Phobos program Phobos program The Phobos (, ) 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
Small Solar System body Small Solar System body A small Solar System body (SSSB) is an object in the Solar System that is neither a planet, a dwarf planet, nor a natural satellite. The term was first defined in 2006 by the International Astronomical Union (IAU) as follows: "All other objects, except satellites, orbiting the Sun shall be referred to collectively as 'Small Solar System Bodies' ". This encompasses all comets and all minor planets other than those that are dwarf planets. Thus SSSBs are: the classical asteroids, with the exception of the dwarf planet Ceres; the trojans; and the centaurs and trans-Neptunian objects,