Spacecraft to Re-Enter Earth's Atmosphere
4 Apr 2002
(Source: NASA Headquarters)
Goddard Space Flight Center, Greenbelt, Md.
The upper stage of a Pegasus launch vehicle with NASA's first High Energy Transient Experiment (HETE-1) and the Argentine SAC-B spacecraft still attached is predicted to re- enter the Earth's atmosphere at approximately 7 a.m. EDT Sunday, April 7. This prediction is uncertain to within plus or minus two days.
The total weight of the upper stage and combined spacecraft is 535 kilograms (1,177 pounds). Initial analysis indicates that only four small stainless-steel batteries, weighing a total of 15 kilograms (33 pounds) will survive re-entry.
"The re-entry is uncontrolled, and due to potential solar flux variations, time and location predictions will not be reliable until only a few hours before the re-entry event," said Scott Hull, Spacecraft Engineering Lead for Space Systems Mission Operations at NASA's Goddard Space Flight Center, Greenbelt, Md.
The U.S. Space Command will track HETE-1/SAC-B and the launch-vehicle third stage until re-entry. NASA will monitor the orbital parameters based on Space Command data and will supply updates and technical information as needed.
The HETE-1 satellite was launched Nov. 4, 1996, along with SAC-B, on a Pegasus rocket from Wallops Island, Va. The Pegasus rocket achieved a good orbit, but the third stage failed to release the two satellites. As a result, SAC-B and HETE-1 were unable to function as designed and both died due to power failure within days of launch.
SAC-B is connected to a Dual Payload Attach Fitting canister containing HETE, which is in turn connected to the Pegasus third stage. The combined stack is just over three and a half meters (11.6 feet) long with a diameter of one meter (3.3 feet).
The HETE mission was rebuilt and re-flown as HETE-2, with a successful Pegasus launch Oct. 9, 2000.
Updated information on the re-entry will be available on the Internet at: http://www.gsfc.nasa.gov/topstory/20020401hetereenter.html