A series of technical issues following a third successful course correction manoeuvre are threatening to sideline NASA’s CAPSTONE mission. Controllers say they’re making progress with the tiny cubesat, but they’re not ready to attempt a recovery operation just yet.
The 55-pound (25-kilogram) satellite ran into difficulties either during or after its third course correction manoeuvre, which it successfully performed on September 8. CAPSTONE remains on its planned course to a Near Rectilinear Halo Orbit (NRHO) around the Moon, but an unknown technical glitch caused it to enter into a tumble. The probe launched on June 28 and is nearing the end of its four-month journey to the Moon.
Controllers are currently working on a plan to detumble the cubesat so that it can properly orient its solar panels and re-charge its batteries. CAPSTONE, short for Cislunar Autonomous Positioning System Technology Operations and Navigation Experiment, is currently operating on low power as a result of the anomaly, but is no longer draining more energy than it is collecting. The probe is also dealing with some worrisome temperature issues. A recovery team consisting of experts from Advanced Space, NASA, Terran Orbital, and Stellar Exploration are currently being hampered by communications issues, though NASA’s Deep Space Network has linked the beleaguered cubesat to controllers on Earth.
There is some good news to report. A spokesperson with Advanced Space told Gizmodo that the communications issue has improved significantly, and that the power state of CAPSTONE “appears to be sufficient” to enable the continuous heating of its propulsion system, “which dropped below its operational temperature.”
CAPSTONE’s power is currently limited as it cannot properly orient its solar panels relative to the Sun. Encouragingly, the spacecraft’s propellant and propulsion system remain in a recoverable state, the spokesperson said. Once the temperature of CAPSTONE’s propulsion system stabilizes to 5 degrees Celsius (41 degrees Fahrenheit) for 12 or more hours, engineers will evaluate the system in preparation of a pending recovery operation. “Information on the cause of the anomaly has been obtained and is being evaluated, and recovery plans that mitigate risk of further anomalous behaviour are being developed,” the spokesperson added.
The recovery team has not reached a decision about when it will attempt to detumble the spacecraft, but a spokesperson said the “team is working hard to make progress guided by what we are learning from the data with an explicit goal to minimise further risk to the mission.” There’s no crazy rush to jump into a recovery procedure, as CAPSTONE’s fourth of seven planned course correction manoeuvres won’t happen until mid-October. The third course correction went as planned, so CAPSTONE is still on its proper trajectory.
The $US30 ($42) million CAPSTONE project is serving as a scouting mission for NASA’s upcoming Artemis program. NASA and its international partners have announced plans to build a lunar space station, called Gateway, in NHRO, but this gravitationally stable orbit has yet to be tested. That’s where CAPSTONE comes in, so fingers are crossed that this important mission can get back on track.