NASA Buys Time for Discovery Launch
A faulty liquid hydrogen valve forced NASA Aug. 27 to delay the launch of
the Space Shuttle Discovery by almost 24 hours. After two postponements earlier
this week, NASA had tentatively scheduled a 12:22
a.m. EDT launch Aug. 28 but
later pushed the blastoff to the International Space Station to no earlier than
11:59 p.m. EDT on Aug. 28.
The Aug. 26 launch delay occurred when NASA engineers commanded the liquid hydrogen valve to close and did not receive a closed indication, indicating either a faulty valve or faulty sensor device. Engineers cycled the valve five times Aug. 26 after the launch cancellation to collect data on the valve and its associated actuator and position indicator.
NASA managers decided Aug. 27 that more time is needed to analyze the test data and develop alternative procedures for confirming that the valve is closed if the valve fails to provide the proper closed indication during Discovery's next launch attempt.
"They want time to assess that data," NASA spokesperson Allard Beutel told Space.com. "The mission managers didn't want to push the team."
Unlike previous missions, which have focused on the ongoing construction of the ISS, the Discovery mission is primarily focused on delivering more than 7 tons of supplies, science racks and equipment, as well as additional environmental hardware to sustain six crew members on the orbital outpost.
Commanded by veteran astronaut Rick "C.J." Sturckow, the Discovery crew will deliver refrigerator-sized racks full of scientific equipment. When the goods are delivered, NASA said, it will be a "quantum leap" in the scientific capability of the orbital laboratory.
The Discovery's payload includes the MSRR-1 (Materials Science Research Rack), the MELFI (Minus Eighty Degree Laboratory Freezer for ISS) and the FIR (Fluids Integration Rack).
MSRR-1 will be used for basic materials research related to metals, alloys, polymers, semiconductors, ceramics, crystals and glasses in the microgravity environment. MELFI will be used for long-term storage of experiment samples that are to be returned to Earth for detailed analysis. FIR is a fluid physics research facility designed to host investigations in areas such as colloids, gels, bubbles, wetting and capillary action, and phase changes, including boiling and cooling.
Discovery's cargo bay also includes the COLBERT (Combined Operational Load-Bearing External Resistance Treadmill), an exercise device named after comedian Stephen Colbert.