50 years ago: NASA selected a contractor for the space shuttle's external tank
In January 1972, President Richard M. Nixon ordered NASA to build the Space Shuttle, a revolutionary and partially reusable space transportation system designed to reduce the cost of sending hardware and people into low Earth orbit. The main components of the system included a winged reusable orbiter, two reusable lateral boosters and a large central external tank, the only expendable main element. In August 1973, NASA selected Martin Marietta to build the external tank for the Space Shuttle. The first contract called for the contractor to design, test and deliver to NASA the first six external tanks (ETs) as well as three ground test cells. Subsequent contracts included the delivery of 136 ETs over the life of the Space Shuttle program, including significant weight reduction measures to increase the system's overall payload capacity.
Left: In January 1972, NASA Administrator James C. Fletcher, left, and President Richard M. Nixon hold
model of the space shuttle as they announce the decision to build a new space transportation system.
Middle: Close-up of the model, showing the winged orbiter, two lateral launch vehicles,
and a central external tank. Right: Schematic of the shuttle's outer tank.
ET was the third major purchase of NASA's space shuttle program, after the orbiter itself and the shuttle main engines. The ET served as a shuttle fuel tank, placed externally to reduce the weight and complexity of the orbiter itself. Its two tanks supplied liquid hydrogen and liquid oxygen to the orbiter's three main engines just seconds from liftoff until just before insertion into orbit. The orbiter then jettisoned the alien, which burned up on reentry. The ET also served as the Space Shuttle's structural backbone, with attachment points for both side-mounted rocket boosters (SRBs) and the winged orbiter. On April 2, 1973, NASA issued a request for proposals (RFP) to four companies—The Boeing Co., New Orleans; Chrysler Corp. Space Division, New Orleans; McDonnell Douglas Astronautics Co., Huntington Beach, Calif.; and Martin Marietta Corp., Denver. On May 17, all four companies submitted proposals to NASA's Marshall Space Flight Center (MSFC) in Huntsville, Alabama, the center responsible for overseeing ET development and production. On August 16, NASA announced the selection of Martin Marietta to design, build, test and deliver the ET for the space shuttle program. This initial cost-price contract included six flight tanks and three ground test tanks valued at $107 million by 1978.
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