Slowed UARS satellite re-entry predicted

September 22, 2011

NASA said Sept. 23 that there was a “low probability” that a falling satellite would hit North America on its predicted re-entry to the atmosphere, now predicted for late Sept. 23 or early Sept. 24.

A change in the orientation of the Upper Atmosphere Research Satellite (UARS) had resulted in a slower descent since earlier predictions of a likely Friday afternoon completion of the descent, NASA said in an update at 10:45 a.m. Sept. 23.

“The satellite’s orientation or configuration apparently has changed, and that is now slowing its descent. There is a low probability any debris that survives re-entry will land in the United States, but the possibility cannot be discounted because of this changing rate of descent. It is still too early to predict the time and location of re-entry with any certainty, but predictions will become more refined in the next 12 to 18 hours,” said NASA in the Friday morning prediction.

NASA continued to urge the public not to touch any objects suspected to be pieces of UARS once it reaches the ground, but to request law enforcement assistance.

On Thursday, Sept. 22, the FAA issued a special notice warning pilots “that a potential hazard may occur” due to the satellite’s descent path through Sept. 26.

The 35-foot-long, 15-foot-wide UARS satellite was launched from the Space Shuttle Discovery in 1991 to measure the ozone layer, chemical compounds detected there, stratospheric winds and temperatures and solar energy output.

NASA is providing updates online.

Dan Namowitz

Dan Namowitz | Aviation Writer

Dan Namowitz is an aviation writer and flight instructor. He has been a pilot since 1985 and an instructor since 1990.