NASA engineers are planning on conducting a tanking test of space shuttle Discovery’s external tank, no-earlier-than Dec. 17. Technicians have been hampered by local weather which has been extremely windy – and cold. Temperatures in the local area have fallen into the twenties. This test will work to ensure that repairs that were made to the large, orange external tank (ET) after several cracks were discovered after the launch attempt on Nov. 5.
The cracks were discovered on the intertank region of the ET. These 21-foot-long aluminum brackets are called ‘stringers’ and NASA has been striving to repair the first crack, only to discover a second and third crack. Engineers are stilling trying to figure the cause of the cracks.
Monday, Dec. 13, shuttle program managers officially decided to roll the shuttle back from launch complex 39A to the massive Vehicle Assembly Building (VAB). It was determined that further tests and scans of the damaged region were warranted and as such a move back to the VAB was viewed as warranted. The rollback should occur on either Dec. 21 or 22. Instrumentation used to test the area out on the pad as well as foam that was re-applied to the area will be removed. X-rays will be conducted to collect information regarding the current status of the stringers.
The instrumentation that has been put in place will be used to test the strain that the ET is under as it is fueled with liquid oxygen and liquid hydrogen. The extreme cold temperatures cause the ET to actually shrink (approximately half an inch). Close to 90 instruments have been placed on the outside of the tank to measure what happens when the tank is fueled.
Currently Discovery is stated to launch no-earlier-than Feb. 3 at 1:34 a.m. EDT. However, NASA officials will review the findings of both the tanking test as well as the scans conducted when the orbiter is in the VAB, it is likely that this launch date will slip back as well.Missions » ISS »