NASA’s CAPSTONE lunar probe has more problems than we thought

Artist's rendering of CAPSTONE.

Artist’s rendering of CAPSTONE.
Image: POT

Controllers with the CAPSTONE mission are trying to regain control of the Moon-bound probe, currently circling, is experiencing temperature problems and is unable to use its solar panels to fully recharge its batteries.

in a to update issued on Monday, Advanced Space described it as a “dynamic operational situation”. The company is managing the project for NASA, in which the 55-pound (25-kilogram) cubesat will test a unique halo orbit around the Moon before a lunar space station. CORNERSTONEshort for Cislunar Autonomous Positioning System Technology Operations and Navigation Experiment, thrown out on June 28 and is in the midst of a four-month trip to the Moon.

the the problem started either during or after the third trajectory correction maneuver (TCM-3) on September 8. An unknown problem caused CAPSTONE to go into a fall, beyond the ability of the probe’s onboard reaction wheels to counteract, according to to NASA

CAPSTONE needs to make seven course corrections to reach its predicted halo orbit around the Moon.  The recent anomaly occurred during or after the third trajectory maneuver on September 8.

CAPSTONE needs to perform seven course corrections to reach its predicted halo orbit around the Moon. The recent anomaly occurred during or after the third trajectory maneuver on September 8.
Graphic: Advanced Space

Multiple course corrections are required to move the probe toward its predicted lunar orbit, known as a near-rectilinear halo orbit (NRHO), which is assumed to CAPSTONE reach November 13. CAPSTONE reached its apogee, its farthest point from Earth, on August 26, at a distance of 951,908 miles (1.53 million km) from our planet.

After the latest course correction, ground stations were unable to receive meaningful communications from CAPSTONE, prompting Advanced Space to declare an operational emergency. When contact was finally restored some 24 hours later, “mission controllers discovered that the spacecraft was spinning, onboard computer systems were periodically reset, and the spacecraft was using more power than it was generating from its solar panels,” NASA explained.

Fortunately, controllers managed to stabilize the spacecraft using NASA’s Deep Space Network, a set of giant radio antennas used to support interplanetary spacecraft missions. “Rapid response enabled by Deep Space Network support and quick thinking by the Terran Orbital team allowed mission operators to quickly reconfigure the spacecraft’s operational status to stabilize the situation while recovery plans could be further evaluated later. background,” according to Advanced space upgrade. A recovery team comprised of experts from NASA, Advanced Space, Terran Orbital (the designer and manufacturer of CAPSTONE), and Stellar Exploration (the propulsion system provider for CAPSTONE) is currently evaluating next steps. Without the Deep Space Network, the team “would have little to no information about the status of the spacecraft,” according to Advanced Space. That said, teams are still hampered by incomplete information.

The good news is that CAPSTONE has been placed in a stable state. It’s still spinning and in safe mode, but now it generates more power than it uses. Currently, the cubesat rotates in such a way that its solar panels are partially illuminated, resulting in weak transmissions from its low-gain antennas. Importantly, the probe successfully completed its third trajectory correction maneuver, meaning it is still on track for its special halo orbit around the Moon.

The recovery team will make a decision on how to move forward in the next few days.. In addition to diagnosing the cause of the abnormality, the team must resolve unspecified temperature issues with various subsystems, including the powertrain. The team is also preparing to disassemble the spacecraft in an effort to regain control over its orientation. There is good reason to believe that this procedure will work, as a similar disassembly operation was performed in July after CAPSTONE separated from the upper stage of the Electron rocket.

Assuming CAPSTONE can be pulled out of its fall, controllers will orient the solar arrays to fully recharge the probe’s batteries, allowing the mission to continue as planned. But as Advanced Space grimly noted: “Many details about the cause of the anomaly remain unknown, and significant risks continue to be analyzed.” CAPSTONE is not out of the woods, but there are reasons for optimism.

CAPSTONE is a precursor mission to the next artemis program, in which NASA seeks a permanent and sustainable return to the lunar environment. To support the Artemis crews, NASA and its international partners are seeking to place a space station, called the Gateway, into the gravitationally stable halo orbit. No probe has ever worked at NHRO, hence the importance of the CAPSTONE exploration mission.

Plus: Blue Origin Booster suffers fiery anomaly during uncrewed suborbital launch.

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