NASA's tiny CAPSTONE moon probe has finally stopped tumbling in space

spacecraft with the moon in behind
CAPSTONE is back on track for a lunar arrival in November, NASA said, after engineers addressed a spinning issue in deep space. (Image credit: NASA/ Daniel Rutter)

NASA's moon-bound CAPSTONE probe is coming under control.

The microwave oven-sized CAPSTONE, which has been in safe mode for a month since an engine burn Sept. 8, finally stopped tumbling in cislunar space following a command from ground control.

The command executed Friday (Oct. 7) resulted in "clearing a major hurdle in returning the spacecraft to normal operations," NASA wrote in an update (opens in new tab) to its Artemis blog. (CAPSTONE is a pathfinder for the planned NASA Gateway space station's orbit, which will support moon operations under the Artemis program.)

The 55-pound (25 kilogram) spacecraft initially entered trouble following "a valve-related issue in one of the spacecraft's eight thrusters," NASA added, noting one of those thrusters was partially open and causing a spin. The team is now moving further ahead on their recovery plan before the cubesat's expected arrival at the moon on Nov. 13.

Related: Why it'll take NASA's tiny CAPSTONE probe so long to reach the moon 

After reviewing CAPSTONE's telemetry and other observational information, NASA and the Colorado company Advanced Space (which operates the spacecraft on behalf of the agency) said engineers now have command of yaw, pitch and roll (the three axes of a craft's orientation) to control the cubesat's position in space.

"CAPSTONE now has oriented its solar arrays to the sun and adjusted the pointing of its antennas to provide a better data connection to Earth," NASA said, which presumably will allow further commands to stabilize the spacecraft even further.

The agency hedged its success bets, however, noting the risks of this procedure alone were "significant" and that more tweaks might be needed to stop the partially open thruster valve from interfering again with CAPSTONE's position in space.

Nevertheless, the spacecraft "remains on track" to occupy and characterize a lunar near rectilinear halo orbit (NRHO), NASA emphasized, to test its stability ahead of Gateway's arrival in a few years. 

Capstone will verify the stability of a lunar orbit as a pathfinder for NASA's Gateway space station. (Image credit: Illustration by NASA/Daniel Rutter)

Advanced Space did several spacecraft tests and ground simulations ahead of attempting the recovery, the company said in its own CAPSTONE update (opens in new tab) on Friday. The company added it is committed to helping the spacecraft along for "upcoming critical events" and to troubleshoot the valve closure "to further reduce the risk of future propulsive operations."

"The CAPSTONE mission team is grateful for the public and private support provided to the team during this challenging phase of the mission." added Advanced Space.

CAPSTONE, short for Cislunar Autonomous Positioning System Technology Operations and Navigation Experiment, launched atop a Rocket Lab Electron booster on June 28 and has already overcome another major glitch. 

On July 4, the spacecraft went dark shortly after separation from Rocket Lab's Photon spacecraft bus. An improperly formatted command caused the issue and engineers addressed it successfully the next day.

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Elizabeth Howell
Staff Writer, Spaceflight

Elizabeth Howell, Ph.D., is a staff writer in the spaceflight channel since 2022. She was contributing writer for Space.com (opens in new tab) for 10 years before that, since 2012. Elizabeth's reporting includes an exclusive with Office of the Vice-President of the United States, speaking several times with the International Space Station, witnessing five human spaceflight launches on two continents, working inside a spacesuit, and participating in a simulated Mars mission. Her latest book, "Why Am I Taller?", is co-written with astronaut Dave Williams. Elizabeth holds a Ph.D. and M.Sc. in Space Studies from the University of North Dakota, a Bachelor of Journalism from Canada's Carleton University and (soon) a Bachelor of History from Athabasca University. Elizabeth is also a post-secondary instructor in communications and science since 2015. Elizabeth first got interested in space after watching the movie Apollo 13 in 1996, and still wants to be an astronaut someday. Mastodon: https://qoto.org/@howellspace