International Space Station program ocean was found to be possible only with Russia's assistance. At the time ISS was launched, the Russian Space Agency had experience from de-orbiting the Salyut 4, 5, 6, and 7 space stations, while NASA's first intentional controlled de-orbit of a satellite (the Compton Gamma Ray Observatory) would not occur for another two years. NASA currently has no spacecraft capable of de-orbiting the ISS at the time of decommissioning. Skylab, the only space station built and launched entirely by the US, decayed from orbit slowly over 5 years, and no attempt was made to de-orbit the station using a deorbital
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