The Phobos (Russian: Фобос, Fobos, Greek: Φόβος) program was an unmanned space mission consisting of two probes launched by the Soviet Union to study Mars and its moons Phobos and Deimos. Phobos 1 was launched on 7 July 1988, and Phobos 2 on 12 July 1988, each aboard a Proton-K rocket.
Phobos 1 suffered a terminal failure en route to Mars. Phobos 2 attained Mars orbit, but contact was lost before the final phase, prior to deployment of a planned Phobos lander. Phobos 1 and 2 were of a new spacecraft design, succeeding the type used in the Venera planetary missions of 1975–1985, last used during the Vega 1 and Vega 2 missions to Comet Halley. They each had a mass of 2600 kg (6220 kg with orbital insertion hardware attached).
The program featured cooperation from 14 other nations, including Sweden, Switzerland, Austria, France, West Germany, and the United States (which contributed the use of its NASA Deep Space Network for tracking the twin spacecraft).