doi:10.1038/nindia.2015.129 Published online 19 September 2015
Researchers have viewed the rare far side of Deimos, one of the two natural satellites of Mars, using the Mars Colour Camera onboard the Indian Mars Orbiter Mission (MOM)1.
Deimos orbits Mars at an altitude of about 20,000 kilometres in the equatorial plane. Deimos has a synchronous orbital period with Mars causing it to have tidal locking with Mars, similar to the Moon orbiting the Earth. The Mariner 9 and Viking missions in the 1970s imaged the far side of Deimos, but more recent space probes have only imaged its near side.
The latest pictures of the far side of Deimos were obtained using the Mars Colour Camera, which imaged Deimos four times during an interval of 12 seconds on 14 October 2014 when Deimos was only 4,400 kilometres from MOM and the Sun provided sufficient illumination.
The images show that the far side of Deimos is less grooved than the near side. They also reveal that the far side lacks the prominent features of the near side. Deimos’ surface is generally smoother than that of Phobos, the other satellite of Mars, because of its thicker dust layer, which covers most of its surface features, including craters and minor surface irregularities.
Deimos is non-spherical and could be an asteroid, captured by Mars gravity in geological past, the researchers say.