The external tank that will fuel NASA's next space shuttle during launch arrived at the agency's Florida spaceport late Wednesday after a five-day trip along the Gulf Coast.
NASA's Pegasus barge delivered the Lockheed Martin-built External Tank-119 (ET-119) at Kennedy Space Center (KSC) in Cape Canaveral, where it will be used to fuel the Discovery shuttle's launch during the upcoming STS-121 spaceflight later this year.
The arrival of the 15-story, orange tank, which holds the liquid oxygen and liquid hydrogen propellant that fuel a shuttle's main engines during liftoff, brings all of the necessary components for Discovery's STS-121 mission to KSC.
Discovery itself sits in its Orbiter Processing Facility, where engineers are working to prepare it for flight. The shuttle's twin solid rocket boosters, which stand to either side of the external tank during launch, are being assembled in the massive, 52-story Vehicle Assembly Building where ET-119 now sits.
NASA hopes to launch ET-119 and the STS-121 mission, commanded by veteran astronaut Steven Lindsey, as early as May 10, though an official flight date has yet to be set. The mission, NASA's second test flight following the 2003 Columbia disaster, will test orbiter inspection methods, heat shield repair techniques, and deliver vital supplies to the International Space Station (ISS).
The mission is also expected to deliver a third space station crewmember - the European Space Agency (ESA) astronaut Thomas Reiter - to return the ISS to a three-person crew.
ET-119's arrival at KSC is the culmination of months of hard work, especially for Lockheed Martin employees at NASA's Michoud Assembly Facility in New Orleans, Louisiana, who prepared the shuttle fuel tank while simultaneously recovering from the effects of Hurricane Katrina. The hurricane devastated the Gulf Coast in September 2005, causing widespread flooding and damage that left many homeless.
"The workforce there is really proud of what they've done," NASA shuttle program manager Wayne Hale said of the Michoud workers Tuesday during a press conference. "My hat is off to them."
Engineers have stripped a protective insulation-covered ramp from ET-119 to prevent the type of foam shedding seen during NASA's first post-Columbia flight, the STS-114 mission also aboard Discovery, last July. A similar foam shedding event also damaged the Columbia orbited during its 2003 launch, breaching its heat shield and dooming its seven-astronaut crew during reentry.
NASA hopes that external tank wind tunnel tests will prove that pressure and fuel lines once covered by the removed ramp can withstand the stresses of launch.
"The proof is in the wind tunnel tests," Hale said Tuesday. "If we find a surprise in the wind tunnel that's good, because you want to find it out in the wind tunnel and not on the flight vehicle.
"The thing that's going to pace getting Discovery off the ground is not the work we're doing at the Kennedy Space Center," Hale added. "It is the engineering analysis and tests that go toward proving what we have assembled is safe to fly."
Hale and other shuttle program officials will meet Thursday to discuss NASA's orbiter flight progress.