Swift: NASA's observatory has ended its life in the atmosphere
· BehindLines newsroom
NASA's Neil Gehrels Swift space observatory fell back into the atmosphere on Wednesday 4 November, almost 22 years after launch. According to the US Space Force, cited by NASA, re-entry took place at 7:39 a.m. East Coast time, above northern Sumatra, near 3.4 degrees north and 98.6 degrees east.
An expected end
Launched in 2004, Swift was built to study gamma-ray bursts, the cosmos's most energetic blasts, using three telescopes that observe at several wavelengths. Its prime mission was meant to last two years. It nonetheless worked for more than twenty, observing active galactic nuclei, stars in X-ray flares, supernovae, comets and asteroids. It also sent alerts to other facilities so they could coordinate follow-up observations.
Its fall comes down to atmospheric drag. According to ABC7, intense activity from the Sun, which reached the peak of its eleven-year cycle in 2024, swelled the upper atmosphere and slowed the satellite. At an altitude of about 275 kilometres (171 miles), it could no longer make up for that drag and went into safe mode. The control team at Penn State sent it a final command on 20 October.
A rescue that did not succeed
A private rescue mission, run by Katalyst Space Technologies with a small spacecraft called LINK, was meant to grab it and lift it into a stable orbit, which could have extended its life by about ten years or more. Launched in July, it failed a few weeks later: the spacecraft began to spin out of control before reaching Swift.
What is left of the satellite?
Weighing about 3,200 pounds, or nearly 1,450 kilograms, Swift was expected to burn up for the most part. NASA nevertheless anticipated that some sturdier components would survive. According to ABC7, it was not yet known whether any debris had reached land. The agency had put the risk of someone being hit at about 1 in 2,100.
This uncontrolled re-entry also points to how the rules have changed: the Aerospace Corporation, a federally funded research centre, says debris-mitigation standards, updated in 2019, now require a risk of less than 1 in 10,000 for uncontrolled re-entries. In its view, a satellite launched today would have to follow far stricter end-of-life rules.