Soil-like deposits observed by Sojourner, the Pathfinder rover


  • Henry J. Moore,

  • Donald B. Bickler,

  • Joy A. Crisp,

  • Howard J. Eisen,

  • Jeffrey A. Gensler,

  • Albert F. C. Haldemann,

  • Jacob R. Matijevic,

  • Lisa K. Reid,

  • Ferenc Pavlics


Most of the soil-like materials at the Pathfinder landing site behave like moderately dense soils on Earth with friction angles near 34°–39° and are called cloddy deposits. Cloddy deposits appear to be poorly sorted with dust-sized to granule-sized mineral or rock grains; they may contain pebbles, small rock fragments, and clods. Thin deposits of porous, compressible drifts with friction angles near 26°–28° are also present. Drifts are fine grained. Cohesions of both types of deposits are small. There may be indurated soil-like deposits and/or coated or crusted rocks. Cloddy deposits may be fluvial sediments of the Ares-Tiu floods, but other origins, such as ejecta from nearby impact craters, should be considered. Drifts are probably dusts that settled from the Martian atmosphere. Remote-sensing signatures of the deposits inferred from rover observations are consistent with those observed from orbit and Earth.