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
Assembly of the International Space Station combinations. The last two Shuttle flights added one of the two final elements of ISS, followed by a Proton launch to deliver the European Robotic Arm in 2019. Other assembly flights consisted of modules lifted by the Russian Proton rocket or in the case of Pirs and Poisk by a Soyuz-U rocket. Some of the larger modules include: The space station is located in orbit around the Earth at an altitude of approximately , a type of orbit usually termed low Earth orbit (the actual height varies over time by several kilometers due to atmospheric drag and reboosts). It orbits