A newly launched rescue spacecraft has already encountered trouble, forcing engineers to rethink how they will reach an observatory running out of orbital altitude.

A daring operation to save one of NASA’s key space observatories is facing a series of technical challenges – but there is still a chance to keep both spacecraft in orbit.

The Neil Gehrels Swift Observatory has operated as a multifunctional instrument in low Earth orbit for nearly 22 years, serving as NASA’s first-response alert system whenever the sky erupts with activity from celestial objects.

However, atmospheric drag, intensified by solar activity, is putting pressure on the spacecraft. Without intervention, Swift is expected to reenter the atmosphere this fall after its orbit drops below approximately 300 kilometers (about 185 miles), according to NASA forecasts.

NASA selected Arizona-based Katalyst Space Technologies to design, build, test, and launch – in just nine months – a spacecraft capable of approaching Swift and raising its orbit.

Timeline and mission status

The robotic LINK satellite launched on July 3. It lifted off aboard a Northrop Grumman Pegasus XL rocket launched from a modified Stargazer aircraft.

Everything appeared to be going according to plan until July 25, when LINK began spinning rapidly in space, causing a temporary loss of communications, Katalyst and NASA reported on July 28.

Although LINK’s spin is now partially under control, its rendezvous with Swift has been delayed. Officials say the final arrival time at the observatory remains unknown.

I think one of the hardest things to convey is how amazing it is that we’ve made it to this point. Even if everyone does everything perfectly, there may still be risks ahead that we can’t control. I’m simply deeply grateful that we’re trying to do this at all.

– Shawn Domagal-Goldman

Here is how events unfolded.

On July 3, LINK successfully reached orbit and established contact with the satellite.
The first few weeks after launch were to involve several weeks of testing LINK’s navigation and sensors in space.
Commissioning checks and engine tests were deemed to be proceeding as planned; the satellite deployed its solar panels and began operating its thrusters.
By July 13, LINK was halfway through its activation phase. Two days later, NASA reported that some systems had encountered problems.
The Katalyst team also quickly resolved early communications and attitude-control issues, including a problem with one of the three reaction wheels, NASA said in a July 15 response.
A week later, the team reported that LINK was preparing for its upcoming rendezvous with Swift by increasing the duration of its impulse burns in preparation for several-hour-long maneuvers.
On July 28, LINK had been in a multi-axis spin for three days; NASA reported that two of the three reaction wheels were not fully operational and that the cold-gas propulsion system had suffered a partial loss of functionality. At the same time, the agency confirmed plans to reduce the spin and reassess any plans involving Swift.
Two days later, LINK was expected to reduce its spin rate to 4 degrees per second through a series of engine firings.
On July 31, NASA reported that the team had been able to assess further options for raising the orbit and was considering new, innovative approaches to interacting with Swift.

For now, LINK is showing progress: its spin rate has decreased to approximately 1.47 degrees per second. The team used one of LINK’s electric thrusters to slow the spacecraft, expending less than 100 grams of propellant in order to preserve fuel for future maneuvers and move away from Swift into the required orbit.

The teams are also continuing to assess LINK’s functionality and determine whether potential paths exist for raising the orbit

– NASA

The current plan is to restore accurate attitude data in space by updating LINK’s software and carry out maneuvers that will align the orbits of both spacecraft. Swift’s inspection, previously expected to take place in late July to determine the best capture points, is now anticipated in approximately one month.

Once LINK captures Swift, the observatory will carefully use its three ion engines to return to its original orbit over the course of two to three months.

All of these actions are complex and risky

– Kieran Wilson

How quickly Swift can return to full scientific observations will depend on many factors, but the idea of “saving” the observatory remains a priority: Swift was named for its ability to respond instantly to transient events in the universe – from comets to gravitational waves and black holes. NASA considers preserving Swift worthwhile, even when the cost of fuel and resources is taken into account. And although Swift has currently suspended scientific observations to conserve power, there is a chance of returning the observatory to active operations as early as this fall, depending on LINK’s success.

What happens next depends on how events unfold and on the results of the collaboration between Katalyst and NASA. The mission demonstrates a new approach to space rescue, using autonomous resources and innovative maneuvers that once seemed impossible.