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The CAPSTONE spacecraft successfully completed a trajectory correction maneuver on Thursday, Oct. 27, teeing up the spacecraft’s arrival to lunar orbit on Nov. 13.

CAPSTONE is no longer in safe mode following an issue in early September that caused the spacecraft to spin. The team identified the most likely cause as a valve-related issue in one of the spacecraft’s eight thrusters. The mission team will design future maneuvers to work around the affected valve, including the two remaining trajectory correction maneuvers scheduled before CAPSTONE’s arrival to orbit at the Moon.

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.

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.

Over the past week, the CAPSTONE spacecraft was able to improve thermal conditions for the propellant and other critical systems while maintaining positive power generation. The operations team has been performing ground and spacecraft testing in preparation for an attempt to stop CAPSTONE’s spin. This operation would return the spacecraft to normal status and will be attempted when preparations and testing are complete.

Updates will be provided as available.

The CAPSTONE team continues work on recovery efforts. The primary ongoing focus now is to heat the spacecraft’s propulsion system, which dropped below its operational temperature limit following the initial issue that put the spacecraft into safe mode on Sept. 8. Over the past few days, CAPSTONE’s power – though limited by the orientation of the spacecraft in its spin relative to the Sun – appears to be sufficient for heating of the propulsion system. Once the spacecraft propulsion system temperature has been at 41° F (5° C) for at least 12 hours, the team will further evaluate the system for use in the recovery operation. Communications with the spacecraft have also improved, providing mission teams with more data from the spacecraft. Teams are evaluating the data to determine the cause of the issue and design recovery procedures to avoid similar problems during the attempted recovery operation.    

Read the full update from Advanced Space, which owns CAPSTONE on behalf of NASA. Additional updates will be provided as available. 

Following the Sept. 10 update on CAPSTONE, mission owner and operator Advanced Space has provided an update on the mission. Read the full update from Advanced Space.

During or shortly after a planned trajectory correction maneuver on Sept. 8, CAPSTONE suffered an issue that caused the spacecraft to tumble beyond the capacity of the onboard reaction wheels to control and counter. CAPSTONE was attempting to communicate with the ground for approximately 24 hours before any telemetry was recovered. After data was received, mission controllers found that the spacecraft was tumbling, the onboard computer systems were periodically resetting, and the spacecraft was using more power than it was generating from its solar panels.

Using NASA’s Deep Space Network, the combined mission team – including Advanced Space, Terran Orbital, Stellar Exploration, and NASA – re-established contact with CAPSTONE and reconfigured the spacecraft’s systems to stabilize the situation while recovery plans are evaluated. CAPSTONE remains in safe mode and now is power positive, meaning that it is generating more power from the solar panels than the system is using. Navigation data collected after the issue began suggests the Sept. 8 trajectory correction maneuver was completed or nearly complete when the issue occurred. This means the spacecraft remains on the intended trajectory and on course to its near rectilinear halo orbit at the Moon.

While work is ongoing to diagnose the cause of the issue, the team is preparing CAPSTONE to attempt a detumble operation to regain attitude control of the spacecraft.  This detumble operation was successfully demonstrated after separation from the launch upper stage in July. A successful detumble would give CAPSTONE control over its orientation, allowing it to orient the solar panels to the Sun to fully charge the batteries of the power used during the detumble. The spacecraft would then orient to the ground and await further instructions. These recovery operations will be further evaluated over the coming days. Recovery timing will be guided by the data and analysis available to maximize the probability of a successful spacecraft operation.

Updates will be provided as available.

The CAPSTONE spacecraft executed a planned trajectory correction maneuver on Thursday evening, Sept. 8, and CAPSTONE mission controllers have since obtained telemetry confirming that an issue put the spacecraft in safe mode near the end of the maneuver. The CAPSTONE mission team has good knowledge of the state and status of the spacecraft. The mission operations team is in contact with the spacecraft and working towards a solution with support from the Deep Space Network. Additional updates will be provided as available.

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.