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Morton Thiokol had another winner Friday as it successfully fired a redesigned rocket booster in subfreezing temperatures.

Dust and debris were kicked up as the 5,000-degree flame from the rocket consumed part of the foothill. A river of snow flowed down the hillside."The nation has a new president today and a new success in the space program," said Royce Mitchell, solid rocket motor program manager.

The 120-second firing culminated a three-year redesign effort that shook up the space industry and the way the nation views manned missions.

"Now we are prepared to launch at any condition" either at Cape Canaveral, Fla., or Vandenberg Air Force Base, Calif., said Gerald Smith, NASA's solid rocket booster program manager.

The booster consumed more than 1 million pounds of rubbery propellant in the cold-fire test. To test the booster, engineers cranked up the refrigeration in test bay T-97 at Morton Thiokol's Wasatch Operations plant for more than 30 days.

The rocket fuel's mean temperature at firing was an estimated 40 degrees Fahrenheit, while skin temperature of the booster was 20 degrees.

"That is by far the coldest motor ever fired in the manned space program and provides us considerable margin" in determining both safety and stress factors, said Mitchell.

Sub-freezing temperatures on Jan. 28, 1986, allowed gases to flow through flawed O-ring seals on a right-side booster rocket and ignite the shuttle Challenger's huge external fuel tank. The disaster put America's space program on hiatus while commissions and NASA revamped the boosters and made the program more cost-efficient.

"This test is somewhat of a landmark because this is the final test" required in the redesign program, Mitchell said, describing the redesign as a "long, hard and arduous test program."

"We will not stop testing today, however," he said. A test using Challenger-style hardware is scheduled next month and includes some design changes in the rocket's nozzle area. The tests using boosters on hand "will enable us to continue to test . . . to show we are continuing to build high-quality motors."

The six tests conducted jointly by Thiokol and NASA were ordered by the presidential commission that investigated Challenger. Although there have been two successful missions, and another is set for February, the cold-fire tests were required to ensure the changes will work in cold weather as advertised.

"The bottom line is we didn't see any indication of any anomolies" in the rocket, Mitchell said. "We do see many indications of a good motor. It's a good day for us."

Heaters positioned on the joints and igniter maintain temperatures above 66 degrees.

"It's a very good test for the functional temperature of those heaters," said Allan McDonald, Space Operations vice president of engineering for Morton Thiokol.

Aside from testing the heaters, loads similar to the stresses at launch were introduced on the 126-foot rocket that is anchored horizontally on the Promontory foothills, about 25 miles east of Brigham City.

"What we're trying to duplicate is the worst structural loading those rockets will see," McDonald said.

The test was delayed 90 minutes while weather watchers waited for upper-level winds to improve. The state Air Quality bureau requires winds of at least 15 mph for the open-air burn. Winds were clocked at about half that at 11:30 a.m. so the test was pushed back. Additionally, freezing temperatures at the test site caused icing on the tracks over which the test bay is moved to expose the booster.

Thiokol spokesman Rocky Raab also announced Friday that analysis of the rockets launched on the shuttles Discovery and Atlantis last year showed a near-perfect performance.