Mission to rescue space telescope may be in jeopardy

The mission to rescue the Neil Gehrels Swift Observatory from burning up in Earth’s atmosphere using a robotic spacecraft has hit a snag, or more specifically, a multi-axis spin.

According to a new update from NASA, the spacecraft, named LINK, "experienced issues with attitude control, causing the spacecraft to spin and resulting in sporadic communications.”

In other words, the spacecraft was spinning out of control for a time.

Katalyst Space, the company that designed LINK, says a preliminary investigation determined that a power-system problem has disabled two of the spacecraft's three reaction wheels, the devices that control its orientation. NASA also reports "some loss of functionality in [LINK’s] cold gas thruster system.” That system is critical for the actual capture of the telescope as it provides precise maneuvering capability.

Katalyst says it is working to stabilize the spacecraft using LINK's gimbaled electric propulsion thrusters. Once the spin is stopped, the company plans to update the craft's guidance, navigation and control systems to compensate for the degraded configuration.

"We have already begun this series of burns and are seeing the intended effect,” the company said on its website.

NASA reports LINK’s other major subsystems are working as they should.

"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 on its website.

Despite the company’s optimism, the future of the mission is still in question.

NASA says that once the control systems are updated, Katalyst and NASA will jointly evaluate the revised plans to approach and capture Swift. Katalyst and NASA say the capture attempt depends on the safety of the approach and the health of the spacecraft.

LINK launched on July 3 on a Northrop Grumman Pegasus XL rocket from Kwajalein Atoll, Marshall Islands. NASA is hoping that this first-of-its-kind mission can boost the aging telescope, which was in heavy demand until operations were paused, out of its decaying orbit and extend its scientific life.

The clock is ticking for the $30 million mission to be completed. Swift has been sinking faster than expected because of space weather and increased drag on the spacecraft. If Swift drops too low, a rescue attempt won't be possible at all. And without a boost into a more stable orbit, it is expected to reenter and break up by the end of the year.

The Neil Gehrels Swift Observatory is a NASA satellite built to study gamma-ray bursts, the brightest and most powerful explosions in the universe. Swift uses three multiwavelength telescopes that can collect data in visible, ultraviolet, X-ray and gamma-ray light. NASA has used it to study black holes, stars, comets and other celestial objects.

Launched in 2004, the observatory was supposed to last only two years, but it's been operating for more than two decades.