June 1, 2000 On Sunday, June 4, the successful nine-year mission of the Compton Gamma Ray Observatory (CGRO) will end when NASA redirects the spacecraft into Earth's atmosphere. Debris from the controlled re-entry is expected to fall in a remote area of the Pacific Ocean, approximately 2,500 miles southeast of Hawaii.
NASA controllers will fire CGRO's thrusters four times to lower the observatory's orbit. After each burn, mission trackers at Goddard Space Flight Center, Greenbelt, MD, will determine the observatory's exact position and, if necessary, adjust the descent. The engine burns have been scheduled to occur at:
Re-entry Burn #1: 9:54 p.m. EDT, Tuesday, May 30
Re-entry Burn #2: 10:41 p.m. EDT, Wednesday, May 31
Re-entry Burn #3: 1:37 a.m. EDT Sunday, June 4
Re-entry Burn #4: 3:05 a.m. EDT, Sunday, June 4
Recorded status reports will be available after each burn on the Goddard Audio News Service (301/286-NEWS). Status reports will be posted the following morning to:
For news media interested in covering the final descent from Goddard, the newsroom in Goddard's Central Flight Control Building (Building 3) will open at 12:30 a.m. June 4. At 6 a.m. EDT, team members will hold a final news briefing in the Building 3 auditorium. The newsroom phone numbers, which will only be operational June 4, are 301/286-4127 or 301/286-4734.
Scientists and members from the Compton re-entry team will periodically stop by the newsroom to speak with reporters throughout the deorbit activities. News media interested in coming to Goddard on June 4 should contact Nancy Neal at 301/286-0039 by noon EDT Friday, June 2.
Live coverage on NASA Television of the deorbit activities will begin at 1 a.m. EDT June 4 and conclude at the close of the 6 a.m. briefing.
NASA Television coverage will include science highlights,re-entry animation and commentary on the re-entry activities by Dr. Neil Gehrels, CGRO project scientist. A NASA fact sheet on the re-entry can be found at:
Unlike most satellites, Compton is too large to burn up entirely in the atmosphere during re-entry. More than 6 tons (12,400 pounds) of metal debris is expected to fall to the Earth's surface. The debris fragments will range in size from the size of a small stone to several hundred pounds or kilograms.
To ensure the safety of aircraft and surface vessels in or near the target impact area, Debris Hazard Warning Areas were established well away from land. Shipping and air traffic in the area have been notified to ensure that craft will not be in the vicinity of the impact area.
NASA decided before Compton was launched that, due to the observatory's size, it would be returned to Earth by controlled re-entry when the mission was over. Extensive research showed that it was significantly safer to perform a controlled re-entry than any other method of dealing with the satellite.
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