Spaceflight Insider

CAPSTONE spacecraft regains attitude control

An illustration of NASA's CAPSTONE mission orbiting near the Moon. Credit: NASA

An illustration of NASA’s CAPSTONE mission orbiting near the Moon. Credit: NASA

Following a month troubleshooting a spin anomaly, NASA’s CAPSTONE spacecraft has been returned to normal operations as it continues toward the Moon.

CAPSTONE is short for “Cislunar Autonomous Positioning System Technology Operations and Navigation Experiment.” This microwave oven-sized spacecraft designed to verify an orbit planned for NASA’s much larger Lunar Gateway, a small space station that is expected to host Artemis program astronauts during Moon missions.

It launched June 28 and was placed into a three-month-long ballistic lunar transfer orbit.

On Sept. 8, after a planned trajectory correction maneuver, NASA’s CAPSTONE spacecraft suffered an anomaly that sent the CubeSat tumbling. The attitude became so erroneous that the onboard navigation system was not able to properly “right” the spacecraft.

The satellite then went into “safe mode,” essentially shutting down communications between the ground and the spacecraft.

Flight controllers would spend the next three weeks troubleshooting and problem solving in an attempt to save the tumbling craft as it continues its trajectory toward its targeted near-rectilinear halo orbit around the Moon.

On Oct. 7, it was announced that the recovery efforts appeared to be successful.

Operators were able to identify the cause of the anomaly as being a partially opened valve on one of the spacecraft’s eight thruster systems.

As the spacecraft’s fuel would pressurize, this would cause a leak in that particular thruster. The equal and opposite reaction from the unwanted propellant leak caused the spacecraft to tumble out of control.

The team on the ground was able to not only identify the cause of this problem, but also upload troubleshooting commands to the spacecraft’s onboard navigation system.

CAPSTONE has since been returned to its nominal attitude with the solar panels facing the sun, and its array of downlink antennae facing Earth.

Over the following weeks, teams will continue to monitor the spacecraft’s progress as it makes its way toward the moon.

CAPSTONE is scheduled to enter lunar orbit on Nov. 13.

The mission has been no stranger to anomalies, having experienced a significant communication issue and “going dark” just days after it was launched into space. Luckily, teams were able to correct the issue caused by an improperly formatted communication command.

Video courtesy of NASA


Having a life-long interest in crewed space flight, Desforges’ passion materialized on a family vacation in 1999 when he was able see the launch of Space Shuttle Discovery on STS-96. Since then, Desforges has been an enthusiast of space exploration efforts. He lived in Orlando, Florida for a year, during which time he had the opportunity to witness the flights of the historic CRS-4 and EFT-1 missions in person at Cape Canaveral. He earned his Private Pilot Certificate in 2017, holds a degree in Aviation Management, and currently works as an Operations Analyst in the aviation industry in Georgia.

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