Re-Entry Seals Peregrine’s Fate

Astrobotic’s Peregrine lunar lander re-entered the Earth’s atmosphere on January 18th, 2024, ending its mission after a 10 day, tumultuous journey through cislunar space. While its launch was fully successful, riding atop the first United Launch Alliance Vulcan rocket, the lander encountered a series of anomalies during its checkout phase which ultimately precluded a lunar landing. The mission came to an end on January 18th when the spacecraft re-entered the Earth’s atmosphere, ensuring safe disposal and minimizing cislunar debris. 

Vulcan launched the Peregrine lunar lander for Astrobotic on January 8th, 2024, flying its first mission as part of NASA’s Commercial Lunar Payload Service program (CLPS). This dynamic mission, sending a lander on a course to the moon, allowed for ULA to demonstrate operations of Vulcan in a variety of different regimes, certifying it for both NASA and Department of Defense missions. CLPS represents a new approach to lunar exploration, leveraging commercial enterprise to provide a wide range of lunar landers.

The launch was a complete success, with the new Centaur V upper stage placing the spacecraft on a trajectory that would see it fly by the Earth once more before intersecting the moon. After spacecraft separation, Peregrine began to activate onboard systems for its several week journey to the Moon. This all took place on schedule; however, the lander encountered an anomaly shortly after establishing a link with the Deep Space Network, preventing the spacecraft from pointing its solar panels correctly. Subsequently, the mission profile changed, as the cause of the anomaly was determined: a leaking valve between the helium pressurant and oxidizer tanks resulted in a dramatic loss of propellant, ultimately precluding the lunar landing scheduled for this mission. 

For the remainder of its mission, Peregrine coasted out to apogee, activating what systems they could during their coast phase. Notably, several payloads for NASA, DLR and the Mexican Space Agency were activated, and some degree of data collection was enabled. On January 13th, the mission teams realized that the leak had altered their trajectory, putting the spacecraft on a course to re-enter the Earth’s atmosphere. According to John Thornton, the CEO of Astrobotic, mission teams consulted with NASA and other government agencies, and made “the painful choice to do nothing” – sending the spacecraft towards its demise. On January 18th, at 3:59 PM, mission teams in Pittsburgh lost ranging with the spacecraft, and at 4:04, telemetry was lost – ending the mission as it broke up in the upper atmosphere. During a press conference on January 19th, Thornton reiterated how proud he was of everyone involved with the mission. Although Peregrine did not achieve its primary objective of landing on the moon, Thornton said the team had “victory after victory” after the anomaly.

Thornton and NASA’s Joel Kearns, Deputy Associate Administrator for Exploration in the Science Mission Directorate, announced that a full anomaly investigation will be underway, both to inform future Peregrine flights as well as Astrobotic’s next mission. Flight 2, the first of Astrobotic’s larger Griffin lander, will carry NASA’s VIPER rover to the lunar surface as part of the Artemis program – a key tool in searching for water ice on the moon. This rover’s data will likely help inform landing sites for the program, an essential element in returning to the moon. Speaking about the review board, Thornton said: “From here, our next steps are very focused on analyzing the anomaly to understand exactly what occurred.” Kearns noted that the results of the anomaly investigation could potentially inform future plans for missions such as VIPER if any risks across the board are identified, stating that VIPER is a very “visible, sophisticated, and costly payload, and there is a need to make sure [we] really understand the root cause here. If plans must be modified, they will be in a timely manner.” 

Astrobotic’s Peregrine Mission One is the first of many lunar landings planned for 2024 as part of NASA’s CLPS program, a new model for landing hardware on the lunar surface. Joel Kearns reiterated the program’s ethos throughout the conference, stating “We will learn from each flight as we go into the future…” Lunar delivery service model is a first, as with anything new, there can be risks. Unforeseen things can occur.” This model of fail fast and fly again quickly is reflected in the manifest of lunar missions, with 6 additional flights planned for the next calendar year. When pressed, Kearns stated that while there would be no direct knowledge sharing between corporations through NASA, as that enters the realm of proprietary data, NASA would do what they could to shepherd industry to ensure successful lunar landings in the future and incorporate lessons learned. 

On the website formerly known as Twitter, Astrobotic posted a fitting tribute – a video of the lander separating from the Centaur V upper stage. The video was captioned: “Peregrine has flown so that Griffin may land,” an emotional tribute to the first American lander of the Commercial Age. In this new age, there will be heartbreak, but with a steely eyed focus, Astrobotic seems ready to confront the challenges and attempt to land on the Moon once more.