Why is the Martian surface so dark in those transit images? Is it because we're on the nightside of Mars' terminator?

The shading suggests that's not right.. not near-terminator either. Maybe it's the filter?

Phil

Couldn't the skylight provide some illumination, mainly from the west, even past the terminator? Didn't one of Dawn's Mars flyby images capture a similar scenario?

Peter 59, please, could you tell us the orbit # of those pics, so that we can retrieve the original pics ? Thanks in advance

Orbit number is contained in the names of the attached images:
H5984_0004_SR2, H6042_0005_SR2, H6217_0005_SR2, H6128_0003_SR2

This is a great honor for me to talk with someone who has played a significant role in the Viking mission. Words of respect.

[quote name='peter59' date='Nov 12 2009, 07:16 PM' post='149916']


Oh... thanks a lot, Peter, I do not deserve so much after all those years, but I like very much your Phobos pics selections ! Thanks again for sharing those with us

...And, Peter, here is your image fully colorized. Enjoy !
Click to view attachment

The craters in the background sure look weird! This isn't a snapshot, of course; time as well as distance are covered along the long axis of the image, and the spacecraft was clearly doing something odd as it was setting up to track Phobos. But I don't understand what was happening to make the craters appear smeared in a stepwise fashion.

Anyway, cool colorization, Olivier.

I wonder if it's a bit like the way Mars stops, goes backwards, then carries on, night to night in the night sky.

Retrograde craters - I think you've got it, Doug.

Phil

That's a really stunning image! Which orbit is the colourised shot from? I can look up our attitude profile and see what might be causing the crater distortion (although I think you've already guessed it!).

"Phobos & Deimos visible in same image for first time"

http://www.dlr.de/en/desktopdefault.aspx/t...600_read-21513/

Remarkable footage to say the least although I expected Phobos to pass even faster throught the image:

Images every 0.1s - slowed significantly in that animation - not surprising it comes across as 'slow'.

That statement needs a qualifier:

http://apod.nasa.gov/apod/ap031024.html

and

http://photojournal.jpl.nasa.gov/catalog/PIA06337


(sorry Stu it seems I've been picking on your posts a lot lately, nothing personal.)

"For the first time, the two tiny Martian moons Phobos and Deimos have been photographed together in a high-resolution image sequence."

If someone fancies putting two copies of the animation together with a one frame time difference that might work as a crosseye 3D animation.

Here is the ESA page on the images: http://www.esa.int/SPECIALS/Mars_Express/SEMDOE7JT2G_0.html

"For the very first time, the martian moons Phobos and Deimos have been caught on camera together. ESA's Mars Express orbiter took these pioneering images last month. Apart from their ‘wow’ factor, these unique images will help the HRSC team validate and refine existing orbit models of the two moons."

More information about how they got the images are on the page. Very cool sequence.

Thanks for the tip, Dan.

The image caption says "for the first time, possible to acquire images of Phobos and Deimos together in high resolution.." It seems like whoever wrote the press release failed to understand the significance of the last three words.

Well I can confirm that consecutive frames from this image sequence make very good 3D pairs, so I'm going to have one more go. This time not a suggestion but a request - on bended knee - a 3D animation please!

Have we ever had a 3D animation from spacecraft images here? Maybe it would be a first.

Mars Express is scheduled to make the closest Phobos flyby at 50 km on March 3.
http://www.esa.int/esaMI/Mars_Express/SEMDUGSJR4G_0.html

i thought that phils deimos was based on that ( oops not from pairs but the outline )

http://www.psi.edu/pds/resource/oshape.html
http://www.psi.edu/pds/asteroid/EAR_A_5_DD...ta/m2deimos.tab

my vid.
http://www.youtube.com/watch?v=g7A4RaaOzho

an artistic enhancement to the above shape model m2deimos.tab

My earlier work on Deimos was the construction of a global photomosaic. The shape model it was based on was by Peter Thomas of Cornell, the leading person in this kind of work, and it used Viking images. The shape model is not ideal - a large region near 270 W longitude has only ever been seen in one image, so no stereo for shape modeling at all. We badly need a future mission to provide new imaging of Deimos.

i thought it was from the Viking images

mine is a hand drawn height map converted to a 3ds model


well a mission there will solve the problem

From AW&ST next issue: "Mars EXpress has begun a series of new flyby of Phobos...at its closest encounter, on Mars 3 the probe will come to within 50 km. (31 mi.) of the Martian moon..."

The latest post on the Mars Express blog has this information:
"New webpages went online today allowing anyone to download data from the digital terrain model of Phobos created by the EuroPlanet project..."
The links for downloading the DEM is at the bottom of this page.

Animated flyover anyone?

i just answered a question on this over at shatters.net
and a very quick pds to png convert of
base_dtm_phobos.pds
Click to view attachment
the above image WAS "normalized " 0 to 256

a better one
from the pds > cub ( ran fx on it os the values are from 1098 to 6585) > exported to 16bit tif > to rgb normalized png
Click to view attachment

Nice one ...


I haven't found published information on the exact flyby times, here's what I've calculated using the SPICE kernels I could find:

I havent come across the 5th flyby yet. It may well be after 9 March which is when the current trajectory data (available to me) runs out.

I will update the MEX realtime simulation at http://www.dmuller.net/mex with these dates in due course.

Why the Mars Express camera (HRSC) would not be taking images at closest approach? It turns out that there are three reasons.
http://webservices.esa.int/blog/post/7/1038

Hey, it's not that bad. Remember Deep Impact, which also wasn't allowed to take photos at closest approach, because of the risk of debris damaging the camera? We still learned a lot about Tempel 1 anyway!

It wasn't?

Why not risk the camera, at that time no follup-mission was planned.
Ofcourse, the impact still had to be photographed.

It wasn't that taking photographs was prohibited - it was that the spacecraft had to orient itself to protect itself during the closest approach because of cometary particles etc, and then continue departure imaging thereafter. It was protecting the entire spacecraft so it could finish its mission, not the camera.

http://www.nasa.gov/mission_pages/deepimpa...line/index.html
"Flyby spacecraft enters shield mode"

Yeah, that's what I meant. The end result was the same though. No more photos or other data until it was well on its way past closest approach and 'looking back'.

The actual closest flyby altitude was ultimately 67km due to an engine overburn ... http://webservices.esa.int/blog/blog/7

New SPICE kernels are in as well, taking us to 20Mar and hence the remaining close flybys. Just to add confusion, the table below states UTC times and not ephemeris times as my earlier table:

Some early pictures are released

This image was taken 656km across.

The grooves are beginning to look more like crater chains.

LOL indeed - the flybys so far have not even included imaging.

The image you direct link to without citation is from here
: http://www.esa.int/SPECIALS/Mars_Express/SEMIPX6K56G_0.html

Which then links to here
: http://www.esa.int/SPECIALS/Mars_Express/SEMIPX6K56G_1.html

Where we find out


So no - they've NOT released early pictures because that's an 18 month old , and they've not even TAKEN any with this new flyby sequence yet.

i see a lot of those chains and these do not look like them
I will go look for some and post pics .

They couldn't take images in this sequence because MEX had to be in "passive mode" for accurate tracking for the Phobos-gravity experiment.
IIRC, this flyby was over the night side, so the images wouldn't have been too enlightening anyway.

Edit:
peter59 already said that.

It's okay-- I know the old debate, which is why I'm curious what they look like at smaller scales. Apparently that photo wasn't it, although I did think they were planning shoots outside the radio science portion of this flyby.

It's late, so take this thought experiment as woolly night owl speculation;

We apparently are seeing 'ring residue' on Rhea's surface from a rather tenuous, but seemingly fairly organized orbiting system. Now imagine for the moment, a mini sub-moon (like maybe in the 1-2km range) placed ~~1000km above Rhea's equator. What does the 'ring residue' look like if it 'splats' onto the 1-2 km sub-moon ? (or more precisely, what does the sub-moon look like after it is splattered)

(I think the size of the sub-moon might need to be closely constrained, I am trying to minimize shepherding effects)

Plausibly Phobos-like, or completely un-Phobos like?

Could dust (crud) knocked off Deimos organize to the extent of the Rhean residue, apparently detected by Cassini's MIMI instrument, on it's way spiraling down to Mars ?

well it is an old one at that

-- idea from above post
?????????????
what if .... a ring ( at mars) was at the same orbit as Phobos
and the moon eat-up the ring .
and the ring material carved out the lines - like from a sand-blaster

i have NO evidence, but...

Oups, so ashamed to have been fooled so easily by a press release.
Thanks a lot for your attention.

Date Altitude (km) * Instruments used during flyby

16 February 991 PFS, SPICAM, ASPERA
22 February 574 PFS, SPICAM, ASPERA
25 February 398 PFS, MARSIS
28 February 226 PFS, MARSIS
03 March 50 MaRS, ASPERA
07 March 107 HRSC, OMEGA, MARSIS, SPICAM, ASPERA
10 March 286 HRSC, OMEGA, MARSIS, ASPERA
13 March 476 HRSC, SPICAM, PFS, ASPERA
16 March 662 HRSC, SPICAM, PFS, ASPERA
19 March 848 HRSC, SPICAM, PFS, ASPERA
23 March 1341 Not used
26 March 1304 HRSC, SPICAM, PFS,

John W,
I would expect the deposition of ring material to build mountains, not canyons (see Atlas, Pan).
Unless it was less of a ring and more of an asteroid belt.



I agree they look like them. (image from MRO below)

The crater chain hypothesis fails to explain why the linear features on Phobos are in series of parallel lines. There are sets of parallel lines pointing one direction, and sets of parallel lines pointing another direction.

What about tidal fracturing (with loose material filling the gaps, falling in a funnel-like pattern to produce the observed crater shapes) followed by reorienting of the moon by some mechanism, then continued tidal stress in a new orientation.

As for the two criss-crosing linear features in the image below, I have no idea.

New massive batch (2010-02-17) - orbits 6402-7094
Click to view attachment Click to view attachment Click to view attachment

Click to view attachment Click to view attachment Click to view attachment
Orbits: 6551, 6637, 6745, 6758, 6757

Too much noise for my limited skills to bring out anything notable on the night side.

I thought there was a theory that the sets of parallel lines were caused by ejecta from impacts on Mars?