|
PARTIAL
LAUNCH VEHICLE AND SPACECRAFT RE-ENTER EARTH'S ATMOSPHERE
According
to early calculations made by the United States Space Command's
Space Control Center, NASA's first High Energy Transient Experiment
(HETE), the Argentine SAC-B spacecraft and part of a Pegasus
launch vehicle are believed to have re-entered the Earth's
atmosphere at approximately 10:55 p.m. Eastern Standard Time
on April 6. The final notification from Space Command indicates
that the debris re-entered at 31.5 degrees North and 92.4
degrees East.
Less
than 8 kilograms (17 pounds) were predicted to survive the
re-entry process. The vast majority of the object was expected
to burn up in the atmosphere, and HETE was not expected to
survive re-entry.
SAC-B
and HETE were attached to the Pegasus third stage using several
payload attachment fittings. The combined stack weighed 535
kilograms (1,177 pounds) and was just over three and a half
meters (11.6 feet) long with a diameter of one meter (3.3
feet).
The
HETE-1 satellite was launched on 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 were
unable to function as designed and both died due to power
failure within days of launch.
PARTIAL
LAUNCH VEHICLE AND SPACECRAFT TO RE-ENTER EARTH'S ATMOSPHERE
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.
Back
to Top
|
