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Morton-Thiokol Delays Test-Fire Full-Scale Rocket Redesign

August 27, 1987

BRIGHAM CITY, Utah (AP) _ A critical first full-scale test of a redesigned space shuttle rocket was aborted today with less than 20 seconds to go before the firing was to begin.

With more than 500 VIP guests watching, technicians from Morton Thiokol Inc. counted down the firing test to within seconds and then announced the test had been aborted.

A few minutes later, officials announced the water-deluged system had failed and that the test would be tried later in the day after technicians evaluate the problem with the water cooling system.

An 8-inch water line sprung a leak, said Morton Thiokol spokesman Roland Raab. The water is used to cool the back of the rocket after it is fired, and is not part of the rocket itself, but is a component of the test stand. The 1.1 million-pound rocket, redesigned to correct the flaw that destroyed Challenger, was fitted with more than 500 monitoring instruments for its first full-scale test, to be done on a horizontal test stand.

Solid propellant in the 126-foot-long rocket was to burn for about two minutes and develop internal pressures typical of a space shuttle launch.

Engineers installed instruments to monitor acceleration, internal pressure, deflection, thrust, strain, temperature and electrical properties.

Following the test, officials said, the rocket joints will be taken apart, allowing engineerings to search for any gas leaks.

A leak from one of the joints in a Thiokol booster was blamed for the Jan. 28, 1986, explosion that destroyed Challenger and killed its seven crew members.

A presidential commission determined that superheated gases escaped through the joint seal, past two rubberized O-rings, igniting propellant in the shuttle’s external fuel tank and causing an explosion 73 seconds after launch.

Since then, Thiokol and National Aeronautics and Space Administration engineers have redesigned the rocket joint.

The new features on the redesigned space shuttle rocket include a metal lip to prevent the joints from opening under pressure; an additional O-ring seal; insulation designed to seal itself, and heaters to keep the joint at 75 degrees.

The scheduled firing was the first of five full-scale tests of the new design. If all goes well, NASA plans to resume flights of the grounded space shuttle fleet, with the first mission scheduled for June 2.

Thiokol and NASA engineers at the Marshall Space Flight Center in Huntsville, Ala., have conducted a series of subscale rocket firings, using both the flawed Challenger-style rocket and the elements of the new rocket design.

A new test stand will be used next year to chill the rocket casing for a full-scale firing. Cold weather on the morning Challenger was launched is thought to have been a factor in the failure of the rocket.

The test comes two days after a solid rocket being developed for NASA’s Delta launch vehicles by Morton-Thiokol skidded along the ground for about 100 yards after a motor failed during a test firing at Huntsville.

The Delta flight program is not part of the space shuttle program.

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