The First Europa Lander, What can be done first, cheapest & best? |
The First Europa Lander, What can be done first, cheapest & best? |
Dec 31 2005, 12:08 AM
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Merciless Robot Group: Admin Posts: 8789 Joined: 8-December 05 From: Los Angeles Member No.: 602 |
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! ), 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. -------------------- A few will take this knowledge and use this power of a dream realized as a force for change, an impetus for further discovery to make less ancient dreams real.
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Nov 29 2007, 05:35 PM
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#2
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Newbie Group: Members Posts: 9 Joined: 7-November 07 Member No.: 3956 |
Hi!
Apparently, NASA's Astrobiology, Science and Technology for Exploring Planets program funded the DEPTHX, an autonomous underwater robot. (See Depthx home here: http://www.frc.ri.cmu.edu/depthx/ many images here: http://www.jsg.utexas.edu/news/rels/030807b.html and here: http://geology.com/zacaton/ or many links at NASA: http://astrobiology.arc.nasa.gov/news/expa...ws.cfm?id=10644 DEPTHX and it's follow-up, ENDURANCE are "advertised" as robots that are largely developed so that their next version would be operating in the oceans of Europa, at least that's what I get from the articles. But the Europa Explorer, if approved, will at best fly around 2015, and then a first Europa lander, if approved, probably not before 10 years later; and THEN probably a submarine (but this still sounds very optimistic) So isn't it too early to start to develop a submarine 20-30 years before it can be launched? Of course it's never too early, and i'm no way against it, but it still sounds strange...? Is this project really seriously meant to have anything to do with Europa? |
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Nov 29 2007, 08:36 PM
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Senior Member Group: Members Posts: 2530 Joined: 20-April 05 Member No.: 321 |
So isn't it too early to start to develop a submarine 20-30 years before it can be launched? Of course it's never too early, and i'm no way against it, but it still sounds strange...? Is this project really seriously meant to have anything to do with Europa? NASA does a lot of low-levels-of-funding exploration of new technologies. I used to work one building over from the robotics building at NASA Ames, and I saw stuff in development over there that doesn't remotely resemble anything that's ever flown, or is scheduled to soon. Whether or not it actually speeds exploration, it also has public outreach value, encouraging interest in exciting ideas that may one day be put into effect. I think a real key is that most of this stuff costs almost nothing compared to an actual mission. One of the interesting things (in a sense, a very uninteresting thing) about a submarine is that remote sensing would be very limited. It would be mainly about analyzing the water immediately in/around the submarine. And maybe the floor, but visual/IR imaging would be limited to meters. There probably wouldn't be much point in wandering horizontally anywhere above the floor. |
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Dec 3 2007, 11:17 AM
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#4
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Member Group: Members Posts: 194 Joined: 8-February 04 Member No.: 10 |
This discussion is of particular interest to me as I am doing an animation sequence soon of a Europa lander. I have visualized such a thing in the past for the PBS show 'Life Beyond Earth' as a surveyor type lander carrying a probe underneath which would be weighed at the bottom with a plutonium 'lens', with the instruments above this. This probe resembes a blunt version of the Galileo probe entry shell. When released the heat from the lower probe lining melts a hole below it and the probe merrily tunnels its way to the liquid far below.
Any thoughts about this general means to get to the deep ocean with a probe as opposed to other spacecraft schemes being contemplated? Don |
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Dec 3 2007, 07:05 PM
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#5
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Senior Member Group: Members Posts: 2530 Joined: 20-April 05 Member No.: 321 |
This discussion is of particular interest to me as I am doing an animation sequence soon of a Europa lander. I have visualized such a thing in the past for the PBS show 'Life Beyond Earth' as a surveyor type lander carrying a probe underneath which would be weighed at the bottom with a plutonium 'lens', with the instruments above this. This probe resembes a blunt version of the Galileo probe entry shell. When released the heat from the lower probe lining melts a hole below it and the probe merrily tunnels its way to the liquid far below. Any thoughts about this general means to get to the deep ocean with a probe as opposed to other spacecraft schemes being contemplated? Don One of the worries is that impurities in the ice would accumulate at the bottom of the hole, eventually creating an obstruction. Even if the fraction of impurity were very low, accumulating one meter of it after ten thousand meters of ice could be a show stopper. I'm curious about what would happen when you actually hit the water. Would it gush out and rocket your sub into a geyser far above the surface -- which, obviously, would disable it as well as prevent access to the ocean. One of the problems I see with Enceladus is that if what we're seeing are geysers, then it may be pretty well impossible to push into the ocean, since it's trying to get out with considerable force. Which makes sense -- there must be nonzero pressure in water under a shell of ice, whereas the pressure above is the vacuum of space. Maybe the saving grace would be if the hole re-freezes above the craft, and then when it reached the ocean, there'd be nowhere for it to go up. Somehow, it would have to handle that pressure transition, though, from surface to ocean. Another issue is how to maintain radio contact. Leaving a chain of repeaters has been mentioned, but that sounds like a lot of mass, not to mention one heck of a lot of failure points. And once the craft got to the ocean, there'd be a lot more to accomplish. A vertical descent to the rocky mantle would be fascinating, but might entail rather tremendous pressures. I think realizing this vision is, however, one of the most exciting goals in solar system exploration, and finding the best location (if there is a best location) to make this descent is the real imperative of the next Europa exploration from orbit. Alternately, if a lander were only to sit on/near the surface and analyze the crust, it's still important to pick a good spot. Good spots Galileo looked at include these: http://photojournal.jpl.nasa.gov/catalog/PIA01405 http://photojournal.jpl.nasa.gov/catalog/PIA01640 http://photojournal.jpl.nasa.gov/catalog/PIA01177 But given how little of the surface Galileo imaged very well, it's imperative to do a more comprehensive survey. |
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