Swift Observatory faces uncontrolled re-entry after failed rescue

Uncontrolled re-entry follows failed rescue

The US Space Force predicts the 3,200lb Neil Gehrels Swift Observatory hits Earth’s atmosphere at 3:30 am ET on 4 November. The satellite, which NASA launched in 2004 to study cosmic gamma-ray bursts, can no longer steer or observe. This uncontrolled re-entry follows a failed attempt last year to push the observatory into a higher orbit using a private space contractor because they failed to rendezvous. NASA designed the observatory to operate with its three telescopes for just two years as part of the Midex program, but it lasted for two decades. Last month, NASA commanded the spacecraft to end operations after it reached an altitude of 171 miles. While most of the spacecraft will burn up, NASA says surviving fragments will fall between 20.6 degrees south latitude and 20.6 degrees north latitude. The risk of harm to anyone on Earth is 1 in 2,100.

Two decades of cosmic observations

The observatory clearly provided exceptional data on the universe by detecting and tracking more than 2,000 gamma-ray bursts. These intense flashes of gamma radiation occur approximately once per day and come from all different directions. They last from a few milliseconds to a few hundred seconds. Scientists theorize these bursts come from the birth of a black hole in a massive stellar explosion or the collision of two neutron stars. In July, the mission observed a wandering mega black hole shredding a star, an event that occurred 2,600 light-years from the center of the host galaxy. The black hole, described as an "orphan", lit up as it devoured the star on the outskirts of a galaxy. Crumbs of the splintering star heat up as they swirl around the black hole, creating a glow astronomers can see from far across the cosmos, and the black hole launches a relativistic jet into space. This tidal disruption event outshone its entire host galaxy in ultraviolet wavelengths, radiating with the light of about 10 billion suns. Robert Stein, a research fellow at the University of Maryland, College Park, and NASA’s Goddard Space Flight Center, observed one such event more than 30,000 light-years away from the center of the host galaxy. Stein noted that these tidal disruption events, which occur about once every 100,000 years, help astronomers find invisible supermassive black holes wandering away from the galactic cores where they usually reside. Swift also studied active galaxies powered by supermassive black holes, stars undergoing X-ray flares, supernova explosions, comets, and asteroids.