com/sites/bridaineparnell/2018/06/22/spacex-bags-130m-military-contract-after-just-one-falcon-heavy-test-flight/#5599ae9d1e37)

That mission and part of the military doesn't count.  It is not the same as the other users of Delta IV heavy.

And on the technical side, the FH cores have several technical advantages over Delta-IV cores - (a) more flight experience, (b) teardown and examination of flown cores,

Not really.  New center core and second stage.
Title: Re: Proposed Europa Missions
Post by: ugordan on 09/04/2018 03:45 pm
And on the technical side, the FH cores have several technical advantages over Delta-IV cores - (a) more flight experience, (b) teardown and examination of flown cores,

Not really.  New center core and second stage.

As much as I hate turning this into another discussion related to SpaceX, why a new center core?

From where I sit, either NASA would mandate either 3 completely new booster cores or they would allow reflight of previously flown cores. Why would the center core be different from the strapons? The fact that it would have, inherently, reentered at higher velocities than the boosters during previous missions?
Title: Re: Proposed Europa Missions
Post by: Blackstar on 09/04/2018 03:55 pm
Can you guys all go make your endless back and forth arguments about rockets on some other thread? Seriously, that's all you guys do on this forum and you don't need to pollute this thread with it here too.
Title: Re: Proposed Europa Missions
Post by: redliox on 09/04/2018 04:22 pm
Can you guys all go make your endless back and forth arguments about rockets on some other thread? Seriously, that's all you guys do on this forum and you don't need to pollute this thread with it here too.

Agreed.  At the least we have an OPAG meeting coming up in a week; wait until we hear about Europa Clipper's status report and if it mentions anything regarding launchers.  'Clipper, as is, is designed to be compatible with most launchers or even the Venus flyby route if necessary.

Any more blabbing about launchers prior the OPAG meeting on the 11th I am going to report; Blackstar is right that this is getting carried away when the answers to these launchers were established months ago.
Title: Re: Proposed Europa Missions
Post by: vjkane on 09/08/2018 02:48 pm
I listened to a talk given yesterday by Bob Pappalardo, project scientist for the Clipper mission, at the Griffith Observatory.  (Sorry, closed the web page and don't have the link.  It's on YouTube.)  He stated that the project is keeping the spacecraft compatible with launch by the Delta IV Heavy, Falcon Heavy, and SLS.  The former two would result in cruises of nearly 8 years, the latter 2 years.

He stated that the mission will do a number of Callisto and Ganymede flybys when they flip the orbit to go from flybys on the anti-Jovian hemisphere to the pro-Jovian hemisphere.  (I've also read that there will be several flybys of these moons early in the mission as they crank down the orbit for to shorten the period and lower the periapsis to  Europa's orbit.)

He also stated that the likely limiting factor for the mission would be the decay of power from the solar cells as they are degraded by the radiation.  (Which brings up the idea to me that at some point they could raise the periapsis of the orbit out of the intense radiation field and become a Jovian system observatory for some period.  ESA's JUICE mission will orbit Ganymede and do a number of Callisto flybys.  Don't know the science return for additional flybys of these moons by the Clipper spacecraft late in its mission.)

The current disposal plan is to dump the spacecraft into Jupiter, although crashing the craft onto Ganymede or Callisto remains a possibility.  (From a previous public lecture, another Clipper manager said his favorite idea was to crash into Io, collecting data on the way in.  Don't know if that remains a feasible option.) 
Title: Re: Proposed Europa Missions
Post by: vjkane on 09/08/2018 02:58 pm
Here's the link to the talk referenced in my previous post.  The Clipper presentation starts somewhere about halfway in.

https://www.youtube.com/watch?v=IlYaOrzvxMA
Title: Re: Proposed Europa Missions
Post by: jbenton on 09/08/2018 05:54 pm
The current disposal plan is to dump the spacecraft into Jupiter, although crashing the craft onto Ganymede or Callisto remains a possibility.  (From a previous public lecture, another Clipper manager said his favorite idea was to crash into Io, collecting data on the way in.  Don't know if that remains a feasible option.)

I remember you saying that. IIRC, it would have been two or three passes by Io before the crash. How would the science of EC performing such an end of mission maneuver compare to the ~ 6 passes of the proposed, dedicated Io Observer mission?
Title: Re: Proposed Europa Missions
Post by: vjkane on 09/08/2018 06:20 pm
The current disposal plan is to dump the spacecraft into Jupiter, although crashing the craft onto Ganymede or Callisto remains a possibility.  (From a previous public lecture, another Clipper manager said his favorite idea was to crash into Io, collecting data on the way in.  Don't know if that remains a feasible option.)

I remember you saying that. IIRC, it would have been two or three passes by Io before the crash. How would the science of EC performing such an end of mission maneuver compare to the ~ 6 passes of the proposed, dedicated Io Observer mission?
You may be right about several passes.  That was awhile ago.

It's hard to compare science with a speculative mission, but here goes:

1) Clipper may well have a much higher data rate than a cheaper Io Discovery or New Frontiers mission, but if the solar panels are seriously degraded, there may not be the power to send back data at the highest rate.
2) Clipper will not have been designed to operate at Io-level of radiation, so there could be faults and noise in the instruments
3) The visual-IR spectrometer will not have been optimized for silicate studies; the same would be true of the dust mass spectrometer.  This may not matter; the Clipper instruments might do well at Io.  I just haven't looked into this.
4) Clipper will carry more instruments than I've seen planned for Io missions such as the radars.  These could provide additional science, but prior Io mission designs have not prioritized these instruments.

Title: Re: Proposed Europa Missions
Post by: redliox on 09/09/2018 12:49 am
IIRC, it would have been two or three passes by Io before the crash. How would the science of EC performing such an end of mission maneuver compare to the ~ 6 passes of the proposed, dedicated Io Observer mission?
You may be right about several passes.  That was awhile ago.

It's hard to compare science with a speculative mission, but here goes:

1) Clipper may well have a much higher data rate than a cheaper Io Discovery or New Frontiers mission, but if the solar panels are seriously degraded, there may not be the power to send back data at the highest rate.
2) Clipper will not have been designed to operate at Io-level of radiation, so there could be faults and noise in the instruments
3) The visual-IR spectrometer will not have been optimized for silicate studies; the same would be true of the dust mass spectrometer.  This may not matter; the Clipper instruments might do well at Io.  I just haven't looked into this.
4) Clipper will carry more instruments than I've seen planned for Io missions such as the radars.  These could provide additional science, but prior Io mission designs have not prioritized these instruments.

Although obviously not 'Clipper's primary mission, I too am curious what it could do with Io, including a spectacular end crashing on that moon.  I'd be thrilled to see an Io Observer, but that sadly remains stuck on paper while 'Clipper has finally reached the assembly process.  In short, it's going to be our best shot at examining Io even at a glance.  JUICE, by comparison, could contribute but isn't as shielded as 'Clipper since (outside of the 2 Europa flybys) it will focus on safer Ganymede and Callisto.  The Voyagers were only meant for the giant planets yet Voyager 2 did well enough with the ice giants; likewise I suspect 'Clipper could contribute toward Io much more than Galileo and perhaps even the Voyagers did...schedule and solar panel strength allowing of course.

The 3rd and 4th points Van pointed out get my attention.  While not optimized for Io, could the mass and Vis-IR spectrometers discern the varieties of sulfur or perhaps organics on the surface or the plumes?  And what could the radar reveal on Io?  How would a radar optimized for water react to lava lakes instead?
Title: Re: Proposed Europa Missions
Post by: jbenton on 09/09/2018 03:43 am
IIRC, it would have been two or three passes by Io before the crash. How would the science of EC performing such an end of mission maneuver compare to the ~ 6 passes of the proposed, dedicated Io Observer mission?
You may be right about several passes.  That was awhile ago.

It's hard to compare science with a speculative mission, but here goes:

1) Clipper may well have a much higher data rate than a cheaper Io Discovery or New Frontiers mission, but if the solar panels are seriously degraded, there may not be the power to send back data at the highest rate.
2) Clipper will not have been designed to operate at Io-level of radiation, so there could be faults and noise in the instruments
3) The visual-IR spectrometer will not have been optimized for silicate studies; the same would be true of the dust mass spectrometer.  This may not matter; the Clipper instruments might do well at Io.  I just haven't looked into this.
4) Clipper will carry more instruments than I've seen planned for Io missions such as the radars.  These could provide additional science, but prior Io mission designs have not prioritized these instruments.

Although obviously not 'Clipper's primary mission, I too am curious what it could do with Io, including a spectacular end crashing on that moon.  I'd be thrilled to see an Io Observer, but that sadly remains stuck on paper while 'Clipper has finally reached the assembly process.  In short, it's going to be our best shot at examining Io even at a glance...

Io Observer will be considered for New Frontiers 5. and the team might continue to try to propose it as a Discovery mission, so there is some chance that it could launch sometime in the 2020's. I heard that NASA wants to make an AO for NF 5 in 2019, but I also heard that such is rather ambitious.

ESA's JUICE will spend a lot of its time looking at all the other wonders of the Jupiter system.  Per the Europa mission's project manager, they haven't spent any time looking at studies of additional bodies.  I did see one orbital study for the mission that included several flybys of Ganymede and Callisto.  Right now the plan to dispose of Clipper is to crash it on Ganymede; the project manager says his dream is to see it do a couple of flybys of Io first before crashing it on that moon.

For the record, that was the post where I got the idea of "several passes", and it was a long time ago...

Part of the excitement of a possible Io mission extension is the crash: could get a nice close-up picture like the one that NEAR-Shoemaker took of Eros:

(https://encrypted-tbn0.gstatic.com/images?q=tbn:ANd9GcQKQX9VIWh0qSbCaJMMTfu1cMy9RRkWUM34g0EV6q4rcbJKvoLW)

On the other hand, it feels more proper to me to send Clipper into the Jovian atmosphere, much like Galileo and Cassini.
Title: Re: Proposed Europa Missions
Post by: redliox on 09/09/2018 04:28 am
Part of the excitement of a possible Io mission extension is the crash: could get a nice close-up picture like the one that NEAR-Shoemaker took of Eros...

On the other hand, it feels more proper to me to send Clipper into the Jovian atmosphere, much like Galileo and Cassini.

In at least Cassini's case, they had a long and hardcore discussion on how to end the mission that had a huge range of options.  What those options all had in common was squeezing out unique science.  In the end they only chose crashing into Saturn since, beforehand, they had the side bonus of obtaining Juno-eque science of Saturn.  So, again, in Cassini's case disposal was only a minor part of that otherwise they could have crashed into Rhea, the rings, or even escaped via Titan's gravity.

I'd be willing to bet the 'Clipper team will be as creative; they will have a good number of years with this probe flying around Jupiter and I'd even be willing to bet at least one mission extension before disposal has to be considered from either the solar arrays degrading or fuel running low.
Title: Re: Proposed Europa Missions
Post by: jbenton on 09/11/2018 05:56 am
I was just reading through the Planet 9/Giant Planet 5 thread and there was some discussion about using data on Cassini's calculations of Saturn's orbit to see if there were perturbations that could be used to narrow down Planet X's location.

Some people sifted through the data and noticed some things, but the folks at JPL said that there was too much "noise" from all of Cassini's orbital changes and thruster firings to know for sure. Any changes were too minute to be statistically significant. Some seemed to be thinking that if Cassini's mission could be extended to 2020, then that  would somehow be helpful.

So I got curious:

Could Europa Clipper or JUICE be used in much the same way? Keeping track of Jupiter's orbit and making note of any minute changes that could be evidence of the missing planet? Has the Galileo probe already done this? What about Juno?

I'm assuming that the answer would be no, or that it would be quite challenging because Jupiter is so much bigger   and closer to the Sun than Saturn, and because the two probe's science mission is more focused on the satellites, but I figured I'd ask anyways.
Title: Re: Proposed Europa Missions
Post by: redliox on 09/11/2018 07:29 am
I was just reading through the Planet 9/Giant Planet 5 thread and there was some discussion about using data on Cassini's calculations of Saturn's orbit to see if there were perturbations that could be used to narrow down Planet X's location.

Some people sifted through the data and noticed some things, but the folks at JPL said that there was too much "noise" from all of Cassini's orbital changes and thruster firings to know for sure. Any changes were too minute to be statistically significant. Some seemed to be thinking that if Cassini's mission could be extended to 2020, then that  would somehow be helpful.

So I got curious:

Could Europa Clipper or JUICE be used in much the same way? Keeping track of Jupiter's orbit and making note of any minute changes that could be evidence of the missing planet? Has the Galileo probe already done this? What about Juno?

I'm assuming that the answer would be no, or that it would be quite challenging because Jupiter is so much bigger   and closer to the Sun than Saturn, and because the two probe's science mission is more focused on the satellites, but I figured I'd ask anyways.

If Cassini could do it 'Clipper probably could.  If anything limits it maybe bandwidth availability and power if the arrays degrade any later in the mission.

In about 8 hours the OPAG meeting is due to start: https://www.lpi.usra.edu/opag/ (https://www.lpi.usra.edu/opag/)
Title: Re: Proposed Europa Missions
Post by: ugordan on 09/11/2018 07:42 am
If Cassini could do it 'Clipper probably could.  If anything limits it maybe bandwidth availability and power if the arrays degrade any later in the mission.

Clipper, however, will have a huge solar panel surface and experience 3x the solar radiation pressure per unit area than Cassini did so those perturbations will be much more significant. Maybe that can be modeled out leaving sufficiently low residuals, I don't know.

I would also think that Mike Brown hopes to find P9 (if it's there) by the time Clipper has spent several years at Jupiter...
Title: Re: Proposed Europa Missions
Post by: jbenton on 09/11/2018 09:15 am
If Cassini could do it 'Clipper probably could.  If anything limits it maybe bandwidth availability and power if the arrays degrade any later in the mission.

Clipper, however, will have a huge solar panel surface and experience 3x the solar radiation pressure per unit area than Cassini did so those perturbations will be much more significant. Maybe that can be modeled out leaving sufficiently low residuals, I don't know.

I would also think that Mike Brown hopes to find P9 (if it's there) by the time Clipper has spent several years at Jupiter...

Oh, I agree that Dr. Brown wants and even expects to find it before Clipper is even launched. Even if that doesn't happen, LSST is much more likely to find it than any outer planets space probe. I was just musing about the craft's capabilities (and that of its sister-ship distant same-age cousin, JUICE)
Title: Re: Proposed Europa Missions
Post by: redliox on 09/12/2018 05:30 am
Currently in Phase B.

Specifically until November by the looks of it.  Nearly onto the next phase.  I'm presuming we won't get the juicier details for a few days yet.
Title: Re: Proposed Europa Missions
Post by: redliox on 09/12/2018 02:38 pm
The OPAG is scheduled to have discussions on the Europa lander today, among them descoping options too.
Title: Re: Proposed Europa Missions
Post by: redliox on 09/15/2018 10:44 pm
How soon before we should expect the OPAG meeting info gets online?  The agenda talked plenty about both 'Clipper and the lander, so I'm eager to see what was talked about for them or say Io and Jovian missions.
Title: Re: Proposed Europa Missions
Post by: TripleSeven on 09/15/2018 11:00 pm
http://www.sciencemag.org/news/2018/09/could-november-elections-scramble-controversial-us-mission-frozen-moon
Title: Re: Proposed Europa Missions
Post by: jbenton on 09/16/2018 12:50 am
Thanks for that, the article reports on quite a bit of interesting opinions. Interesting that they're saying that only the lander is on the line, there seems to be no mention of 'Clipper, except in reference to its role as a scout for the lander.

BTW, Blackstar, one or two of the slides you posted said that the lander will have a RTG. But the radiation will kill the lander after a month at most.
I thought the thing was to be battery-powered, what need does it have of an RTG?
Title: Re: Proposed Europa Missions
Post by: redliox on 09/17/2018 03:34 am
Europa Clipper was in the decadal survey as a recommended mission (as Jupiter Europa Orbiter). There was no lander as a recommended mission. It only exists because a congressman wants it. That's also why it is controversial.

The article is a pretty accurate reflection of that particular discussion, although the writer took Louise Prockter's comment out of context. She was saying that without a broad constituency (i.e. being recommended by the scientific community), the lander is politically vulnerable. That's totally true.

Sounds about right.  Although, after 'Clipper's mission would have been done, the traditional order has been: flyby, orbiter, lander, rover, SR.  'Clipper, while not a direct orbiter, was the best compromise to mitigate the radiation plague.  Eventually a lander would have been desired, but politics basically jumped the gun a little soon.  Not impossible or inevitable, but no doubt very inconvenient from the engineers and scientists' pov to be told "Oh cram this giant project in with minimal effort please-I-mean-now."
Title: Re: Proposed Europa Missions
Post by: ccdengr on 09/17/2018 04:34 am
I thought the thing was to be battery-powered, what need does it have of an RTG?
Maybe this is not politically viable, but it didn't keep NASA from issuing an AO for instruments for it, and it didn't keep people from busting their a*es proposing for it.  https://nspires.nasaprs.com/external/solicitations/summary!init.do?solId=%7b17B73E96-6B65-FE78-5B63-84C804831035%7d&path=open

Yes, battery-powered, no RTG.  From the PIP: "The nominal Lander design is planned to operate for 20 Earth days before depleting its batteries."
Title: Re: Proposed Europa Missions
Post by: ncb1397 on 09/17/2018 05:49 am

We could very well end up with a lander that is not properly designed to do the mission, in part because you really want to design the lander AFTER you gather good data on Europa from Clipper.

Huygens was designed after flybys of Saturn, not after the Cassini Orbiter and worked out just fine. And we are already past the Cassini stage for the Jupiter system, having already operated Galileo there for 8 years (and Juno after that). We know far more about the Jupiter system and the hazards there, including the radiation, than we did about the Saturnian system when Huygens was designed and operated successfully.

It should be noted that NASA hasn't soft landed on any solar system surface other than Mars since 1972. They need to branch out.
Title: Re: Proposed Europa Missions
Post by: ugordan on 09/17/2018 07:14 am

We could very well end up with a lander that is not properly designed to do the mission, in part because you really want to design the lander AFTER you gather good data on Europa from Clipper.

Huygens was designed after flybys of Saturn, not after the Cassini Orbiter and worked out just fine. And we are already past the Cassini stage for the Jupiter system, having already operated Galileo there for 8 years (and Juno after that). We know far more about the Jupiter system and the hazards there, including the radiation, than we did about the Saturnian system when Huygens was designed and operated successfully.

Apples and oranges. Voyager 1 flyby of Titan gave us an accurate atmospheric profile to be able to design an *atmospheric* probe, which is what Huygens really was. When it comes to science that a Europa lander would like to do, we don't even know what kind of environment we're looking at down there. Surface roughness, what kind of trace materials, etc.
Title: Re: Proposed Europa Missions
Post by: ncb1397 on 09/17/2018 07:32 am

We could very well end up with a lander that is not properly designed to do the mission, in part because you really want to design the lander AFTER you gather good data on Europa from Clipper.

Huygens was designed after flybys of Saturn, not after the Cassini Orbiter and worked out just fine. And we are already past the Cassini stage for the Jupiter system, having already operated Galileo there for 8 years (and Juno after that). We know far more about the Jupiter system and the hazards there, including the radiation, than we did about the Saturnian system when Huygens was designed and operated successfully.

Apples and oranges. Voyager 1 flyby of Titan gave us an accurate atmospheric profile to be able to design an *atmospheric* probe, which is what Huygens really was. When it comes to science that a Europa lander would like to do, we don't even know what kind of environment we're looking at down there. Surface roughness, what kind of trace materials, etc.

On the flip side, because of plumes, tectonics due to the liquid subsurface, tidal flexing, a ferocious energetic particle environment, debris impacts, cratering,  etc, you probably want the most up to date maps possible. You would likely want to target an area that has had recent plume activity but not current plume activity and an orbiter in the same time frame would be extremely helpful. The plan is I think Europa ~2022 with arrival 2024-2025, with the lander launching in 2026 and arriving in 2033. If you do it sequentially after arrival in 2025, you are probably looking at 2040, in which case your maps are over a decade old, you lose potential orbiter relay options (without sending up another orbiter), etc.

The scientific justification for targeting a geologically active region that is still safe practically requires close orbiter/lander time frames.

See, that is the problem with "what ifs". People fill in the "what" with whatever they want to suit their view point. Just as scientists can smack themselves when they figure out the landing gear won't work on Europa(seriously, how likely is it that you are going to have to target a cliff face or that you even could? That actually came up in the conference as a what if show stopper). They can just as easily smack themselves when they get there and are going to need an orbiter for the landing, and Europa clipper will likely be 90% toast by then. BTW, Juice would be arriving around 2030, which would line up with 2033 a lot better than 2040. Besides, there would probably be a 1 year gap + with Europa doing mapping and the lander on the ground. You could change the landing gear if that unlikely scenario ever happened.
Title: Re: Proposed Europa Missions
Post by: ccdengr on 09/17/2018 01:40 pm
Note that this was only a call for instrument concepts, not actual instruments.
It was an AO for instrument development to the tune of millions of dollars per selection.  Word on the street was that, like Clipper where an analogous process was followed, if the actual mission goes forward, selections will be made from the winners of this AO.
Title: Re: Proposed Europa Missions
Post by: Eric Hedman on 09/17/2018 03:42 pm
See, that is the problem with "what ifs".

And you cannot look at this in isolation from the rest of the planetary budget and the planetary program. The decadal survey is where priorities get set. At the last decadal survey they did not even consider a Europa lander. It was only mentioned as a "far term" mission. Why should Europa get a ~$3+ billion orbiter and a ~$2.7 billion (WAG) lander in this decade? Why should other scientists and other parts of the solar system get locked out?
Simply because Congress controls the purse.  When they feel like doing something, they have the power regardless of what is logical or follows normal protocol.  If people don't like what their member of Congress is doing, vote them out.  It may happen to the member who pushed this.
Title: Re: Proposed Europa Missions
Post by: vjkane on 09/17/2018 03:57 pm
Simply because Congress controls the purse.  When they feel like doing something, they have the power regardless of what is logical or follows normal protocol.  If people don't like what their member of Congress is doing, vote them out.  It may happen to the member who pushed this.
The people of his district are not going to consider this issue in decided how to cast their votes.  Any representative from this district will be a friend of NASA -- the Houston flight center is either in or adjacent to this district.  Like the rest of this fall's election, the votes will largely be a referendum on the occupant of the White House.

There are a couple of problems with the approach that Culberson took.  First, why shouldn't other planetary scientists go get their favorite representative or senator to add their favorite mission and turn this into a free for all?  That is exactly what the Decadal process is designed to prevent.

Second, representatives don't have the scientific or engineering chops to plan planetary programs or missions.  If Congress wants to prioritize a field of study - life detection or ocean worlds - one could argue that that is in their purview.  Congress and the administration are responsible for setting NASA's priorities.  That is essentially what happened with Mars in the late 1990s.  Congress then, however, had the sense to set a direction and let the scientific community and NASA determine the steps and pacing of the missions.

Say, for example, that Europa has reliable plumes that chemical analysis suggest come from the deep ocean.  The terrain may be so rugged around the plumes that a landing isn't possible or requires a completely different design than is currently envisioned.  The next best step may not be a lander but rather a craft that makes multiple slow traverses of the plumes or returns samples to Earth. 
Title: Re: Proposed Europa Missions
Post by: UltraViolet9 on 09/17/2018 04:47 pm

NASA projects are capital-intensive and multi-year by nature with demanding budget curves.

Only the White House and OMB develop multi-year (five-year) budgets.

Congressional appropriations are year-to-year.

For a mission or spacecraft to survive the federal budget process and be supported at the levels needed to meet its cost and schedule goals, it should really start in the President's five-year budget.

Relying on a congressman to stay in office, maintain a committee position, and reach handshake agreements with competing congressional interests for their multi-hundred million dollar (and increasing) earmark to go through year after year is a much less viable path.

But that's the scientific community shooting itself in the foot by taking itself out of the decision making process and devolving into Mad Max chaos. If the outer planets community is going to do that, why shouldn't MEPAG, SBAG and the others all just start buttering up their own preferred congresspeople to get what they want? Just give up on the decadal process completely.

Strongly agree.  Hang together or hang separately.
Title: Re: Proposed Europa Missions
Post by: redliox on 09/17/2018 05:21 pm
The posters and OPAG info is finally online: https://www.lpi.usra.edu/opag/meetings/sep2018/posters/index.shtml (https://www.lpi.usra.edu/opag/meetings/sep2018/posters/index.shtml)
Title: Re: Proposed Europa Missions
Post by: JH on 09/17/2018 05:44 pm
If the outer planets community is going to do that, why shouldn't MEPAG, SBAG and the others all just start buttering up their own preferred congresspeople to get what they want? Just give up on the decadal process completely.

Culberson is an odd duck. If there were others like him, I'm pretty confident that some members of the planetary science community would opt for Mad Max. Fortunately, he appears to stand alone.
Title: Re: Proposed Europa Missions
Post by: ncb1397 on 09/17/2018 06:45 pm
The decadal survey is where priorities get set.

Apparently not....

Quote
Why should Europa get a ~$3+ billion orbiter and a ~$2.7 billion (WAG) lander in this decade? Why should other scientists and other parts of the solar system get locked out?

Cassini, adjusted for inflation, was a similar amount to both of those numbers combined. Why did that happen? Should that have not happened?  Was the rest of the solar system locked out during the period of its development?

Quote
But that's the scientific community shooting itself in the foot by taking itself out of the decision making process and devolving into Mad Max chaos.

Yeah, yeah, Mob rule/democracy is "Mad Max" chaos. The best form of government is a technocracy ran by technocrats, not the unwashed masses. Unfortunately, our government is a democracy, not a technocracy. Elections have consequences, the bureaucrats don't get to run their little fiefdoms with zero affects or "interference" from that process.

Quote
Relying on a congressman to stay in office, maintain a committee position, and reach handshake agreements with competing congressional interests for their multi-hundred million dollar (and increasing) earmark to go through year after year is a much less viable path.

Some congressman stay around a lot longer than presidents. Culberson is going on 4-5 years as chair of CJS. Could easily outlast the presidential term limits. And we should also appreciate that the decadal recommendation of a Europa orbiter wouldn't have happened without him...so ignoring the decadal isn't something that just Congress does.

And it should also be pointed out that Congress has responsibilities/priorities beyond the particular hobbies and professional interests of planetary scientists which may account for diverging priorities. For instance, the decadal process doesn't seem too interested in the threat from NEOs, as they don't seem to prioritize NEO detection. Congress has much more of a focus on national security objectives. Scientists are more interested in stuff that happened billions of years ago. Again, different objectives between governments and a particular group of people.
Title: Re: Proposed Europa Missions
Post by: ncb1397 on 09/17/2018 07:44 pm

Cassini, adjusted for inflation, was a similar amount to both of those numbers combined. Why did that happen? Should that have not happened?  Was the rest of the solar system locked out during the period of its development?


You know, I could write 2000 words here explaining how space science priorities are established, what a decadal survey is, how space science policy has evolved over the past several decades, what a CATE is, and why all of this is important. But I'd be explaining it to somebody who probably wouldn't listen anyway and would just reply with a snarky remark. i won't bother. Feel free to think you understand how all of this works. Ignorance is blissful.

Culberson wasn't the one that blew up the lander into some gigantic independant flagship class mission. The people running the show back then had a fit and wanted to kill it, so they concocted that it couldn't be launched at the same time and had to be a x size and y mass with z instruments. They should have attempted to land a rad hard cubesat with a microscope to meet his objective. Load it with thermite or whatever.  If it dies or doesn't work, the radiation will sterilize it.

And it wasn't just the lander that they were trying to kill, it was the Decadal Survey's Europa orbiter.

Anyways, he called their bluff and actually funded the mission, the opposite of their intended result. The bed they are lying in was put there by themselves. The scientists grumble about any interference from Congress, even easy to accomodate ones like the Mars helicopter technology demonstrator. The scientists don't care about the technology development/demonstration aspect of NASA's portolio because it isn't planetary science, so they hate it, even though it is a relatively modest request.

Anyways, why don't you have a frank conversation with Culberson, bury the hatchet, and try to partner with other parts of the government rather than continue this pointless turf war.

edit:
cubesat lander - https://space.skyrocket.de/doc_sdat/omotenashi.htm
Title: Re: Proposed Europa Missions
Post by: zubenelgenubi on 09/17/2018 08:00 pm
If the outer planets community is going to do that, why shouldn't MEPAG, SBAG and the others all just start buttering up their own preferred congresspeople to get what they want? Just give up on the decadal process completely.

Culberson is an odd duck. If there were others like him, I'm pretty confident that some members of the planetary science community would opt for Mad Max. Fortunately, he appears to stand alone.

My opinion: Committee decadal/demi-decadal priority sets is better than most or all alternatives (including 3-legged race heats!).

Re: individual Congressperson favorites/un-favorites of NASA non-manned missions in decades past (which is partially why the committee decadal priorities exists in the first place):
SETI (1982--Sen. Proxmire/"Golden Fleece" and 1993--Sen. Richard Bryan)
Voyager-Mars
Grand Tour
The Rep. Boland-created battle of Space Telescope vs. Galileo budget new start...

I'm sure there are more.
Title: Re: Proposed Europa Missions
Post by: UltraViolet9 on 09/18/2018 01:51 am
Yeah, yeah, Mob rule/democracy is "Mad Max" chaos. The best form of government is a technocracy ran by technocrats, not the unwashed masses.

It's not about mobocracy versus technocracy.  It's about a coherent technocracy versus an incoherent technocracy.  Honestly, it's about herding cats.

It's about getting the different members of a science community to agree to a clear set of priorities for spending a finite set of resources to advance their field in the best way possible over the next 10 years.

The alternative of having each member of said science community lobby their individual congressmen for their individual projects may get a telescope or some processing power at some local colleges.  It might even get a small mission off the ground if a loud PI backed by the right appropriator can insert themselves in an ongoing competitive process like Explorer, Discovery, or New Frontiers.

But it's not going to set or produce field-changing, flagship-scale priorities like Hubble, Parker, a Mars sample return, or even a Europa mission.

Quote
Some congressman stay around a lot longer than presidents.

OMB staff are civil servants.  They provide budget continuity between administrations that is usually lacking on congressional appropriations.

Quote
And we should also appreciate that the decadal recommendation of a Europa orbiter wouldn't have happened without him...

This makes no sense.

Congressional staff may brief an NRC survey committee, usually about what the budget outlook is from their POV.

But they and their bosses do not sit on the committee and have no influence over its deliberations.

Similarly, Congress may direct an agency like NASA to fund a study of interest at the NRC.

But Congress has no influence over the findings and recommendations of said studies.

The whole reason for the NRC's existence is to provide technical advice to the Administration and Congress that is free of political influence.

If, in some alternate reality, Culberson actually influenced the flagship priorities in the last planetary science decadal survey, then something is seriously wrong with that reality.  Heads should roll...

Quote
For instance, the decadal process doesn't seem too interested in the threat from NEOs,

Of course not.  NASA (by design during the Eisenhower Administration) and NSF are not chartered to address national security concerns.  A survey to inform the planetary research priorities of these agencies is not going to weigh in on priorities to address the NEO threat.

Quote
Congress has much more of a focus on national security objectives.

Then Rohrbacher should refer the NEO threat to the appropriate congressional committees that deal with national security issues.

Quote
Scientists are more interested in stuff that happened billions of years ago.

Yes, that's why astrobiologists are so focused on obtaining current atmospheric spectra from Earth-sized exoplanets in the solar neighborhood and on the current life-bearing potential of the subterranean oceans of our solar system's icy moons.
Title: Re: Proposed Europa Missions
Post by: ncb1397 on 09/18/2018 02:42 am

If, in some alternate reality, Culberson actually influenced the flagship priorities in the last planetary science decadal survey, then something is seriously wrong with that reality.  Heads should roll...


My statement can be parsed more than one way. It wasn't that he influenced the decadal, the decadal recommendation of an orbiter for Europa wouldn't have happened (as in, wouldn't be being built, not wouldn't be recommended). Bolden was talking in 2013 about no more Flagships and it wasn't showing up in their funding requests until that specific decadal recommendation was inserted by Congress.

Quote
Flagship   missions—The planned continuation of the Cassini mission through 2017 is the most cost-effective and highest-priority way to advance understanding of planetary satellites in the near term. The highest-priority satellite-focused missions to be considered for new starts in the coming decade are, in priority order: (1) Jupiter Europa Orbiter component of EJSM as described in the Jupiter   Europa   Orbiter   Mission   Study   2008:   Final   Report97 and refined subsequently (including several Io science flybys);

A ice giant mission was also recommended, but wasn't inserted by Congress, and therefore never happened. Same thing could have happened for JEO/Clipper.
Title: Re: Proposed Europa Missions
Post by: jbenton on 09/18/2018 06:27 pm

We could very well end up with a lander that is not properly designed to do the mission, in part because you really want to design the lander AFTER you gather good data on Europa from Clipper.

Huygens was designed after flybys of Saturn, not after the Cassini Orbiter and worked out just fine. And we are already past the Cassini stage for the Jupiter system, having already operated Galileo there for 8 years (and Juno after that). We know far more about the Jupiter system and the hazards there, including the radiation, than we did about the Saturnian system when Huygens was designed and operated successfully.

Apples and oranges. Voyager 1 flyby of Titan gave us an accurate atmospheric profile to be able to design an *atmospheric* probe, which is what Huygens really was. When it comes to science that a Europa lander would like to do, we don't even know what kind of environment we're looking at down there. Surface roughness, what kind of trace materials, etc.

On the flip side, because of plumes, tectonics due to the liquid subsurface, tidal flexing, a ferocious energetic particle environment, debris impacts, cratering,  etc, you probably want the most up to date maps possible. You would likely want to target an area that has had recent plume activity but not current plume activity and an orbiter in the same time frame would be extremely helpful. The plan is I think Europa ~2022 with arrival 2024-2025, with the lander launching in 2026 and arriving in 2033. If you do it sequentially after arrival in 2025, you are probably looking at 2040, in which case your maps are over a decade old, you lose potential orbiter relay options (without sending up another orbiter), etc.

The scientific justification for targeting a geologically active region that is still safe practically requires close orbiter/lander time frames.

They can just as easily smack themselves when they get there and are going to need an orbiter for the landing, and Europa clipper will likely be 90% toast by then. BTW, Juice would be arriving around 2030, which would line up with 2033 a lot better than 2040. Besides, there would probably be a 1 year gap + with Europa doing mapping and the lander on the ground. You could change the landing gear if that unlikely scenario ever happened.

I think there are a couple ways around this.

I emailed Curt Niebur, whose in charge of both Cassini and the efforts tied to Europa.  I asked the following regarding solar power to get a straight answer:

Quote
I wrote to you previously regarding the schedule for a Europa mission's planning.  This time I write because a surprising rumor has popped up on twitter, stating that solar power has been chosen for the mission.  I thought it prudent to get straight answers from a legitimate source rather than rumor.
 
 This is what was stated via twitter: APL's Thomas Magner: We've selected solar power for the Europa Clipper mission, baselined for launch on SLS in June 2022. #IAC2014
 
 I find it doubtful this could be true, mainly because mission concepts are still being viewed.  I believe solar power could be both useful and practical, so long as radiation decay can be mitigated.  However I'm more concerned this is just a rumor and I don't like the idea of amateurs making assumptions while your colleagues are making though choices and evaluations.  Please look into this if you can.

Niebur replied:
Quote
Yes, this is true.  While we haven’t decided on a final concept, for the Clipper concept in particular we have baselined solar.  We did look at the radiation effect on the panels, which degrades their power output.  But testing shows that the panels are good for over 200 flybys, well beyond the 45 flybys in the Clipper concept.

Presuming the panels can retain the better part of their power production, this would be good news for mission extensions.  Considering Galileo held up reasonably well during its Jupiter cruise, sans the antenna and tape recorder issues (neither of which related to radiation), it should be safe to presume 'Clipper could live through it's primary mission and one mission extension; I don't go so far as to say two since even Galileo didn't as long as this potential successor will in the radiation belts.

Hopefully we'll hear good news for Europa.  Obviously much is still in the air but I'm feeling good vibes.

This was from 2014, and much has changed since then, but I don't see how the solar panels could have become less durable - though they have become much bigger.

In presentations, the mission team has said that the spacecraft and instruments likely could survive many more encounters with Europa than the planned 45.
He also stated that the likely limiting factor for the mission would be the decay of power from the solar cells as they are degraded by the radiation.  (Which brings up the idea to me that at some point they could raise the periapsis of the orbit out of the intense radiation field and become a Jovian system observatory for some period.  ESA's JUICE mission will orbit Ganymede and do a number of Callisto flybys.  Don't know the science return for additional flybys of these moons by the Clipper spacecraft late in its mission.)

So if the solar arrays are the rad-limiting factor, then 'Clipper won't be "90% toasted" at the end of primary mission, it will be ~22.5% fried. After a second 45 flybys (3.5 years) it will be ~45% toasted. Also, it could 'take a breather' so to speak and have an extended mission in a higher orbit to do magnetosphere science for several years.

Also, redilox, how did you get to know Curt Niebur?
Title: Re: Proposed Europa Missions
Post by: jbenton on 09/19/2018 05:21 am

We could very well end up with a lander that is not properly designed to do the mission, in part because you really want to design the lander AFTER you gather good data on Europa from Clipper.

Huygens was designed after flybys of Saturn, not after the Cassini Orbiter and worked out just fine. And we are already past the Cassini stage for the Jupiter system, having already operated Galileo there for 8 years (and Juno after that). We know far more about the Jupiter system and the hazards there, including the radiation, than we did about the Saturnian system when Huygens was designed and operated successfully.

It should be noted that NASA hasn't soft landed on any solar system surface other than Mars since 1972. They need to branch out.

Apples and oranges. Voyager 1 flyby of Titan gave us an accurate atmospheric profile to be able to design an *atmospheric* probe, which is what Huygens really was. When it comes to science that a Europa lander would like to do, we don't even know what kind of environment we're looking at down there. Surface roughness, what kind of trace materials, etc.

When I first read this I was thinking "wasn't Huygens a soft-lander?" then I realized that was ESA, as was Philae. ISRO lands on Luna next year, China did that recently and will do it again soon, JAXA plans to land on Phobos in 2024. NASA's only proposed non-Martian extraterrestrial landings are Europa and the Titan quadcoptor. I agree, NASA should do some landing somewhere other than Mars (if they can afford it); on the flip-side, though, no one other than NASA has made a successful soft landing on Mars; I feel that this dichotomy is no coincidence.

All that said, a Europa Lander is not comparable to Huygens.  With 4X the atmosphere of Earth and less than 1/6th the gravity, Titan is one of the easiest landings in the solar-system. Europa could be like trying to skydive into the Needles (https://en.wikipedia.org/wiki/The_Needles_(Arizona)[b) with a jet-pack instead of a parachute whilst also dealing with the fallout of a recently detonated nuclear bomb. We shouldn't do that blind, we need more reconnaissance. Then there's also the skycrane, because a conventionally-placed rocket could sublimate the landing area, eradicating the science mission before it even begins. There's also not much useful we can learn about Europa just by landing anything there; as was the case with Huygens. Huygens helped us characterize what the surface was made of. There's no hazy atmosphere to obscure the surface; we can find out everything about Europa that Cassini and Huygens told us about Titan's surface from orbit. EL needs to find the best place to land to try and answer the big questions.

edit:
cubesat lander - https://space.skyrocket.de/doc_sdat/omotenashi.htm

Thanks for this, I really like this design. Glad that it's flying to Luna in 2020!  :)
That being said, I'd be really surprised if it could survive the radiation environment around Europa long enough to do anything useful.

Why should Europa get a ~$3+ billion orbiter and a ~$2.7 billion (WAG) lander in this decade? Why should other scientists and other parts of the solar system get locked out?

Could someone remind me how the $2 billion Clipper concept became the $3 billion Clipper reality? It's more than just inflation, that much is clear. I think it's something like that they started to develop the instruments, but the instrument payload grew too big and power-hungry for the spacecraft they originally designed. The mid-decadal report says that Clipper will be "~$3.1 billion - ~$4 billion, depending on the launch vehicle." Thanks  :)

Title: Re: Proposed Europa Missions
Post by: jbenton on 09/19/2018 05:21 am
Yeah, yeah, Mob rule/democracy is "Mad Max" chaos. The best form of government is a technocracy ran by technocrats, not the unwashed masses.

It's not about mobocracy versus technocracy.  It's about a coherent technocracy versus an incoherent technocracy.  Honestly, it's about herding cats.

For what it's worth our government is supposed to be a fusion of democracy and technocracy (hence the Supreme Court). In the Federalist Papers, one of the authors (I think it was James Madison) said something along the lines of the new, proposed government being 'a mix of monarchy, aristocracy, and democracy, but from democratic principles.'

Some congressman stay around a lot longer than presidents.

OMB staff are civil servants.  They provide budget continuity between administrations that is usually lacking on congressional appropriations.

I definitely don't think that presidents have anything to do with any of this. The Obama Administration was against Europa Clipper and the Lander, the Trump Admin. pushed to delay it and is against the Lander. Same story with WFIRST, to give another example. Both admin.s were/are against it, both Congresses have been for it. That being said, the observation that some Congressmen stick around for awhile is important. They last longer, not only than the presidents, but also Department Secretaries, Directors and Administrators. Of course the civil servants stick around the longest.

My statement can be parsed more than one way. It wasn't that he influenced the decadal, the decadal recommendation of an orbiter for Europa wouldn't have happened (as in, wouldn't be being built, not wouldn't be recommended). Bolden was talking in 2013 about no more Flagships and it wasn't showing up in their funding requests until that specific decadal recommendation was inserted by Congress.
And it wasn't just the lander that they were trying to kill, it was the Decadal Survey's Europa orbiter.

That's the interesting part about all this. With the Europa Clipper, Rep. Culberson was agreeing with the Decadal; the Lander, however, is straight out of left field. Personally, I consider him a hero for pushing Clipper through and increasing NASA's top line budget in order to do it.

That being said, whenever I read "Europa Lander" and "Culberson" in the same sentence, or even in the same paragraph, I feel the need to face-palm. When I first heard of the meeting he had at JPL where they brought up the lander, I couldn't help but to think of what was then QuantumG's sig line: "When someone's wishing for a pony, it usually doesn't help to say a unicorn would be even better!"

The mid-Decadal report was optimistic and supportive about the Europa Clipper, it suggested, that the Lander, on the other hand, ought to be postponed until after it could be considered by the next DS.
One interesting effect of this is that it seems that a bunch of the work of figuring out what this thing is actually going to look like. I'd think that this would make the Decadal Survey people's job easier, but what do I know?
Title: Re: Proposed Europa Missions
Post by: jbenton on 09/19/2018 05:21 am
You know, I could write 2000 words here explaining how space science priorities are established, what a decadal survey is, how space science policy has evolved over the past several decades, what a CATE is, and why all of this is important. But I'd be explaining it to somebody who probably wouldn't listen anyway and would just reply with a snarky remark. i won't bother. Feel free to think you understand how all of this works. Ignorance is blissful.

I would read it. I find all this policy and budget stuff fascinating.
Title: Re: Proposed Europa Missions
Post by: vjkane on 09/19/2018 10:09 pm
Could someone remind me how the $2 billion Clipper concept became the $3 billion Clipper reality? It's more than just inflation, that much is clear. I think it's something like that they started to develop the instruments, but the instrument payload grew too big and power-hungry for the spacecraft they originally designed. The mid-decadal report says that Clipper will be "~$3.1 billion - ~$4 billion, depending on the launch vehicle." Thanks  :)

But I'll correct you and note that Europa Clipper was never really a $2 billion concept. All early cost estimates are blurry, not only because some things are not known, but because some things are not decided. If you go back to the 2011 decadal survey, you'll see (I think--too lazy to check right now) that the DS never recommended a specific cost for a Europa orbiter mission. It only stated that the $4.7 billion CATE estimate for the Jupiter Europa Orbiter was too much, and NASA needed to descope the mission to come up with something more affordable--for various definitions of "affordable."

One other thing.  There were a range of proposals for the instrument list and spacecraft capabilities when what became Clipper was still a concept.  Some of those likely would have come in around $2B for the spacecraft and instruments.  NASA decided, and as long as Congress was willing to foot the bill I think this was the right decision, to go with a rich instrument set and a highly capable spacecraft.  This way, we won't be in the position of needing to send a second remote sensing spacecraft to fill in the holes left by the first.
Title: Re: Proposed Europa Missions
Post by: JH on 09/20/2018 03:54 am
About a year or so ago this seemed to be in danger of biting them on the butt. The issue, as I remember it, was that they had approved (and started building) more instruments than the spacecraft could actually accommodate. So they ran the risk that they would then have to pull one of the instruments off because they could not provide enough power, mass, whatever for all of them. I don't know if they have solved that problem, but I have not heard any more kvetching about it, so maybe they have (or maybe I just have not asked the right people--there's too much to keep track of).

I've been hearing more reassuring noises from people on different instrument teams in the last few months. It was looking dicey for a little while there, though.
Title: Re: Proposed Europa Missions
Post by: vjkane on 09/20/2018 03:57 am

I've been hearing more reassuring noises from people on different instrument teams in the last few months. It was looking dicey for a little while there, though.
In my experience, solving dicey engineering problems almost always drives up cost.  We are getting the Rolls Royce of Europa missions.  Thank you Culberson.
Title: Re: Proposed Europa Missions
Post by: Lar on 09/20/2018 04:26 pm
How did this topic morph into a discussion of the Federalist Papers? With a side order of snark in both directions?

I am glad it morphed back. Let's try to keep it that way, thanks.
Title: Re: Proposed Europa Missions
Post by: Star One on 09/20/2018 05:50 pm
How did this topic morph into a discussion of the Federalist Papers? With a side order of snark in both directions?

I am glad it morphed back. Let's try to keep it that way, thanks.

It felt like it had become more of a space policy thread than anything else of late.
Title: Re: Proposed Europa Missions
Post by: vjkane on 09/21/2018 01:33 am
How did this topic morph into a discussion of the Federalist Papers? With a side order of snark in both directions?

I am glad it morphed back. Let's try to keep it that way, thanks.
A number of posts have disappeared.  ???
Title: Re: Proposed Europa Missions
Post by: Star One on 09/21/2018 08:21 am
How did this topic morph into a discussion of the Federalist Papers? With a side order of snark in both directions?

I am glad it morphed back. Let's try to keep it that way, thanks.
A number of posts have disappeared.  ???

I expect possibly for the reason I posted above.
Title: Re: Proposed Europa Missions
Post by: Star One on 10/09/2018 07:02 am
Well this could make life more difficult for any lander.

Europa’s Equator May Be Covered in Perilous Ice Towers (https://www.scientificamerican.com/article/europas-equator-may-be-covered-in-perilous-ice-towers/)

Quote
Exploring the tropics of Jupiter’s ocean moon Europa would be no walk on the beach.
Equatorial regions of the potentially life-supporting Europa, which harbors a huge ocean of salty liquid water beneath its icy shell, are probably studded with blades of ice up to 50 feet (15 meters) tall, a new study suggests.
This finding should be of interest to NASA, which is developing a lander mission that will hunt for signs of life on the 1,900-mile-wide (3,100 kilometers) satellite.
Title: Re: Proposed Europa Missions
Post by: speedevil on 10/09/2018 10:09 am
Well this could make life more difficult for any lander.
Quote
are probably studded with blades of ice up to 50 feet (15 meters) tall, a new study suggests. 
It would also greatly reduce the radiation dose if you can find a nice crevice, so it's not wholly bad.
Title: Re: Proposed Europa Missions
Post by: Zed_Noir on 10/09/2018 10:40 am
Well this could make life more difficult for any lander.

Europa’s Equator May Be Covered in Perilous Ice Towers (https://www.scientificamerican.com/article/europas-equator-may-be-covered-in-perilous-ice-towers/)

Quote
Exploring the tropics of Jupiter’s ocean moon Europa would be no walk on the beach.
Equatorial regions of the potentially life-supporting Europa, which harbors a huge ocean of salty liquid water beneath its icy shell, are probably studded with blades of ice up to 50 feet (15 meters) tall, a new study suggests.
This finding should be of interest to NASA, which is developing a lander mission that will hunt for signs of life on the 1,900-mile-wide (3,100 kilometers) satellite.

You just have to use the traditional US Army method of clearing landing zone obstacles by blasting them away, Instead of Daisy Cutters use "Rods from God". Using a bunch kinetic impacter rods should do the job.

Only semi kidding.  :)
Title: Re: Proposed Europa Missions
Post by: b0objunior on 10/09/2018 10:46 am
Well this could make life more difficult for any lander.

Europa’s Equator May Be Covered in Perilous Ice Towers (https://www.scientificamerican.com/article/europas-equator-may-be-covered-in-perilous-ice-towers/)

Quote
Exploring the tropics of Jupiter’s ocean moon Europa would be no walk on the beach.
Equatorial regions of the potentially life-supporting Europa, which harbors a huge ocean of salty liquid water beneath its icy shell, are probably studded with blades of ice up to 50 feet (15 meters) tall, a new study suggests.
This finding should be of interest to NASA, which is developing a lander mission that will hunt for signs of life on the 1,900-mile-wide (3,100 kilometers) satellite.

You just have to use the traditional US Army method of clearing landing zone obstacles by blasting them away, Instead of Daisy Cutters use "Rods from God". Using a bunch kinetic impacter rods should do the job.

Only semi kidding.  :)
Ha... I thought of the same thing.
Title: Re: Proposed Europa Missions
Post by: gongora on 10/16/2018 07:43 pm
https://twitter.com/LASPatCU/status/1052278701931413504
Title: Re: Proposed Europa Missions
Post by: JetGlider on 11/07/2018 09:06 am
It looks like the OPAG meeting presentations are uploaded.
Europa Clipper update by Bob Pappalardo:
https://www.lpi.usra.edu/opag/meetings/sep2018/presentations/Pappalardo-Europa.pdf
Title: Re: Proposed Europa Missions
Post by: JetGlider on 11/07/2018 10:08 am
We also got very nice updates on the Europa Lander:

Europa Lander reduced-scope mission process – Robert Braun
https://www.lpi.usra.edu/opag/meetings/sep2018/presentations/Braun.pdf

Europa Lander technical mission plan – Roger Gibbs (with landing simulation and excavation videos!)
https://www.lpi.usra.edu/opag/meetings/sep2018/presentations/Gibbs.pdf

Panel discussion and Q&A about new Europa Lander concept by Kevin Hand (with the lander on the surface video!)
https://www.lpi.usra.edu/opag/meetings/sep2018/presentations/Hand.pdf

Panel discussion and Q&A about new Europa Lander concept by Chris McKay
https://www.lpi.usra.edu/opag/meetings/sep2018/presentations/McKay.pdf
Title: Re: Proposed Europa Missions
Post by: Zed_Noir on 11/07/2018 11:15 am
With both Bill Nelson and John Culberson leaving Congress after electoral defeats. Will the Europa mission get de-scoped and/or delay?
Title: Re: Proposed Europa Missions
Post by: vjkane on 11/07/2018 03:13 pm
With both Bill Nelson and John Culberson leaving Congress after electoral defeats. Will the Europa mission get de-scoped and/or delay?

The Clipper mission now seems to have solid political support from OMB and both houses.  I would not be surprised to see the target launch date slip to the mid 2020s from the Culberson target of 2022.  The launch vehicle may also switch to a commercial launcher from the SLS, although Shelby is still in the Senate.  If both happen, Clipper is likely to arrive in the early 2030s.

I expect that a Europa lander that was so strongly supported by Culberson will disappear for a least another decade.
Title: Re: Proposed Europa Missions
Post by: redliox on 11/07/2018 11:03 pm
I would not be surprised to see the target launch date slip to the mid 2020s from the Culberson target of 2022.  The launch vehicle may also switch to a commercial launcher from the SLS, although Shelby is still in the Senate.  If both happen, Clipper is likely to arrive in the early 2030s.

Unless they prioritize sending Clipper first over Orion and keep SLS on a tighter track, I agree that it makes sense to put it on a working vehicle; I'd prefer anything than can minimize the GA trajectories to a single Earth flyby but technically the team designed Clipper to handle a longer route on a smaller vehicle if necessary.

I expect that a Europa lander that was so strongly supported by Culberson will disappear for a least another decade.

I definitely agree; the lander was a bit forced.  I'd hope that a delayed design might be able to incorporate a longer lifespan and streamlined mass, neither of which looks practical with current plans.
Title: Re: Proposed Europa Missions
Post by: Don2 on 11/08/2018 04:42 am
I'm sorry to see Culberson go. He was a good supporter of planetary science.

There might be a case for a descoped lander that just focuses on the basics. The information available from IR spectroscopy is limited. It would be helpful to have information on the trace elements present in the ice from something like an APXS. Forget life detection. Are there any organic compounds present on the surface of Europa? What salts are present, if any?

We have never seen the surface of an ice moon up close. Is it a powdery regolith, like what we find on rocky bodies like the moon? Is it a solid sheet of ice?

If the science payload was 1kg, could a cheap miniaturized lander be built to provide ground truth for the orbiter? Delta-v depends on fuel fraction, so small probes can in theory have as much delta-v as large ones.
Title: Re: Proposed Europa Missions
Post by: AegeanBlue on 11/08/2018 05:57 am
We do not know what the new House majority wants, but I do not see the SLS going away. It was the Democratic majority Senate that created it and the current Republican majority loves it because it is in their district. I remember a NASA study that SLS has contractors in 43 states. I do see Europa Lander going, there wasn't much love in the community. Europa Clipper now looks unlikely to be cancelled. My hypothesis though would be a delay so that it launches on the first Block 1B test flight. Right now the first Block 1B flight is the crewed EM-3, and the Aerospace Safety Advisory Panel is not happy with the idea it being the first flight without a test. Then again, let's wait for January
Title: Re: Proposed Europa Missions
Post by: TakeOff on 11/08/2018 08:59 am
We do not know what the new House majority wants, but I do not see the SLS going away.
I also don't see it going away (from the launch pad).
I want to recommend the radio podcast of the Planetary Society who comments space policy once a month and have waited with the next episode (not out yet) until after the mid term election. I think they seem quite initiated and realistic. The "Policy Editions" here:
http://www.planetary.org/multimedia/planetary-radio/show/
Title: Re: Proposed Europa Missions
Post by: Don2 on 11/08/2018 08:03 pm
I agree that is the most likely outcome. SLS stays because of support from southern senators. Clipper continues. Europa lander gets cut or 'deferred.'

Dems will want to cut planetary and put the funding into Earth science. Repubs in the Senate will want to do the opposite. They will compromise on doing nothing.
Title: Re: Proposed Europa Missions
Post by: redliox on 11/08/2018 11:52 pm
Dems will want to cut planetary and put the funding into Earth science. Repubs in the Senate will want to do the opposite. They will compromise on doing nothing.

Don't be so sure.  Actual scientists became elected this year, and NASA has been one of the few bipartisan items both sides at least occasionally compromise on.
Title: Re: Proposed Europa Missions
Post by: Star One on 11/10/2018 07:56 pm
Looks like certain posters on here were spot on about the Europa lander now it has lost its champion.

 NASA’S EUROPA LANDER MAY BE IN JEOPARDY AFTER THE MIDTERMS — AND SOME ARE FINE WITH SEEING IT GO (https://www.theverge.com/2018/11/10/18075556/jupiter-moon-europa-lander-nasa-john-culberson-midterms-life)

Quote
Now that Culberson is about to leave public office, the Europa lander will no longer have its champion, making its future at NASA uncertain. NASA never formally requested a lander for Europa, and the president’s latest budget request noted that the administration had no intention of funding such a program. No other lawmaker seems to be as passionate about the project, nor in the same position to keep the program alive.

Quote
The Europa lander, on the other hand, was not included as a top priority in the decadal survey. “That’s why the lander is in a much more uncertain position when Culberson leaves Congress,” says Dreier. “Because you don’t have any sort of institutionalized support for the concept.” And while most scientists agree that sending a lander to touch down on Europa’s surface is crucially important, some think that it’s too soon to start designing such a vehicle now. Even though we’ve sent a few spacecraft near the vicinity of Europa, we still don’t have detailed high-resolution imagery of the surface nor do we have much data from the space environment around the Moon. And it’s hard to design a lander for a terrain and environment you don’t know that well. “I actually put in a proposal for a potential instrument to be on the lander, and I struggled with writing a proposal because we have so many unknowns,” says Yingst.

Quote
Still, 2018 isn’t over yet. Culberson is still in office and it’s possible he could negotiate some last-ditch funding for the Europa projects before the end of the year. NASA is being funded through a continuing resolution that lasts until December 7th. It all depends if lawmakers can come to an agreement in the next few months on how funds should be appropriated for fiscal year 2019. But once Culberson leaves, it seems likely the funding for the Europa lander will dry up — and that could mean more waiting before we ever touch down on the mysterious moon’s icy exterior. “This is part of the deal of doing science in a democracy,” says Yingst.
Title: Re: Proposed Europa Missions
Post by: Coastal Ron on 11/10/2018 08:18 pm
Looks like certain posters on here were spot on about the Europa lander now it has lost its champion.

Quote
The Europa lander, on the other hand, was not included as a top priority in the decadal survey. “That’s why the lander is in a much more uncertain position when Culberson leaves Congress,” says Dreier. “Because you don’t have any sort of institutionalized support for the concept.”...

When you have projects or programs that require "swimming against the current", you need to be able to exert constant pressure. I see that dissipating with the departure of Rep. Culberson.

However, as the article states, a probe to Europa has had a high priority for a quite a while, so it's still possible that something will be sent to Europa in the next decade - depending on which way the current is flowing...  ;)
Title: Proposed Europa Missions
Post by: Star One on 11/10/2018 08:25 pm
Looks like certain posters on here were spot on about the Europa lander now it has lost its champion.

Quote
The Europa lander, on the other hand, was not included as a top priority in the decadal survey. “That’s why the lander is in a much more uncertain position when Culberson leaves Congress,” says Dreier. “Because you don’t have any sort of institutionalized support for the concept.”...

When you have projects or programs that require "swimming against the current", you need to be able to exert constant pressure. I see that dissipating with the departure of Rep. Culberson.

However, as the article states, a probe to Europa has had a high priority for a quite a while, so it's still possible that something will be sent to Europa in the next decade - depending on which way the current is flowing...  ;)

At least it appears from the article that after a rocky start that Clipper should keep going.
Title: Re: Proposed Europa Missions
Post by: Zed_Noir on 11/10/2018 10:05 pm
So is the Europa Clipper staying the way it is now. Or will there be some de-scoping to make it less costly and quicker to launched?

IMO the Europa lander might get fast tracked or delay further depending on what the Clipper finds. So decision on a lander mission will be a couple of years after the Clipper gets to Europa.


edit: typo
Title: Re: Proposed Europa Missions
Post by: vjkane on 11/11/2018 06:40 pm
So is the Europa Clipper staying the way it is now. Or will will there be some de-scoping to make it less costly and quicker to launched?

IMO the Europa lander might get fast tracked or delay further depending on what the Clipper finds. So decision on a lander mission will be a couple of years after the Clipper gets to Europa.
The only descoping that I've heard about is to use a much cheaper commercial launch vehicle instead of the SLS.  OMB proposed it, and we'll see what the final budget passed by Congress says.

A lander that builds on the discoveries of an orbiter is likely to follow by a decade or more.  So, say Clipper launches in 2025, arrives in 2031, does its first couple of years of science.  Then a lander is designed to take advantage of those findings (5-7 years) and then flies to Europa (another 5-7 years).

Culberson was trying to circumvent that long delay.  That plan depended on the lander being designed prior to the Clipper launch still being the right lander after the first couple of years of the Clipper's findings (like whether there are fields of ice blades covering much of the moon).
Title: Re: Proposed Europa Missions
Post by: Star One on 11/11/2018 07:19 pm
So is the Europa Clipper staying the way it is now. Or will will there be some de-scoping to make it less costly and quicker to launched?

IMO the Europa lander might get fast tracked or delay further depending on what the Clipper finds. So decision on a lander mission will be a couple of years after the Clipper gets to Europa.
The only descoping that I've heard about is to use a much cheaper commercial launch vehicle instead of the SLS.  OMB proposed it, and we'll see what the final budget passed by Congress says.

A lander that builds on the discoveries of an orbiter is likely to follow by a decade or more.  So, say Clipper launches in 2025, arrives in 2031, does its first couple of years of science.  Then a lander is designed to take advantage of those findings (5-7 years) and then flies to Europa (another 5-7 years).

Culberson was trying to circumvent that long delay.  That plan depended on the lander being designed prior to the Clipper launch still being the right lander after the first couple of years of the Clipper's findings (like whether there are fields of ice blades covering much of the moon).

The only alternative launcher I’ve seen mentioned is the Atlas 551, and that would involve adding a Venus flyby and slower journey. Is this the only viable other choice to SLS?
Title: Re: Proposed Europa Missions
Post by: redliox on 11/11/2018 11:00 pm
The only alternative launcher I’ve seen mentioned is the Atlas 551, and that would involve adding a Venus flyby and slower journey. Is this the only viable other choice to SLS?

I'm pretty sure, officially, the Delta IV was considered as another alternative.  Unofficially (especially here and the SpaceX threads), the Falcon Heavy could do the deed too although only the Falcon 9 has been fully certified for science missions, and the '9 wouldn't be much better than the Atlas V.  Probably the SLS has been stressed so heavily in government circles that nobody wants to talk about alternatives outside of the Atlas until "permission" is granted so no one has to worry about careers getting jeopardized.

There are plenty of choices, it just depends on getting permission, certification, and the actual capacity of the rocket; regarding the later, only the SLS could loft the 'Clipper directly to Jupiter although, for any of the gravity-assist routes (with or without Venus) there are plenty, or at least a decent handful, of rockets to choose from.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 11/13/2018 02:21 am
The only descoping that I've heard about

No, there's other stuff going on.
Title: Re: Proposed Europa Missions
Post by: Star One on 11/13/2018 07:26 am
The only descoping that I've heard about

No, there's other stuff going on.

Politically driven?
Title: Re: Proposed Europa Missions
Post by: JH on 11/13/2018 02:53 pm
The only alternative launcher I’ve seen mentioned is the Atlas 551, and that would involve adding a Venus flyby and slower journey. Is this the only viable other choice to SLS?

People are starting to warm to the idea of a Falcon Heavy because it would eliminate the Venus flyby.
Title: Re: Proposed Europa Missions
Post by: plutogno on 11/13/2018 06:23 pm
The only alternative launcher I’ve seen mentioned is the Atlas 551, and that would involve adding a Venus flyby and slower journey. Is this the only viable other choice to SLS?

People are starting to warm to the idea of a Falcon Heavy because it would eliminate the Venus flyby.
Elaborate. What do you mean by "people"?
Title: Re: Proposed Europa Missions
Post by: Jim on 11/20/2018 04:11 pm
The only alternative launcher I’ve seen mentioned is the Atlas 551, and that would involve adding a Venus flyby and slower journey. Is this the only viable other choice to SLS?

People are starting to warm to the idea of a Falcon Heavy because it would eliminate the Venus flyby.

To others vehicles, not just FH.
Title: Re: Proposed Europa Missions
Post by: Star One on 11/21/2018 04:41 pm
A good summation on the Europa Clipper and lander programs especially in light of Congress, Rep. John Culberson of Texas who has been a powerful backer of both programs losing his seat.

http://www.thespacereview.com/article/3603/1 (http://www.thespacereview.com/article/3603/1)
Title: Re: Proposed Europa Missions
Post by: Star One on 11/21/2018 04:42 pm
The only alternative launcher I’ve seen mentioned is the Atlas 551, and that would involve adding a Venus flyby and slower journey. Is this the only viable other choice to SLS?

People are starting to warm to the idea of a Falcon Heavy because it would eliminate the Venus flyby.

To others vehicles, not just FH.

I really hope that Europa Clipper can be disentangled from SLS as I don’t want the former sunk by the latter.
Title: Re: Proposed Europa Missions
Post by: FutureSpaceTourist on 12/03/2018 01:26 pm
Eric Berger’s take on impact of mid-terms on Europa missions:

Quote
A congressman’s loss clouds the future of two demanding missions to Europa
During a recent update, Clipper planners revealed they are looking at Falcon Heavy.

by Eric Berger - Dec 3, 2018 1:00pm GMT

https://arstechnica.com/science/2018/12/will-the-europa-missions-be-iced-after-congressmans-defeat-not-right-now/
Title: Re: Proposed Europa Missions
Post by: leovinus on 12/03/2018 04:48 pm
Eric Berger’s take on impact of mid-terms on Europa missions:

Quote
A congressman’s loss clouds the future of two demanding missions to Europa
During a recent update, Clipper planners revealed they are looking at Falcon Heavy.

by Eric Berger - Dec 3, 2018 1:00pm GMT

https://arstechnica.com/science/2018/12/will-the-europa-missions-be-iced-after-congressmans-defeat-not-right-now/

Which includes some interesting quotes and discussion on Falcon Heavy as alternative to SLS, as hinted at earlier in this thread

Quote
The breakthrough referenced by Goldstein involved the addition of a Star 48 "kick stage" to the Falcon Heavy rocket, which would provide an extra boost of energy after the rocket's upper stage had fired. With this solid rocket motor kick stage, Goldstein said Clipper would need just a single Earth gravity assist and would not have to go into the inner Solar System for a Venus flyby.

"Nobody is saying we're not going on the SLS," Goldstein said. "But if by chance we don't, we don't have the challenge of the inner Solar System. This was a major development. This was a big deal for us."
Title: Re: Proposed Europa Missions
Post by: Blackstar on 12/03/2018 05:38 pm
I quibble with a couple of statements in the article. One is stating that Mike Griffin canceled a mission to Europa. I believe that the author is referring to Griffin's cancellation of the Jupiter Icy Moons Orbiter (JIMO) mission. This was really a no-brainer: the cost estimates on that mission were over $20 billion (yes, you read that right), and nobody expected it to ever progress very far in development. He did everybody a favor before even more money was thrown down that bottomless pit. One could argue that JIMO actually got in the way of NASA developing a realistic Europa mission for many years.

The article also misses some things about opposition to the lander mission and refers to "some influential voices..." in favor of an Enceladus lander, but that's misleading. I don't think Porco is all that influential, and it is not really a case of dueling landers, it's more a case of the Europa lander vs. the rest of the scientific community, which would rather see that money spent on a bunch of other priorities. For instance, an ice giants mission. The author also neglected to mention the recent planetary science decadal survey midterm report, which had a few things to say about Europa lander as well.

These are minor issues, but I think there's a bigger one that he missed, which is that the Europa lander's scientific support is mostly at JPL and not among the rest of the planetary science community. It's not not all that surprising that the people who would most benefit from two missions with a total price tag of over $5 billion (at least) are the loudest supporters.

Title: Re: Proposed Europa Missions
Post by: vjkane on 12/03/2018 06:51 pm
1) One could argue that JIMO actually got in the way of NASA developing a realistic Europa mission for many years.

2) and it is not really a case of dueling landers, it's more a case of the Europa lander vs. the rest of the scientific community, which would rather see that money spent on a bunch of other priorities.
1) I would argue that the real purpose of JIMO was to delay or cancel any consideration of a real mission.  It was a complete fantasy from the start.

2) In addition to the question of scientific balance, there's a question of whether or not we know enough about Europa to design a mission that will cost at least $2.5B (I doubt that includes the SLS launch, either).  Where should we land, what are the conditions, what are the right instruments to carry?  Remember that Galileo returned only a trickle of information.  The current lander proposal is a credit to JPL's engineers, but it makes a lot of assumptions that may prove wrong.
Title: Re: Proposed Europa Missions
Post by: JH on 12/03/2018 06:52 pm
This was really a no-brainer: the cost estimates on that mission were over $20 billion (yes, you read that right), and nobody expected it to ever progress very far in development. He did everybody a favor before even more money was thrown down that bottomless pit.

I always suspected that you were a traitor to the Galactic Empire, Blackstar.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 12/03/2018 06:55 pm
1) One could argue that JIMO actually got in the way of NASA developing a realistic Europa mission for many years.

2) and it is not really a case of dueling landers, it's more a case of the Europa lander vs. the rest of the scientific community, which would rather see that money spent on a bunch of other priorities.
1) I would argue that the real purpose of JIMO was to delay or cancel any consideration of a real mission.  It was a complete fantasy from the start.


Well, one man's fantasy is another man's reality. JIMO has long deserved a good history article explaining its origins and its evolution. Sean O'Keefe is the one who pushed it, and he apparently did so while totally misunderstanding the physics. He kept referring to JIMO as a high speed mission to the outer planets, confusing it with nuclear thermal propulsion. Still, NASA spent over $400 million on that mission that was never going anywhere. There are in fact many parallels between JIMO and Europa lander, foremost being an example of what happens when somebody who controls the money gets captured by one of NASA's field centers (in both cases JPL). The field center is more interested that the money be spent there than they are in the project's actual goals and milestones.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 12/03/2018 06:56 pm
This was really a no-brainer: the cost estimates on that mission were over $20 billion (yes, you read that right), and nobody expected it to ever progress very far in development. He did everybody a favor before even more money was thrown down that bottomless pit.

I always suspected that you were a traitor to the Galactic Empire, Blackstar.

Did I ever hide that?
Title: Re: Proposed Europa Missions
Post by: Blackstar on 12/03/2018 07:03 pm
2) In addition to the question of scientific balance, there's a question of whether or not we know enough about Europa to design a mission that will cost at least $2.5B (I doubt that includes the SLS launch, either).  Where should we land, what are the conditions, what are the right instruments to carry?  Remember that Galileo returned only a trickle of information.  The current lander proposal is a credit to JPL's engineers, but it makes a lot of assumptions that may prove wrong.

Yeah, I didn't want to get into that because it gets big and complicated fast--and also hard to understand. I think that at the most basic level you have to break the issue down into two parts: the topography information about Europa necessary both to design and land a spacecraft, and the scientific information about Europa necessary to design a good lander. One of the worst things you could do is lock in the design of the Europa lander early and then learn from Europa Clipper's data that the lander won't be able to land, or can only land in boring locations, or cannot perform really useful science. You don't want to spend billions of dollars on a lander that produces lousy data (or that crashes).

There have also been people who have argued (most recently at OPAG) that NASA's effort at driving down the cost of the Europa lander may be the wrong thing to do because you end up with a minimally capable spacecraft. Instead, they argue that the proper thing to do is to have the scientific community hash out the requirements (possibly including waiting for data from Europa Clipper over a decade from now) and then design a larger and more capable lander.

There is a very good argument to be made to do all of these things in steps, with pauses to collect and analyze the data before taking the next step. The typical complaint is that nobody really wants to wait 20-30 years to land on Europa. But is the goal to do it now so that we can see it, or do it right?
Title: Re: Proposed Europa Missions
Post by: vjkane on 12/03/2018 07:09 pm
There is a very good argument to be made to do all of these things in steps, with pauses to collect and analyze the data before taking the next step. The typical complaint is that nobody really wants to wait 20-30 years to land on Europa. But is the goal to do it now so that we can see it, or do it right?
Europa landers will suffer from the same problem as Venus landers -- it's a damn hostile environment and any lander is going to be bloody expensive and short lived.  (While landers can survive days or even weeks at Europa, unlike Venus with present technology, Europa sits deep in a gigantic gravity well and lacks an atmosphere to provide braking.)  Imagine the pain of your Europa lander sitting down and the camera shows that the spot you really, really want to sample is 20 m away.  To avoid that, you need to find locations that have that condition across a landing eclipse, and then you want to make sure you design the lander for the conditions in that area.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 12/03/2018 07:13 pm
Europa landers will suffer from the same problem as Venus landers -- it's a damn hostile environment and any lander is going to be bloody expensive and short lived.  (While landers can survive days or even weeks at Europa, unlike Venus with present technology, Europa sits deep in a gigantic gravity well and lacks an atmosphere to provide braking.)  Imagine the pain of your Europa lander sitting down and the camera shows that the spot you really, really want to sample is 20 m away.  To avoid that, you need to find locations that have that condition across a landing eclipse, and then you want to make sure you design the lander for the conditions in that area.

The comparison to Venus is a good one, but in some ways it is even more exaggerated for a Europa lander: very limited time on the surface (so you have to do a whole buncha things fast), but also a very high price tag. Nobody wants to spend $3+ billion for a mission that doesn't get the best data, or that just misses getting the best data. You're only going to get one shot to do this mission in many decades, so you better do it right the first time.
Title: Re: Proposed Europa Missions
Post by: Tulse on 12/03/2018 07:19 pm
What are the arguments for Europa rather than Enceladus?  The latter has a far more benign radiation environment, and is actively pumping out water (and thus perhaps other things).  It would seem a far simpler mission, with far more likelihood of successfully sampling the interior.  Is it just the size of its ocean that makes it less likely to harbour life?
Title: Re: Proposed Europa Missions
Post by: clongton on 12/03/2018 10:05 pm
What are the arguments for Europa rather than Enceladus? 

Because the message from 2001 A Space Odyssey was that we are not allowed to go to Europa. That, of course, is why we have to go there. Did you learn nothing as a child? When mother told you not to do something, it was because she was hiding something from you and therefore that's exactly what you did. 
Title: Re: Proposed Europa Missions
Post by: Star One on 12/11/2018 03:21 pm
What are the arguments for Europa rather than Enceladus? 

Because the message from 2001 A Space Odyssey was that we are not allowed to go to Europa. That, of course, is why we have to go there. Did you learn nothing as a child? When mother told you not to do something, it was because she was hiding something from you and therefore that's exactly what you did.

Also it looks like Enceladus will hopefully be covered by the Breakthrough Initiatives with NASA help.

https://spacenews.com/nasa-to-support-initial-studies-of-privately-funded-enceladus-mission/

Title: Re: Proposed Europa Missions
Post by: launchwatcher on 12/11/2018 07:08 pm
Because the message from 2001 A Space Odyssey 2010: Odyssey Two was that we are not allowed to go to Europa. That, of course, is why we have to go there. Did you learn nothing as a child? When mother told you not to do something, it was because she was hiding something from you and therefore that's exactly what you did.
(note correction above).

We're free to go until the monoliths ignite Jupiter.
Title: Proposed Europa Missions
Post by: Star One on 12/17/2018 08:49 pm
NASA's Nuclear-Powered Tunneling Bot Could Hunt for Life on Europa (https://futurism.com/nasa-nuclear-powered-tunnel-bot-life-europa/amp/?)

Quote
Now, researchers at with NASA’s Glenn Research COMPASS team have devised an idea for a probe that could access that ocean: a nuclear-powered tunneling bot that could burrow through the moon’s icy shell to probe its composition and, potentially, access the watery darkness under it.

The researchers dreamed up two versions of the “tunnelbot,” one of which would use a small nuclear reactor and the other of which would use a “radioactive heat source module.” In both cases, the tunnelbot would use excess heat from its reactors to melt the ice as it traveled down.

As it went, the tunnelbot would analyze the ice and search it for signs of current or extinct life, reporting back to Earth with a fiber optic cable connected to communication equipment at Europa’s surface. It would even be equipped to explore lakes buried in the ice before it reached Europa’s oceanic depths.
Title: Re: Proposed Europa Missions
Post by: Star One on 01/16/2019 08:22 pm
Sounds like it is possible that if you’re visiting Europa just hoping to find life then you are wasting your time.

Ocean Moons, Promising Targets in Search for Alien Life, Could Be Dead Inside (https://www.scientificamerican.com/article/ocean-moons-promising-targets-in-search-for-alien-life-could-be-dead-inside/)

Quote
The interiors of Europa and other watery moons in the outer solar system might be too geologically inactive to support life
Title: Re: Proposed Europa Missions
Post by: redliox on 01/16/2019 09:43 pm
Sounds like it is possible that if you’re visiting Europa just hoping to find life then you are wasting your time.

Ocean Moons, Promising Targets in Search for Alien Life, Could Be Dead Inside (https://www.scientificamerican.com/article/ocean-moons-promising-targets-in-search-for-alien-life-could-be-dead-inside/)

Quote
The interiors of Europa and other watery moons in the outer solar system might be too geologically inactive to support life

It does bring out a legitimate point about how not all ocean planets might be capable of harboring life.  Tidal heating setups like Europa or Enceladus might be too short lived or the chemistry not quite right.  Among exoplanets there are numerous arguments that different minerals can cause tectonics to stop even with sufficient heat and water, so I would expect similar limitations to exist for wet planets.  Not every puddle has a fish in it here on Earth to put it one way.

As far the odds of Europa having life, I'd give it a 50/50 chance; much higher than modern Mars and maybe slightly higher than Enceladus.  However we won't know for a very long time at best.  For the moment all we can do is verify if and how extensive the oceans are on Europa, perhaps adding better numbers to calculate the chemistry.

I treat the question of if Europa has life the same way regarding of Proxima or Epsilon Eridani having life: we don't know.
Title: Re: Proposed Europa Missions
Post by: Fequalsma on 01/16/2019 11:19 pm
More likely Griffin was afraid those moneys would come out of his preciousss Constellation.
F=ma

This was really a no-brainer: the cost estimates on that mission were over $20 billion (yes, you read that right), and nobody expected it to ever progress very far in development. He did everybody a favor before even more money was thrown down that bottomless pit.

I always suspected that you were a traitor to the Galactic Empire, Blackstar.
Title: Re: Proposed Europa Missions
Post by: redliox on 01/30/2019 03:14 am
Is the Europa Clipper coming up on Critical Design Review at last?  Space.com posted a story alluding to it.  With the government shutdown I had presumed most programs were on momentary pause.
Title: Re: Proposed Europa Missions
Post by: Star One on 01/30/2019 06:44 am
Scientists Prepare for Mission to Europa (https://www.scientificamerican.com/article/scientists-prepare-for-mission-to-europa/)

Quote
Europa Clipper will launch as soon as 2023, then trek out to the Jupiter system for about 40 close passes over the mysterious icy moon. Once it arrives, the spacecraft will gather vital information about the moon’s geology, composition and hidden interior ocean. But before the team can get to work building the spacecraft, it has one final review to pass.

Quote
But there are new challenges to tackle as well, like selecting a path for the spacecraft to follow around the Jupiter system, in a process called trajectory planning, which Senske jokingly refers to as “black magic.” (The spacecraft won’t orbit Europa directly, because it would receive too much radiation if it did. But that restriction offers benefits as well—like catching a peek at other moons. “Io happens to be right there,” Richey said. “Who doesn’t want to look at the planetary body that looks like a pox-ridden abyss?”)

Quote
While they’re waiting on a decision, the team is focused on the current hurdle: addressing questions raised on reviews of individual components of the project and how they interact. Once those are addressed, the project will enter what mission designers call phase C, which includes setting the final budget for the project and beginning to build the real spacecraft. “That’s when the fun starts,” Richey said.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 01/30/2019 05:32 pm
Is the Europa Clipper coming up on Critical Design Review at last?  Space.com posted a story alluding to it.  With the government shutdown I had presumed most programs were on momentary pause.

Well, "eventually" is pretty much the same as "forever," right? (Think about that one deeply for a few moments.) It will happen eventually.

As I think I posted here late last fall, Europa Clipper had run into problems. The science instruments were all growing out of their boxes and had to be shoved back into them. That is why KDP-C kept getting delayed. You can go back and look to see when KDP-C was originally supposed to happen. We're still waiting. It will happen eventually.

Now what happened is not all that surprising. It's kinda what you would expect, right? Europa Clipper and Europa lander both had a sugar daddy in the form of Congressman Culberson. With Culberson promising all the monies, there was no real incentive for the people working on those programs to keep their costs down. And in fact, I witnessed that at OPAG last fall when some Europa cheerleaders stood up and essentially said "We're not getting canceled no matter what happens." And in fact, that's one reason why the planetary decadal midterm (which I ran) said that keeping Europa Clipper in its box was so important--we knew that there were pressures to spend more money and we wanted to warn that doing so has consequences.

And then? Well, Culberson lost reelection. And the Republicans also lost the House, which means that Culberson's fellow Republicans--who might have tried to uphold his legacy--are gone as well. And then? Well, the government shut down for awhile. That meant that no senior NASA officials were calling up JPL every other day and saying "get Europa Clipper into its cost box, I really mean it." Plus, you have no idea how much the shutdown scrambles everybody's brains. Nobody in Congress right now is paying attention to anything other than getting a workable spending bill. So nobody's thinking (much) about hearings for the next year, or bills that they're going to submit, or anything like that. They might think about these future things a little bit, but everything is very higgledy piggledy right now. And because of that, there's not a lot of clear indication of which way the wind is blowing for space programs. Is planetary going to do fine in the coming budget, or is it going to get whacked? So while some senior managers may be saying "get your projects back into their boxes," there may be some lower level people who are dragging their feet because they still think that the money might still flow and they'll be fine.*




*(Hey, look! It's a footnote!) Here's another thing: for over a month during the shutdown a lot of nothing was happening. When nothing happens, costs go up. That might not make sense until you think about it, but I'll give an example that I heard about at a meeting I was in a short while ago: some people were planning a meeting at a conference facility and had booked hotel rooms. Even though the meeting is planned for a few weeks from now, a bunch of people can no longer attend because they did not get their paperwork done during the shutdown. So the meeting has to be delayed to a later date. But the conference facility and hotels are charging cancellation fees. So now this meeting's costs include: the initial staff preparation time (paid hours), plus the cancellation fees, plus even more staff preparation time (more hours). So that meeting is now costing more than it would have without the shutdown. Similar things are going to happen with many of the space projects NASA runs. Their costs are going to increase because of the lost work hours and things like cancellation fees and facility overhead and stuff. And it will also take time to re-calculate those costs. You can expect that a few months from now you'll see reports from NASA about how much cost the shutdown added to various NASA projects, and I wouldn't be surprised if that's affecting EC as well.

Title: Re: Proposed Europa Missions
Post by: vjkane on 01/31/2019 01:48 pm
Is the Europa Clipper coming up on Critical Design Review at last?  Space.com posted a story alluding to it.  With the government shutdown I had presumed most programs were on momentary pause.
As I think I posted here late last fall, Europa Clipper had run into problems. The science instruments were all growing out of their boxes and had to be shoved back into them. That is why KDP-C kept getting delayed. You can go back and look to see when KDP-C was originally supposed to happen. We're still waiting. It will happen eventually.
In addition, my sense is that NASA selected instruments promising cutting edge measurements.  It's the 5-star compliment.  If this is correct, one downside is that this may have meant a fair amount of development was needed to meet all those goals.  So I wouldn't be surprised to learn that some of the instruments are having problems fitting (literally it sounds) into their design boxes.

One of the roles of flagship missions is to develop new technologies, and so this is not a criticism.  Those new instrument capabilities will become the proven cutting edge capabilities that future missions will be able to draw upon.  For example, the Io Volcanic Observer being proposed for the next Discovery selection proposes to use Clippers imaging system and JUICE's (another flagship) neutral mass spectrometer instruments.  Those are big ass instruments a Discovery mission could never afford to develop within its own budget.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 01/31/2019 02:55 pm
In addition, my sense is that NASA selected instruments promising cutting edge measurements. 

And this goes back to how the mission was initiated. It was backwards. Remember that Culberson kept shoving money into NASA's budget for a mission that had not been formally approved. The budget implications of this are nutty. NASA is stuck in the middle. They have a big pile of money labeled "Europa" and then they have OMB/White House people telling them that they do not have a Europa program. So what is NASA supposed to do? NASA officials get yelled at by members of Congress who say "You have to spend that money how we told you to spend it. It's the law!" And so ultimately, NASA came up with the solution that they would spend it on instruments (not a Europa spacecraft) and they could then tell OMB that those instruments might be able to get used on other spacecraft, maybe. OMB/White House is just playing a waiting game, hoping that the next election changes who runs the House, so they can divert the money elsewhere. That doesn't happen, so now NASA has a big pile of money to spend on instruments.

And of course, that sets a precedent for all the people who are getting that money: they are not being told to economize and find clever solutions to solve funding shortfalls; they can just throw cash at every problem. And then, when money gets tighter, they don't know how to economize or be efficient, and they might have larger staffs than you would need, and more expensive overhead, etc.

I'm not saying that anybody was doing anything wrong, just that when these are your incentives at the start, it is harder to run more efficiently later, like a rich kid who doesn't know how to economize when daddy cuts off his allowance.

One more thing: if you want to go back a few more years, something similar happened in the last decade. The previous iterations of Europa Orbiter were big and expensive. And then the 2011 decadal survey came along and said "Do it a lot cheaper or don't do it at all." That shocked the heck out of a lot of people and it took them a few years to reform themselves. They got a lot better. And then Culberson started throwing money their way and so things started growing out of the box again.

This is not the same as JWST. But all programs require careful management and oversight.
Title: Re: Proposed Europa Missions
Post by: Blackstar on 02/15/2019 03:40 am
FYI: For details of the budget bill working its way through Congress see https://docs.house.gov/billsthisweek/20190211/CRPT-116hrpt9_u2-.pdf and  https://docs.house.gov/billsthisweek/20190211/CRPT-116hrpt9_u2-.pdf or below for highlights from the explanatory text.  Europa Clipper gets $545 million and Europa lander gets $195 million.

NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
The agreement includes $21,500,000,000 for the National Aeronautics and Space
Administration (NASA). The agreement includes substantial new resources for activities related
to Moon exploration and retains language regarding submission of a detailed report prior to
obligating certain funds. As noted elsewhere in this statement, the lack of progress across science
and exploration programs despite continued significant and sustained investments in these
programs is dismaying. Reports by the NASA Inspector General (IG), the Government
Accountability Office (GAO), and independent experts point to a number of deficiencies that
NASA and its private sector partners must address. During fiscal year 2019, NASA is expected
to show marked success in addressing the myriad deficiencies identified by oversight bodies.

SCIENCE
The agreement includes $6,905,700,000 for Science.

Earth Science.-The agreement includes $1,931,000,000 for Earth Science and adopts all
funding levels designated by the House and the Senate.

Planetary Science.-The agreement includes $2,758,500,000 for Planetary Science. The
agreement adopts House language regarding the Europa Clipper and Lander missions modified
to reflect launch dates of 2023 for the Clipper and 2025 for the Lander. The agreement includes
$97,000,000 for the Double Asteroid Redirection Test and no less than the fiscal year 2018 level
for NEOcam. The agreement includes up to $218,000,000 for the Lunar Discovery and
Exploration program, including $21,000,000 for the Lunar Reconnaissance Orbiter. The
agreement adopts Senate language regarding the helicopter technology demonstration planned
for Mars 2020.
Title: Re: Proposed Europa Missions
Post by: zubenelgenubi on 03/06/2019 10:20 pm
Please note that a Europa Clipper mission thread has started, also in the Space Science sub-forum, here: https://forum.nasaspaceflight.com/index.php?topic=47579.0
Title: Re: Proposed Europa Missions
Post by: Blackstar on 03/06/2019 11:54 pm
Please note that a Europa Clipper mission thread has started, also in the Space Science sub-forum, here: https://forum.nasaspaceflight.com/index.php?topic=47579.0

And it's worth going back a little in this thread and reading some previous posts.
Title: Re: Proposed Europa Missions
Post by: ncb1397 on 08/25/2020 02:44 am
I found this in a presentation from a few months ago from JPL...

I imagine this will be quite controversial.

Looks like an orbiter, lander, rover, a drilling rig, a stationary sub-surface platform, an ocean ice rover and two submarines designed for different depths.

The campaign would be similar in scope to the mars exploration program from Mariner 8 in 1971 through to Mars Sample Return in the mid 2020s (~50 years).
Title: Re: Proposed Europa Missions
Post by: vjkane on 08/25/2020 05:19 am
I found this in a presentation from a few months ago from JPL...

I imagine this will be quite controversial.

Looks like an orbiter, lander, rover, a drilling rig, a stationary sub-surface platform, an ocean ice rover and two submarines designed for different depths.

The campaign would be similar in scope to the mars exploration program from Mariner 8 in 1971 through to Mars Sample Return in the mid 2020s (~50 years).
It's an aspirational vision for the next 30 years, part of building support for an ambitious set of missions.  That doesn't make it controversial.