Author Topic: Proposed Europa Missions  (Read 368138 times)

Online Blackstar

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Re: Proposed Europa Missions
« Reply #1600 on: 10/26/2017 03:11 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.

The lander is a different issue entirely. We'll see what happens there (cue mysterious, slightly ominous music...)

Offline redliox

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Re: Proposed Europa Missions
« Reply #1601 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.
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Offline vjkane

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Re: Proposed Europa Missions
« Reply #1602 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. 


Offline redliox

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Re: Proposed Europa Missions
« Reply #1603 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?
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Offline Zed_Noir

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Re: Proposed Europa Missions
« Reply #1604 on: 10/27/2017 03:51 AM »
....
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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.

Offline vjkane

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Re: Proposed Europa Missions
« Reply #1605 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?).

Offline Star One

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Re: Proposed Europa Missions
« Reply #1606 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 itís next year they have to pick a launch vehicle.

Offline Jim

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Re: Proposed Europa Missions
« Reply #1607 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

Online Blackstar

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Re: Proposed Europa Missions
« Reply #1608 on: 10/27/2017 03:17 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

What I heard (about a year ago, so it could have changed) was that the EC timeline was such that the decision to start building the SLS to carry it would have to be made before the EC program had to lock down their design, so it was not actually driving the design (yet). The lead time for the SLS required a build decision by 2018 to meet a 2022 launch date for EC.

Offline redliox

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Re: Proposed Europa Missions
« Reply #1609 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).
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Online Blackstar

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Re: Proposed Europa Missions
« Reply #1610 on: 10/27/2017 04:23 PM »
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).

It will be one of the vehicles currently in existence or SLS, because they will have to sign the contract for a vehicle within only a few years, and that will have to be a vehicle within NASA's existing stable. Even if Delta IV or Atlas V are scheduled to be retired around then, they'll grab one of the last ones.

Offline LouScheffer

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Re: Proposed Europa Missions
« Reply #1611 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.

Online Blackstar

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Re: Proposed Europa Missions
« Reply #1612 on: 10/27/2017 08:44 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.

Yeah... I'm not quite sure I agree with your analysis there. First, while you might get a "deal" with buying a bunch of dishes at once, I suspect that the biggest cost is not the hardware but the installation/construction costs, and buying ten means you have to construct ten, and union labor tends not to give deals for working them ten times as much. Also, infrastructure is more than just an up-front cost, it's a recurring maintenance cost. So you add all that capability and then you have to pay to operate it for years.

There is a constant push/pull issue with the DSN and a question of where to spend your dollars. But even if you put new hardware in space and upgrade the DSN, you still need the capability to communicate with all the legacy hardware that is up there, and that's actually the majority of everything (three quarters of NASA's operating space missions are in their extended mission phase).

I do think that there have long been DSN upgrade issues that have not been properly addressed, and the fact that NASA has shifted the responsibility for the DSN back and forth internally for many years has not helped. But a massive upgrade to the DSN is not going to substantially improve things for spacecraft, especially all the ones in extended mission phase. The improvements have to happen on the ground and with new spacecraft in coordination.

Offline Proponent

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Re: Proposed Europa Missions
« Reply #1613 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?

Offline JH

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Re: Proposed Europa Missions
« Reply #1614 on: 11/29/2017 08:40 PM »
Low atomic weight and won't release volatiles.

Offline Star One

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Re: Proposed Europa Missions
« Reply #1615 on: 12/05/2017 08:10 PM »
Research bolsters possibility of plate tectonics on Europa

Quote
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

Online UltraViolet9

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Re: Proposed Europa Missions
« Reply #1616 on: 12/22/2017 04:18 PM »

Quote
Rep. Culbersonís 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 Jupiterís 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/


Online Blackstar

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Re: Proposed Europa Missions
« Reply #1617 on: 12/22/2017 06:33 PM »

Quote
Rep. Culbersonís 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 Jupiterís 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/



Direct link: http://www.rollcall.com/news/gonzales/ratings-change-culbersons-texas-seat-creeps-closer-toss