CAPE CANAVERAL – It would have been quite a tight, the space shuttle Discovery rolling back from Launch Pad 39A to the Vehicle Assembly Building (VAB) under a lunar eclipse at NASA’s Kennedy Space Center in Florida. However, as with many elements of the shuttle program – it was not to be. The shuttle needed to be taken back to the VAB for additional tests and scans of its external tank (ET).
In the VAB, technicians will scan underneath the insulation surrounding the intertank region of Discovery’s ET to look for any problems, like the numerous cracks that were discovered after the Nov. 5 scrubbed launch attempt. After the 89 sensors are stripped off the tank the foam that was removed will be replaced. These scans will be done to see how the repaired sections fared after the tanking test (where super-cool oxygen and hydrogen was filled into the ET). When the tank is placed under these extreme conditions the ET can shrink – by as much as an inch. NASA’s engineers conducted the tanking test in the morning hours of Dec. 17.
After the cracks were discovered, technicians stripped off the foam, applied what is known as a ‘doubler’ to strengthen the affected section of the tank. Information from the test will be used to try and find out what caused cracks. The shuttle wheeled back to the VAB atop the massive transporter-crawler and will now await the outcome of these scans. If the tank held up to the stress of the tanking test NASA will probably try for the Feb. 3 launch date.
There are only enough tanks for STS-133 (Discovery’s final flight) STS-134 (Endeavour’s last mission) and potentially an additional flight – STS-135. If NASA is allowed to go ahead with a third flight – Atlantis would be the orbiter that finishes out the shuttle era. However – including the tank that is currently strapped to Discovery – there are only enough for these three missions. If Discovery’s tank is not able to be repaired it means that one of these flights should effectively be taken off the manifest.