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NASA Puts Redesigned Space Shuttle External Tank to the Test
Allard Beutel
Headquarters, Washington April 14, 2005
(Phone: 202.358.4769)

June Malone
Marshall Space Flight Center, Huntsville, Ala.
(Phone: 256.544.0034)

Jessica Rye
Kennedy Space Center, Fla.
(Phone: 321.867.2468)
Status Report: H-05-098

Oxygen vapors stream from the Gaseous Oxygen Vent Hood positioned above Space Shuttle Discovery during the April 14 tanking test. NASA engineers and managers are now evaluating the data from today’s Space Shuttle Discovery's External Tank (ET) tanking test at NASA's Kennedy Space Center, Fla. (KSC). The tanking test was yet another milestone in NASA's work to return the Space Shuttle safely to flight after more than two years of safety modifications to the ET.

The 11-hour test also readied Discovery’s main propulsion system and allowed technicians operating the hardware to gain first-hand experience on the redesigned tank. It also allowed crews to evaluate the overall operation of ground systems in preparation for launch of Discovery's Return to Flight mission, designated STS-114, being planned for next month.

"With the completion of this tanking test, NASA is one step closer to returning the Space Shuttle fleet to flight," said Michael Kostelnik, NASA's deputy associate administrator for International Space Station and Space Shuttle Programs. “Although we have further milestones to complete before we fly, we are proud of the technical advancements we have made the last two years to ensure a safe mission."

The tanking test consisted of ground crews at KSC filling Discovery's ET with liquid oxygen and liquid hydrogen fuel to evaluate how the orbiter, tank, Solid Rocket Boosters and ground systems perform under "cryo-load"-- when the tank is filled with two super cold propellants. During the test, NASA's ice/debris team thoroughly inspected the fueled tank from every angle, looking for frost and ice build-up. Although ice is expected to form on the tank in some areas, the team has strengthened its inspection criteria based on results from tests performed at several NASA centers and other research facilities.

"This test provides another data point for us to consider," said Neil Otte, chief engineer for the External Tank Project Office at NASA's Marshall Space Flight Center. "The information we gain will give us added confidence in the tank."

The tanking test is not required by NASA to certify redesigns that have been made on the External Tank. However, it’s done to demonstrate the effectiveness of the redesigned tank bipod heater system that replaces the original bipod ramp design, which had foam on it. The investigation into the Space Shuttle Columbia accident in 2003 determined foam broke free during launch from the bipod ramp, which attaches the Space Shuttle to the ET, and hit Columbia’s left wing causing a hole to open up. Columbia and its crew were lost during reentry 16 days later. Today’s test also checks out the new "drip-lip" design that’s intended to reduce the potential for ice accumulation on the liquid oxygen feedline bellows, which are joints that allow the tank's fuel line to adjust.

Eight similar tests have been conducted. Seven of those tests were performed from 1981 to 1983, the first three years of the Space Shuttle program. The first super-lightweight ET was tested prior to its flight on STS-91 in June 1998. There have also been seven flight readiness firings that included tanking and firing the main engines.

During launch, the ET delivers 535,000 gallons of liquid hydrogen and oxygen propellants to the three Space Shuttle Main Engines. The tank, the only component that cannot be reused, is covered by a polyurethane-like foam that insulates the propellants, keeps ice from forming on the tank's exterior and protects its aluminum skin from aerodynamic heat during ascent.

Photos of the tanking test can be found online at:

Video and sound bites from the tanking test will feed on NASA Television. NASA TV is available on the Web and via satellite in the continental U.S. on AMC-6, Transponder 9C, C-Band, at 72 degrees west longitude. The frequency is 3880.0 MHz. Polarization is vertical, and audio is monaural at 6.80 MHz. In Alaska and Hawaii, NASA TV is available on AMC-7, Transponder 18C, C-Band, at 137 degrees west longitude. The frequency is 4060.0 MHz. Polarization is vertical, and audio is monaural at 6.80 MHz. For NASA TV information, visit:

For the latest information on NASA's Return to Flight efforts, visit:

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