CAPSTONE

CAPSTONE (Cislunar Autonomous Positioning System Technology Operations and Navigation Experiment) is a lunar orbiter that is testing and verifying the calculated orbital stability planned for the now canceled Lunar Gateway space station. The spacecraft is a 12-unit CubeSat that is also testing a navigation system that is measuring its position relative to NASA's Lunar Reconnaissance Orbiter (LRO) without relying on ground stations. It was launched on 28 June 2022, arrived in lunar orbit on 14 November 2022, and was scheduled to orbit for six months. On 18 May 2023, it completed its primary mission to orbit in the near-rectilinear halo orbit for six months, but will stay on this orbit, continuing to perform experiments during an enhanced mission phase.

== Background == The Lunar Gateway was an in-development space station being planned by several national space agencies since at least 2018, including NASA, European Space Agency (ESA) and Canadian Space Agency (CSA). The Gateway was planned to be placed in a novel lunar orbit that had never been used until CAPSTONE, where it was expected to serve as a communications hub, science laboratory, short-term habitation module, and holding area for rovers and other robots. Gateway was slated to play a major role in NASA's Artemis program. These plans were canceled in March 2026, when NASA announced it would cancel plans for the station and instead focus developing a lunar surface base between 2029 and 2036.