WASHINGTON — With the Peregrine lunar lander mission now complete, astrobotics is turning its attention to understanding what went wrong with the spacecraft and adding any modifications to NASA's largest lander.
The US Space Command confirmed on January 19 that Peregrine had re-entered earlier in the day, but did not provide a specific time or location of the re-entry. Astrobotic targeted re-entry into the South Pacific at approximately 4:00 p.m. ET on January 18.
In a call with reporters, John Thornton, Astrobotic's chief executive, said the company lost telemetry from the spacecraft at 3:50 pm Eastern and lost contact with the spacecraft nine minutes later, which coincides with our scheduled re-entry at 4:04 pm. East.” During the call, he said he was still waiting for confirmation of that reentry from U.S. government agencies, which later came in the form of a Space Command statement.
The United Launch Alliance recaptured the Peregrine mission, which began 10 days earlier, with a successful launch at Vulcan Center. The spacecraft suffered a propellant leak just hours after liftoff, which prevented the spacecraft from attempting to land on the moon. Instead of attempting a maneuver that would have sent it to the Moon as originally planned, the agency chose to re-enter the spacecraft while orbiting the Earth in its highly elliptical orbit.
Thornton said it was a „difficult decision” to allow the peregrine to re-enter. „What we were weighing was, should we send it back to Earth or should we take the risk to operate it in cislunar space?” Running it long enough, depending on the health of its propulsion system and remaining propellant, could either fly the spacecraft or hit the moon or go into orbit around it.
Space security led them to choose Earth impact. „It's important that we all act as responsible parties and ensure that we have a place that is available and accessible to all,” he said. Of particular concern, he later explained, was that continued use of the lander's damaged propulsion system „could have caused a catastrophic situation that could have created more debris.”
The decision was made in consultation with NASA, the mission's largest customer through its Commercial Lunar Payload Services (CLPS) program. „Peregrine Mission One is Astrobotic's mission and Astrobotic's spacecraft, but we, as one of their big customers, shared our vision for the data with them,” said Joel Kearns, deputy associate administrator for exploration in NASA's Science Mission Directorate. NASA gave Astrobotik recommendations on how to proceed with the mission.
Now that the mission is complete, Astrobotic is focusing on investigating what went wrong. The leading hypothesis for the propellant leak is a valve that fails to reset properly in the helium pressure system. „It sent helium to the oxidizing side” of the propulsion system, Thornton said. After more than a minute, the oxygen tank pressure exceeded the tank limit, causing a rupture.
The agency plans to convene a review board to analyze the data to determine what caused the propellant leak. This includes determining what corrective actions are needed for Griffin, the largest lander astrobotic is developing to carry NASA's Volatiles Investigating Polar Exploration Rover (VIPER) to the Moon's South Pole.
Griffin, scheduled to launch in November, continues to investigate the astropodic peregrine. „The effect this will have on Griffin's work will depend on the findings,” Kearns said of the Peregrine investigation. „It's a relatively short window from now in January to the year-end Griffin mission, so we don't want to rush the findings.”
He said NASA will wait to see the results of the review before deciding whether to change the CLPS award to carry VIPER to the Moon. „VIPER is the most visible, most sophisticated and most expensive payload,” he said. „We want to make sure we really understand the root cause and the contributing factors of what happened in Peregrine.”
While Peregrine failed to land on the moon, Thornton revealed what Peregrine was able to accomplish through the work of engineers and air traffic controllers. „Our mission control team in Pittsburgh was cool, they focused on the problem and figured out what happened,” he said, reconfiguring the spacecraft so its solar panels could generate power before its batteries ran out. .
They were able to launch payloads on board, including four NASA instruments, which provided data scientists said would be useful, even if it wasn't collected as originally planned from the lunar surface. „The data collected in flight sets the stage for understanding how some of our instruments might perform in the harsh environment of space when some copies fly on future CLPS flights,” NASA's Associate Administrator for Science Nicola Fox said in a statement.
Thornton said he was proud of the astrobotic team's work on the aborted mission. „We didn't achieve the primary objective of landing on the surface of the Moon,” he said, but after initial hiccups „we had success after success, showing the spacecraft could operate in space, showing payloads could operate. And getting data back from those payloads.”