SPACE.com -- Scientists Prepare for Compton Gamma Ray Observatory Return to Earth

NASA plans to have Compton hit the atmosphere at a steep angle, dramatically slow down, break up, and fall into the ocean.

The flaming remains of Compton will splash down in the Pacific Ocean, allowing enough margin of error to keep it away from land.

Controllers Put Compton On Course for Suicide Dive

Tonight: The First Thruster Burn to Deorbit Compton Observatory

Scientists Test-Fire Thrusters to Bring Down Compton

Scientists Try to Save Gamma Ray Observatory


	Scientists Prepare for Compton Gamma Ray Observatory Return to Earth By Paul Hoversten Washington Bureau Chief posted: 11:45 am ET 31 May 2000

WASHINGTON -- NASA's controllers tonight will push the doomed Compton Gamma Ray Observatory closer toward Earth -- and certain death -- with the second firing of the satellite's thruster rockets

WASHINGTON -- NASA's controllers tonight will push the doomed Compton Gamma Ray Observatory closer toward Earth -- and certain death -- with the second firing of the satellite's thruster rockets.

Commands will be sent at 10:41 p.m. Eastern Daylight Time (Thursday, 02:41 GMT) from the Goddard Space Flight Center in Greenbelt, Maryland for the nine-year-old Compton to fire its thrusters for 23 to 30 minutes.

View a video animation of Compton's return to earth .

Tuesday night's initial engine burn dislodged the ailing Compton from its orbit around Earth, sending it on course for a suicide dive into Earth's atmosphere by early next week.

Tonight's thruster firing -- the second of four -- should drop the 17-ton, school bus-sized satellite from its altitude of 217 miles (350 kilometers) above Earth to 155 miles (250 kilometers).

Compton Gamma Ray Observatory

See an interactive graphic on the Compton Observatory. Requires Flash 4 .

Left on its own at that orbital height, the Compton would survive at least 80 days before gravity would pull it into Earth's atmosphere for a fiery destruction.

But NASA plans two additional thruster firings early on Sunday, June 4 to give the $670 million spacecraft a final nudge toward Earth. Each of those burns also should last from 23 to 30 minutes in length.

Those maneuvers will force Compton into what NASA hopes is a controlled crash-landing at 4:05 a.m. EDT (09:05 GMT) into a remote part of the eastern Pacific Ocean about 2,500 miles (4,025 kilometers) southeast of Hawaii.

Most of the satellite is expected to burn up during the plunge, but about 6 tons of metal debris -- from ounce- (gram-) size chips to bigger chunks weighing hundreds of pounds (kilograms) -- could survive the fall to splash in the ocean.

NASA opted to bring Compton down because one of its three stabilizing gyroscopes has failed. Managers feared another failure would prevent them from being able to control the spacecraft. This is the first time NASA has tried to bring a science satellite to a controlled crash-landing.

Compton will be the largest spacecraft to enter Earth's atmosphere since Skylab came to a fiery end in 1979.