A robot rescue team has set out to save a space telescope that is falling, pushed by solar particles. The mission is to push the space telescope up and raise its altitude. If the operation succeeds, the rescue team will separate from the space telescope and instead burn up and disappear in Earth's atmosphere. Like the movie "Saving Private Ryan," it is an operation that sacrifices itself to save a teammate.
At 8:36 p.m. on the 3rd (5:36 p.m. Korea time), the spacecraft "LINK" of U.S. company Katalyst Space Technologies was launched from the Kwajalein Atoll in the Marshall Islands in the South Pacific. LINK plans to dock with the National Aeronautics and Space Administration (NASA) space telescope "Neil Gehrels Swift Observatory" within three months and raise its altitude.
Swift, launched into space in 2004, observes gamma-ray bursts, the last moments of stars, but its altitude has recently dropped sharply. When it was first launched, its mission orbit was 600 km above Earth, but over the past two years it has fallen to 360 km. It was pushed by high-energy particles ejected from the sun. LINK plans to grab the space telescope with three robotic arms and ignite its engine to raise the altitude.
◇ Must rescue within the one-year golden time
According to Katalyst, Swift has less than a year left to operate before it falls below 300 km, an altitude at which a rescue is impossible. With NASA's support, the company built and tested a robotic spacecraft to rescue Swift in eight months.
LINK is an uncrewed spacecraft about the size of a refrigerator with three robotic arms. After three failed launch attempts, it finally headed to space. Two were canceled due to bad weather, and the third was scrubbed due to a technical problem. Katalyst said that over the next few weeks it will sequentially activate LINK's power, navigation system, cameras, and sensors to check whether any problems arose during launch.
That is because LINK was unusual from launch. Instead of riding a space rocket that lifted off from the ground like other satellites or spacecraft, LINK entered orbit by air launch. That day, the large "Stargazer" aircraft of U.S. defense contractor Northrop Grumman separated a Pegasus XL rocket carrying LINK at an altitude of 12 km. The rocket immediately ignited its engine, flew near Swift's orbit, and deployed LINK.
That does not mean LINK can dock with Swift right away. Swift is not in a stable orbit and its altitude continues to change. To dock, it must first precisely aim at the moving rescue target. LINK is expected to take position right next to Swift in about three to four weeks.
The docking process will proceed carefully. First, LINK must come up close to Swift and film it with cameras from multiple angles. Although there is a plan for where to grab with the robotic arms, it must also consider the possibility that Swift's exterior has deformed after more than 20 years of operating in space.
On D-day of the rescue mission, LINK will grab the Swift telescope, which is flying at 27,000 km/h, with its three robotic arms. It will then immediately ignite its engine to raise the altitude. Experts predicted that to avoid damaging the telescope, the ascent will be slow and graceful rather than shooting up like a rocket. LINK will run its small thrusters for two to three months to climb from 360 km to Swift's former orbit 600 km above Earth.
◇ Telescope that observed the largest gamma-ray burst on record
Swift's main body measures 5.6 by 5.4 meters, about the size of a large car. It weighs 1.6 tons. On Nov. 20, 2004, it went into space aboard a Delta II launch vehicle carrying three astronomical cameras. As its original name "Swift Gamma-Ray Burst Explorer" indicates, observing gamma-ray bursts is its primary mission.
Gamma-ray bursts are the most powerful explosions in the universe, releasing in just a few seconds the energy the sun emits over its 10 billion-year lifetime. They occur when a dying star becomes a black hole or when stars collide. To observe such cataclysms that unfold in an instant, a space telescope must be nimble, which is why it was named Swift, meaning "quick."
Swift originally had no propulsion system, so its orbit was destined to gradually drop over time due to trace atmospheric drag and friction. But in late 2024, the sun's 11-year sunspot cycle became stronger than forecast, accelerating the orbital decay. Sunspots are the source of eruptions of high-energy particles on the sun. When high-energy particles ejected from the sun push away Earth's atmosphere, the drag on Swift increases.
Left as is, it will keep descending and burn up through friction with Earth's atmosphere. Numerous satellites have reached the end of their lives and burned up upon reentry. NASA determined Swift is scientifically special and could not be left as is. Swift already observed, together with the Fermi Gamma-ray Space Telescope, GRB 221009A, the most powerful gamma-ray burst in the history of space observations, on Oct. 9, 2022.
The gamma-ray burst occurred in the direction of Sagittarius about 2.4 billion light-years from Earth (one light-year is the distance light travels in a year, about 9.46 trillion km). One hour after GRB 221009A was first detected, Swift's X-ray telescope captured its afterglow in a dust layer within our galaxy along the direction of the explosion.
To save Swift, NASA signed a $30 million (about 45.9 billion won) contract with Katalyst. NASA officials said the Swift rescue is a "high-risk, high-reward" effort worth trying. Swift is still operating, and even if a replacement space telescope were built, it would take years and cost more expense. The world is watching to see whether the space "Saving Private Swift" will succeed.
References
NASA (2026), https://science.nasa.gov/mission/swift/swift-boost-mission/