The Neil Gehrels Swift observatory, weighing approximately 1,450 kg, is set to reenter Earth's atmosphere today after nearly 22 years of service. Launched in November 2004 to study gamma-ray bursts, the most energetic explosions in the universe, the satellite operated for significantly longer than its intended two-year lifespan. The decision to allow the descent came as increased solar activity, which peaked during its 11-year cycle in 2024, caused the upper atmosphere to expand and intensify drag on the spacecraft.
On October 20, with its altitude reduced to 275 km, the satellite entered safe mode as it could no longer compensate for the atmospheric drag. Consequently, the team at Penn State, a NASA partner on the project, issued the final command to deactivate the observatory. Prior to this outcome, NASA had contracted Katalyst Space Technologies in September 2025 to attempt raising Swift to a stable orbit using the LINK spacecraft, which was launched on July 3. However, after LINK entered an uncontrolled rotation shortly after launch and engineers struggled to regain full control, NASA and Katalyst announced on August 19 that the capture and orbit-raising attempt was cancelled, leaving reentry as the inevitable conclusion.
Because this is an uncontrolled reentry, predictions carry margins of error spanning several hours. Various agencies provided differing estimates for the event time in Portugal continental time: the U.S. Space Force initially pointed to 8:30 with an 11-hour uncertainty, later projecting 12:42 with a two-hour margin; The Aerospace Corporation estimated 10:19 with a similar two-hour window; and South Korea's space agency, based on KASI analysis, predicted 11:46. As of now, there is no confirmed data that the reentry has already occurred.
Debris from the observatory is expected to fall within a latitude band between 20.6° North and 20.6° South. This zone covers large oceanic areas as well as parts of Central and South America, Central Africa, southern India, Southeast Asia, and northern Australia, excluding Portugal. NASA anticipates that most of the spacecraft will disintegrate, though some components may survive, including tungsten pieces and parts of the mirrors, according to mission principal investigator Brad Cenko. The Aerospace Corporation notes that NASA estimated the risk of damage to people at approximately 1 in 2,100, which exceeds the current 1 in 10,000 limit imposed by orbital debris mitigation standards updated in 2019 for uncontrolled reentries.
Looking ahead, NASA has already requested proposals from commercial companies regarding how to raise, repair, or extend the life of the Hubble Space Telescope. Analysis indicates a 10% probability of Hubble's reentry by 2032 and a 50% probability by 2033, with no replacement scheduled before the 2040s.
Sources: Pplware.