Author Topic: Proposed Europa Missions  (Read 464008 times)

Offline jbenton

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Re: Proposed Europa Missions
« Reply #1660 on: 08/30/2018 10:34 PM »
https://spacepolicyonline.com/news/today-tidbits-december-21-2017/

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...


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.
« Last Edit: 08/31/2018 02:42 AM by jbenton »

Offline jbenton

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Re: Proposed Europa Missions
« Reply #1661 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?
« Last Edit: 08/31/2018 05:46 AM by jbenton »

Offline jbenton

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Re: Proposed Europa Missions
« Reply #1662 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?

Offline TripleSeven

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Re: Proposed Europa Missions
« Reply #1663 on: 08/30/2018 10:43 PM »
https://spacepolicyonline.com/news/today-tidbits-december-21-2017/

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...


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.

Offline vjkane

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Re: Proposed Europa Missions
« Reply #1664 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.

Offline LouScheffer

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Re: Proposed Europa Missions
« Reply #1665 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, 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.

Offline jbenton

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Re: Proposed Europa Missions
« Reply #1666 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.

Offline jbenton

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Re: Proposed Europa Missions
« Reply #1667 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.
« Last Edit: 09/18/2018 04:43 PM by jbenton »

Offline jbenton

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Re: Proposed Europa Missions
« Reply #1668 on: 08/31/2018 03:49 AM »
Looking at recent NASA launch vehicle specs for high energy trajectories, 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)

Offline JH

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Re: Proposed Europa Missions
« Reply #1669 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 ó 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) ó but I can tell you that it didn't have anything to do with cost.

Offline Star One

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Re: Proposed Europa Missions
« Reply #1670 on: 08/31/2018 06:28 AM »
Looking at recent NASA launch vehicle specs for high energy trajectories, 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.

Offline LouScheffer

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Re: Proposed Europa Missions
« Reply #1671 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.

Offline MATTBLAK

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Re: Proposed Europa Missions
« Reply #1672 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..?
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Online ugordan

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Re: Proposed Europa Missions
« Reply #1673 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.

Offline vjkane

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Re: Proposed Europa Missions
« Reply #1674 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.

Offline MATTBLAK

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Re: Proposed Europa Missions
« Reply #1675 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...
« Last Edit: 08/31/2018 02:05 PM by MATTBLAK »
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Offline TripleSeven

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Re: Proposed Europa Missions
« Reply #1676 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.

Offline LouScheffer

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Re: Proposed Europa Missions
« Reply #1677 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.

Offline Star One

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Re: Proposed Europa Missions
« Reply #1678 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.

Thatís might come true but at the moment the first flight wouldnít count for NASA as that wasnít using the block 5 configuration and the first flight with this appears to be drifting out of 2018.

Offline vjkane

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Re: Proposed Europa Missions
« Reply #1679 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.