Shuttle Booster Fired in First of Six Ground Tests

A shuttle booster rocket spewing a 500-foot-long jet of flame was successfully fired for two minutes Wednesday in the first of six ground tests to prove that engineers have eliminated flaws that led to the Challenger explosion, a spokesman said.

Smoke soared thousands of feet into the air; the ground shook, and a roar like prolonged thunder swept through the remote Morton Thiokol Inc. desert test range, 25 miles west of Brigham City and about 70 miles northwest of Salt Lake City.

Allan J. McDonald, director of Morton Thiokol’s effort to make the boosters safe, said all indications were that the 126-foot, 2.65-million-pound rocket, fired in a horizontal position, performed as planned, although he said a complete analysis will take a month.

Opposed Launching

“All in all, the motor was very successful,” said McDonald, a Morton Thiokol engineer who argued against launching the Challenger on Jan. 28, 1986, because of concern that cold weather would weaken seals between the joints of boosters carrying solid propellant.

The Challenger was destroyed and its crew of seven died when a joint between the lower two fuel segments of the shuttle’s right booster ruptured, a presidential commission found. Hot gas ate through two rubber O-ring seals with catastrophic results.

The test Wednesday did not feature the major elements of the new joint design, but the rocket did test new O-ring materials, heaters to keep the joint seals warm and different types of insulation to protect the seals from the 5,000-degree flame generated inside the rockets.

The first booster with all the design changes is scheduled to be test-fired in August.