NASA Says Six-Ton Research Satellite Falls to Earth Over the Pacific Ocean

By Dan Hart - Sep 25, 2011 1:51 AM GMT+0700

An 11,023-pound research satellite used in the study of Earth’s ozone layer came down today off the West Coast of the U.S., the National Aeronautics and Space Administration said on its website.

The Upper Atmosphere Research Satellite, which weighed five metric tons, entered Earth’s atmosphere between 11:23 p.m. yesterday and 1:09 a.m. New York time this morning, NASA said. The Joint Space Operations Center at Vandenberg Air Force Base in California said the satellite came down over the northern Pacific Ocean, off the coast.

Nicholas Johnson, an orbital decay scientist for NASA at Johnson Space Center in Houston, said the agency doesn’t know the precise point where the satellite entered the atmosphere. Earlier, the agency said it anticipated 26 objects from the satellite’s breakup to survive and land in an area more than 500 miles (804 kilometers) long.

“The vast majority of that track was over water,” said Johnson in a conference call. He said there hadn’t been any sightings of the satellite or debris.

UARS was released by the space shuttle Discovery in 1991 to study chemicals in the atmosphere, including chlorine monoxide, which destroys ozone, and methane. It was decommissioned in 2005, with six of its 10 instruments still functioning, and moved into a lower orbit.

The last time a large NASA satellite made an uncontrolled landing was in 1979, when Skylab, a space station weighing 75 metric tons and Pegasus 2, a satellite, both fell to Earth.

To contact the reporter on this story: Dan Hart in Washington at dahart@bloomberg.net

To contact the editor responsible for this story: Sylvia Wier at swier@bloomberg.net