CAPSTONE team members successfully executed an operation to stop the spacecraft’s spin on Friday, Oct. 7, clearing a major hurdle in returning the spacecraft to normal operations.
Following a planned trajectory correction maneuver on Sept. 8, CAPSTONE suffered an issue that caused the spacecraft to spin beyond the capacity of the onboard reaction wheels to control and counter. Data from the spacecraft suggests the most likely cause was a valve-related issue in one of the spacecraft’s eight thrusters. The partially open valve meant the thruster produced thrust whenever the propulsion system was pressurized. The mission team extensively reviewed telemetry and simulation data and conducted multiple tests on the spacecraft in order to formulate a plan to stop the spacecraft’s spin despite this issue.
Recovery commands were executed Friday morning. Initial telemetry from CAPSTONE and observation data points to a successful maneuver, indicating the spacecraft has stopped its spin and regained full 3-axis attitude control, meaning CAPSTONE’s position is controlled without unplanned rotation. CAPSTONE now has oriented its solar arrays to the Sun and adjusted the pointing of its antennas to provide a better data connection to Earth.
The risks of this anomaly and recovery process were significant, and the team worked extensively and collaboratively to mitigate these risks. Over the coming days, the team will monitor the spacecraft status and make any needed adjustments to procedures in order to account for and mitigate the effects of the partially open thruster valve. The mission team also will work to design possible fixes for this valve-related issue in order to reduce risk for future maneuvers. CAPSTONE remains on track to insert into its targeted near rectilinear halo orbit at the Moon on Nov. 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. Operations are performed jointly by teams at Advanced Space and Terran Orbital.
Read the full update from Advanced Space. Additional updates will be provided, as available.