Mercury Landers Options

[gndonald]

While the likelyhood of a Mercury Lander mission is very low, I was wondering if any planning/studies have been done on such a project?

[edstrick]

JRehling observed " We probably have, or will have, Mercury meteorites in collections "

Maybe but it's doubtful. They'll look, in all probability like lunar highlands breccias, but bulk compsition will be obviously non-lunar... a different pattern of volatile element depletion from what we think really heavily stripped the moon of "volatile" elements, including things like potassium, halogens, lead, zinc... in the mega impact that lead to our double planet.

More distinctive, and telltale, will be oxygen isotope fractionation patterns. The solar system was mixed thoroughally, but not completely, and martian, earth/moon, asteroidal (many different batches) and cometary isotopes are utterly distinctive in an 016/17 vs O16/18 plot.

There is *ONE* oddball meteorite I read about 2 or 3 years ago that resembles lunar meteorites but has an odd oxygen isotope pattern and it was being discussed as a possible mercurian ejecta sample, but I haven't heard a peep in the public reporting since.

Expectations, as I recall, from orbital dynamics stuff is that we should get about 1 merc meteorite for every 100 lunar ones <separate impacts?>.. and we dont' have 100 lunar ones.

Where we *should* put a lander down is on the mercury polar ice deposits in permanent shadows in craters. Keeping the lander warm will be the problem, not cool. This stuff is radar-bright and depolarizing.. the radar penetrates many wavelengths into the scattering ice without being absorbed and gets diffusely scattered back out with high reflectance.

Utterly unlike the marginally detected radar signature of lunar polar volatiles, if the detection claims aren't bogus anyway.

[Stephen]

Where we *should* put a lander down is on the mercury polar ice deposits in permanent shadows in craters.  Keeping the lander warm will be the problem, not cool.  This stuff is radar-bright and depolarizing.. the radar penetrates many wavelengths into the scattering ice without being absorbed and gets diffusely scattered back out with high reflectance.

If the crater lay in "permanent shadow" wouldn't that cause problems if the lander was solar powered? (I guess you'd need an RTG lander. But that would presumably increase the weight & the expense of the thing. Not to mention political complications here on Earth.

Also how would that affect (direct) communications with Earth? If it shadowed from the Sun wouldn't that increase the risk that Earth would not be visible above the lip of the crater? If it wasnt, you would need some kind of orbital relay, either one already in place (as in the case of the MERs, who had Odyssey already conveniently in orbit around Mars) or one the lander brought along with them (eg Beagle 2 & Mars Express).

It would make for a complex and expensive mission, and so presumably one unlikely to be funded any time soon.

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Stephen