NASA to fix foam; launch still set for Oct. 23

NASA is going to remove and replace cracked foam covers on the external tank for shuttle Discovery's upcoming mission to the International Space Station, but launch remains scheduled for Oct. 23.

The extra work, however, will push back preparations for the planned Dec. 6 launch of Atlantis and a European science laboratory, making it less likely NASA will be able to send up that mission during a short seven-day window.

A chunk of foam the size of a baseball broke free from one of five aluminum brackets that held the liquid oxygen feedline to the tank used during Endeavour's Aug. 8 launch on an International Space Station assembly mission. The foam ricocheted off a metal strut attaching the tank to Endeavour, damaging fragile heat shield tiles on the underside of the orbiter.

NASA ordered up x-ray inspections of the brackets on the tank being readied for the planned Oct. 23 launch of Discovery. The 15-story tank now is located in the checkout cell on the northwest side of the Kennedy Space Center Vehicle Assembly Building.

The x-rays showed evidence of small hairline cracks in four of the five foam-and-cork covers that keep ice from building up on the brackets. Two different types of foam and cork laced with an epoxy bonding material are used to form the bracket covers, which are about three inches wide, five inches long and 2.5 inches thick. The cracks all were found in the cork layers of the covers.

Shuttle program manager Wayne Hale said the covers will be removed and then replaced with ones fashioned only from foam. The higher-density cork would be left out of the mix. The repair work on the foam covers on Discovery's tank is expected to take about nine days. That would leave about five days padding in the schedule leading to the Oct. 23 target date.

However, a consequential delay in the rollout of Discovery to launch pad 39A will stall preparations for the Atlantis flight in December. That's because long-overdue repair work in the Vehicle Assembly Building is temporarily limiting shuttle stacking operations to one high bay in the landmark edifice.

NASA is facing a seven-day window to launch Atlantis and the Columbus lab module. The mission cannot be launched between Dec. 14 and Dec. 29 because the sun angle on the docked shuttle-station complex would produce too much heat to be dispensed by radiators on the spacecraft.

IMAGE NOTE: Click to enlarge the NASA photo of ET-120 in the checkout cell inside the Kennedy Space Center Vehicle Assembly Building. Take a look at the workers on access platforms to get an idea of the size of the tank. Photo credit: NASA/George Shelton.