#deimos — Public Fediverse posts

Gulliver was a sample return mission to Deimos, proposed in 2006 and 2020 but not selected. The spacecraft would touch down briefly and rise up again, using a rotating brush system to gather several kg of the surface material. The sampling site would be chosen using new high resolution images from the spacecraft, but 5 sites were mentioned as candidates in the proposal and a sixth was also suggested, as shown on this map.
#maps #mars #phobos #deimos

These maps show the areas on Phobos and Deimos imaged by HiRISE. The Phobos map shows an area seen only in light reflected off Mars ('marsshine'). I didn't mention this, but it is shown in an image linked to from the website I gave a link for earlier. This is the direct link to the Marsshine image:

https://static.uahirise.org//images/2008/details/phobos/PSP_007769_9015_MarsShine.jpg

Now it's time to look at another mission proposal which didn't quite make it. Tomorrow!
#maps #mars #phobos #deimos

HiRISE imaged Deimos in 2009. This link gives a description of the images:

https://www.uahirise.org/releases/deimos/

This link gives you both images:

https://static.uahirise.org/images/2009/deimos/Deimos.png

Here I have turned the two images upside down (or right way up, north at the top) to make them easier to compare with maps, and I have done some extra processing to increase visibility in both bright and dark areas. Deimos is a very cute moon.
#mars #phobos #deimos

To back up my assertion... here is an early report on Viking images of Mars:

Carr et al., 1976. Preliminary results from the Viking orbiter imaging experiment. Science, 193(4255), pp.766-776.

Tomorrow - let's look at Deimos.
#mars #phobos #deimos

So imaging scientists interested in geology or clouds in an atmosphere had to fight to get cameras accepted. To make them sound more like science than postcards they were called experiments. Voyager - the most amazing voyage of discovery ever undertaken, in my view - would have flown without cameras in early plans for it. Outer planet clouds would be fuzzy and icy moons would be flat like ice on a lake. Nothing to see here. Luckily... we got pictures.
#mars #phobos #deimos

The top left corner of that image is the rim of Stickney crater. Grooves cross the surface and individual small rocks are scattered across the surface. HiRISE... why is a camera called an 'experiment'? This goes back to the early days of space exploration, which was largely the domain of physicists. Particles, fields, plasma, dust, radiation... you can get pretty good data in a small number of bytes, but a decent image might need hundreds of thousands of bytes.
#mars #phobos #deimos

HiRISE, the High Resolution Imaging Science Experiment on Mars Reconnaissance Orbiter, has taken amazing images of Phobos and Deimos despite never getting very close to them. They can be seen here:

https://www.uahirise.org/releases/phobos/

There are 2 pictures, so we have stereo. HiRISE can image in a kind of exaggerated colour using blue, red and infrared bands. Look down the page to 'image products' to see 2 B/W images and 2 colour images. My cropped view is rotated and more contrasty.
#mars #phobos #deimos

I have been taking images from my first Mars book, and adding extra details, but now book 1 is finished. Tomorrow we will have to start looking at images from book 2.
#mars #phobos #deimos

B in that last image shows Phobos and Deimos in a single frame, one of many such views used to refine the orbits of the moons. C looks down into Stickney crater and D is one of many high resolution images showing craters and grooves near the north pole of Phobos.One 'groove' is really a crater chain cutting diagonally across a set of parallel linear grooves. They look like they would have two different modes of formation.
#mars #phobos #deimos

The next orbiter to look at the moons of Mars was Mars Express, ESA's veteran spacecraft which has pretty much fully covered Mars with gorgeous stereo multispectral images. It also has imaged all of Phobos at high resolution, giving us the best dataset for global mapping. It could not get close to Deimos but has taken many distant images showing the regions facing Mars. Here are some sample images. A is a set of three views of Deimos.
#mars #phobos #deimos

Deimos’s shape and geology explained by a subcatastrophic impact: https://www.nature.com/articles/s41550-026-02956-w -> Hera's Mars flyby guided impact study of #Deimos moon: https://www.esa.int/Space_Safety/Hera/Hera_s_Mars_flyby_guided_impact_study_of_Deimos_moon

Mars Global Surveyor only got 5 high resolution images, all of similar areas so not very wide coverage. It also took low resolution views of Phobos and Deimos (one each). This map shows the coverage of Phobos. Sunlit areas are outlined, and the much larger area seen by reflected light is also shown. It took a ridiculous amount of time to make that map. A strip of test data from the MOLA laser altimeter is also shown here.
#maps #mars #phobos #deimos

Here is another MGS image of Phobos, with a more useful view of territory imaged by light reflected off the planet. If no other images existed, that reflected light would be very valuable, extending mapping considerably. That applies to Yoyager 2 images of Uranus's Ariel, and Cassini and Juno used it as well. Even New Horizons at Pluto tried it but the results were very limited. There are other examples (e.g. Dimorphos) - it's very useful.
#mars #phobos #deimos

That image is reduced, but here is the full resolution data for a prominent boulder sometimes called (inevitably) 'the monolith'. I was with a bunch of students at Sternberg State Astronomical Institute in Moscow, looking at the raw images which I had taken for them. We joked that the object was Phobos 2. That spacecraft may indeed by splattered across Phobos - it failed in an orbit that would bring it near Phobos repeatedly. MMX (launching on 19 October) might see it.
#mars #phobos #deimos

The next mission to give us data for the moons of Mars was Mars Global Surveyor, and here I am especially thinking of its camera, MOC (Mars Orbiter Camera). It took several great pictures of Phobos during close flybys while it was adjusting its orbit early in the mission. This was the closest. I have exaggerated brightness in the shaded area to show the surface lit by light reflected off Mars. Not very well... someone else could do a better job!
#mars #phobos #deimos

Here are higher resolution maps of the Aladdin sites. Note that the middle map shows that the trailing side sample point was moved from a complex area to a nice smooth area in 1999. The Deimos high albedo site is a small bright patch in the middle of the circle. I am now thinking that I should make a map of Phobos showing all of these suggested sites - we will be seeing more - before MMX gets busy.

Our next mission will be an orbiter.
#maps #mars #phobos #deimos

#UniBE:
"
Asteroideneinschlag formte das Aussehen des Marsmonds Deimos
"
".. mithilfe hochauflösender Computersimulationen und dem Vergleich mit den neusten Aufnahmen der ESA-Raumsonde Hera gezeigt, dass ein einzelner Asteroideneinschlag den Marsmond Deimos geformt und seine glatte, staubige Oberfläche geschaffen hat. .."

https://mediarelations.unibe.ch/medienmitteilungen/2026/medienmitteilungen_2026/einschlag_deimos/index_ger.html

18.8.2026

#Asteroid #Bern #Deimos #Einschlag #ESA #Hera #Marsmond #Raumfahrt #Raumsonde #Regolith #Schweiz #Simulation #Spaceflight #Supercomputing

The map image is a photomosaic which I compiled from Viking images and one Mariner 9 image. We didn't have good multispectral data for Deimos as we had for Phobos, so albedo is the only distinguishing characteristic to aim for. Next we will look at all these sampling areas at higher resolution.
#mars #phobos #deimos

Aladdin would look at Deimos as well - and sample it. Here is a map of Deimos - again it uses my morphographic projection which shows you the shape of the body as well as where surface features are. The shape in this case is the convex hull, which reduces distortions where large concavities are present. The white strip would be covered by high resolution data (images, composition etc.), and there are 2 sample sites, in light and dark areas.
#maps #mars #phobos #deimos

The drawing is a US Geological Survey map made by their very talented airbrush artists, the way many lunar and planetary maps were made before computers took over. But USGS based the drawing on a faulty shape model, which meant that some feature locations were displaced (and one crater was shown twice). I used a photomosaic from Cornell (where Peter Thomas, Damon Simonelli and others had a better shape model) to warp the USGS drawing to the Cornell geometry, then to mine.
#mars #phobos #deimos

The white rectangles are areas which would be observed at very high resolution by Aladdin's instruments during flybys. Dots show points which would be sampled by firing a projectile and collecting material ejected by the impact during a very low altitude flyby. This idea has also been proposed for the Moon and Europa (and maybe elsewhere). Note there was a revised site in a 1999 discussion. The image forming this map deserves some description too.
#mars #phobos #deimos

This map refers back to Phobos 2 by showing the location of the red-blue boundary on the anti-Mars side of the moon (the corresponding boundary opposite it was not observed). Also shown are two potential sampling areas (one on the red side, one on the blue side) for a very interesting mission proposal: Aladdin. This mission, which of course did not fly, would put a spacecraft into an orbit which made multiple close approaches by both Phobos and Deimos.
#maps #mars #phobos #deimos

The origins of the moons of Mars have been much debated. Some prefer an origin as a captured asteroid - or two, or one which broke or hit an existing moon... but basically it is very hard to make the physics of capture work. Others prefer the idea that a huge impact blasted material into a ring surrounding Mars, which eventually collected to form the moons. MMX should resolve this issue, but right now I think impact is favoured.
#mars #phobos #deimos

Here are the estimated areas covered by Pathfinder data. The lander is on Mars so it only sees the Mars-facing side of each moon. Phobos 2 saw the opposite side. We know enough to say that Pathfinder saw a mix of red and blue areas in the unresolved image, which doesn't help much. Deimos spectra were weaker but seemed to suggest that it was more like mafic rocks (ejecta from Mars) than C-type asteroids. Both types of material have been suggested...
#maps #mars #phobos #deimos

That last map of Phobos has vertical lines crossing it - they are approximate boundaries of data obtained by a mission we would not usually associate with Phobos and Deimos... Mars Pathfinder. The lander imaged both moons through several filters to create rough spectra, from which some composition information might be extracted. Those lines just represent simplified longitude limits, but I estimated the actual regions covered using the shape model...
#mars #phobos #deimos

This paper describes the colour dichotomy on Phobos:

Murchie et al., 1999. Mars Pathfinder spectral measurements of Phobos and Deimos: Comparison with previous data. JGR Planets, v. 104(E4), pp.9069-9079. https://agupubs.onlinelibrary.wiley.com/doi/pdfdirect/10.1029/98JE02248

This map is from that paper. The boundary between red and blue materials is diffuse and irregular but is sketched on with a curving dashed line. Is the blue Stickney ejecta?
#maps #mars #phobos #deimos

Back in the saddle... It would be easy to assume from what we have seen of Phobos 2 that no very useful results were obtained from it, but this is not correct. Its images (visible and infrared) revealed something unexpected: the two sides of Phobos, leading and trailing in its orbit, have different colours, roughly a bit more blue on the leading side and a bit more red on the trailing side. The blue might be associated with the big crater Stickney.
#mars #phobos #deimos

Neither lander would have been able to see Mars in the sky (a favourite subject for space artists). Most landing plans target the region opposite Mars. That way the lander is hidden behind Mars while it is facing away from Earth, minimizing communication loss. Land facing Mars and the two comm loss periods are separate.
#mars #phobos #deimos

PSA: I will be on the road for a few days. Normal service will resume as soon as possible.

The Phobos 2 images can be made into a photomap to show coverage. This version (top) also shows two instrument footprints (both were infrared detectors). The lower image shows the lander targets from this paper:
Sagdeev, R.Z. and Zakharov, A.V., 1989. Brief history of the Phobos mission. Nature, 341(6243), pp.581-585. https://doi.org/10.1038/341581a0
A small hopper would move around on the surface, another lander would last longer.
#maps #mars #phobos #deimos

...which we got about 2 weeks after publication. But pictures were slow to arrive (a bit like the current Tianwen-2 asteroid mission). Phobos 2 made several passes by Phobos, each closer than the last, but it failed before the landing phase of the mission. We got some images and other data including IR spectroscopy. Here are 3 images. Mars-shine is seen (exaggerated) on one image. We are seeing the end facing away from Mars, 180 longitude.
#mars #phobos #deimos