  Phobos, a moon of Mars, is below the Clarke 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 extra-synchronous orbit and almost stay
put in the present orbit. The reported altitude loss of Phobos is two meter per
century by wikipedia and sixty ft per century according to ozgate url . The
reported time in which the destruction will take place is fiftyMy and fortyMy
respectively. The authors had proposed a planetary-satellite dynamics based on
detailed study of Earth-Moon. Based on this planetary satellite dynamics, two
meter/century approach velocity leads to the age of Phobos to be twenty three
Gyrs which is physically untenable since our Solar System age is four and a
half Gyrs. Hence the present altitude loss is assumed to be twenty meter per
century. This leads to the age of Phobos to be two decimal three Gyrs and age
of Deimos to be two decimal two six Gyrs which is an acceptable result and from
this analysis it is predicted that the travel time from the present orbital
radius of nine thousand three hundred and eighty km to the Martian surface at
three thousand, three hundred and ninety seven km is ten decimal and four Myrs.
Hence doomsday of Phobos is at ten decimal and fourMyrs from now. Mars Express
studies have confirmed that Phobos is indeed trapped in a death spiral.
