NASA Says Tanks for the Boost

There was something new on NASA’s most recent space shuttle Discovery launched from NASA’s Kennedy Space Center, Florida, in the form of a new external fuel tank, ET-128. The new fuel tank features design changes made to improve performance and flight safety. They have been assessed by the External Tank Project Office and contractor teams’ STS-124 flight performance review as the best that have ever flown.

STS-124 post flight analysis of ET-128 revealed no observed foam loss from either liquid oxygen feedline brackets or hydrogen tank ice frost ramps. These redesigned elements flew for the first time on ET-128. The redesign of the foam in those two areas on ET-128 and all subsequent tanks dramatically reduces the potential of liberated foam during the first 135 seconds of launch, which is the most critical time concerning foam loss. The ET-128 is the first tank to fly with all Return to Flight improvements incorporated during production instead of being added after manufacturing was complete.

Lockheed Martin Space Systems workers have built and assembled space shuttle external tanks at NASA’s Michoud Assembly in New Orleans, Lousiana, for more than 30 years. The workers were commended for their commitment to continue building quality tanks and delivering them on schedule, despite hardships they face in the continuing aftermath of hurricanes Katrina and Rita in 2005.

The agency is gearing up for the transition from shuttle to the Constellation Program, which is responsible for development of NASA’s next generation of crew exploration and launch vehicles and related systems and technologies for exploration of the moon, Mars and destinations beyond.

ET-127, the external tank for the next shuttle mission, STS-125, departed Michoud on July 10, headed to the Kennedy Center, where it will be mated to space shuttle Atlantis and prepared for a scheduled October 8 launch on a servicing mission to the Hubble Space Telescope. ET-129, the next tank, is scheduled for delivery to NASA later this summer and will fly on space shuttle Endeavour on the STS-126 mission to the International Space Station. Launch is scheduled November 10. Endeavour also will serve as a backup rescue mission for Atlantis, if needed.

At 153.8 feet long and 27.6 feet in diameter, the external tank is the largest and, when loaded, the heaviest element of the space shuttle. It consists of three major components, the liquid oxygen tank, an unpressurized intertank that contains most of the electrical components and the liquid hydrogen tank. The giant, rust-colored structure is the “gas tank” for the orbiter and contains the propellants used by the space shuttle main engines. The tank also is the “backbone” of the shuttle during launch, providing structural support for attachment with the solid rocket boosters and orbiter. It is the only component of the space shuttle that is not reused. Approximately 8.5 minutes into the flight, with its propellant used, the tank is jettisoned and falls in a preplanned trajectory with the majority of it disintegrating in the atmosphere and the remainder falling into the ocean.