monthly to maintain the spacecraft in the station-keeping orbit. The James Webb Space Telescope will use propellant to maintain its halo orbit around the Earth-Sun L2, which provides an upper limit to its designed lifetime: it is being designed to carry enough for ten years. However, the precision of trajectory following launch by an Ariane 5 is credited with potentially doubling the lifetime of the telescope by leaving more hydrazine propellant on-board than expected. The CAPSTONE orbiter and the planned Lunar Gateway will be stationed along a Near Rectilinear Halo Orbit (NRHO) around the Earth-Moon L2 Lagrange point. See also Delta-v budget Orbital perturbation analysis Reboost Teleoperator Retrieval System (robotic device for attaching to another spacecraft and boosting or changing its orbit) References External links Station-keeping at the Encyclopedia of Astrobiology, Astronomy, and Spaceflight XIPS Xenon Ion Propulsion Systems Jules Verne boosts ISS orbit Jules Verne boosts ISS orbit (report from the European Space Agency) Orbital maneuvers Astrodynamics Earth orbits