Phobos is the innermost and larger of the two natural satellites of Mars, the other being Deimos. Both moons were discovered in 1877 by American astronomer Asaph Hall. Phobos is named after the Greek god Phobos, a son of Ares and Aphrodite and twin brother of Deimos.

Does Phobos experience gravity?

Phobos has dimensions of 27 km × 22 km × 18 km, and retains too little mass to be rounded under its own gravity. Phobos does not have an atmosphere due to its low mass and low gravity.

Can you walk on Phobos?

Walk, don't run, on the martian moon Phobos. A new study finds that traveling faster than about 5 kilometers per hour on some regions of the Red Planet's largest satellite could shoot you straight off into space. ... The findings could pose problems for planned missions to Phobos.