A long-running NASA mission is about to come crashing home. A satellite named Van Allen Probe A, launched in 2012 to study the radiation belts encircling Earth, is currently expected to plunge back into the atmosphere around 7:45pm Tuesday—though a NASA post cites a 24-hour window of uncertainty. The entry time will be updated. Most of the roughly 1,300-pound craft should burn up, though some pieces may survive.
A post at Space.com points out that any surviving parts are more likely to splash down in the open ocean rather than on land, with NASA calculating the risk to people on the ground at about 1 in 4,200. The probe and its twin, Van Allen Probe B, spent nearly seven years flying through the belts, collecting unprecedented data and even revealing a temporary third belt that can appear during intense solar activity. An unexpectedly strong solar cycle hastened Probe A's return, but Probe B isn't expected to re-enter before 2030.