Goodbye Swift: After 22 years, NASA spacecraft burns up in atmosphere

NASA's Neil Gehrels Swift Observatory, a space telescope that spent over two decades studying powerful cosmic explosions, has ended its mission with a fiery descent back to Earth. The observatory, the size of a 1.5-ton vehicle, was set to enter Earth's atmosphere on November 4, with most of it expected to burn up upon re-entry. However, experts anticipated that a small fraction of the telescope's durable components might survive the descent and reach the planet's surface.

NASA officials put the odds of any harm caused by Swift's falling debris at less than 1-in-2,100. The telescope's last observation was made on October 20, after which its orbit was lowered to just below 171 miles above Earth, making continued operations impossible. The Swift telescope, named after the swift bird family due to its swift ability to focus on faraway gamma-ray bursts (GRBs), was equipped with three instruments to detect gamma rays, X-rays, and ultraviolet and optical light.

These tools provided astronomers with unique insights into GRBs, which are extremely luminous eruptions occurring in distant galaxies when massive stars explode or collide, often resulting in neutron stars or black holes. Since its launch in 2004, Swift had documented nearly 2,000 of these events. Additionally, Swift served as a crucial sentinel for scientists, alerting them within seconds of any incoming cosmic blasts so that terrestrial telescopes could follow-up with their own observations.

As Swift's orbit gradually decreased due to factors like high-energy particles from solar activity and atmospheric drag, it lost speed. Starting two years ago, the expansion of this part of Earth's atmosphere hastened the telescope's demise. NASA attempted a last-ditch rescue mission to boost its orbit, but this effort failed in July when the rescue spacecraft experienced several malfunctions.

The reentry of Swift and any resulting debris was projected to occur over a vast area stretching nearly 1,500 miles in latitude above and below the equator, potentially impacting parts of South and Central America, Africa, Southeast Asia, and Australia. However, no eyewitness sightings of fireballs or falling debris have been reported, suggesting that Swift might have instead landed harmlessly in the remote stretches of open ocean that constituted the majority of the at-risk area.