[X] My Assistant

[dilo]

This mosaic of 4 Panoramic frames from Sol442 show a strong increase in density of rocks, even big ones! Don't know if could be an issue for further movements toward the hill top?

[Guest_BruceMoomaw_*]

Getting back for a moment to whether humans should be put on the surface of Mars: if it wasn't for the biocontamination issue, the argument for going that small remaining distance if you've already put them into Mars orbit would be extremely strong, thanks to the fact that Mars (unlike the Moon) has easily accessible resources (atmosphere and ground ice) that can be used to sustain a surface crew but not an orbiting crew.

But the biocontamination argument against it is still extremely strong. If one argues that Mars is already contaminated by terrestrial organisms transferred from Earth to Mars via meteorite, then the main scientific argument for running up the huge expense of sending humans to Mars promptly collapses too. And if one argues that it's unlikely that manned crews would contaminate more than a very small slice of Mars: the problem is that they WILL, at an absolute minimum, seriously contaminate every single local part of the planet that they actually try to examine scientifically. For all these reasons -- more than the expense of the expedition, although the latter is also a serious problem -- I think it will be a very long time before we send humans to the surface of Mars.

By the way, keep in mind that if you're going to adopt the alternative of just putting a crew into orbit around Mars and having them teleoperate surface-exploration robots without that maddening radio time lag, you can explore Venus in exactly the same way. And it's closer (if less scientifically interesting, and more exposed to solar particle radiation and X-rays...)

[David]

By the way, keep in mind that if you're going to adopt the alternative of just putting a crew into orbit around Mars and having them teleoperate surface-exploration robots without that maddening radio time lag, you can explore Venus in exactly the same way.  And it's closer (if less scientifically interesting, and more exposed to solar particle radiation and X-rays...)

If there were no intention of putting humans on the surface Mars, then I don't see any particular advantage to prioritizing a human mission to Mars. It seems to me that if we want to move in easy steps from moon landings to human exploration of other parts of the solar system, the natural sequence would be:
1) Near-earth asteroid rendezvous/landing (I don't think there are serious contamination issues here!); possibly a sequence of such trips, to work out problems in extended space missions
2) Manned Venus orbiter + unmanned probes (obviously this is a big leap from (1), but I can't think of anything in between)
3) Manned Mars orbiter (landing on Phobos?)

It's true that Venus is subject to more radiation; but that also means more power available for the orbiter . Exposure to solar radiation would be a problem for any extended manned space mission anywhere. Venus' advantage is that the travel times would be shorter. I'm not an engineer, though, so I have no idea what the technical problems would be in not only sending a crew out and bringing them back; I imagine they are different from, but not more complex than, returning a crew from Mars.