Physical properties of the regolith of Phobos

Results of two experiments performed onboard the Phobos spacecraft are presented: spectrophotometry in the 300-600 nm range and thermal radiometry, i.e., intrinsic thermal emission in the 6-50 micron range. The thermophysical characteristics of the Phobos regolith are indicated by a thermal inertia coefficient which is similar to that of the moon. The reflectivity of the regolith is inhomogeneous in the region investigated and depends mostly on the relief features, primarily craters and their age. The expected similarity of the reflection spectra with those of carbonacenous chondrites was not confirmed.