Rock size-frequency distributions on Mars and implications for Mars Exploration Rover landing safety and operations

cumulative effective thermal inertias of 1700–2100 J m � 2 s � 0.5 K � 1 and are consistent with the model rock distributions applied to total rock abundance estimates. The Mars Exploration Rover (MER) airbags have been successfully tested against extreme rock distributions with a higher percentage of potentially hazardous triangular buried rocks than observed at the Pathfinder and Viking landing sites. The probability of the lander impacting a >1 m diameter rock in the first 2 bounces is 1.5 m and >2 m diameter, respectively. Finally, the model rock size-frequency distributions indicate that rocks >0.1 m and >0.3 m in diameter, large enough to place contact sensor instruments against and abrade, respectively, should be plentiful within a single sol’s drive at the Meridiani and Gusev landing sites. INDEX TERMS: 6225 Planetology: Solar System Objects: Mars; 5470 Planetology: Solid Surface Planets: Surface materials and properties; 5464 Planetology: Solid Surface Planets: Remote sensing; 5460 Planetology: Solid Surface Planets: Physical properties of materials; KEYWORDS: Mars Exploration Rover landing sites, Mars Pathfinder landing site, thermal inertia, rocks, Gusev, Meridiani