The Cislunar Autonomous Positioning System Operations and Navigation Experiment, or CAPSTONE, is a CubeSat that will fly a single orbit around the Moon destined for NASA’s future Artemis Lunar Gateway. Its six-month mission will help launch a new era of deep space exploration. Credit: NASA Ames Research Center
On Friday, October 7, members of the CAPSTONE team successfully executed an operation to stop the spin of the spacecraft. This removes a major obstacle to returning the spacecraft to normal operations.
After a planned trajectory correction maneuver on September 8, CAPSTONE suffered a problem that put the spacecraft into safe mode. It was soon discovered that the spacecraft was spinning beyond the ability of the onboard reaction wheels to control and counter. According to spacecraft data, the most likely cause was a valve-related problem in one of the spacecraft’s eight thrusters. The partially open valve meant that the faulty propellant generated thrust whenever the propulsion system was pressurized. After extensively reviewing telemetry and simulation data, the mission team performed several tests on the spacecraft in order to formulate a plan to stop the spacecraft from spinning despite this problem.
Recovery orders were executed Friday morning. The maneuver appears to have been successful, based on initial CAPSTONE telemetry and observational data, indicating that the spacecraft has stopped its spin and regained full 3-axis attitude control. This means that CAPSTONE position can be controlled without unplanned rotation. CAPSTONE has now oriented its solar panels towards the Sun to maximize power generation. It has also adjusted the pointing of its antennas to provide a better data connection to Earth.
The risks of this anomaly and recovery process were substantial, and the team worked extensively and collaboratively to mitigate those risks. Over the next few days, the team will continue to monitor the spacecraft’s condition and make necessary adjustments to procedures to account for and mitigate the effects of the partially open thrust valve. In order to reduce the risk of future maneuvers, the mission team will also strive to design possible solutions for this valve-related problem.
CAPSTONE is still on track to enter its near-rectilinear halo orbit around the Moon on November 13.
CAPSTONE, short for Cislunar Autonomous Positioning System Technology Operations and Navigation Experiment, is owned by Advanced Space on behalf of NASA. The spacecraft was designed and built by Terran Orbital. The operations are carried out jointly by Advanced Space and Terran Orbital teams.
Read the full Advanced Space update. Additional updates will be provided as they become available.