Astrobotic’s Peregrine lunar lander ends mission in fiery reentry

Astrobotic’s Peregrine lunar lander captured by a camera mounted onboard the lander on its second day in space. Image: Astrobotic

The first U.S. lander bound for the Moon since 1972 burned up in Earth’s atmosphere on Thursday. The unfortunate ending for Astrobotic’s spacecraft was deemed the most responsible choice given its hopes of reaching the Moon were dashed less than a day after it launched.

The Peregrine lunar lander is believed to have reentered Earth’s atmosphere on Thursday, Jan. 18, according to Astrobotic. The company has been providing continuous insights into the mission, giving the public the opportunity to see the challenges of spaceflight with ongoing detail.

Astrobotic said any debris from the lander was expected to splash down in the South Pacific Ocean around 4:04 p.m. EST (2104 UTC) around longitude of 176.594 degrees West and a latitude of 23.087 degrees South, which is south of Fiji. The company said it lost telemetry from the spacecraft as expected at 3:50 p.m. EST (2050 UTC).

The reentry marked the end of the mission that launched on Jan. 8 onboard the first flight of United Launch Alliance’s (ULA) Vulcan rocket.

This was the first lander that launched as part of NASA’s Commercial Lunar Payload Services (CLPS) program. The agency paid $108 million to secure spots for five of its payloads among a total of 20 onboard the lander.

What went wrong?

Hours after its launch, the Peregrine lander encountered an issue with its propulsion system. The day after it began its journey, Astrobotic said its preliminary determination was “that a valve between the helium pressurant and the oxidizer failed to reseal after actuation during initialization.”

“This led to a rush of high-pressure helium that spiked the pressure in the oxidizer tank beyond its operating limit and subsequently ruptured the tank,” Astrobotic said in a statement. “While this is a working theory, a full analysis report will be produced by a formal review board made up of industry experts after the mission is complete.”

In a subsequent update, Astrobotic noted that ULA’s Vulcan rocket did its job and “inserted Peregrine into the planned translunar trajectory without issue.”

Prior to launch, Sharad Bhaskaran, the Peregrine Mission One director, said that getting in-space data on the propulsion system was one of the most important parts of this mission.

“As far as pulsing of the engines, I think it’s something that’s been developed before and we’re just implementing it with a different architecture. But ultimately, this is about proving the technology and proving the spacecraft can operate successfully and carry out its mission,” Bhaskaran said in a joint interview with Spaceflight Now and Ars Technica.

“You can do all the testing you want on the ground, and you can do all the simulations, but once you get to space, that’s when everything gets proven.” 

Members of the aerospace industry community, including ULA CEO Tory Bruno, offered their engineering support and insight to Astrobotic to do what they could to mitigate the situation.

Did what we could. Provided our facilities for their anomaly team. Got several engineers out of bed to come back in, include Chris D. our head of Engr, in case we could assist in any way. The Astrobotic team valiantly sorted how to get as much science as possible. https://t.co/U3vJWRwJ7N

— Tory Bruno (@torybruno) January 10, 2024

While the teams were able to stabilize the spacecraft’s orientation and point its solar panels towards the Sun to charge its batteries, Astrobotic said the propellant leak forced the lander’s Attitude Control System (ACS) thrusters to work beyond their intended parameters.

Despite the hurdles, the lander was able to reach lunar distance (about 238,000 miles from Earth) on Jan. 12, a date when the Moon was not at that location. The original plan would’ve seen the lander then make a slingshot around the Earth and synch up with the Moon on the 15th day of the mission.

Late in the mission, once the propellant leak slowed significantly, Astrobotic was able to conduct a 200 millisecond burn, which the company said “indicated Peregrine could have main engine propulsive capability.”

“However, due to the anomaly, the fuel to oxidizer ratio is well outside the normal operating range of the main engines, making long controlled burns impossible,” Astrobotic stated.

But based on the remaining capabilities of the lander, Astrobotic and NASA decided that it was most responsible for the lander to return to Earth where it would break apart upon reentry.

In order to make its way back Peregrine first conducted a series of 23 short burns using the five main engines. That was followed by adjusting the attitude to align it with a South Pacific Ocean splashdown.

Silver linings

While goal of having the first private lander safely reach the Moon wasn’t achieved, Astrobotic was able to gain some valuable data, both for its future landers as well as for its customers.

Less than a day after launch, it was able to send back its first in-space photo, which showed disturbed Multi-Layer Insulation (MLI) in the foreground. Astrobotic said this was a visual clue that backed up data indicating the lander had run into a propulsion system problem.

(1/4) We’ve received the first image from Peregrine in space! The camera utilized is mounted atop a payload deck and shows Multi-Layer Insulation (MLI) in the foreground. pic.twitter.com/dUuu0Idz8K

— Astrobotic (@astrobotic) January 8, 2024

On Jan. 11, NASA said in a blog post that it was able to power on four of its five payloads:

NSS (Neutron Spectrometer System) LETS (Linear Energy Transfer Spectrometer) PITMS (Peregrine Ion Trap Mass Spectrometer) NIRVSS (Near Infrared Volatile Spectrometer System)

The fifth instrument, the Laser Retroreflector Array (LRA) is a passive instrument, so it didn’t have any operations to conduct.

“Measurements and operations of the NASA-provided science instruments on board will provide valuable experience, technical knowledge, and scientific data to future CLPS lunar deliveries,” said Joel Kearns, deputy associate administrator for exploration with NASA’s Science Mission Directorate, in a statement.

NASA added that NSS and LETS were also able to make observations on the radiation between the Earth and the Moon.

“The two instruments are measuring different components of the radiation spectrum, which provide complementary insights into the galactic cosmic ray activity and space weather resulting from solar activity,” NASA said in a statement. “This data helps characterize the interplanetary radiation environment for humans and electronics.”

Other commercial payloads, such as the IRIS rover from Carnegie Mellon University, were also able to send back communications to the their mission control teams on Earth.

Update #13 for Peregrine Mission One: pic.twitter.com/boDu78hmoh

— Astrobotic (@astrobotic) January 12, 2024

NASA and Astrobotic are set to host a teleconference regarding this first CLPS mission on Friday, Jan. 19, at 1 p.m. EST (1800 UTC).