NASA steps up preparations at Kennedy for Discovery return-to-flight mission
The external tank (ET) that will be used for the Discovery STS 114 return-to-flight mission - due be launched after 14 May - was shipped from NASA's Michoud Assembly Facility, Mississippi on 31 December for the Kennedy Space Center (KSC).
The insulation-foam-covered ET 120 will be mated to two solid- rocket boosters in the vehicle assembly building at the KSC.
Several modifications have been made to the ET since the Columbia re-entry accident on 1 February 2003, which killed all seven crew. The in-flight break up resulted from the loss of insulation foam from the ET's upper, raised bipod ramp area that hit the orbiter's left-wing leading edge during launch. This caused a breach that allowed hot gases to invade the interior of the wing during re-entry. The foam insulates the liquid-oxygen and liquid-hydrogen propellants and keeps ice from forming on the tank's exterior, while protecting the vessel's aluminium skin from aerodynamic heating during flight.
The bipod area now includes struts that directly connect the upper section of the ET to the orbiter, eliminating the ramp. Heaters have also been installed on the strut attachment fittings to prevent the ice build-up that contributed to the accident.
TIM FURNISS / LONDON
Source: Flight International
