The Neil Gehrels Swift Observatory has spent nearly 22 years detecting gamma-ray bursts, X-ray transients, and ultraviolet afterglows from low Earth orbit. It’s one of the most productive space telescopes ever launched — over 1,600 gamma-ray bursts catalogued, thousands of follow-up observations forwarded to ground-based telescopes within seconds. And it’s falling.
No later than Tuesday, a refrigerator-sized spacecraft built by a startup in nine months will ride the last Pegasus XL rocket ever launched in an attempt to grab Swift, lock onto its structure with three robotic arms, and push it back up. If it works, it’ll be the first time anyone has docked with a satellite that was never designed for servicing.
Why Swift is falling
Swift launched on November 20, 2004 into a 585 km circular orbit. It carries no propulsion — the mission planners expected the orbit would last decades without intervention. For most of its life, it did.
Then solar cycle 25 arrived. The Sun’s magnetic activity peaked with unusual intensity around 2024, driving powerful coronal mass ejections and sustained high UV output that heated Earth’s upper atmosphere. The thermosphere expanded, and satellites in low orbits felt stronger drag. Swift began losing altitude faster than anyone had modelled.
By mid-2026, the observatory had dropped to roughly 363 km — losing altitude at a rate that would bring uncontrolled reentry before the end of this year. Swift weighs about 1,470 kg. Without a controlled deorbit, the ground track of its reentry would be unpredictable.
The contract and the spacecraft
In September 2025, NASA awarded a $30 million fixed-price contract through its Small Business Innovation Research programme to Katalyst Space Technologies, a Flagstaff, Arizona company founded in 2019. The scope was clear: design, build, test, and fly a spacecraft that could rendezvous with Swift, capture it, and raise its orbit. The timeline was brutal — about nine months from contract signature to launch day.
Katalyst’s spacecraft is called LINK (Lightweight In-space Navigation and Kinematics). It weighs roughly 400 kg, stands about 1.5 metres tall, and carries three xenon-fueled Hall-effect ion thrusters with approximately 60 kg of propellant; two accordion-folding solar arrays spanning nearly 6 metres; three robotic arms, each fitted with a LiDAR sensor for precision ranging and imaging; and sixteen reaction control thrusters for fine attitude adjustments during approach.
Here’s the hard part: Swift has no docking port, no grapple fixture, no cooperative capture interface. It was built in the early 2000s with no expectation that anything would ever touch it again after the Delta II fairings separated. LINK’s arms will instead grip the pre-launch transportation flanges — the same structural hard points that held Swift to its launch vehicle in 2004. Katalyst tested this at NASA Goddard earlier this year using a full-scale mockup, confirming the approach geometry and the clamping force needed to hold the two spacecraft together during thrusting.
Riding the last Pegasus XL
LINK will fly on the final Pegasus XL rocket ever built, closing a 36-year chapter in commercial launch history. Pegasus is air-launched: a modified Lockheed L-1011 TriStar — NASA’s Stargazer aircraft — takes off from Kwajalein Atoll in the Marshall Islands, climbs to about 12,000 metres, and releases the three-stage solid-fuel booster. Five seconds after drop, the first stage ignites.
Orbital Sciences first flew Pegasus in 1990. Northrop Grumman (which absorbed Orbital) built this final unit specifically for Swift Boost. After this mission, the production line closes for good.
Launch is currently scheduled for no earlier than Tuesday, June 30, 2026, at 10:23 UTC.
After separation, LINK will spend several weeks raising its own orbit and phasing toward Swift. The approach will be cautious: LINK closes in slowly, surveys the telescope with onboard sensors, and only then attempts capture. If the three arms lock onto Swift’s flanges, LINK’s ion thrusters will gradually push the combined stack from ~363 km to roughly 600 km. The reboost phase is expected to take several months.
What the precedent means
On-orbit servicing isn’t entirely new. Northrop Grumman’s MEV-1 extended Intelsat 901’s life in 2020 by docking with its apogee kick motor nozzle, and MEV-2 repeated the approach with Intelsat 10-02 in 2021. But those were cooperative targets — telecommunications satellites with a standard engine nozzle geometry designed to accept a grappling mechanism.
Swift is a science observatory with solar panels, star trackers, and a coded-aperture gamma-ray mask. Nobody in 2004 designed it to be grabbed. If LINK succeeds, it’ll demonstrate that unprepared satellites — which make up the vast majority of hardware in orbit — can be repositioned, serviced, or deorbited on demand. The implications run from keeping ageing science missions alive past their orbital expiry to actively removing defunct satellites from crowded orbital shells.
Why amateur astronomers should care
Swift punches above its weight in ground-based follow-up. Its Burst Alert Telescope scans roughly one-sixth of the sky at any moment. When BAT detects a gamma-ray burst, Swift autonomously slews its X-ray and UV/optical telescopes to the burst position — typically within about 50 seconds — then pushes precise coordinates and light-curve data to the Gamma-ray Coordinates Network (GCN). The chain from detection to public alert takes seconds.
Professional robotic telescopes subscribe to GCN and respond automatically. So do a growing number of amateur setups. If you’ve caught a nova alert through your astronomy club or chased a GRB afterglow candidate with a fast telescope, there’s a solid chance Swift was the instrument that told you where to look.
The Chinese-French SVOM satellite (launched June 2024) covers some of the same transient detection space, and the Einstein Probe (also 2024) watches for X-ray transients. But Swift’s wider BAT field of view, faster slew rate, and two decades of calibrated multi-wavelength data make it hard to replace quickly. Losing Swift wouldn’t just mean losing a telescope — it would thin out the alert network that feeds rapid follow-up across the entire observing community.
I’ve used GCN-distributed Swift alerts myself, mostly for nova confirmations. The pipeline is simple: BAT or XRT triggers, GCN distributes, and within an hour the amateur photometry network has light curves. Remove Swift from that chain and you lose response time that matters for fast-fading transients.
The numbers
Swift has been in orbit for nearly 22 years on a planned 2-year mission. It has detected over 1,600 gamma-ray bursts. Katalyst’s $30 million contract is roughly what NASA pays for a single Falcon 9 launch slot. The entire LINK spacecraft — design, build, test, launch — took about nine months. Swift’s current altitude sits at ~363 km, down from 585 km at launch. If the reboost succeeds, the target altitude of ~600 km could extend operations by another decade.
What to watch
NASA will webcast the launch. After that, the timeline stretches out: rendezvous and approach will take weeks, and the orbit-raising phase will run for months. Updates should appear on NASA’s Swift mission blog and on Katalyst’s site.
The moment to watch is the capture — when LINK’s three arms close around Swift’s flanges and two spacecraft become one stack. For the on-orbit servicing industry, that’s the proof of concept. For everyone who uses GCN alerts to know where to point a telescope on short notice, it’s the moment a 22-year-old observatory gets to keep finding things that go bang in the night sky.