NASA Places Countdown of Atlas Launch on Hold

Seeking a fourth straight U.S. space launch success and continued rebound from a disastrous 1986 start, NASA readied an Atlas-Centaur rocket Thursday night for an after-dark launch of a $125-million military communications satellite.

The countdown that began during the morning, aiming for liftoff of the two-stage, 137-foot-tall booster at 6:04 p.m., was put on hold five minutes before scheduled launch time, officials said.

A success would continue a modest string of successes that began in September with the launch of a Delta rocket carrying a payload for the Reagan Administration’s Strategic Defense Initiative program, popularly known as “Star Wars.”

Since then, an Atlas launched a weather satellite and a Scout booster orbited a science payload.

Those flights followed a nightmarish 1986 start for the U.S. space program. The space shuttle Challenger exploded on Jan. 28, killing seven crew members; an Air Force Titan 34D exploded on April 18 as it boosted a reconnaissance satellite, and a Delta failed on May 3 with a weather satellite aboard.

Before those failures, space shuttles had logged 24 straight successes and the Delta and Titan rockets had recorded success rates of better than 90%, including 43 in a row for the Delta.

The accidents grounded U.S. unmanned space rockets for several months. The shuttle will not fly again until at least February, 1988.

Military Payload

The launch scheduled for Thursday night is the National Aeronautic and Space Administration’s last one schedueled in 1986.

The Atlas-Centaur payload is the sixth in a series of Fleet Satellite Communications satellites developed by the Navy and TRW Inc. Operating in stationary orbit 22,300 miles high, the satellites relay ultra-high frequency communications over 23 channels to military commands around the world.

The launching previously has been delayed eight times in seven months. It originally was scheduled last May 22, but after the May 3 Delta failure it was postponed because of similarities between the Delta and Atlas guidance systems. A faulty guidance package was blamed for the Delta failure.

That problem was resolved, but a series of other technical problems forced other delays.

NASA conceded that it is being exceedingly cautious because of the earlier failures.