Problem cancels moon rocket test firing in Utah

PROMONTORY, Utah -- A mechanical failure forced a NASA contractor on Thursday to call off the first test firing of the main part of NASA's powerful new moon rocket.

The test wasn't immediately rescheduled as officials scrambled to learn the root cause of the failure.

Alliant Techsystems called off the rocket burn with just 20 seconds left on the countdown clock. Operators cited failure of a power unit that drives hydraulic tilt controls for the rocket's nozzle. The rocket was anchored to the ground in a horizontal position for the test.

It was a setback for a carefully staged, $75 million event that drew thousands of onlookers. Alliant hoped the routine test would prove the performance of a new program for space exploration that, like the test rocket, may not fly because of NASA budget problems.

There was no indication anything was wrong with the rocket itself, which packs 1 million pounds of chemical propellant, enough to boost a 321-foot-long vehicle 190,000 feet into the atmosphere.

At a news conference in Utah, officials said the power unit for the nozzle controls, which steer a rocket in flight, was robbed of fuel, apparently because of a faulty valve.

That had potential implications for the space shuttle, which uses a nearly identical system. Officials in Utah notified their counterparts at the Kennedy Space Center in Florida, where NASA has had to twice delay the launch of Discovery for other reasons.

The Ares test problem could introduce a new delay in the launch of Discovery, previously set back because of weather and again because of a problem with a different shuttle fuel valve.

Shuttle managers said Thursday they will examine what went wrong with Ares and decide by early Friday whether to go ahead with a launch set for 11:59 p.m. ET Friday.

In Utah, Alliant executives said their valve problem had never before emerged to scrub a rocket's test firing. Engineers could have fired the rocket anyway, but they halted the two-minute burn because they wouldn't have been able to test the agility of the rocket nozzle.