NASA repairing new cracks today on Discovery's tank

Technicians have begun work today repairing newly discovered cracks on the support beams on the fuel tank of the space shuttle Discovery.

Four new cracks were discovered last week following x-ray scans of the inter tank region on the opposite side of where Discovery is mated on the external tank.

The four cracks being repaired are located on three vertical support beams known as stringers. The work is expected to finish up on Wednesday.

Around the center area of the tank are 108 twenty-one foot long aluminum brackets call stringers. The stringers help strengthen the tank's skin from crushing like a soda can as the space shuttle passes through MAX-Q -- the time in flight when the shuttle traveling at a high speed encounters the heavy atmosphere beginning at about forty-five seconds after launch.

Once the cracks are repaired, the NASA contractors will apply new foam insulation over the repaired areas.

Engineers today are also making aditional x-ray images on all of the tank's stringers using a backscatter method, NASA stated earlier.

The fuel tank is loaded with 535,000 gallons of super cold liquid hydrogen and liquid oxygen on launch day. The fuels are stored inside two inner tanks and at launch they mix together to power the orbiter's three main engines during the first eight-plus minutes of flight.

Discovery's launch remains targeted for February 3 at 1:37 am EST, from launch pad 39-A.

Discovery must launch during a brief window which ends on Feb. 10, or stand down until Feb. 27 due to activity centered around the orbiter's port-of-call -- the International Space Station.