WASHINGTON — A Cubesat launched as a secondary payload on Artemis 1 may cease operations at the end of the month unless it can get its propulsion system up and running.
The LunaH-Map spacecraft was one of 10 CubeSats launched as secondary payloads on the Space Launch System’s inaugural flight last November. The spacecraft had planned to use an ion propulsion system on the 6U cubesat to perform a maneuver while flying past the moon days later, eventually allowing it to go into orbit.
However, that engine failed to fire because engineers believe it was a stuck valve. In a May 1 presentation at the Interplanetary Small Satellite Conference, Craig Hardgrove, principal investigator on the mission at Arizona State University, said the project expected problems given the long delay between the spacecraft’s delivery to NASA in mid-2021 and its November delivery Start 2022.
“We had informed NASA that this propulsion system was not rated for a long launch delay of more than four or five months,” he said, but there was no way to access the CubeSat once the Orion spacecraft connected to the stage adapter was where The CubeSats were assembled in autumn 2021.
The engine, a Busek BIT-3, uses iodine as a propellant, and Hardgrove said engineers expected iodine may have vaporized and got into the valves during the long wait. They tried using heaters to loosen the valve, but these efforts were unsuccessful both before the moon flyby and in the months that followed. “As far as we can tell, this valve is very, very tight.”
Those efforts are ongoing, but he said time is running out to try to get LunaH-Map’s engines working. “If we can’t fire the system, we expect to shut down operations at the end of May.”
In a final attempt to open the valve, the controllers increase the temperature of the entire propulsion system to vaporize more iodine and build up the pressure. “Eventually we could burst through the valve, which could be a good thing or a very bad thing,” he said. “It’s really all we can try at this point.”
The propulsion system is the only spacecraft system that isn’t working, Hardgrove said. “If we didn’t have to wait over a year, I think we would have at least had a chance to complete our entire scientific mission.”
That mission involved entering an orbit that would take the spacecraft close to the lunar south pole, using a neutron spectrometer to map the presence of hydrogen associated with water ice deposits there. He noted that the mission tested the spectrometer at higher altitudes during the November lunar flyby.
LunaH-Map was one of 10 CubeSats launched on Artemis 1, many of which suffered from various technical issues. They ranged from problems with the propulsion system on the LunaH map to spacecraft that were never heard of after deployment by the SLS, or lost contact shortly thereafter.
“On some of these missions on Artemis 1, we had to abort the mission,” said Dan Grebow, a former JPL engineer who now works at mission design and navigation company Nabla Zero Labs, during a panel discussion at the conference.
He gave the example of NEA Scout, a CubeSat that was designed to deploy a solar sail and fly to a near-Earth asteroid, but was never heard of after launch. He said the project gave up after not hearing about it, instead continuing to seek time for the Deep Space Network that could be used by other missions instead. “At some point you have to know when to let go.”
Hardgrove, also on the podium, defended the CubeSat missions flown on Artemis 1. “It’s not fair to characterize any of them as failures,” he said. “They have all developed a significant amount of technology.”
“Many of these missions were very close to success,” he said. “Throwing the whole thing away isn’t fair.”
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