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Unmanned Spaceflight.com _ Mars Odyssey _ Has Odyssey Imaged Phobos?

Posted by: Decepticon Aug 16 2005, 02:13 AM

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

Was there any planned?

Posted by: um3k Aug 16 2005, 03:06 AM

I don't think so.

Posted by: 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

Posted by: 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.

Posted by: 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

Posted by: 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

Posted by: 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"

Posted by: 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. sad.gif

Posted by: 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

Posted by: 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.

http://marsprogram.jpl.nasa.gov/mro/mission/sc_instru_optical.html

Rodolfo

Posted by: 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.

http://marsprogram.jpl.nasa.gov/mro/mission/sc_instru_optical.html

Rodolfo
*

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

Posted by: Phil Stooke Oct 9 2017, 03:55 PM

Resurrecting a very ancient thread here - because it's finally happened. (Also I accidentally posted this in the wrong thread earlier and have now removed the erroneous post).

--------------------------------

A new release:

https://mars.nasa.gov/news/8280/examining-mars-moon-phobos-in-a-different-light/

with THEMIS images of Phobos. This is the image, here a composite of five frames from the animated GIF, rotated so Phobos north is up. Stickney is at far left.

Phil


Posted by: stevesliva May 10 2019, 08:33 PM

More news on Odyssey and Phobos:
https://www.jpl.nasa.gov/news/news.php?feature=7398

Themis imaging the full Phobos disk.

Posted by: Phil Stooke May 12 2019, 05:52 PM

I made a couple of images from the Odyssey data by combining multiple frames:



Phil

Posted by: Phil Stooke Nov 29 2023, 06:37 PM

https://mars.nasa.gov/news/9514/nasa-orbiter-snaps-stunning-views-of-mars-horizon/

This link has a very nice image of the horizon of Mars (or the limb) seen by the THEMIS instrument on Mars Odyssey. At the bottom of the page is a video clip of Phobos.

I combined the frames to create a composite view:



Phil

Posted by: stevesliva Nov 29 2023, 08:28 PM

Yes Phil but your stack doesn't show Phobos moving Stickney-first, like a cosmic sandworm, as in the animation. Mnahm-mnahm-mnahm

Posted by: Phil Stooke Nov 29 2023, 09:01 PM

I'm not really clever enough to do that sort of thing.

Phil

Posted by: StargazeInWonder Dec 13 2023, 01:27 PM

Wow, what an old thread. Seeing that it began just as Cassini was beginning to image some of Saturn's small, irregular moons, I might chime in, nearly two decades later, that Phobos and Deimos and Saturn's small moons show some signs of superficial similarity. They're in the same size class and show signs of accumulated material mantling to various depth whatever crust might be down there. Telesto and Deimos, to cite one unlikely pair, have a superficially similar appearance, Telesto being just about double the size of Deimos. Presumably, there's more ice in the composition of the saturnian members of this set. Maybe Adrastea and Metis would also merit comparison, if we had images of comparable quality.

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