HiSCI EXPERIMENT ON EXOMARS TRACE GAS ORBITER.

The High-resolution Stereo Color Imager (HiSCI) has been chosen for the payload of the ExoMars Trace Gas Orbiter (TGO), an ESA/NASA joint mission scheduled to arrive at Mars in 2016. There are 3 major HiSCI partners: (1) the telescope will be built in Switzerland overseen by the University of Bern; (2) the overall design, electronics, and integration will be from Ball Aerospace in Colorado; and (3) operations will be at the University of Arizona. The chief objective of TGO is to search for and map the spatial and temporal distribution of disequilibrium trace gases of possible biological importance, such as methane, with high-resolution spectrometers. Once localized, a key question is: What is the nature of the source regions? Spectra obtained in both occultation and nadir modes combined with atmospheric monitoring and modeling will make it possible to determine source locations to ~100 km. HiSCI will then image candidate features within these source regions at 2 m/pixel, in color and in stereo, over an 8.5- km swath width. If no sources are identified or confirmed, HiSCI will nevertheless lead to many new results on active and ancient Martian processes. Many viable hypotheses exist for the origin(s) and release of Martian atmospheric trace gases such as methane; all involve active surface processes. Dust deposition homogenizes surface colors over time, but other active processes create spatial and temporal color variability. To identify color anomalies and hence active locations, color imaging at high spatial resolution and high signal to noise ratio (SNR) is essential. Topographic data at similar resolution are also needed to understand physical processes and to orthorectify images for reliable change detection.