Engineers at Katalyst Space Technologies have cut in half the spin of the Link satellite that tumbled out of control last week during its attempt to rescue NASA’s $500 million Swift gamma-ray observatory, and the company still plans to push toward the spacecraft by the end of August.
Link, built and operated by Katalyst under a $30 million NASA contract, launched July 3 on what is the first commercial satellite-servicing mission ever contracted by the space agency. About 200 miles above Earth, the refrigerator-size spacecraft began rotating on multiple axes, lost reliable communications with the ground, and two of its three reaction wheels used for pointing stopped working.
Chief executive Ghonhee Lee said the spacecraft’s fault-protection logic rebooted the satellite after 24 hours without contact, and that power cycle triggered a thermal spike that overheated the electronics controlling the reaction wheels. A separate problem emerged with the cold gas thrusters used for fine attitude control, and engineers have not yet determined whether the emergency stemmed from an internal fault or a collision with space junk.
The ground team, working from a control center near Denver, has used the satellite’s xenon-fueled electric thrusters to counter the rotation. “We’ve been able to use the thrusters to point in the opposite direction of the rotation rate and affect the attitude control that way, which has been highly effective,” Lee told Ars Technica. As of Friday, the spin had dropped from about 9 degrees per second to roughly 4 degrees per second.
Katalyst plans to uplink a new control algorithm that manages orientation using the satellite’s one remaining reaction wheel plus thrusters, and may later try to recover the two inoperable wheels. Once high-bandwidth communications are restored, two onboard cameras will look for signs of damage. The company hopes to move Link toward Swift around the end of August.
Time is short. In a few months, Swift will drop too low for Katalyst to complete the rescue, and atmospheric drag would eventually destroy the aging gamma-ray observatory. NASA gave the startup less than a year to assemble the mission, a sign of how the agency is leaning on commercial servicing to extend the life of its spacecraft.
A successful capture would mark the first time a private company has serviced a NASA satellite in orbit, a milestone with broad implications for satellite servicing, orbital debris management, and the growing commercial space economy. If Link can stabilize and complete the rendezvous, the mission could open the door to routine on-orbit maintenance of government spacecraft, a capability the Pentagon and NASA have long sought.
Sources: Ars Technica, Ars Technica (earlier report), NASA Swift Mission, Katalyst Space Technologies
Author: Technology Desk
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