Phobos 1 system was badly designed. "Phobos 1" failed before it could achieve its main scientific objectives, and while the Phobos program as a whole can be considered a failure, the probes discovered previously unknown information concerning Mars and Phobos during their lengthy orbital flights. In 1988, less was known about Mars and its satellites than the more distant gas giants. Phobos 1 Phobos 1 was an unmanned Russian space probe of the Phobos Program launched from the Baikonour launch facility on 7 July 1988. Its intended mission was to explore Mars and its moons Phobos and Deimos. The mission failed on
Moons of Neptune orbit Neptune at an average of 125 times the distance between Earth and the Moon. Neptune has the largest Hill sphere in the Solar System, owing primarily to its large distance from the Sun; this allows it to retain control of such distant moons. Nevertheless, Jupiter's S/2003 J 2 orbits at the greatest percentage of the primary's Hill radius of all the moons in the Solar System on average, and the Jovian moons in the Carme and Pasiphae groups orbit at a greater percentage of their primary's Hill radius than Psamathe and Neso. The mass distribution of the Neptunian moons