NASA Swift Mission Ends, Leaving Behind a Scientific Bonanza for Science
Operations come to an end
Swift’s telescopes can no longer maintain stable views of astronomical targets because of stronger atmospheric drag at the spacecraft’s current altitude, less than 171 miles above Earth. The observatory made its final science observation on Oct. 20 and is expected to re-enter the atmosphere within weeks.
The mission was planned to operate for two years, but continued for more than 10 times that long. NASA Astrophysics Division director Shawn Domagal-Goldman said the agency is considering ways to support rapid follow-up of cosmic events using existing telescopes and new missions.
A record of cosmic events
During its career, Swift observed more than 2,000 gamma-ray bursts and studied over 1,400 supernova explosions. It also tracked stars torn apart by black holes, monitored active galaxies, surveyed the sky in X-rays, and studied asteroids and comets.
Its measurements have contributed to about 7,000 published scientific papers. The archive holds nearly 22 years of brightness data, multiwavelength spectra, and more than 1.5 million images from the Ultraviolet/Optical Telescope.
Fast observations changed research
Swift was built to detect gamma-ray bursts, determine their locations, alert other observatories, and turn its own telescopes toward them before their afterglows faded. Mission principal investigator S. Bradley Cenko said the process generally took about a minute.
The spacecraft’s speed helped researchers study short gamma-ray bursts, which reach peak brightness in under two seconds. In May 2005, Swift detected 11 X-ray photons from GRB 050509B, a burst lasting 0.03 seconds; the observations provided the first detected afterglow from a short burst and supported the theory that such bursts can arise when two neutron stars merge.
A flexible mission design
Swift launched on Nov. 20, 2004, and began work the following month. Its design brought together optical, ultraviolet, and X-ray telescopes that could quickly locate and refine the position of a burst; in 2018, NASA renamed it to honor its first principal investigator, Neil Gehrels, after his death.
Astronomers could request urgent observations from the ground within minutes or arrange monitoring that lasted from minutes to months. The planning system could schedule as many as 75 separate targets in a day.
Key points
- Swift ended science operations after atmospheric drag disrupted stable telescope pointing.
- The spacecraft made its final observation on Oct. 20 and is expected to re-enter within weeks.
- Swift observed more than 2,000 gamma-ray bursts and contributed data to about 7,000 papers.
- Its public archive includes nearly 22 years of measurements and more than 1.5 million ultraviolet and optical images.