NASA has extended to September 2008 its six-year, $1.15
billion contract with Lockheed Martin Space Systems, New
Orleans, to provide 35 Super Lightweight External Tanks for
the Space Shuttle Program.

Under the modified contract, the 35 tanks will be produced at
a rate of not less than six per year, versus the eight per
year agreed upon in the original contract issued in October
2000. The modification adds $341 million to the contract.

The contract includes the manufacture, assembly, test and
delivery of the Super Lightweight Tanks and the operations
and maintenance of NASA’s Michoud Assembly Facility in New
Orleans. The contract also includes activities at NASA’s
Marshall Space Flight Center, Huntsville, Ala., and Kennedy
Space Center, Fla. This is the sixth contract for production
of tanks and the first to be comprised totally of Super
Lightweight Tanks.

This latest version of the tank, which flew for the first
time in June 1998, is the same size as the tank it replaces,
but is about 7,500 pounds (3,401.9 kilograms) lighter. Since
the tank goes almost to orbit, every pound of weight saved is
equivalent to a pound of increased payload. The weight
reduction allows the Space Shuttle to carry more payload.

The Super Lightweight Tank features major changes in
materials and design. Its liquid hydrogen tank and the liquid
oxygen tank are constructed of a new aluminum lithium, a
lighter, stronger material than the metal alloy used to
manufacture previous External Tanks.

The External Tank, which holds the liquid hydrogen fuel and
liquid oxygen for the Shuttle’s three main engines, is the
largest single component of the Space Shuttle and the only
part of the Shuttle that is not reused. Standing 154 feet
tall (approximately 50 meters), the gigantic rust-colored
tank is taller than a 15-story building and as wide as a
silo, with a diameter of about 27.5 feet (approximately 8
meters).

During launch, the tank also acts as the structural backbone
for the Shuttle orbiter and Solid Rocket Boosters attached to
it. The first tank of the sixth production is scheduled for
delivery to the Kennedy Space Center this year. Marshall is
NASA’s key leader for development of space transportation and
propulsion systems.