BRIGHAM CITY, UTAH, DEC. 23 -- -- Engineers successfully test-fired a completely redesigned space shuttle booster rocket today, passing another critical milestone in America's return to manned space flight.

The two-minute test, following a 90-minute delay in the countdown because of snow, sent light-brown smoke billowing hundreds of feet above and behind the horizontally positioned rocket as it burned 1.1 million pounds of solid propellent.

"The time was right and the plume was good. That looked like it was dead-on," said Carver Kennedy, vice president for space services of Morton Thiokol, builder of the rocket.

The full-scale test was the second of four required by the National Aeronautics and Space Administration before shuttle flights can resume in June. The third is set for sometime in March and the fourth in April.

The test was originally scheduled for last Saturday but was scrubbed because of problems with ground-support circuitry.

The firing today posed a test for the efficiency of new rocket joint heaters as wind-chill temperatures fell to an estimated 25 degrees Fahrenheit below zero. A presidential commission found that cold pre-launch weather may have contributed to failure of O-rings sealing a joint on one of the two boosters of the space shuttle Challenger, which exploded Jan. 28, 1986, killing its seven-member crew.