Phobos And Deimos & Mars Environment (PADME) is a low-cost NASA Mars orbiter mission concept that would address longstanding unknowns about Mars' two moons Phobos and Deimos and their environment.

The PADME mission competed for Discovery Program funding, but lost to the Psyche and Lucy missions. The Principal Investigator is Anthony Colaprete. Other principals include Pascal Lee (Deputy Principal Investigator) and Butler Hine (Project Manager).

The origin of Mars' moons, which were discovered by astronomer Asaph Hall, remains unknown. PADME would advance the scientific understanding of the origin of Phobos and Deimos by studying:

In addition, PADME would assess potential resources (water, organics, regolith) and potential hazards (dust) that Phobos and Deimos might present for future human exploration in Mars orbit.

Once in Mars orbit, PADME would carry out 16 flybys of Phobos followed by 9 flybys of Deimos. Flybys would take place at two-week intervals. Flyby altitudes at closest approach to Phobos and Deimos would be ~2 km. Following completion of its primary mission, PADME could remain in high Mars orbit for long-term monitoring of the martian system and search for potential additional moonlets around Mars. Alternatively, PADME could be made to escape Mars and eventually fly by a Near-Earth Object (NEO).

NASA Ames Research Center would design, develop, build, and test the PADME spacecraft, and manage mission operations. The proposal is to employ the proven Modular Common Spacecraft Bus (MCSB), previously used by the LADEE Moon orbiter. Major partners include the SETI Institute, Jet Propulsion Laboratory, NASA Goddard Space Flight Center, and University of Colorado's Laboratory for Atmospheric and Space Physics.

The PADME mission has four science instruments plus a radio science experiment which uses the spacecraft's radio communications system.

The orbiter could also carry an optional laser communications experiment.