The Phoenix Surface Stereo Imager SSI investigation

Introduction: The Phoenix Mars Lander will begin a 90-sol mission in Mars’ north polar terrain on 25 May 2007. A Robotic Arm (RA) on the lander will dig one or more trenches, providing soil and ice samples to two deck chemistry instruments. Through the mission, a meteorology station (MET) and Lidar will measure pressure, temperature, and boundary layer properties. This abstract describes the multispectral science camera on Phoenix, the Surface Stereo Imager (SSI). The capabilities of the SSI respond to a number of constraints, both scientific and operational. SSI will be used to derive digital terrain maps used to guide the RA in digging and sampling operations; thus it requires stereo viewing capabilities. Selection of scientific targets for digging and sampling will be guided by images of the RA workspace: a Robotic Arm camera offers close-up detail views and SSI adds multispectral imaging. Documentation of sample material around the on-deck instruments requires special diopter filters for maximum resolution. SSI will monitor atmospheric optical depths both for studying polar weather and for understanding spacecraft performance in combination with solar panel data; thus neutral density filters capable of direct solar imaging are included. Phoenix includes a tell-tale for wind measurements, and SSI is used to monitor the tell-tale.