NASA's Neil Gehrels Swift Observatory Burns Up Over Indonesia After High‑Risk Re-Entry and Failed Rescue

NASA's Neil Gehrels Swift Observatory burned up over Indonesia on Wednesday after a re-entry that followed a risk assessment exceeding the US Government's own benchmark for acceptable risk to the public and followed a failed private rescue attempt, almost 22 years after launch.

The 3,200lb (1,452kg) spacecraft re-entered Earth's atmosphere over North Sumatra at about 7.39am EST (12.39pm GMT). NASA said no injuries or damage had been reported.

The agency had expected most of the observatory to disintegrate but warned that some components could survive. It is not yet clear whether any fragments have been found on the ground.

Higher-Than-Normal Risk to People on the Ground

Before re-entry, NASA estimated the risk of harm to anyone on Earth at about 1 in 2,100. That is higher than the 1-in-10,000 casualty-risk threshold adopted under the US Government Orbital Debris Mitigation Standard Practices in 2019.

The Aerospace Corporation, a federally funded research and development centre, said Swift's estimated risk exceeded that benchmark. In this context, a casualty means serious injury or death.

Swift's orbit decayed faster as the Sun approached the peak of its 11-year cycle in 2024. Increased solar activity heated and expanded the upper atmosphere, which raised drag on the spacecraft.

By 20 October, the observatory had fallen to about 171 miles (275km) and could no longer compensate for the drag. It entered safe mode after making its final scientific observation. The mission operations team at Penn State University then sent a command that ended its science operations.

Private Rescue Mission That Never Happened

Katalyst Space Technologies, an Arizona-based company, said it designed, built, tested and launched a servicing spacecraft called LINK within nine months. LINK launched on 3 July. It was designed to rendezvous with Swift, capture it and use its thrusters to lift the combined spacecraft into a higher orbit.

Shortly after launch, LINK suffered an attitude-control anomaly that sent it into an uncontrolled multi-axis spin. Engineers worked to stabilise it, but on 19 August NASA announced that LINK would not attempt to capture or boost Swift. The spacecraft went on to conduct technology demonstrations, and Katalyst said its mission concluded on 25 September.

Science Switched Back on After Rescue Was Dropped

To reduce drag, NASA had switched off Swift's ultraviolet/optical and X-ray telescopes in February and its Burst Alert Telescope in April. After the rescue was abandoned, two instruments resumed operations on 26 August, and the Burst Alert Telescope was confirmed operational again on 18 September.

Swift was designed to detect gamma-ray bursts, some of the most powerful explosions in the universe. It outlived its two-year primary mission and helped astronomers study active galaxies, stellar X-ray flares, comets and asteroids.

Hubble Now Under Scrutiny

On 29 October, NASA issued a Request for Information inviting commercial companies to outline their capabilities for potentially boosting, servicing or safely disposing of the Hubble Space Telescope. The agency has not selected a mission.

NASA's July analysis estimated a 10% probability that Hubble, launched in 1990, would re-enter the atmosphere by September 2032. That rises to 50% by December 2033 if no action is taken.

NASA is also developing the Habitable Worlds Observatory as a future flagship telescope, although it is not intended to replace all of Hubble's capabilities.