Astrobotic’s Peregrine lunar lander failed to succeed in the moon due to an issue with a single valve within the propulsion system, in line with a report on the mission launched Tuesday. Firm management mentioned in a press convention that engineers have redesigned the valve and launched further redundancy into the propulsion system of its subsequent lander, Griffin, to make sure the issue doesn’t reoccur.
The report comes from a assessment board assembled shortly after the Peregrine mission concluded in January. That mission encountered hassle simply hours after launch on January 8, when engineers activated the spacecraft’s propulsion system for the primary time on orbit.
At that time, the gasoline and oxidizer tanks ought to’ve been pressurized with helium, upon the opening of two stress management valves, or PCVs. However helium started to stream “uncontrollably” by means of the second valve into the oxidizer tank, Astrobotic CEO John Thornton defined through the press convention.
“That brought about a big and fast over-pressurization of the tank,” he mentioned. “Sadly, the tank then ruptured and subsequently leaked oxidizer for the rest of the mission.”
That PCV was unable to reseal, possible on account of a mechanical failure attributable to “vibration-induced leisure” between some threaded parts contained in the valve, the assessment board’s chair John Horack mentioned. Telemetry information was capable of pinpoint the situation and timing of the anomaly, and this information was according to the autonomous sequence to open and shut the PCV, and the place of the valve on the propulsion system. Engineers had been additionally capable of replicate the failure in floor testing.
Whereas the oxidizer leak continued, Astrobotic’s group was capable of stabilize the spacecraft, cost its batteries, and energy its payloads. However the situation was finally deadly to the mission, and after 10.5 days, the spacecraft returned to Earth and burned up within the ambiance.
The 34-person assessment board included 26 individuals inside to the corporate and eight from exterior. The board reviewed not simply the information collected through the mission, but in addition all the information from the flight qualification marketing campaign and part testing. Ultimately, it decided that the possible reason behind the malfunction was the failure of that single helium PCV within the propulsion system.
The board additionally compiled a timeline of occasions that led to the failure, and it begins all the way in which again in 2019, when Astrobotic contracted an unnamed vendor for the event of the propulsion feed system. When that vendor began struggling technical and provide chain points as a result of COVID-19 pandemic, Astrobotic made the choice in early 2022 to terminate their contract and end the partly assembled feed system in-house.
“By this time, we’d already made the choice to do Griffin’s propulsion system in-house, to do extra vertical integration,” Astrobotic’s mission director Sharad Bhaskaran mentioned. “We’d already developed a whole lot of the capabilities to do this propulsion integration. … This additionally burned down a few of the danger going into the Griffin program, which is way extra complicated than Peregrine.”
However Astrobotic engineers began encountering points with the unique vendor’s propulsion parts — specifically the PCVs. In August 2022, they switched to a unique, unnamed PCV provider, and people valves had been put in on the lander.
A last set of assessments on the propulsion system confirmed leaks in one of many two PCVs — however not the one which finally leaked on orbit. That one examined superb; the one which leaked was repaired. Whereas Bhaskaran acknowledged that the second PCV was recognized “as a danger in our danger register” as a result of leak with the primary throughout testing, engineers finally deemed that the failure was low as a result of the lander handed last acceptance testing.
He justified not changing the second PCV, saying it was situated a lot farther into the spacecraft and would have required “intensive surgical procedure” on the lander, invalidated the ultimate testing, and carried further danger that comes with disassembly and reassembly.
Horack echoed that the group’s decision-making was sound all through: “I actually discovered that, in trying on the group and taking a look at what occurred … I can’t see any choices that had been made within the stream main as much as the launch the place I’d have mentioned, ‘Hey, I feel it’s best to have executed this otherwise.’”
These findings have already began to tell the event of the a lot bigger Griffin lander, which is at the moment scheduled to launch to the moon earlier than the top of 2025. Along with redesigning the valve, engineers have launched a regulator within the propulsion system to manage the stream of helium to the gasoline and oxidizer tanks, and backup latch valves as added redundancy in case the problem reoccurs with a PCV.
