Mars Global Surveyor bistatic radar probing of the MPL/DS2 target area

Mars Global Surveyor bistatic radar was used to probe the Mars Polar Lander and Deep Space 2 target areas (76 degreesS, 195 degreesW) in May 2000. The behavior of quasi-specular echoes at wavelength lambda = 3.6 cm indicates that the top few centimeters of regolith are similar in their reflecting pr operties everywhere along a track of approximately 1000 km which crosses th e MPL/DS2 area. Our provisional estimate of surface dielectric constant eps ilon similar to 2.25 is consistent with loose soil, moderately packed H2O s now, solid CO2, or a mixture of at least two. But other data rule out both H2O and CO2 near the surface in late southern summer (L-s = 351 degrees), l eaving dry soil with density similar to 1.4 g/cm(3) as the most likely mate rial. (C) 2001 Academic Press.