NASA's Upper Atmosphere Research Satellite, or UARS, is expected to re-enter Earth's atmosphere later this week, almost six years after the end of a productive scientific life. Although the spacecraft will break into pieces during re-entry, not all of it will burn up in the atmosphere.
The risk to public safety or property is extremely small, and safety is NASA's top priority. Since the beginning of the Space Age in the late-1950s, there have been no confirmed reports of an injury resulting from re-entering space objects. Nor is there a record of significant property damage resulting from a satellite re-entry.
It is too early to say exactly when UARS will re-enter and what geographic area may be affected.
The actual date of re-entry is difficult to predict because it depends on solar flux and the spacecraft's orientation as its orbit decays. As re-entry draws closer, predictions on the date will become more reliable.
As of Sept. 19, 2011, the orbit of UARS was 130 mi by 143 mi (210 km by 230 km). Re-entry is expected Sept. 23, plus or minus a day. It is impossible to pinpoint just where in that zone the debris will land, but NASA estimates the debris footprint will be about 500 miles long.
If you find something you think may be a piece of UARS, do not touch it. Contact a local law enforcement official for assistance.