The Orbital Piloted Assembly and Experiment Complex (Russian: Орбитальный Пилотируемый Сборочно-Экспериментальный Комплекс, Orbital'nyj Pilotirujemyj Sborochno-Eksperimental'nyj Kompleks) (ОПСЭК, OPSEK) is a Russian proposed third-generation modular space station in Low Earth orbit. OPSEK would initially consist of modules from the Russian Orbital Segment of the International Space Station (ISS). The proposal would use OPSEK to assemble components of manned interplanetary spacecraft destined for Mars, the Moon, and possibly Saturn. The returning crew would also recover on the station before landing on Earth. This OPSEK could form part of a future network of stations supporting manned exploration of the Solar System.