International Space Station program with on-orbit refurbishment in mind. According to the Outer Space Treaty the United States is legally responsible for all modules it has launched. In ISS planning, NASA examined options including returning the station to Earth via shuttle missions (deemed too expensive, as the station(USOS) is not designed for disassembly and this would require at least 27 shuttle missions), natural orbital decay with random reentry similar to Skylab, boosting the station to a higher altitude (which would simply delay reentry) and a controlled targeted de-orbit to a remote ocean area. The technical feasibility of a controlled targeted deorbit into a remote
Space logistics significant focus of space logistics is on "upmass", or payload mass carried up to orbit from Earth, space station operations also have significant downmass requirements. Returning cargo from low-Earth orbit to Earth is known as transporting "downmass", the total logistics payload mass that is returned from space to the surface of the Earth for subsequent use or analysis. Downmass logistics are important aspects of research and manufacturing work that occurs in orbital space facilities. For the International Space Station, there have been periods of time when downmass capability was severely restricted. For example, for approximately ten months from the time