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 formed "in situ". Triton and Nereid are unusual irregular satellites and are thus treated separately from the other five irregular Neptunian moons, which are more like the outer irregular satellites of the other outer planets. Firstly, they are the largest two known irregular moons in the Solar System, with Triton being almost an order of magnitude larger than all other known irregular moons. Secondly, they both have atypically small semi-major axes, with Triton's being over an order of magnitude smaller than those of all other known irregular moons. Thirdly, they both have unusual orbital eccentricities: Nereid has one of the