Phobos
The larger of Mars's two natural satellites, with a mean diameter of approximately 22.2 kilometers, an orbital altitude of about 6,000 kilometers above the Martian surface, and an orbital period of about 7.6 hours. Two hypotheses exist for its origin: capture of an asteroid, and accretion from impact debris.
Timeline (last 90 days)
The largest impact crater on Phobos' surface is Stickney crater, about 9 kilometers in diameter.
Phobos' surface is covered with material ejected from Mars, and may preserve records of Mars' early atmosphere and geology.
Surface gravity on Phobos is extremely low, so a probe tends to bounce upon landing and requires special anchoring or adhesion mechanisms.
Phobos is the larger of Mars' two natural satellites, with an average diameter of about 22.2 kilometers.
The origin of Phobos has long been disputed: one hypothesis holds that it is a captured asteroid, while another holds that it accreted from debris produced by a giant impact on Mars.
A cable hanging downward from Phobos would have a lower end moving at only about 500 meters per second (approximately Mach 1.5) relative to the Martian surface, far below the several kilometers per second required for a rocket to reach orbit.
Phobos orbits approximately 6,000 kilometers above the Martian surface, with an inclination of about 1 degree and an orbital period of approximately 7 hours and 39 minutes, which is faster than Mars's rotation period of 24 hours and 37 minutes, causing it to rise in the west and set in the east.
All Facts (7)
The largest impact crater on Phobos' surface is Stickney crater, about 9 kilometers in diameter.
50%UnverifiedPhobos' surface is covered with material ejected from Mars, and may preserve records of Mars' early atmosphere and geology.
50%UnverifiedSurface gravity on Phobos is extremely low, so a probe tends to bounce upon landing and requires special anchoring or adhesion mechanisms.
50%UnverifiedPhobos is the larger of Mars' two natural satellites, with an average diameter of about 22.2 kilometers.
50%UnverifiedThe origin of Phobos has long been disputed: one hypothesis holds that it is a captured asteroid, while another holds that it accreted from debris produced by a giant impact on Mars.
50%UnverifiedA cable hanging downward from Phobos would have a lower end moving at only about 500 meters per second (approximately Mach 1.5) relative to the Martian surface, far below the several kilometers per second required for a rocket to reach orbit.
50%UnverifiedPhobos orbits approximately 6,000 kilometers above the Martian surface, with an inclination of about 1 degree and an orbital period of approximately 7 hours and 39 minutes, which is faster than Mars's rotation period of 24 hours and 37 minutes, causing it to rise in the west and set in the east.
50%