Super cold liquid hydrogen and liquid oxygen drained out of space shuttle Discovery’s external fuel tank following the end of the tanking test shortly before 5 p.m. EST Friday. Initial data and a walk down by the inspection team identified no cracks in the foam or anything out of the ordinary. The remaining propellants will “boil off” through Saturday.
Teams collected data from sensors placed on the shuttle’s external tank. Eighty-nine sensors, 39 strain gauges and 50 thermocouples, were installed on the aluminum skin of the tank to precisely measure changes as propellants were pumped in. Engineers want to find out what caused two stringers on the tank’s ribbed section to crack during fueling on Nov. 5. Discovery’s launch attempt was scrubbed after a leak developed in the ground umbilical carrier plate, GUCP, which also was evaluated. The GUCP did not leak.
Sensors will continue to record readings through Dec. 18. Analysis could take several weeks.
Discovery’s next milestone is a trip back to the Vehicle Assembly Building no earlier than Tuesday, Dec. 21. There, the back side of the intertank will be scanned and foam reapplied to areas where sensors were placed for the tanking test. The STS-133 mission to the International Space Station is planned to launch no earlier than Feb. 3, 2011.