NASA Targets Shuttle Discovery's Launch For No Earlier Than Feb. 3
WASHINGTON -- NASA managers have targeted space shuttle Discovery's
launch for no earlier than Feb. 3 at 1:34 a.m. EST. Shuttle managers
determined more tests and analysis are needed before proceeding with
the launch of the STS-133 mission to the International Space Station.
The Program Requirements Control Board met Thursday and reviewed
engineering evaluations associated with cracks on two 21-foot-long,
U-shaped aluminum brackets, called stringers, on the shuttle's
external tank. NASA repaired the cracks and reapplied foam to the
exterior of the stringers.
Managers decided the analysis and tests required to launch Discovery
safely are not complete. They are planning to conduct an instrumented
test on the external fuel tank and structural evaluations on stringer
test articles to determine if the analysis is correct. Details and
timelines for the tanking test are in work, but plans call for
temperature and strain gauge measurements in the intertank region
near the top of the tank during the test.
The test also will verify the integrity of repairs made earlier when
two cracked stringer sections and foam were replaced. A team of
engineers and technicians will inspect the tank for evidence of any
foam cracking as it would on an actual launch day. The test also will
verify the integrity of repairs to the Ground Umbilical Carrier
Plate, which leaked an unsafe amount of gaseous hydrogen during
Discovery's Nov. 5 launch attempt. The date of the test is under
evaluation, but likely will occur this month.
Engineers will continue to search for the root cause of the stringer
cracks through data analysis and tests, including placement of
manufacturing defects in separate stringers to demonstrate structural
integrity in an effort to duplicate the same type of failure that
occurred in November.
NASA will review and analyze the data from the tests before setting a
launch date. Because of Discovery's delayed launch, the earliest
opportunity for the liftoff of the final scheduled shuttle mission,
STS-134 on Endeavour, is April 1.
For continued STS-133 updates as well as crew and mission information, visit:
http://www.nasa.gov/shuttle
Source: NASA
