Friday, September 9, 2011

NASA Satellite To Fall Back To Earth Uncontrolled


NASA's Upper Atmosphere Research Satellite, or UARS, is expected to re-enter Earth's atmosphere in late September or early October 2011, 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 according to NASA.  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, but NASA is watching the satellite closely.

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. 8, 2011, the orbit of UARS was 152 miles by 171 miles (245 km by 275 km) with an inclination of 57 degrees. 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.

The possible landing zone includes all major metropolitan areas around the world.