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The First Europa Lander, What can be done first, cheapest & best?
nprev
post Dec 31 2005, 12:08 AM
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I think that many people in this forum would agree that somebody's going to have to land on Europa someday before the rather elaborate schemes to penetrate the outer ice layer will ever fly, if for no other reason than to get some relevant ground truth before committing to such an elaborate, expensive, and risky mission.

EO seems to have ruled out any surface science package for that mission (though it would be nice to change their minds! wink.gif ), but I think that there is a valid requirement at some point to directly assess the surface properties of Europa in an inexpensive yet creative way. Some candidate instrument payloads might be:

1. A sonar transducer/receiver set embedded within a penetrometer to determine crust density and examine the uniformity of the ice layer within the operational radius of the instrument (looking for cracks and holes, in other words).

2. A conductivity sensor again embedded inside a penetrometer to measure the native salinity of the surrounding material and possibly derive some constraints on the composition of metallic salts in the European crust (saltiness has a major effect on ice properties, in addition to the obvious need to derive the salt content of any underlying ocean).

3. A seismometer for all sorts of reasons.


How does this sound? Any critiques, additions, or subtractions? I omitted a surface imager not only because of bandwidth/extra complexity considerations but also because it seems desirable to penetrate the crust in order to minimize as much as possible reading any contaminants from Io during surface measurements. The orbiter data could be used to sense and subtract this from the penetrometer readings.


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Guest_BruceMoomaw_*
post Dec 31 2005, 03:33 AM
Post #2





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JPL's study of useful instruments for a small Europa lander listed, in order of priority:

(1 & 2): A surface GCMS (or, better, a mass spectrometer combined with some kind of liquid chromatography) to look for organics and other interesting compounds; and a seismometer to try to sound the thickness of the total ice layer.

(3) A magnetometer to make induced-field measurements simultaneously with an orbiter to obtain data on the thickness of both the ice layer AND the underlying liquid-water layer.

(4) A surface panoramic camera.

There was, as I've noted, a knockdown debate on this subject at the November COMPLEX meeting -- including an unbelievably dreary and nitpicking debate over the usefulness of seismometers and magnetometers, culminating in the general conclusion that you'd need at least 1 or 2 weeks of data from them, which requires powering the lander with a small RTG rather than batteries.

But the trouble, again, is that the most important measurement by far would be a search for possibly biological organic compounds buried deeply enough in the ice that Jupiter's radiation won't have scrambled them unrecognizably -- and such a small lander probably can't drill the 1 or 2 meters necessary for that purpose. Any of the other measurements that a small lander could make can just as well be delayed and then put on the first dedicated larger Europa Astrobiological Lander mission to look for near-subsurface organics, at a site selected by Europa Orbiter.

The obvious possible solution to this problem would be a penetrator, and in fact at the meeting I spoke up and suggested just that. (It has other major advantages, too -- elimination of the need for a heavy final braking or shock-absorption system, shielding of the lander from Jupiter's destructive radiation by the ice itself, and better coupling of the seismometer to Europa's surface.) Unfortunately, Torrance Johnson was one step ahead of me. He said that just this possibility was examined in depth by the JIMO science definition team, and it turned out that penetrators on airless worlds have one huge Achilles heel -- there's no airflow to keep their nose pointed straight in their direction of travel when they hit the surface. So you need to add a big and complex attitude-control system to do this, or your penetrator will hit the surface slightly skewed, at which point you're screwed.

Still, Paul Lucey of the University of Hawaii is proposing "Thunderbolt" -- a Europa penetrator to look for subsurface organics (a descendant of his "Polar Night" Discovery proposal that would launch three small penetrators from a lunar orbiter to look for polar ice). The COMPLEX people actually suggested that I should get in touch with him to see if he's found a possible solution to the attitude-control problem, and while I haven't been able to contact him yet I intend to do so after New Year.

By the way, I'm telling you guys all this because every crumb of it had to be cut out of the shortened version of my upcoming article on the COMPLEX meeting for "Astronomy".
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- nprev   The First Europa Lander   Dec 31 2005, 12:08 AM
- - Steve G   QUOTE (nprev @ Dec 30 2005, 05:08 PM)I think ...   Dec 31 2005, 02:40 AM
- - BruceMoomaw   JPL's study of useful instruments for a small ...   Dec 31 2005, 03:33 AM
|- - JRehling   QUOTE (BruceMoomaw @ Dec 30 2005, 07:33 PM)St...   Dec 31 2005, 04:38 AM
|- - tty   QUOTE (BruceMoomaw @ Dec 31 2005, 05:33 AM)Th...   Jan 1 2006, 11:04 PM
- - edstrick   as Bruce points out.. hit the surface slightly off...   Dec 31 2005, 12:17 PM
|- - Bob Shaw   There are *natural* penetrators as well as man-mad...   Dec 31 2005, 12:40 PM
- - gpurcell   I think it is going to be pretty difficult to argu...   Jan 1 2006, 05:01 PM
|- - nprev   Re the penetrometer descent alignment problem: Wou...   Jan 1 2006, 09:11 PM
|- - RNeuhaus   QUOTE (gpurcell @ Jan 1 2006, 12:01 PM)I thin...   Jan 5 2006, 05:06 PM
- - BruceMoomaw   Uh-uh. An object that short would take weeks -- a...   Jan 1 2006, 09:42 PM
|- - nprev   Hmm. How about a "semi-hard" lander al a...   Jan 1 2006, 10:22 PM
- - ermar   QUOTE Europa has an atmosphere though it is extrem...   Jan 1 2006, 11:52 PM
- - tasp   Perhaps a future mission would drop an impactor at...   Jan 2 2006, 03:42 AM
|- - ljk4-1   QUOTE (tasp @ Jan 1 2006, 10:42 PM)Perhaps a ...   Jan 3 2006, 03:49 PM
- - tty   It's too bad there is no GPS system on Europa....   Jan 3 2006, 06:19 PM
|- - nprev   QUOTE (tty @ Jan 3 2006, 11:19 AM)It's to...   Jan 3 2006, 08:40 PM
- - nprev   AlexBlackwell posted the fact that the 2006 Discov...   Jan 3 2006, 11:59 PM
- - ljk4-1   Tell me this wouldn't be useful for an Europan...   Mar 29 2006, 07:47 PM
- - ljk4-1   Karl Hibbitts describes a proposed hyper-velocity ...   May 1 2006, 06:55 PM
- - PhilHorzempa   It seems that at the November 2005 COMPLEX meeting...   Jun 27 2006, 04:07 AM
|- - Richard Trigaux   Why to limit the life time of a surface lander? if...   Jun 27 2006, 07:16 AM
|- - JRehling   QUOTE (Richard Trigaux @ Jun 27 2006, 12...   Jun 27 2006, 07:04 PM
|- - nprev   QUOTE (JRehling @ Jun 27 2006, 12:04 PM) ...   Jun 28 2006, 01:30 AM
|- - Richard Trigaux   QUOTE (nprev @ Jun 28 2006, 01:30 AM) ......   Jun 28 2006, 07:42 AM
- - RNeuhaus   A panoramic camera plus an astronamic telescope to...   Jun 28 2006, 10:49 PM
|- - JRehling   QUOTE (RNeuhaus @ Jun 28 2006, 03:49 PM) ...   Jun 29 2006, 12:31 AM
|- - djellison   QUOTE (RNeuhaus @ Jun 28 2006, 11:49 PM) ...   Jun 29 2006, 07:23 AM
- - algorimancer   Considering the deliverable mass potential, and ou...   Jun 29 2006, 12:49 PM
- - djellison   I'm sure everyone would love a massive long li...   Jun 29 2006, 01:00 PM
|- - Stephen   QUOTE (djellison @ Jun 29 2006, 01:00 PM)...   Jul 3 2006, 11:20 AM
|- - Richard Trigaux   QUOTE (Stephen @ Jul 3 2006, 11:20 AM) Wo...   Jul 3 2006, 11:44 AM
- - Myran   Yes I agree with djellison and others. To give the...   Jun 29 2006, 03:36 PM
|- - JRehling   I don't think we can bet that a Europa rover w...   Jun 29 2006, 05:51 PM
|- - JRehling   QUOTE (Myran @ Jun 29 2006, 08:36 AM) The...   Jun 29 2006, 05:55 PM
- - RNeuhaus   Now I understand that it is very expensive to send...   Jun 29 2006, 08:14 PM
|- - djellison   QUOTE (RNeuhaus @ Jun 29 2006, 09:14 PM) ...   Jun 29 2006, 09:07 PM
|- - JRehling   QUOTE (RNeuhaus @ Jun 29 2006, 01:14 PM) ...   Jun 30 2006, 05:52 PM
|- - Bob Shaw   QUOTE (JRehling @ Jun 30 2006, 06:52 PM) ...   Jun 30 2006, 07:26 PM
|- - RNeuhaus   QUOTE (Bob Shaw @ Jun 30 2006, 02:26 PM) ...   Jul 1 2006, 02:45 AM
- - nprev   Harkening back to the origin of this thread, I com...   Jun 30 2006, 12:50 PM
- - algorimancer   My rationale behind sending a rover initially is t...   Jun 30 2006, 01:13 PM
|- - Bob Shaw   QUOTE (algorimancer @ Jun 30 2006, 02:13 ...   Jun 30 2006, 01:50 PM
- - djellison   Perhaps the cunning technique that would have been...   Jun 30 2006, 07:35 PM
|- - DDAVIS   QUOTE (djellison @ Jun 30 2006, 07:35 PM)...   Jul 1 2006, 01:16 AM
- - Richard Trigaux   There are three ways to protect electronics from r...   Jul 1 2006, 06:01 AM
|- - Bob Shaw   QUOTE (Richard Trigaux @ Jul 1 2006, 07:0...   Jul 1 2006, 01:55 PM
|- - mchan   QUOTE (Richard Trigaux @ Jun 30 2006, 11...   Jul 3 2006, 12:20 AM
|- - Richard Trigaux   QUOTE (mchan @ Jul 3 2006, 12:20 AM) Besi...   Jul 3 2006, 09:52 AM
- - edstrick   In the outer solar system, we have tended to find ...   Jul 1 2006, 08:50 AM
- - Myran   Just offhand and without checking I dont think any...   Jul 1 2006, 02:26 PM
- - djellison   Pushbroom? Doug   Jul 3 2006, 07:36 AM
- - nprev   Richard, that sounds good for a long-lived stand-a...   Jul 4 2006, 01:09 AM
- - Roly   March 26 2006 Powerpoint on various Europa Lander ...   Sep 3 2006, 07:07 AM
|- - angel1801   Has anyone thought of putting an Europa Lander at ...   Sep 3 2006, 04:27 PM
|- - ugordan   I would think the landing site will be determined ...   Sep 3 2006, 06:37 PM
|- - JRehling   QUOTE (angel1801 @ Sep 3 2006, 09:27 AM) ...   Sep 4 2006, 05:15 PM
- - Roly   Any chance that the launch vehicle for the Europa ...   Sep 4 2006, 03:01 AM
- - edstrick   The radiation is not FROM Jupiter. The radiation ...   Sep 4 2006, 11:07 AM
- - Julius   Being modest,I'd still say that 3 days lifetim...   Sep 5 2006, 08:03 PM
- - nprev   I still think a hard-lander, a penetrometer, or so...   Sep 6 2006, 01:43 AM
- - algorimancer   Something like the MER's autonomous navigation...   Sep 6 2006, 12:55 PM
|- - ugordan   Still, the biggest problem is soft landing via pow...   Sep 6 2006, 01:27 PM
- - algorimancer   I just had one of those Aha! moments and came ...   Sep 9 2006, 09:24 PM
- - Myran   Thats a wild idea algorimancer. But regardless ho...   Sep 10 2006, 07:42 AM
|- - algorimancer   QUOTE (Myran @ Sep 10 2006, 02:42 AM) Tha...   Sep 10 2006, 01:05 PM
- - nprev   Hmm. Given that the Galileo data was a bit limited...   Sep 10 2006, 09:00 PM
- - Drkskywxlt   I think any such impact with the surface of Europa...   Sep 11 2006, 01:32 PM
|- - AndyG   The (admittedly ill-fated) penetrators of Deep Spa...   Sep 11 2006, 03:34 PM
- - remcook   Most importantly IMO is the whole uncertainty of t...   Sep 11 2006, 04:12 PM
|- - algorimancer   QUOTE (remcook @ Sep 11 2006, 11:12 AM) ....   Sep 11 2006, 05:47 PM
- - Julius   Main objective should be to get a Europa lander sa...   Sep 12 2006, 07:37 PM
- - rasun   Hi! Apparently, NASA's Astrobiology, Scie...   Nov 29 2007, 05:35 PM
|- - JRehling   QUOTE (rasun @ Nov 29 2007, 09:35 AM) So ...   Nov 29 2007, 08:36 PM
|- - DDAVIS   This discussion is of particular interest to me as...   Dec 3 2007, 11:17 AM
|- - JRehling   QUOTE (DDAVIS @ Dec 3 2007, 03:17 AM) Thi...   Dec 3 2007, 07:05 PM
- - nprev   Wow. Don, only thing I can think of is that th...   Dec 3 2007, 12:46 PM
- - dvandorn   I would say that not only is it imperative that a ...   Dec 4 2007, 07:54 AM
|- - JRehling   QUOTE (dvandorn @ Dec 3 2007, 11:54 PM) T...   Dec 4 2007, 03:02 PM
|- - hendric   QUOTE (JRehling @ Dec 4 2007, 09:02 AM) U...   Dec 4 2007, 04:55 PM
- - nprev   Nihilistic, but IMHO painstakingly plausible, oDou...   Dec 4 2007, 12:19 PM
- - Cugel   Why would you go all the way down to the liquid wa...   Dec 4 2007, 01:06 PM
|- - JRehling   QUOTE (Cugel @ Dec 4 2007, 05:06 AM) Why ...   Dec 4 2007, 03:06 PM
|- - centsworth_II   QUOTE (JRehling @ Dec 4 2007, 10:06 AM) I...   Dec 4 2007, 03:55 PM
||- - marsbug   I dont know about squid but there are many studies...   Dec 4 2007, 04:35 PM
|- - Cugel   QUOTE (JRehling @ Dec 4 2007, 04:06 PM) I...   Dec 4 2007, 07:30 PM
||- - nprev   QUOTE (Cugel @ Dec 4 2007, 11:30 AM) At l...   Dec 5 2007, 01:45 AM
|- - tty   QUOTE (JRehling @ Dec 4 2007, 04:06 PM) I...   Dec 4 2007, 07:42 PM
- - centsworth_II   I think it's safe to say that the first Europa...   Dec 4 2007, 05:58 PM
- - dvandorn   I don't think I'd be good with just openin...   Dec 4 2007, 07:12 PM
- - charborob   A probe melting its way all through Europa's i...   Dec 4 2007, 08:03 PM
- - dvandorn   My thoughts exactly -- it's going to be a very...   Dec 4 2007, 08:58 PM
- - hendric   Well, RTGs actually put out quite a bit of heat, a...   Dec 5 2007, 01:41 AM
- - DDAVIS   Wow, this discussion is great! I am imaginin...   Dec 5 2007, 07:10 PM
- - tty   Let's do some order-of-magnitude calculations ...   Dec 5 2007, 07:23 PM
|- - hendric   QUOTE (tty @ Dec 5 2007, 01:23 PM) Let...   Dec 6 2007, 05:47 PM
- - mchan   QUOTE (dvandorn @ Dec 4 2007, 11:12 AM) A...   Dec 6 2007, 04:20 AM
- - nprev   Gotta say that I'm pretty sold on the pristin...   Dec 6 2007, 07:14 AM
- - edstrick   Both from a science and an engineering perspective...   Dec 6 2007, 09:39 AM
- - centsworth_II   At the least, a first Europa mission should map th...   Dec 6 2007, 05:02 PM
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