Author Topic: Proposed Europa Missions  (Read 641012 times)

Offline Star One

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Re: Proposed Europa Missions
« Reply #300 on: 01/06/2014 08:36 pm »

Europa Ice Clipper.

Thanks for that.

Offline jongoff

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Re: Proposed Europa Missions
« Reply #301 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

Offline jongoff

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Re: Proposed Europa Missions
« Reply #302 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

Offline vjkane

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Re: Proposed Europa Missions
« Reply #303 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).

Offline jongoff

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Re: Proposed Europa Missions
« Reply #304 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

Offline Robotbeat

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Re: Proposed Europa Missions
« Reply #305 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.
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Offline Star One

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Re: Proposed Europa Missions
« Reply #306 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.

Offline vjkane

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Re: Proposed Europa Missions
« Reply #307 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). 

Offline darkbluenine

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Re: Proposed Europa Missions
« Reply #308 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



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...

« Last Edit: 01/07/2014 11:56 pm by darkbluenine »

Offline savuporo

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Re: Proposed Europa Missions
« Reply #309 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
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Offline plutogno

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Re: Proposed Europa Missions
« Reply #310 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

Offline EE Scott

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Re: Proposed Europa Missions
« Reply #311 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.
Scott

Offline baldusi

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Re: Proposed Europa Missions
« Reply #312 on: 03/04/2014 02:57 am »
Don't they need like four MMRTG? Is there enough weaved fabric?

Offline redliox

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Re: Proposed Europa Missions
« Reply #313 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...


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?
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Offline Drkskywxlt

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Re: Proposed Europa Missions
« Reply #314 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).

Offline redliox

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Re: Proposed Europa Missions
« Reply #315 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.
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Offline vjkane

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Proposed Europa Missions
« Reply #316 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?
« Last Edit: 03/05/2014 05:29 am by vjkane »

Offline darkbluenine

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Re: Proposed Europa Missions
« Reply #317 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...
« Last Edit: 03/05/2014 02:09 pm by darkbluenine »

Online Blackstar

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Re: Proposed Europa Missions
« Reply #318 on: 03/06/2014 04:45 pm »
Here you go.

Offline Star One

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Re: Proposed Europa Missions
« Reply #319 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.

 

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