Discovery Poised for Scientific Mission to ISS
Fueling of the space
shuttle Discovery continued Aug. 24 with NASA predicting an 80 percent
chance of good weather for a 1:36 a.m. Aug. 26 blastoff to the
International Space Station. The launch marks the 128th mission in
shuttle program history and the 30th shuttle visit to the ISS.
Unlike previous missions, which have focused on the ongoing construction of the ISS, the Discovery mission is primarily focused on delivering more than seven tons of supplies, science racks and equipment, as well as additional environmental hardware to sustain six crew members on the orbital outpost.
"I'm really pleased to report that launch countdown activities are proceeding normally and we are working no issues," Pete Nickolenko, launch director, said in a statement. NASA said current predictions call for four launch windows within the next five days. With that many launch windows, NASA said there is a 96 percent chance of a successful launch.
Commanded by veteran astronaut Rick "C.J." Sturckow, the Discovery crew will deliver refrigerator-sized racks full of scientific equipment. When the good are delivered, NASA says it will be a "quantum leap" in the scientific capability of the orbital laboratory.
"We really are starting to outfit the research capability of the station," said NASA's space station Program Manager Michael Suffredini.
The Discovery's payload includes the Materials Science Research Rack (MSRR-1), the Minus Eighty Degree Laboratory Freezer for ISS (MELFI) and the Fluids Integration Rack (FIR).
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. The 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) treadmill, an exercise device named after comedian Stephen Colbert.
The COLBERT, once simply known as T-2, is no ordinary treadmill. Engineers started with a medical treadmill available to anyone on Earth. NASA asked Wyle to nickel plate the parts and make some other modifications, including elastic straps that fit around the shoulders and waist to keep the runner from rocketing across the space station with the first hard step.
Engineers also faced the serious problem of keeping the treadmill from shaking the whole station with every step taken since the ISS is floating just like the astronauts and wants to react against any movement. Even small actions can shake up delicate microgravity experiments taking place inside the station's laboratories.
While another, older treadmill on the ISS relied on a powered system of gyroscopes and mechanisms to reduce vibrations, the COLBERT's Vibration Isolation System was designed to work without power and be more reliable than its predecessor. The COLBERT rests on springs that are hooked to dampeners. That unit is connected to a standard-sized rack that has been extensively reinforced to handle the power produced by COLBERT users. The rack alone weighs 2,200 pounds.
The one tradeoff? Perhaps fitting for a treadmill named after Stephen Colbert, it is loud.
"Noise and reliability are fighting against each other here," Wiederhoeft said. "With a lot more time we could have had both quiet and reliable. We went for reliable, and did what we could with noise."