UARS - Keep Those Helmets Handy Folks

Friday morning update to the UARS Web page changed the scenario: NASA says that the satellite’s descent has slowed and is expected to fall sometime late Friday or early Saturday. There is an increased, "low" probability that the expected 26 pieces of surviving debris could land in the United States.

The odds that any of the wayward satellite chunks will hit a person remain slim. There's only a one in 3,200 chance that a piece of UARS will hit anyone anywhere on Earth. Your individual chances of getting hit remain around one in 21 trillion.

This information direct from NASA:

NASA's Upper Atmosphere Research Satellite, or UARS, is expected to re-enter Earth's atmosphere late Sept. 23 or early Sept. 24 Eastern Daylight Time, 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 still too early to say exactly when UARS will re-enter and what geographic area may be affected, but NASA is watching the satellite closely and will keep you informed. Visit this page for updates on the satellite's orbital track and predicted re-entry date.

› Re-Entry and Risk Assessment (498 KB PDF)
› Frequently Asked Questions: Orbital Debris

The updates posted here come from the Joint Space Operations Center of U.S. Strategic Command at Vandenberg Air Force Base, Calif., which works around the clock detecting, identifying and tracking all man-made objects in Earth orbit, including space junk.

The actual time 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.

Because the satellite's orbit is inclined 57 degrees to the equator, any surviving components of UARS will land within a zone between 57 degrees north latitude and 57 degrees south latitude. 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.