Teams began space shuttle Discovery’s tanking test on time at 7 a.m. EST. Teams will fill the spacecraft’s external fuel tank with liquid hydrogen and liquid oxygen just as they do during a launch attempt to verify repairs made to the tank. The test will end at the T-31 second mark in the test countdown. The liquid oxygen is minus-297 degrees F and the hydrogen is at minus-423 degrees F. Technicians added 89 sensors to the outside of the tank recently including strain gauges to gather precise measurements of how much the tank moves during the fueling process. Thermal couplers will take careful temperature readings throughout the evaluation as well.