Peregrine Mission One Review Board Completed
Peregrine Mission One Review Board Completed
Corrective Actions Enacted for Future Missions
Astrobotic’s Peregrine Mission One (PM1) journeyed through space from January 8, 2024, until January 18, 2024. While the launch of the spacecraft was successful, a propulsion anomaly encountered during flight prevented it from making its intended landing on the Moon.
After the propulsion anomaly occurred, the team stabilized the spacecraft and shifted mission priorities to gathering propulsion system data for a mission investigation, providing on-board payloads power and communications to capture science data, and obtaining performance data on the lander’s subsystems to increase technology readiness levels for future missions. The Astrobotic team ultimately operated the spacecraft for 10 days and 14 hours as it traveled to and from cislunar space, and two science teams published scientific papers from the data collected by their payloads.
After its conclusion, the company assembled external experts for an investigation team and review board to analyze the mission. The board was chaired by independent third-party investigator Dr. John Horack, Professor and Neil Armstrong Chair, Ohio State University.
Now, Astrobotic has published a Post-Peregrine Report, which includes information from Peregrine’s review board. The report begins with an overview of the mission, anomaly findings, and a path forward; it ends with a more detailed account of Peregrine’s entire journey, from launch to mission end.
According to the report, after an extensive review of the events before, during, and after Peregrine’s mission, the board concluded that the most likely cause of Peregrine’s anomaly was the failure of a singular helium pressure control valve, called PCV2, within the propulsion system. PCV2 suffered a loss-of-seal capability, most likely due to a mechanical failure caused by vibration-initiated relaxation between threaded components internal to the valve. Spacecraft telemetry data (temperature, roll-rates, and tank pressure data) confirmed both the location and timing of the mission anomaly, which coincided with the position and autonomous sequence to open and close PCV2. All spacecraft data was consistent with a tank rupture and subsequent leak near the top of “Tank 5,” the oxidizer tank located downstream from PCV2.
As a result of this investigation, the board recommended a set of corrective and preventative actions to mitigate risk for future missions. Those include:
The primary PCVs for future landers have been redesigned to address the mechanical sealing flaw that was seen in failure replication testing. Additionally, all future valve designs will also be evaluated and tested at the component level specifically for similar mechanical sealing flaws.
Future lunar landers will utilize multiple, dissimilar PCVs to ensure that no single valve failure can result in a loss of mission.
In addition to the PVC anomaly, the Peregrine spacecraft experienced 24 total in-flight anomalies. Eight of these were mission critical and potentially mission-ending, all of which were resolved in real-time during flight by the company’s Mission Control team. Five non-mission-critical in-flight anomalies were also resolved in real-time. The remaining eleven anomalies were deemed minor and analyzed post-flight with corrective and preventative actions being implemented for future missions.