NASA has carried out some notable rescue missions over the past few years, including bringing home the astronauts stranded on the International Space Station last year. More recently, the agency sent up a probe in hopes of saving the Neil Gehrels Swift Observatory, a satellite first launched in 2004 that began falling out of our planet’s orbit.
The plan was for robotic arms on the probe, known as LINK, to grab onto the aging satellite and—with a powerful set of thrusters—drag the observatory back into position. The rescue robot was launched into space this past July but soon after suffered issues with its altitude systems, a key set of controls for moving in space. The mission had to be canceled.
“Swift wasn’t designed to be serviced,” Ghonhee Lee—CEO of Katalyst Space, the company that developed LINK—stated just before the probe’s launch. And as Shawn Domagal-Goldman, director of NASA’s astrophysics division, also noted at the time, this was “a high-risk, high-reward mission.”
Now, Swift will continue sinking. Like all low-orbit satellites, the observatory experiences air resistance from Earth’s upper atmosphere, causing it to gradually descend. Originally, scientists predicted the telescopes might not reach critical depths until 2030, but in recent years, intense solar activity has caused the Earth’s atmosphere to expand, increasing drag. Swift is expected to reenter the atmosphere as soon as the end of this year, though it may still capture some fascinating information about our cosmos before burning up on its descent.
The satellite has been NASA’s eyes on some of the most explosive and short-lived phenomena in the universe. Equipped with three primary telescopes, it’s capable of observing multiple wavelengths, including visible light, ultraviolet, x-rays, and gamma rays. Over 21 years, this has made the observatory indispensable for recording and alerting ground teams about supernovas, gamma-ray bursts, and black holes shredding stars.
The Swift operations team has announced a plan to conduct as many observations as possible during the remaining lifetime. Prior to the rescue mission, the observatory had shut down its telescopes to conserve power, to keep its solar panels oriented, and to minimize air resistance.
But shortly after the rescue mission was abandoned, two of the three telescopes aboard were successfully restarted, and the x-ray telescope captured images of the Tycho supernova remnant, located approximately 13,000 light-years away. Adjustments are also underway for the Burst Alert Telescope, which is still powered down, with the goal of resuming observations within a few weeks.
Once Swift’s altitude falls below 185 miles above the Earth’s surface, operating the telescopes becomes increasingly challenging, and its descent will further accelerate. But researchers are looking forward to what else it might capture before finally expiring.
This story was originally published in WIRED Japan and has been translated from Japanese.
