The CaSSIS camera sends its first images from Mars

“The camera has performed extremely well and we are looking forward to working with these exciting data”. Scientist at the EPFL's Space Engineering Center, Anton Ivanov leads the EPFL team involved in the ExoMars project, more specifically, in the CaSSIS project - for Colour and Stereo Surface Imaging System. Developed by a team from the University of Bern, this instrument just returned its first images from Mars’s orbit. The EPFL team is involved with the camera geometric calibration algorithms using stars and developing novel methods for stereo matching.

CaSSIS was launched with the European Space Agency’s ExoMars Trace Gas Orbiter (TGO) on March 14 and placed into the red planet’s orbit on October 19. At that time, a lot of attention was focused on the failed landing of the Schiaparelli probe. Yet,since then, the orbiter, which main mission is to look for trace gases in Mars’s atmosphere, is operating flawlessly.

Currently on an elliptical orbit of 240 km x 100’000 km, the TGO makes a fast close fly-by of the surface every 4 days. The camera could be tested during one of these close approaches, on November 22, over a region called Hebes Chasma. 11 high-quality images were returned during the first fly-by.

«The first images we received are absolutely spectacular ….. and it was only meant to be a test», says Nicolas Thomas, principal investigator of the Colour and Stereo Surface Imaging System (CaSSIS) and Director of the Physics Institute at the University of Bern.

Other data have been acquired to improve the quality of the data after post-processing. The resulting image quality has impressed the entire team. «We were quite nervous but it looks as though almost everything functioned as we planned it. The resulting images are really sharp», says Antoine Pommerol, co-investigator of the Colour and Stereo Surface Imaging System (CaSSIS) of the Center of Space and Habitability (CSH) at the University of Bern.

Stereo images

The colour and stereo capabilities of CaSSIS were also successfully tested within the Noctis Labyrinthus region, although some improvements in the onboard software and in the ground post-processing have to be made. The EPFL team is now beginning processing and understanding newly acquired data to prepare for full science operations later next year. , TGO will use “aerobraking” (skimming into the atmosphere) to slow the spacecraft down and enter a roughly circular orbit 400 km above this surface. This process will start in March 2017 and take around 9-12 months. The primary science phase will start around the end of 2017. CaSSIS will then enter nominal operations acquiring 12-20 high resolution stereo and colour images of selected targets per day.

Technical Background

CaSSIS is a high resolution imaging system designed to complement the data acquired by the other payload on TGO and other Mars orbiters while also enhancing our knowledge of the surface of Mars. The camera is a cooperation between the University of Bern, the Astronomical Observatory of Padua, and the Space Research Center in Warsaw with the support of local industries and funded by the Swiss Space Office (SSO), the Italian Space Agency (ASI) and the Polish Space Agency (POLSA).

The structure, onboard computer, and rotation mechanism were built by the University of Bern. The telescope was built in Zurich by RUAG Space AG. The detector and read-out electronics were developed by SELEX-ES in Campi Bisenzio, Italy. The power converter was produced by the Space Research Center in Warsaw. The flight software was developed by SGF Ltd. in Budapest, Hungary.