NASA Ends Swift Mission After Years of Gamma-Ray Discoveries

First reported 23 Oct, 21:51 UTCSource: NASA News ReleasesLast editorial activity 23 Oct, 21:51 UTCWrite a comment ↓

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NASA has closed the science mission of its Neil Gehrels Swift Observatory, now flying too low for its telescopes to keep steady on astronomical targets. The spacecraft is expected to fall back into the atmosphere within the next few weeks.

Final observation and falling orbit

According to the agency, Swift made its last observation on Oct. 4. The observatory now circles less than 171 miles (275 kilometers) above the planet, where heavier atmospheric drag makes it impossible to hold the telescopes pointed at a fixed target.

Mission far outlasted its design

Shawn Domagal-Goldman, director of the Astrophysics Division at NASA Headquarters in Washington, said the satellite had been built for a two-year primary mission but kept producing results for more than ten times that span, a return he described as lasting for the nation.

Swift was built to chase gamma-ray bursts, flashes that arrive and vanish too quickly for large telescopes to be aimed at them in time. It detected and pinpointed these bursts, passed their positions to other observatories and swung its own instruments toward them within about a minute, before their afterglows faded. Under its first principal investigator, Neil Gehrels, it was conceived as a multiwavelength observatory carrying co-aligned optical, ultraviolet and X-ray telescopes.

Breadth of the scientific harvest

Beyond gamma-ray bursts, the observatory studied more than 1,400 supernova explosions, watched stars torn apart by black holes, monitored active galaxies, carried out an all-sky X-ray survey and examined asteroids and comets. Its data has supported about 7,000 published scientific papers.

Speed mattered most for short gamma-ray bursts, which peak in brightness in under two seconds. In May 2005 Swift reacted fast enough to record 11 X-ray photons from GRB 050509B, a burst lasting just 0.03 seconds, making it the first short burst with a detected afterglow.

Open questions

Where and when will the spacecraft re-enter the atmosphere?

Key facts

NASA's Neil Gehrels Swift Observatory has ended its science mission.

The spacecraft orbits less than 171 miles (275 kilometers) above Earth's surface.

Atmospheric drag at this height prevents the telescopes from steadily observing their targets.

Swift is expected to re-enter the atmosphere in the next few weeks.

Swift has observed more than 2,000 gamma-ray bursts.