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
Orbital station-keeping Global Geoscience WIND satellite—each have annual station-keeping propellant requirements of approximately 1 m/s or less. Earth-Sun —approximately 1.5 million kilometers from Earth in the anti-sun direction—is another important Lagrangian point, and the ESA Herschel space observatory operated there in a Lissajous orbit during 2009–2013, at which time it ran out of coolant for the space telescope. Small station-keeping orbital maneuvers were executed approximately monthly to maintain the spacecraft in the station-keeping orbit. The James Webb Space Telescope needs to use propellant to maintain its halo orbit around the Earth-Sun L2, which provides an upper limit to its designed lifetime: it