Shuttle Liftoff Aborted With Seconds to Go

A dangerous engine shutdown aborted Discovery’s launch at the last moment Thursday, delaying the flight for up to six weeks and setting back NASA’s already snarled shuttle program.

It was the second engine shutdown this year and only the fourth in the program’s 12-year history.

“We know we can launch them and we know we can operate the system safely,” said John Logsdon, director of the Space Policy Institute at George Washington University. “What we are finding out is we cannot operate the systems so we’re certain we’re ready to go on any given day.”

All three main engines on Discovery fired on cue with 6 1/2 seconds left in the countdown and were roaring when the shuttle computers automatically shut them down three seconds later. A white, billowing cloud engulfed the launch pad as NASA officials rushed to prevent the 4.5-million-pound shuttle from leaking fuel or throwing off sparks.

Within an hour, all five astronauts were off the shuttle.

“We’ll be back,” commander Frank Culbertson Jr. said before crawling out of the cabin. “Call us when you’re ready.”

“We can’t get much closer,” replied shuttle test director Mike Leinbach.

NASA came within 19 seconds of sending Discovery on the satellite-delivery mission July 24 and within one hour on July 17. Both countdowns were halted by mechanical failures, one at the pad and one in Discovery’s right solid rocket booster.

This time, the problem appeared to be with an instrument designed to monitor the fuel flow for a main engine.

Launch director Bob Sieck said the launch delay probably would last at least three weeks, perhaps six. The flight already was running one month late; NASA had postponed the launch from last week to avoid potential damage from Wednesday night’s meteor shower.

“We’ve had three scrubs and a delay, and every one of them was a totally independent event,” Culbertson said. “They weren’t related to each other at all. They could have happened in four separate missions. . . . It happened to happen in one mission four times.”

Shuttle operations director Brewster Shaw said he will study the many hardware problems to make sure they are unrelated and not due to shuttle operation budget cuts or some other factor. The last time shuttle engines shut down at the pad was in March on Columbia.

“Are we starting to squeeze the program too hard? I think the answer is no,” Shaw said. “I think these were unrelated string-of-bad-luck items, but I do intend to answer that question.”

Eight shuttle flights had been planned by the National Aeronautics and Space Administration this year, but Discovery’s repeated delays virtually guarantee that there will be only seven.

“Every launch is a unique venture, not like an airplane. We have to live with it,” said Gerhard Brauer, an official with the German Space Agency, which had a science satellite aboard Discovery.

Aaron Cohen, director of the Johnson Space Center in Houston, said the shuttle must become more reliable.

“We tend to be a little bit more on the conservative side for the shuttle orbital missions, which I think is prudent because we’re protecting a very valuable resource,” Cohen said.

Many stringent launch rules were instituted after the 1986 Challenger explosion, which killed seven crew members.