Has Odyssey Imaged Phobos? Options

[Decepticon]

I can't seam to find any images done on Phobos by Odyssey?

Was there any planned?

[edstrick]

Deimos just plains looks *STRANGE*, too. It's all rounded, with a very active regolith creaping downhill away from topographic highs making bright streaks and burying craters. All the asteroids we've looked at, including Ida's tiny moon Dactyl (very few things so far Deimos' size) don't remotely look like Deimos.

We have very limited info on their surface composition. Black.. minimal or zero well defined spectral features in not very good data from Earth and Phobos 2 and the like. And I don't trust the analysis of what little we have. "Space Weathering" clearly modifies asteroid spectral features, much as it does lunar regolith specta. Mature regolith has a much less structured and interpretable spectrum compared with fresh rayed crater ejecta and the like.

Phobos and Deimos are both inside Mars' gravity well. Ejecta from them may have escape velocity from their local gravity, but not readily from Mars gravity. A much larger fraction of their ejecta (for their size) is probably recaptured than for comparable size asteroids... the resulting surface material may be a very mature regolith indeed. One negative result is that there is no so-far detectable water-of-hydration in Phobos spectra, unlike low-temperature carbonaceous chondrite specta. That's been used to rule out a C2 or C2 composition in captured-body scenarios, but in a fully mature regolity, that spectal feature may be totally obliterated.

I'd really like to get sample return from both of them. Enough sample from Phobos might contain Deimos, as well as Martian ejecta. If Deimos's weirdness is due to composition difference, not some mechanical property difference or orbital-environment difference, we'd likely be able to spot Deimos grains in Phobos dirt as "non-phobos, non-mars"