Simulation of Dust Sedimentation on the Calibration Targets for the Surface Stereo Imager Onboard the Phoenix Mars Lander

Introduction: The Phoenix Mars Lander 2007 mission will carry three identical calibration targets to verify and validate the preflight calibration of the Surface Stereo Imager (SSI) and to monitor the stability of this calibration during the mission. The specially designed calibration targets (‘the caltargets’) are at least in one respect more advanced than calibration targets on earlier missions, as they contain magnets. The caltarget is an aluminum plate with six different color chips each in two sizes and with additionally four experimental color chips. The pigments for the first set of chips consist of inorganic pigment material dispersed in silicone RTV material and they are green (chromium oxide), yellow (goethite), blue (cobalt aluminate). The second set of chips is three shades of gray (mixture of titanium dioxide and carbon black, reflectivity: 60%, 40%, 20%).