A robot rescue team has set out to save a space telescope that is falling, pushed down by solar particles. The mission is to push the telescope up and raise its altitude. If the operation succeeds, the rescue team will separate from the telescope and instead burn up in Earth's atmosphere. It is, in effect, a mission that sacrifices itself to save a comrade, like the movie "Saving Private Ryan."
At 8:36 p.m. on the 3rd (5:36 p.m. Korea time), a spacecraft "LINK" from Katalyst Space Technologies of the United States 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, which went into space in 2004 to observe gamma-ray bursts, the final moments of stars, has recently experienced a sharp drop in altitude. 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 has been pushed by high-energy particles ejected from the sun. LINK plans to grab the space telescope with three robot arms, ignite its engine, and raise the altitude.
◇ Must rescue within the one-year golden time
According to Katalyst, Swift has less than a year left to carry out its mission before it falls below 300 km, an altitude at which 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 robot arms. After three failed launch attempts, it finally headed to space. Two were canceled due to bad weather, and the third was foiled by a technical issue. Katalyst said that over the coming 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 the moment of launch. Unlike other satellites or spacecraft that ride a space rocket lifting off from the ground, LINK entered orbit via air launch. On that day, the Stargazer, a large aircraft from U.S. defense contractor Northrop Grumman, released 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 keeps changing. To dock, the moving rescue target must first be precisely aimed at. LINK is expected to take position right next to Swift in three to four weeks.
The docking process will proceed carefully. First, LINK must tuck in close to Swift and take images from multiple angles. Although there is a plan for where the robot arms will grab, the team must consider the possibility that Swift's exterior has deformed after more than 20 years of operations in space.
On D-day for the rescue mission, LINK will grab the Swift telescope, which is traveling at 27,000 km per hour, with its three robot arms. It will then immediately ignite its engine to raise the altitude. Experts predicted the climb would be slow and graceful, rather than rocketing upward, to avoid damaging the telescope. LINK will operate 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 observation cameras. As its original name, "Swift Gamma-Ray Burst Explorer," suggests, observing gamma-ray bursts is its primary mission.
Gamma-ray bursts are the most powerful explosive events in the universe, releasing in a few seconds as much energy as the sun emits over its 10-billion-year lifespan. They occur when a dying star becomes a black hole or when stars collide. The telescope was named Swift, meaning "quick," because a space telescope must be nimble to observe such fleeting cataclysms.
Swift originally lacked a propulsion system and was destined to see its orbit gradually decay over time due to trace atmospheric drag and friction. But in late 2024, the sun's 11-year sunspot cycle intensified beyond predictions, 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.
If left alone, it will keep descending and burn up from friction with Earth's atmosphere. Numerous satellites to date have reached the end of their lives, reentered the atmosphere, and burned up. NASA judged that Swift is too scientifically special to leave as is. In fact, on Oct. 9, 2022, Swift, together with the Fermi Gamma-ray Space Telescope, observed GRB 221009A, the most powerful gamma-ray burst in the history of space observations.
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 dust layers within our galaxy along the direction of the burst.
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 attempting. Swift is still operating, and building a replacement space telescope would take years and cost more expense. People around the world are watching to see whether the universe's "Saving Private Swift" will succeed.
References
NASA (2026), https://science.nasa.gov/mission/swift/swift-boost-mission/