Valve downside blamed for Peregrine lunar lander failure

WASHINGTON — Astrobotic’s Peregrine lunar lander was unable to make it to the moon due to a failure of a single valve, resulting in work to revamp the valve and total propulsion system on the corporate’s bigger Griffin lander.

Astrobotic launched Aug. 27 a report by a failure overview board that examined the Peregrine Mission One flight in January. That mission suffered a propellant leak hours after launch that stored the spacecraft from trying a lunar lander. The spacecraft as a substitute flew by cislunar house for 10 days earlier than reentering over the South Pacific.

The investigation concluded the leak was almost definitely induced when a stress management valve (PCV) malfunctioned, permitting the uncontrolled circulate of helium pressurant into the spacecraft’s oxidizer tank, rupturing it. The valve, designated PCV2, had labored usually in prelaunch testing however failed after launch.

The valve misplaced its capacity to seal as a result of “vibration-induced rest” in threaded parts that induced a mechanical failure within the valve, mentioned John Horack, the Ohio State College professor who chaired the overview board, at a briefing concerning the report.

“In the event you shake it sufficiently, you will get some adjustments within the mechanical configuration that can forestall the valve sealing. It’s just about no completely different than when your sink begins to drip,” he mentioned.

As a part of the investigation, engineers took a spare PCV and put it by shock and vibration environments like that skilled by the valve on the spacecraft. “We then put helium on it and after a average, small, variety of cycles, the valve leaked. You can hear it leak from about 4 ft away,” he mentioned. The report famous the leak charges in these assessments have been much like these noticed on the spacecraft.

The valve leak got here after a number of twists and turns within the improvement of Peregrine’s propulsion system. Astrobotic initially determined in 2019 to outsource the event of the propulsion feed system to a provider, however that firm encountered provide chain issues after the pandemic that led Astrobotic to convey that work in-house in early 2022.

Astrobotic then skilled issues with the unique PCVs on that system, and it determined in August 2022 to change distributors. Whereas the oxidizer valve, PCV2, from that new vendor handed acceptance assessments, an analogous one on a line to pressurize the gasoline tank, PCV1, skilled leaks. Astrobotic repaired PCV1 and located it labored usually. The corporate then put the spacecraft by a collection of environmental assessments, together with vibration and acoustics.

“We nonetheless carried PCV2 as a danger” after these prelaunch assessments, mentioned Sharad Bhaskaran, Peregrine Mission One director at Astrobotic, due to the repairs to PCV1. The corporate elected to not make any preemptive repairs to PCV2 as a result of that valve was not leaking and in addition as a result of its location within the spacecraft was a lot tougher to entry.

“To entry it to do repairs or change it might have required intensive surgical procedure on the spacecraft,” he mentioned, and within the course of invalidate the just-completed environmental assessments. “That, together with the danger of doing a little harm if we had de-integrated and reassembled the spacecraft, led us to the conclusion that it was finest to proceed to the following stage of this system and to not change PCV2.”

Horack mentioned the overview board didn’t fault the corporate for that call. “I can’t see any choices made within the circulate main as much as the launch the place I might have mentioned, ‘Hey, I feel you need to have completed this otherwise,’” he mentioned. “These choices have been fairly sound. I feel the decision-making of the crew was excellent.”

Classes discovered for Griffin

Astrobotic is incorporating technical and different adjustments from Peregrine into its bigger Griffin lunar lander, which is about to launch by the top of 2025. Steve Clarke, vice chairman of landers and spacecraft at Astrobotic, mentioned the corporate is working with the valve vendor, which the corporate declined to call, to revamp the valve.

Griffin’s propulsion system can even have a regulator to manage the circulate of helium used to pressurize the tank in addition to backup latch valves ought to the redesigned PCVs malfunction. “If we did see the identical failure mechanism on the stress management valves, the latch valve would even be a strategy to management the circulate into the oxidizer and gasoline tanks,” he mentioned.

Astrobotic can be incorporating different corrective and preventative actions that stemmed from the Peregrine mission. Peregrine suffered 24 inflight anomalies past the valve downside, eight of which have been deemed “mission important” however have been resolved. Bhaskaran these issues included points with flight software program and steering, navigation and management techniques, in addition to one with NASA’s Deep House Community used for speaking with Peregrine.

“These have been resolved in actual time by the flight management crew,” he mentioned. “All these classes discovered from these have been infused into GM1 as properly.” GM1 is the corporate’s designation for Griffin Mission One.

That mission was to hold NASA’s Volatiles Investigating Polar Exploration Rover (VIPER) to the south polar area of the moon, however NASA introduced in July it was canceling VIPER due to value and schedule overruns even supposing the rover is assembled and going by environmental testing. NASA is retaining the Business Lunar Payload Providers (CLPS) activity order it awarded to Astrobotic for that mission, with plans to switch VIPER with different payloads or ballast.

John Thornton, chief govt of Astrobotic, mentioned within the name that there are a number of smaller payloads on GM1 which can be nonetheless flying, together with a small CubeRover the corporate developed in addition to from NASA, ESA and an undisclosed buyer.

“We’ve had dozens of conversations with of us that need to fly on Griffin. A few of these are extra superior than others,” he mentioned. “Now that we now have the additional payload capability, we’re in conversations with a number of events.”

He and different firm executives mentioned they have been optimistic concerning the prospects for Griffin making a profitable touchdown regardless of the failure of Peregrine to even try a touchdown. Peregrine’s mission allowed the corporate to realize flight heritage on many subsystems that can be used on Griffin. The mission additionally gave firm personnel expertise in working a spacecraft and coping with anomalies.

Thornton added that the CLPS program’s method to working with new lander firms at value factors far lower than conventional authorities missions required a better acceptance of danger. “We’re attempting to do a mission at a value level that has by no means been attainable earlier than, and as such we now have choices on the place to focus and the way rapidly we will get to launch,” he mentioned.

“I feel we received actually, actually shut” with Peregrine, he mentioned. “I’m very assured that Griffin goes to hit the proper steadiness and we’re going to stay that touchdown.”

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