Phobos' Stickney Crater
This image of Phobos, the inner and larger of the two moons of Mars, was taken by Mars Global Surveyor in 1998. This image shows a close-up of the largest crater on Phobos, Stickney, 10 kilometers in diameter. Individual boulders are visible on the near rim of the crater, and are presumed to be ejecta blocks from the impact that formed Stickney. Some of these boulders are enormous, more than 50 meters across. Also crossing at and near the rim of Stickney are shallow, elongated depressions called grooves. This crater is nearly half the size of Phobos, and these grooves may be fractures caused by its formation. Phobos was observed by both the Mars Orbiter Camera (MOC) and Thermal Emission Spectrometer (TES). This image is one of the highest-resolution images (4 meters per pixel) ever obtained of the martian satellite.
Date: 19 Aug 1998
Image Credit: NASA, Jet Propulsion Laboratory, Malin Space Science Systems
Credit: Lunar and Planetary Institute