NASA’s Neil Gehrels Swift Observatory is expected to re-enter Earth’s atmosphere in the coming hours. Most of the spacecraft, which weighs about 1.5 tons, is forecast to burn up, but some larger, heavier pieces may survive to reach the surface.
As of Tuesday afternoon, the Aerospace Corporation predicted that the re-entry would occur at 5:12 a.m. Eastern time on Wednesday, with an uncertainty of eight hours.
NASA said potential debris could include titanium components such as an instrument mount, rings and fittings, as well as the mirror assembly, which is made of nickel. The agency estimates the chance that a fragment will injure someone at about one in 2,100.
The risk is limited by Swift’s orbit, which is inclined 20.6 degrees to the Equator. According to the information provided, areas north of 20.6 degrees north latitude and south of 20.6 degrees south latitude are outside the spacecraft’s possible debris path. That includes Europe and the United States. Hawaii’s Big Island is also far enough south, but Swift is not expected to pass over it during its final orbits.
Sources: The New York Times Science.