NASA'S UARS RE-ENTERS EARTH'S ATMOSPHERE
WASHINGTON - NASA's decommissioned Upper Atmosphere Research Satellite
(UARS) fell back to Earth between 11:23 p.m. EDT Friday, Sept. 23 and
1:09 a.m. Sept. 24, 20 years and nine days after its launch on a
14-year mission that produced some of the first long-term records of
chemicals in the atmosphere.
The precise re-entry time and location of debris impacts have not been
determined. During the re-entry period, the satellite passed from the
east coast of Africa over the Indian Ocean, then the Pacific Ocean,
then across northern Canada, then across the northern Atlantic Ocean,
to a point over West Africa. The vast majority of the orbital transit
was over water, with some flight over northern Canada and West
Six years after the end of its productive scientific life, UARS broke
into pieces during re-entry, and most of it up burned in the
atmosphere. Data indicates the satellite likely broke apart and
landed in the Pacific Ocean far off the U.S. coast. Twenty-six
satellite components, weighing a total of about 1,200 pounds, could
have survived the fiery re-entry and reach the surface of Earth.
However, NASA is not aware of any reports of injury or property
The Operations Center for JFCC-Space, the Joint Functional Component
Command at Vandenberg Air Force Base, Calif., which works around the
clock detecting, identifying and tracking all man-made objects in
Earth orbit, tracked the movements of UARS through the satellite's
final orbits and provided confirmation of re-entry.
"We extend our appreciation to the Joint Space Operations Center for
monitoring UARS not only this past week but also throughout its
entire 20 years on orbit," said Nick Johnson, NASA's chief scientist
for orbital debris, at NASA's Johnson Space Center in Houston. "This
was not an easy re-entry to predict because of the natural forces
acting on the satellite as its orbit decayed. Space-faring nations
around the world also were monitoring the satellite's descent in the
last two hours and all the predictions were well within the range
estimated by JSpOC."
UARS was launched Sept. 12, 1991, aboard space shuttle mission STS-48
and deployed on Sept. 15, 1991. It was the first multi-instrumented
satellite to observe numerous chemical components of the atmosphere
for better understanding of photochemistry. UARS data marked the
beginning of many long-term records for key chemicals in the
atmosphere. The satellite also provided key data on the amount of
light that comes from the sun at ultraviolet and visible wavelengths.
UARS ceased its scientific life in 2005.
Because of the satellite's orbit, any surviving components of UARS
should have landed 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 landed, but NASA estimates the debris
footprint to be about 500 miles long.
For more information about UARS, visit: http://www.nasa.gov/uars