Decepticon
Aug 16 2005, 02:13 AM
I can't seam to find any images done on Phobos by Odyssey?
Was there any planned?
um3k
Aug 16 2005, 03:06 AM
I don't think so.
Phil Stooke
Aug 16 2005, 03:14 AM
I asked the Odyssey people if they were going to do any Phobos imaging during aerobraking. They said no. But I would like to know if MRO will do any. They might be interesting. However, Deimos is the moon we really need better images of right now. We have great coverage for Phobos from Viking, MGS and Mars Express (yes, and Meriner 9 at low res). But Deimos is in comparison very poorly imaged, with one whole side seen only in two high sun images.
Phil
BruceMoomaw
Aug 16 2005, 04:35 AM
It will be very interesting to see what Mars Express and MRO can provide for Phobos not only in the way of near-IR minerology, but (in Mars Express' case) radar sounding.
dvandorn
Aug 16 2005, 06:57 AM
QUOTE (Phil Stooke @ Aug 15 2005, 10:14 PM)
... We have great coverage for Phobos from Viking, MGS and Mars Express (yes, and Mariner 9 at low res). ...
Don't forget the Russian Phobos mission. While it did die just before beginning its intensive Phobos encounter, it did get a suite of some pretty high-quality images of Phobos as it approached.
-the other Doug
djellison
Aug 16 2005, 08:07 AM
The MRO chaps said specifically no science during aerobraking at a press conf (and also no UHF between MRO and MER even as a checkout )
Doug
edstrick
Aug 16 2005, 11:52 AM
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"
Decepticon
Aug 16 2005, 12:08 PM
QUOTE
The MRO chaps said specifically no science during aerobraking at a press conf (and also no UHF between MRO and MER even as a checkout )
Whoa, that's sad.
Phil Stooke
Aug 16 2005, 06:32 PM
I'm very embarrassed to have forgotten to mention Phobos 2. Yes, it did give some very useful images. In particular it greatly increased the low phase coverage available for Phobos, allowing albedo and/or photometric variations to be mapped over much larger areas than Viking alone provided... plus spectral variations. I really hope Phobos-Grunt is successful. At least they have finally managed to get funding for it after years of trying.
Phil
RNeuhaus
Aug 16 2005, 06:53 PM
MRO will take pictures on Phobos (big and closer) and Deimos (small and farther)during its approach to Mars.
"To help future missions in the Mars Exploration Program, Mars Reconnaissance Orbiter will carry an optical navigation camera. From 30 days to 2 days prior to Mars Orbit Insertion, the spacecraft will collect a series of images of Mars' moons Phobos and Deimos. By comparing the observed position of the moons to their predicted positions, relative to the background stars, the mission team will accurately determine the position of the orbiter in relation to Mars."
The probably date of picture is between February 6 to March 8, 2006.
Optical Navigation CameraRodolfo
RNeuhaus
Aug 16 2005, 07:02 PM
QUOTE (RNeuhaus @ Aug 16 2005, 01:53 PM)
MRO will take pictures on Phobos (big and closer) and Deimos (small and farther)during its approach to Mars.
"To help future missions in the Mars Exploration Program, Mars Reconnaissance Orbiter will carry an optical navigation camera. From 30 days to 2 days prior to Mars Orbit Insertion, the spacecraft will collect a series of images of Mars' moons Phobos and Deimos. By comparing the observed position of the moons to their predicted positions, relative to the background stars, the mission team will accurately determine the position of the orbiter in relation to Mars."
The probably date of picture is between February 6 to March 8, 2006.
Optical Navigation CameraRodolfo
Please forgot it, I realized that this camara will not take high resolution pictures on these Mars moons and its purpose is only for testing navigation purposes.
Rodolfo
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