Martian Cave Probe?, Designs for the DEEP Search for Life Options

[Shaka]

Does anyone consider it worthwhile to speculate on how we might explore Martian caves or lava tubes for the traces of life - past or present? I have not yet run across any 'official' proposals for "spelunker probes", so perhaps we could have some fun and get in on the ground floor with some feasible early designs. With the engineering and scientific expertise we have at UMSF we should be able to whittle down the possible features for such a rover to a practical core. If the planned surface scrapers and drillers don't turn up conclusive evidence to answer The Big Question, can we justify a search of the Martian Underground?

I can envisage a RTG-powered rover that enters a cave, or rappels down a skylight opening, leaving a base communication stage outside connected to it with a fiber-optic umbilical cable. Some form of laser or other illumination - in the visible and/or infrared - would presumably be required. How many of the MSL instruments could be included? What novel instruments would be appropriate? What is the optimal size and mobility design? 'Do we yet have 'hot' prospects for accessible caves? How should we choose the best candidates?

We can leave this to some JPL bright spark to develop, or we can dive right in. Any takers?

[Shaka]

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".