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On January 8, 2024 the Astrobotic Mission One for the Peregrine spacecraft flawlessly launched atop a United Launch Alliance new Vulcan rocket but unfortunately shortly after launch and after the spacecraft reported in without any issues, an anomaly occurred which doomed the mission. The root cause has now been identified.
Today Astrobotic released the 21 page Peregrine: Mission 1 Post-Mission Report. In releasing the report Astrobotic said, “In the spirit of increasing the likelihood of future mission success for all, Astrobotic is publishing this post-mission report. 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.”
The accident investigation was led by Dr. John Horack, Professor and Neil Armstrong Chair, Ohio State University. Dr. Horack was appointed chair of the accident investigation board and acted as a independent third-party investigator. The board included 34 people including “government, industry, and in-house multidisciplinary subject matter experts.”
The Root Cause
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.”
By way of background, and outlined in the summary, the report outlines the sequence of events that occurred after liftoff when the Perigrine propulsion system was commissioned.
The launch occurred on “January 8, 2024, at 2:18 am ET with the goal of landing on the Moon. At 3:16 am ET, the Peregrine spacecraft successfully activated its avionics and power management system, established communications with Astrobotic’s Mission Control Center via NASA’s Deep Space Network, and commenced spacecraft commissioning and operations.”
“During this commissioning phase, Peregrine’s propulsion system was activated. This involved pressurizing the fuel and oxidizer tanks with helium from the pressurant tank by opening two Pressure Control Valves (PCVs), PCV1 and PCV2. Upon actuating (opening and closing) PCV2, helium began to flow uncontrollably into the oxidizer tank, causing a significant and rapid over pressurization of the tank. The tank then ruptured and subsequently leaked oxidizer for the remainder of the mission.”
“This anomaly inhibited the propulsion system from pressurizing to the levels needed for Peregrine to land on the Moon.”
Astrobotic also stated in the report that they replicated the failure in ground testing. “To confirm the mechanical failure mode of PCV2, the Astrobotic team replicated the suspected failure mode in ground testing by subjecting a spare flight PCV to similar conditions seen during the mission. In this testing, Astrobotic subjected the valve to qualification-level shock and vibe, pressurized cycling, and a final seat force and then measured the internal leak rate. After cycling under pressurization, the spare PCV began leaking at a rate that was roughly equivalent to that observed during PM1 in-space operations. Subsequent disassembly of the valve showed that a threaded joint in the valve was loosened, and that the primary seating O-ring in the valve had been damaged along the sealing surface.”
“The review board believes this to be a replication of the failure that occurred on Peregrine. The review board’s findings were reported to the NASA Commercial Lunar Payload Services initiative as well as the NASA Science Mission Directorate leadership.”
Addressing the Issue for Future Missions
Astrobotic outlined six forward actions for future spacecraft missions:
- 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.
- Astrobotic personnel have been embedded at key supplier facilities to manage schedule compliance, quality standards, and technical performance. Additional oversight has been implemented at key suppliers to ensure a greater level of accountability and control.
- In addition to the valve 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.
- Additional quality management personnel have been brought onboard to further enhance Astrobotic’s mission assurance. While this is still a commercially minded program, Astrobotic is augmenting quality management to focus deeply on key subsystem deliveries such as propulsion components.
- Astrobotic strategically reinforced its workforce by enlisting two industry experts with proven track records to strengthen future mission assurance:
- Steve Clarke, former Deputy Associate Administrator for Exploration in NASA’s Science Mission Directorate, is now Astrobotic’s Vice President of Landers & Spacecraft and with 40 years of expertise in executive leadership, systems engineering, program management, and operations
- Frank Peri, former Director for the Safety and Mission Assurance Office at NASA Langley Research Center, is now Astrobotic’s Director of Engineering with a focus on safety and mission assurance. He brings 35 years of executive leadership, most recently leading the institutional safety and mission assurance program.
The Next Mission – Griffin Mission One
The next mission for Astrobotic is the Griffin Mission One (GM1) which is also part of NASA’s Commercial Lunar Payload Services (CLPS) program.
That mission includes a collaboration with the Canadian Space Agency and Mission Control. As we reported earlier this year from the Space Symposium in Colorado Springs, Mission Control’s Spacefarer™ will be a payload on Astrobotic’s CubeRover.
At a news conference at the Space Symposium Ewan Reid, Founder and CEO of Mission Control described the Spacefarer™ operations platform as follows, “Spacefarer is our platform that allows partners and customers mission controllers to operate and engage with space based robotics and advanced payloads. It allows developers to streamline and reduce the development time and to increase the efficiency of missions and ultimately maximize the potential for scientific and commercial return for missions.”
Other payloads on the GM1 mission include the European Space Agency’s LandCam-X, and a NASA laser retroreflector array (LRA). GM1 is scheduled for launch in late 2025 on SpaceX Falcon Heavy and is meant to land at the lunar south pole.
Peregrine: Mission 1 Post-Mission Report
Download the Peregrine: Mission 1 Post-Mission Report below or read it online.
