Research Groups

Planetary Imaging Group (PIG)

Phobos and Deimos

Observations by the Imager for Mars Pathfinder of Phobos and Deimos were used to produce low resolution spectra of the satellites [Thomas et al., 1999; Murchie et al., 1999]. HiRISE has been used to image them, in colour with high spatial resolution, to reveal inhomogeneities in material properties on on the surface. Preliminary colour maps of one face of each object have been produced showing remarkable structure on their surfaces. We are currently using digital terrain models of Phobos from DLR in Germany to try to model the Stickney impact and investigate its grooves and ejecta.  

Phobos seen with HiRISE
Phobos seen with HiRISE. Right-hand image is a NIR/BG colour ratio showing the strong blue colour of the material draped over the rim of Stickney crater.

Phobos Research

We are currently working with Martin Jutzi (SNSF Ambizione fellow) with a view to modelling impact structures on the surface of Phobos. He has run a model of the Stickney impact and looked at the velocity field but preliminary studies suggest that this doesn't provide a good match to the observed grooves.

Velocity field from an impact into Phobos

Deimos Images

Some of the best ever images of Deimos have been returned by HiRISE.

Image of Deimos acquired by HiRISE (left) and a colour ratio map showing inhomogeneity on the surface of the satellite


Pieters, C.M., S. Murchie, N. Thomas, and D. Britt, (2014), Composition of surface materials on the moons of Mars, Planetary and Space Science, accepted, 19 February 2014, doi: 10.1016/j.pss.2014.02.008.

Thomas, N., R. Stelter, A. Ivanov, N.T. Bridges, K.E. Herkenhoff, and A.S. McEwen, (2010), Spectral heterogeneity on Phobos and Deimos: HiRISE observations and comparisons to Mars Pathfinder results, Planetary and Space Science, 59, 1281-1292, doi:10.1016/j.pss.2010.04.018.

Thomas, N. Britt, D.T., Herkenhoff, K.E., Murchie, S.L., Keller, H.U., and Smith, P.H. (1998) Observations of Phobos, Deimos, and bright stars with the Imager for Mars Pathfinder. J. Geophys. Res., 104, 9055-9068.