Irregularly Shaped Satellites-Phobos & Deimos-Moons of Mars, and Their Evolutionary History

Abstract

Bijay Kumar Sharma

Phobos, a moon of Mars, is below the Clarke�??s synchronous orbit and due to tidal interaction is losing altitude. With this altitude loss it is doomed to the fate of total destruction by direct collision with Mars. On the other hand Deimos, the second moon of Mars is in extrasynchronous orbit and almost stay put in the present orbit. The reported altitude loss of Phobos is 1.8 m per century by wikipedia and 60ft per century according to ozgate url . The reported time in which the destruction will take place is 50My and 40My respectively. The authors had proposed a planetary-satellite dynamics based on detailed study of Earth-Moon[personal communication: http://arXiv.org/abs/0805.0100 ]. Based on this planetary satellite dynamics, 2 m/century approach velocity leads to the age of Phobos to be 23 Gyrs which is physically untenable since our Solar System�??s age is 4.567Gyrs. Hence the present altitude loss is assumed to be 20 m per century. This leads to the age of Phobos to be 2.3Gyrs and age of Deimos to be 2.26Gyrs which is an acceptable result and from this analysis it is predicted that the travel time from the present orbital radius of 9380 km to the Martian surface at 3397 km is 10.4Myrs. Hence doomsday of Phobos is at 10.4Myrs from now. Mars Express studies have confirmed that Phobos is indeed trapped in a death spiral.

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