Mars Odyssey Observes Martian Moons

Image credit: NASA/JPL-Caltech/ASU/SSI

February 23, 2018 – Phobos and Deimos, the moons of Mars, are seen in this movie put together from 19 images taken by the Mars Odyssey orbiter’s Thermal Emission Imaging System, or THEMIS, camera. The images were taken in visible-wavelength light. THEMIS also recorded thermal-infrared imagery in the same scan.

The apparent motion is due to progression of the camera’s pointing during the 17-second span of the February 15, 2018, observation, not from motion of the two moons. This was the second observation of Phobos by Mars Odyssey; the first observation was on September 29, 2017. Researchers have been using THEMIS to examine Mars since early 2002, but the maneuver turning the orbiter around to point the camera at Phobos was developed only recently.

The distance to Phobos from Odyssey during the observation was about 3,489 miles (5,615 kilometers). The distance to Deimos from Odyssey during the observation was about 12,222 miles (19,670 kilometers).

THEMIS was developed by and is operated by a team based at Arizona State University, Tempe. In normal operating mode, Odyssey keeps the THEMIS camera pointed straight down as the spacecraft orbits Mars. In 2014, the spacecraft team at Lockheed Martin Space Systems and NASA’s Jet Propulsion Laboratory and the THEMIS team at Arizona State University, developed procedures to rotate the spacecraft for upward-looking imaging of a comet passing near Mars. The teams have adapted those procedures for imaging the Martian moons.

NASA’s Jet Propulsion Laboratory, Pasadena, California, manages the Mars Odyssey mission for NASA’s Science Mission Directorate, Washington. Lockheed Martin Space Systems of Littleton, Colorado, built the orbiter and partners in its operation. JPL is a division of Caltech in Pasadena.