This Week, NASA Will Launch a First-of-Its-Kind Mission to Save a Space Telescope That Has Observed the Sky for Nearly 22 Years
In 2024, researchers realized that the Neil Gehrels Swift Observatory was falling from its orbit faster than expected. Now, a robotic spacecraft called LINK aims to give the satellite a boost
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At the end of this week, a rescue mission funded by NASA will launch with an unprecedented goal. Rather than recovering its target and bringing it back to Earth, a robotic spacecraft will attempt to keep a slipping satellite in orbit.
If successful, the longshot mission could mean the difference between keeping the Neil Gehrels Swift Observatory operational, potentially into the 2030s, and seeing it break apart in the atmosphere by the end of this year.
NASA launched the satellite in November 2004 to collect data on gamma rays, X-rays and ultraviolet light emitted by celestial objects like stars, Daniel Clery reports for Science. In the two decades since, the observatory has documented more than 2,000 gamma-ray bursts—intense flashes of high-energy radiation—some of which originated at the fringes of the observable universe. While Swift isn’t the only space telescope that can see faraway objects, the speed at which it collects and transmits data makes it especially valuable to researchers.
“Hubble takes at least one to two days to re-point to a target of interest in the best-case scenario, where Swift can routinely conduct follow-up of things that go bump in the night within minutes,” Brad Cenko, Swift’s principal investigator at NASA’s Goddard Space Flight Center, said during a press conference on June 17. “It really is NASA’s first responder.”
Did you know? Swift’s scientific instruments
The satellite is equipped with three instruments: a gamma-ray burst alert telescope, an X-ray telescope and an ultraviolet/optical light telescope. When the burst alert telescope detects a gamma-ray burst, the spacecraft automatically moves to point its other two telescopes at the source.
The observatory was initially projected to last just two years in orbit, but it exceeded expectations, sticking around for nearly 22, reports Tariq Malik for Space.com. Now, the biggest threat to the craft is its precarious position. Swift’s orbit has fallen from 363 miles above the Earth’s surface to a height of just 225 miles, where it was last Thursday, per Ars Technica’s Stephen Clark.
The culprit is increased solar activity in recent years, which has caused our planet’s atmosphere to expand outward and put extra drag on the satellite. If left alone, NASA fears it could fall out of orbit within months. The agency estimates that it’ll fall below a viable rescue point, roughly 186 miles above the planet’s surface, around October.
In 2024, NASA found that Swift was falling faster than expected. So, the agency came up with an ambitious plan to extend its lifespan, hiring Arizona-based startup Katalyst Space Technologies in September 2025 to build a spacecraft to boost the satellite’s orbit, reports Jamie Carter for Forbes. Seven months later, a refrigerator-size, 937-pound robotic servicing craft dubbed LINK was sent to NASA’s Goddard.
If successful, the mission will mark the first time a research satellite has been robotically seized and raised into higher orbit on this scale. But regardless of the outcome, the speed at which the plan was put into action has already made the mission noteworthy for NASA.
“No one thought it was going to be possible. No one thought we would get as far as we’ve already gotten today,” Shawn Domagal-Goldman, division director for astrophysics at NASA Headquarters, said during the press conference.
LINK is on track to launch aboard Northrop Grumman’s Pegasus XL rocket, which will be deployed from an airplane, from Kwajalein Atoll in the Pacific Ocean on Saturday, June 27. After that, the spacecraft will spend a few weeks in orbit to confirm its functions are working properly before approaching Swift. The craft is decked out with millions of dollars’ worth of sophisticated equipment designed to help it pull off the boost without damaging the observatory, including reaction-control thrusters, robotic arms and rendezvous sensors. The actual process of lifting Swift into a higher orbit is expected to take a few months.
Swift’s scientific operations have been paused since February to keep drag at a minimum, but if the mission pays off, they could resume as early as this fall.
“The whole community is very much rooting for this to work,” Daniel Perley, an astrophysicist at Liverpool John Moores University in England, tells Science. “We are already missing it badly.”
All satellites are subject to orbital decay, and LINK’s outcome could change how boost missions are performed in the future. While the Hubble Space Telescope has previously required crewed missions to reposition it into higher orbit, the latest effort with Swift could open the possibility of more fully robotic missions down the road.
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