CAPSTONE: A Unique CubeSat Platform for a Navigation Demonstration in Cislunar Space

Abstract

As cislunar space is poised for significant increases in mission activity, missions large and small are inherently constrained by the current availability of ground tracking systems. Increasing the complexity of this problem is the ambiguity with which schedule and mission scope can be accurately projected. Many of these missions will be operating in orbital regimes that require frequent tracking and station keeping, which drives the demand for navigation even higher. Advanced Space is aiming to mitigate the existing Earth based tracking and communications resource limitations by enabling spacecraft in the cislunar environment to navigate autonomously and reduce the need for oversubscribed ground assets for navigation and maneuver planning. Launched on June 28th, 2022 the Cislunar Autonomous Positioning System Technology Operations and Navigation Experiment (CAPSTONE) mission is utilizing a highly capable 12U CubeSat to demonstrate the Cislunar Autonomous Positioning System (CAPS) software, as well as validate performance of navigation and stationkeeping for future operations in the Near Rectilinear Halo Orbit (NRHO) that NASA has baselined for the Artemis Lunar Gateway architecture. The CAPS software enables cislunar missions to manage their navigation functions on-board and reduces the reliance on Earth based systems. Thus, this mission will provide tangible flight experience to NASA, commercial, and international missions for operations in a demanding orbital regime alongside a technical demonstration of a navigation capability that will support the establishment of necessary infrastructure for activities at the Moon. The mission will have an approximate four month flight with several maneuvers leading up to the NRHO insertion and then perform its primary mission over the next six months. From the launch deployment state, the spacecraft will traverse a low-energy Ballistic Lunar Transfer (BLT), which is an energy-efficient means of transferring from the LEO environment to an orbit near or about the Moon. The spacecraft will perform up to six Trajectory Correction Maneuvers (TCMs) to clean up launch injection, navigation, and maneuver execution errors prior to arriving at its lunar destination. The spacecraft will then perform a relatively small maneuver to insert into the NRHO. Two small clean-up maneuvers are planned to ensure that the spacecraft is successfully inserted into the NRHO. From there, small stationkeeping maneuvers, known as Orbit Maintenance Maneuvers (OMMs), are performed on a weekly cadence to remain in the NRHO. Upon arrival in the NRHO and settling into its daily operations cadence, the CAPSTONE spacecraft will initiate its navigation demonstration mission in collaboration with the Lunar Reconnaissance Orbiter (LRO) team at NASA’s Goddard Space Flight Center to demonstrate the CAPS autonomous navigation system. Success criteria for CAPSTONE in this demonstration are defined as 1) semi-autonomous operations and orbital maintenance of a spacecraft in an NRHO, 2) collection of inter-spacecraft ranging data in support of the autonomous navigation process, and 3) execution of the CAPS navigation software in an autonomous mode on-board the CAPSTONE spacecraft. Additionally, CAPSTONE will demonstrate an innovative one-way ranging navigation approach utilizing a Chip Scale Atomic Clock (CSAC) and additional autonomous navigation algorithms. Advanced Space, along with our partners at NASA, the Jet Propulsion Lab (JPL), Terran Orbital, Stellar Exploration, and Rocket Lab, have developed and implemented the CAPSTONE mission to support both NASA’s upcoming Gateway operations development and the expanding commercial cislunar economy. This high value mission will demonstrate an efficient low energy orbital transfer and NRHO insertion as well as full-scale operations in this unique orbit. Over the next 21 months, CAPSTONE will validate these key operations and navigation technologies required for the success of NASA’s l