By Liz White, UT staffWashington-A newly designed external fuel tank, with various adaptations to its rigid polyurethane foam insulation covering, has been delivered to NASA's Kennedy Space Center in Florida, for the Space Shuttle Discovery's next missionIn the redesign, intended to minimise the risk of any polyurethane foam coming away from the tank and damaging the shuttle itself, the two Protuberance Air Load (PAL) ramps have been eliminated. These ramps protected a cable tray and two pressurised oxygen and hydrogen lines during the launch. The liquid oxygen ramp was 14-ft (4.3-m) long and weighed 14 lb (6.4 kg) while the liquid hydrogen one was 38-ft long and contains 21 lb of foam.Following last summer's shuttle flight, NASA's inspections, analysis and testing on external tanks at Michoud resulted in a decision that it would be safer to fly the remaining shuttle missions without the ramps. NASA said it will carry out wind tunnel testing to try and corroborate those conclusions. NASA's redesign of these parts followed the realisation that, during the previous flight, 16 pieces of foam came away from the tank. "Although the majority of these foam losses took place late in the ascent and, therefore, posed less risk to the Orbiter, the large size of some of the foam losses caused concern because they were much larger than analysis had predicted was likely," NASA's return-to-flight documentation says. Minor redesign of the ice/frost ramps and work on foam segments that cover support brackets along the pressurisation lines was also carried out. The tank's bipod fittings were also adapted to prevent nitrogen leakage into the intertank area. Void spaces beneath the cables in this region were eliminated with improved bonding, to ensure complete adhesive coverage.NASA's statement on the tank's movement from Michoud to Florida paid tribute to workers at the NASA Michoud Assembly Facility near New Orleans, who "persevered through their own personal hardships," to deliver the new tank. At Kennedy, the tank will go to the Vehicle Assembly Building for final checkout and will eventually be attached to the twin solid rocket boosters and Discovery for its mission (STS-121) to the International Space Station. NASA managers are targeting a launch window for Discovery in May, said a 24 Feb statement from NASA. PIC: The Pegasus barge carrying space shuttle external tank ET-119 approaches Port Canaveral in Florida just a few hours before docking at nearby Kennedy Space Center (NASA/KSC). "
