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
NASA spent Saturn IB upper stage, the station was constructed on Earth and launched on May 14, 1973, atop the first two stages of a Saturn V, into a orbit inclined at 50° to the equator. Damaged during launch by the loss of its thermal protection and one electricity-generating solar panel, it was repaired to functionality by its first crew. It was occupied for a total of 171 days by 3 successive crews in 1973 and 1974. It included a laboratory for studying the effects of microgravity, and a solar observatory. NASA planned to have a Space Shuttle dock with it,