Martian Cave Probe?, Designs for the DEEP Search for Life |
Martian Cave Probe?, Designs for the DEEP Search for Life |
Nov 16 2007, 02:48 AM
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#16
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Merciless Robot Group: Admin Posts: 8783 Joined: 8-December 05 From: Los Angeles Member No.: 602 |
I keep thinking of the cable getting wedged between two rocks, or wrapped around one from a long-forgotten loop many meters back. If the terrain's rough enough to require Shelob in the first place, then something like those things happening is a near certainty. Wouldn't be such a problem if there was a big power budget & correspondingly powerful motors, response capability, etc., but you just don't get that kind of juice from RTGs.
No worries; an RF link could be designed with a really good bit rate, though considering the bit error rate & multipath effects it might not be adequate for video (think lots of noise & ghost images). Stills would make it okay, though. -------------------- 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 16 2007, 03:02 AM
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#17
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Member Group: Members Posts: 599 Joined: 26-August 05 Member No.: 476 |
All I gotta say is you guys here have designed descent and comm for a probe to bore thru Europa's ice crust and return data from the submarine ocean. Dropping into and exploring a Martian cave should be a piece of cake!
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Nov 16 2007, 04:09 AM
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#18
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Senior Member Group: Members Posts: 1229 Joined: 24-December 05 From: The blue one in between the yellow and red ones. Member No.: 618 |
Devilsfood, to be precise.
All we need is to cultivate a techie in the Pentagon. -------------------- My Grandpa goes to Mars every day and all I get are these lousy T-shirts!
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Nov 16 2007, 01:45 PM
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#19
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Merciless Robot Group: Admin Posts: 8783 Joined: 8-December 05 From: Los Angeles Member No.: 602 |
Shaka, let's compromise. Shelob can drag a fiber optic line from the descent platform (which goes back up to the rover/lander) till it gets snagged...then either an electrical or pyro-actuated cable cutter on the spider does its thing, and the vehicle switches to its backup RF link to the descent platform.
Thanks for the compliment, mchan! I ain't even gonna discuss the problem of drilling a hole on Europa, though... -------------------- 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 16 2007, 03:09 PM
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#20
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Member Group: Members Posts: 153 Joined: 11-December 04 Member No.: 120 |
Good fundamental astrobiological question, Cugel. A quick dip into Google Scholar suggests that the answer is "Yes, maybe." Mars Methane Sources and see also:Carbon AND Hydrogen Isotopes Thank you for those links. That's very interesting and encouraging news! (And not just for Mars caves) |
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Nov 16 2007, 03:41 PM
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#21
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Senior Member Group: Members Posts: 2173 Joined: 28-December 04 From: Florida, USA Member No.: 132 |
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Nov 16 2007, 04:05 PM
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#22
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Senior Member Group: Moderator Posts: 2785 Joined: 10-November 06 From: Pasadena, CA Member No.: 1345 |
Hmmm...I'd worry about possible backtracking. Unlike a TOW missle (which doesn't backtrack - unless it's a really bad day), I'll be our future cave explorer will have to find paths around fallen debris. Some of these paths might be false starts and dead ends, in which case you'll have to backtrack. Getting tangled up underground would be no fun.
I'd assume that lava tubes on Mars are very similar to lava tubes on Earth. Once you drop in, you'll want to go horizontal for as far as the cave will allow. Inside the cave, you could have smooth surfaces but you could also have incredibly rough surfaces as well, especially where debris fell or where lava drips occured. (And don't discount the fact that it is likely that there are multiple levels of tubes, so you may want to rappell down again once inside the first tube). [There is a cave in Lava Beds National Monument where I counted 12 distinct levels - I completely shredded a pair of jeans that day - lotsa twists and turns getting around debris and dropping down tight holes to get to the next level]. Having the ability to drop small radio repeaters as needed might work out best. -Mike -------------------- Some higher resolution images available at my photostream: http://www.flickr.com/photos/31678681@N07/
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Nov 16 2007, 05:41 PM
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#23
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Senior Member Group: Members Posts: 2173 Joined: 28-December 04 From: Florida, USA Member No.: 132 |
... our future cave explorer will have to find paths around fallen debris. The spider will just walk over most debris, but I'm no fan of a dedicated cave explorer anyway. A cave is a pig in a poke. You don't know what you'll find until -- after much planning and expense -- you get in there. I like the idea of going to sites that have been examined as closely as possible from orbit and show evidence of great science potential from a ground mission. Now, if a future orbiter identifies a methane-belching cave.... |
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Nov 16 2007, 06:14 PM
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#24
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Senior Member Group: Moderator Posts: 2785 Joined: 10-November 06 From: Pasadena, CA Member No.: 1345 |
At some point we will need to go in and explore harsh cave environments with robotic exploration.
Suppose we find hydrothermal vents on Europa, I'll bet we'd want to probe the inside the vent itself. Heck, I bet it'd be pretty neat to sneak a probe down deep inside a hydrothermal vent here on Earth, or deep exploration of crevasses (very cool). These evironments share the same problems: figuring the route, tight confined areas to maneuver in, communication with the surface, and really harsh physical environments. -Mike -------------------- Some higher resolution images available at my photostream: http://www.flickr.com/photos/31678681@N07/
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Nov 16 2007, 09:52 PM
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#25
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Senior Member Group: Members Posts: 1229 Joined: 24-December 05 From: The blue one in between the yellow and red ones. Member No.: 618 |
For starters I'll concede that no interplanetary probe could be infallible in the face of sufficiently fiendish challenges from the environment. But if our surface probes don't turn up any incontrovertible evidence for life, we will still have the possibility that it persists deeper underground.
My understanding of living species communities is that they will tend to expand outside of their optimum core area over time. This is because of species competition for resources. The superior competitor will push its inferiors toward the periphery, where they will have to adapt to conditions or go extinct. The process repeats until the community occupies all the habitable space up to the boundary of entirely unsurvivable conditions. This uncrossable boundary could be very deep on Mars (kilometers), in which case our life search will be long and frustrating, or it could be just 10 meters inside a cave, say where radiation levels drop sufficiently. In this case our first cave probe could succeed brilliantly on its first day. You pays your money and takes your chances. Cents2 understands how Shelob's silk should function, however it would help avoid tangles when backing up if the line can be retracted simultaneously. This complicates the mechanism, of course, but the alternative is to avoid backing up. I'm aware that some of the fiber-optic towed RF decoys (pulled behind war planes to distract radar-guided anti-air missiles) can be reeled in and out again. This implies some kind of small winch at work, but the details are classified, of course. I like the fiber-optic silk because it can combine reliable, high-bandwidth communication/control from earth, with a means to rappel down from skylights or precipices - also because Nature thought of it first . Theoretically Shelob could descend multiple drops, but there are limits to everything. Cents, where the existence of life is concerned, Mars itself is a "pig in a poke". -------------------- My Grandpa goes to Mars every day and all I get are these lousy T-shirts!
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Nov 16 2007, 10:59 PM
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#26
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Member Group: Members Posts: 213 Joined: 21-January 07 From: Wigan, England Member No.: 1638 |
Would a modified version of LEMUR be up to the job?
-------------------- "I got a call from NASA Headquarters wanting a color picture of Venus. I said, “What color would you like it?” - Laurance R. Doyle, former JPL image processing guy
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Nov 17 2007, 01:32 AM
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#27
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Senior Member Group: Members Posts: 1229 Joined: 24-December 05 From: The blue one in between the yellow and red ones. Member No.: 618 |
LEMUR How sweet it is! I'm relieved to see that JPL has read the writing on the wall: Build a walking, climbing robot. I suspect that model 2B may still be a number of iterations away from a sufficiently agile climber (the videos don't show climbing over obstacles), but the journey has begun. Goody. Now all we need to do is graft on an analytical lab-in-a-shoebox, a power supply, and a communication link come rappelling line. Devilsfood cake! Actually, we probably have more competition than that. I know the army would like robots creeping through caves in Afghanistan, sniffing out W.M.D.s and U.B.L.'s B.O. We just need the right contacts to bring the technology together.
P.S. I note that the latest issue of Science has a special section on robotics. Soon as it reaches the library, I'll do some homework. -------------------- My Grandpa goes to Mars every day and all I get are these lousy T-shirts!
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Nov 17 2007, 01:57 AM
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#28
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Merciless Robot Group: Admin Posts: 8783 Joined: 8-December 05 From: Los Angeles Member No.: 602 |
The fiber is payed out from the rover/spider as it moves. Once on the ground the fiber moves no more... no snag worries. I was thinking of that, too, but was a bit worried about adding weight to the spider. You're right, though, esp. if the spider is completely self-powered. As a side note: Hey, Shaka! You know about MOCNESS? God, what a beast that was...I've gone a few rounds with that thing... -------------------- 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 17 2007, 05:21 AM
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#29
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Senior Member Group: Members Posts: 1229 Joined: 24-December 05 From: The blue one in between the yellow and red ones. Member No.: 618 |
Helllll, yessss, nprev! It was about 25 years ago when I was proudly shown one of the early models on the dock at WHOI. I never had the budget for MOCNESS, but planktonology was my line! Bongos, Mantas and one-net Tuckers were my stock in trade. I've still got the scars!
-------------------- My Grandpa goes to Mars every day and all I get are these lousy T-shirts!
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Nov 17 2007, 11:23 AM
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#30
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Merciless Robot Group: Admin Posts: 8783 Joined: 8-December 05 From: Los Angeles Member No.: 602 |
...I was an ET, sailed several times on the Albatross IV out of WHOI, and once on the Ferrel! (1994-1996). We just might know some of the same people...
Back OT here, have we defined a complete instrumentation suite here yet? Also, I'd like to suggest that a 'sample return' (back to the surface lander) capability. In this scenario, Shelob would cut the cable (if necessary) & navigate back to the descent platform using the backup RF comm link, and deliver the sample(s) back to the lander, where the major experiments like a GCMS, atomic force microscope, etc. would reside. -------------------- 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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