Cubesat launched on Artemis 1 trying to repair the propulsion system

WASHINGTON — A cubesat launched on Artemis 1 missed its initial chance to orbit the moon but could still complete its primary mission if engineers repair its thrusters in the coming weeks.

The NASA-funded LunaH-Map spacecraft, a six-unit cubesat, was one of 10 secondary cubesat payloads flown on the Artemis 1 mission during the Space Launch System’s inaugural launch Nov. 16. These payloads were deployed from the SLS upper stage several hours after liftoff.

In the months leading up to liftoff, there were fears that LunaH-Map’s batteries had run out during its long wait for launch. The cubesat could not be loaded after being attached to the rocket in the fall of 2021.

However, the batteries were in good condition when the spacecraft transmitted its first telemetry shortly after deployment. “Our batteries were at 70 percent state of charge,” said Craig Hardgrove, principal investigator for LunaH-Map at Arizona State University, during a presentation on the mission at the fall meeting of the American Geophysical Union on December 15. “It was in line with our very optimistic forecasts.

While the spacecraft had sufficient power, it encountered problems with its propulsion system. “We had a very short window to trigger our propulsion system and hit a lunar gravity assist to get back to the moon,” he said. However, the thrusters did not work as expected to allow this maneuver to pass into lunar orbit.

LunaH-Map is equipped with Busek’s BIT-3 ion thruster which uses solid iodine. Hardgrove said Doppler telemetry data suggests a valve is partially blocked, letting in some iodine but not enough to generate the required thrust.

Spacecraft engineers attempt to correct the problem with radiators in the propulsion system to release the valve. “The blockage is something we knew about,” he said, suggesting it came from the long wait for the launch.

If the issue can be resolved by mid-January, he said the spacecraft could take an alternate trajectory to the moon, arriving in January 2024. After that, there are options to send LunaH-Map to the rendezvous. you or fly over a near-Earth asteroid. .

Other spacecraft systems work well, he said. The spacecraft’s main instrument, a neutron spectrometer designed to search for water ice deposits at the lunar south pole, collected data as it flew by the moon five days after launch. “It shows that this instrument is capable of performing the scientific investigation that we planned to do,” Hardgrove said.

LunaH-Map is not the only cubesat launched on Artemis 1 that suffered technical problems. A Japanese cubesat called OMOTENASHI, designed to make a “semi-hard” landing on the Moon, failed to generate enough power from its solar panels to communicate with Earth and was declared lost.

Controllers had trouble contacting the CubeSat to Study Solar Particles (CuSP), which also appeared to be having a battery issue, and Near Earth Asteroid Scout, a cubesat with a solar sail to fly past an asteroid. Lockheed Martin’s LunIR cubesat encountered an “unexpected problem with our radio signal,” the company said Dec. 8, but still viewed the mission as a useful technology demonstration.

Hardgrove, in his conference keynote, remained optimistic about LunaH-Map. “We are not dead. We are doing very well,” he said. “I think we’ll be turning on our propulsion system soon.”

Leave a Reply

Your email address will not be published. Required fields are marked *