In situ measurements to determine if Phobos is layered

The complex system of linear features on Phobos—the inner moon of Mars—found by the Viking Orbiters in 1976, can be classified morphologically into three types according to their appearance as well as their geometrical distribution on the surface. One kind of grooves appears to form arcs of small circles normal to the Phobos-Mars direction. We propose that these grooves are the surface manifestation of layering within Phobos4–6] which could have been formed when Phobos was a part of a much larger and geologically active parent planet.Here we suggest some measurements to observe whether Phobos has a layered structure or not. The suggestion contains remote sensing measurements (particularly determination of the magnetic field by magnetometer and by electron reflection method) by a spacecraft orbiting around Mars as well as surface measurements (active seismic reflection experiment) by a landing module on Phobos.