NASA and Katalyst Space address attitude-control problems on Swift rescue mission

NASA said the robotic spacecraft LINK, launched to retrieve the Neil Gehrels Swift Observatory, experienced a multi-axis spin caused by a power-system fault that disabled two of its three reaction wheels and reduced performance of its cold-gas thruster system. The loss of reaction-wheel control led to sporadic communications and a temporary loss of precise orientation.

Katalyst Space, which built LINK, identified the problem and is using the vehicle’s gimbaled electric propulsion thrusters to halt the spin. The company reported that a series of burns has begun and is producing the intended effect. It added that once the spin is stopped, the guidance, navigation and control software will be updated to compensate for the degraded hardware configuration.

"While these technical issues require a revised approach, our team is working around the clock alongside our NASA partners. The mission remains active and we continue to believe that with these changes, LINK has a viable path to rendezvous with Swift," Katalyst said.

NASA confirmed that the spacecraft’s other major subsystems remain functional and that after the control-system updates, the agency and Katalyst will jointly evaluate a new plan for approaching and capturing Swift. The success of the rescue depends on the safety of the approach and the health of both vehicles.

The $30 million mission aims to boost Swift, launched in 2004 and originally designed for a two-year lifespan, into a higher, more stable orbit before atmospheric drag forces cause re-entry, which is projected by year-end if the rescue is not completed.