NASA's Swift observatory, launched in 2004, is expected to re-enter Earth's atmosphere after a rescue mission that was not successful. The telescope, functioning for more than two decades, will disintegrate upon re-entry. Majority of the debris will combust in the atmosphere. Experts estimate that the impact area might span over 80% of Earth's surface. Authorities are observing the scenario to gauge threats to populated zones. The exact location of impact has not been determined. NASA's Swift Observatory Falling to Earth: Who Is Responsible If Debris Results in Harm?