Illustration of the Cislunar Autonomous Positioning System Technology Operations and Navigation Experiment (CAPSTONE) spacecraft facing the Sun. This lunar orbiter will be the first CubeSat (a low cost miniature satellite) to fly in cislunar space, the orbital space near and around the Moon. In its nine month mission expected to launch in May 2022, CAPSTONE will test a navigation system that will measure its distance to the Lunar Reconnaissance Orbiter (LRO) without using ground stations.