Astrobotic’s Peregrine lunar lander completes its fiery return mission – Spaceflight Now

Astrobotic’s Peregrine lunar lander completes its fiery return mission – Spaceflight Now

Astrobotic’s Peregrine lunar lander was captured by an onboard camera on its second day in space. Image: Astrobotic

The first American lunar lander since 1972 burned up in Earth’s atmosphere on Thursday. The Astrobotic spacecraft’s unfortunate end was considered the most responsible choice since its hopes of reaching the Moon were dashed less than a day after launch.

The Peregrine lunar lander is believed to have re-entered Earth’s atmosphere on Thursday, January 18, according to Astrobotic. The company provides ongoing insights into the mission, giving the public the opportunity to see the challenges of spaceflight in ongoing detail.

Any debris from the lander is expected to fall into the South Pacific Ocean around 4:04 p.m. EDT (2104 UTC) around longitude 176.594 degrees west and latitude 23.087 degrees south, south of Fiji, Astrobotic said. The company said it lost telemetry from the spacecraft as expected at 3:50 PM EDT (2050 UTC).

The re-entry marked the end of the mission, which blasted off on January 8 aboard the maiden flight of United Launch Alliance’s (ULA) Vulcan rocket.

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

What happened?

Hours after launch, the Peregrine lander experienced a problem with its propulsion system. The day after its flight began, Astrobotic said its initial determination was that “the valve between the helium compressor and the oxidizer failed to reclose after powering on during initialization.”

“This resulted in a high-pressure helium surge that caused the pressure in the oxidizer tank to rise beyond its operating limit, thus rupturing the tank,” Astrobotic said in a statement. “While this is a working theory, a full analytical report will be issued by a formal review board made up of industry experts after the mission is completed.”

In a later update, Astrobotic noted that ULA’s Vulcan rocket had done its job and “entered Peregrine on the planned path across the moon without issue.”

Before the launch, Sharad Bhaskaran, director of Peregrine Mission One, said obtaining data from space about the propulsion system was one of the most important parts of this mission.

“In terms of the thrusters, I think it’s been developed before and we’re implementing it with a different architecture. But in the end, it’s about proving the technology and proving that the spacecraft can operate successfully and execute its mission,” Bhaskaran said in a joint interview with Spaceflight Now and Ars Technica.

“You can do all the tests you want on Earth, you can do all the simulations, but once you get to space, that’s when everything is proven.”

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

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

Despite the obstacles, the lander was able to reach lunar distance (about 238,000 miles from Earth) on January 12, a date when the Moon was not in that location. The original plan was for the probe to slingshot around Earth and coincide with the Moon on the 15th day of the mission.

Late in the mission, once the propellant leak had slowed significantly, Astrobotic was able to perform a 200-millisecond burn, which the company said “suggested that Peregrine could have the main thrust of the engine.”

“However, because of this anomaly, the fuel-to-oxidizer ratio is outside the normal operating range of the main engines, making prolonged controlled burns impossible,” Astrobotic said.

But based on the lander’s remaining capabilities, Astrobotic and NASA decided that the greater responsibility was to return the lander to Earth, where it would disintegrate upon its return.

In order to return, Peregrine first conducted a series of 23 short burns using the five main engines. This was followed by an adjustment of the position to bring it into line with the South Pacific subsidence.

Silver lines

Although the goal of the first private lander to safely reach the Moon was not achieved, Astrobotic was able to obtain some valuable data, both for future landers and for its customers.

Less than a day after launch, it was able to send its first image into space, which showed a turbulent multi-layer insulation (MLI) in the foreground. Astrobotic said this was visual evidence that supported data that the lander had encountered a problem with its propulsion system.

On January 11, NASA said in a blog post that it had managed to get four of its five payloads operational:

  • 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 Reflector Array (LRA), is a passive instrument, so it did not have any operations to perform.

“NASA’s onboard science instrument measurements and operations will provide valuable experience, technical knowledge and science data for future CLPS lunar deliveries,” Joel Kearns, deputy associate administrator for exploration in NASA’s Science Mission Directorate, said in a statement.

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

“The two instruments measure different components of the radiation spectrum, providing complementary insights into galactic cosmic ray activity and space weather resulting from solar activity,” NASA said in a statement. “These data help describe the interplanetary radiation environment for humans and electronics.”

Other commercial payloads, such as Carnegie Mellon University’s IRIS rover, have also been able to send communications to their mission control teams on the ground.

NASA and Astrobotic are scheduled to host a conference call regarding the first CLPS mission on Friday, January 19 at 1 p.m. EDT (1800 UTC).

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