Lightning, Payload Flaw Not Held Threat : Launch of Discovery Presses Forward

Despite periodic flashes of lightning in the Florida sky and a brief concern over the payload aboard the shuttle Discovery, officials pressed forward here Tuesday with the expectation of launching the big bird Thursday morning.

“In general the whole picture is very good for going flying,” veteran astronaut Robert L. Crippen said at the conclusion of an exhaustive review of launch progress.

Crippen heads a management review committee of about 20 people that was set up in the aftermath of the Challenger disaster to ensure that any concerns on the working level are brought to the attention of top management.

Identical Satellite

That process was clearly evident Tuesday after engineers at the space center discovered problems with a future payload that is identical to the huge tracking and data relay satellite nestled in Discovery’s cargo bay. About seven hours after Discovery is launched, a solid-rocket propulsion system attached to the satellite is to blast it to high Earth orbit.

A sister satellite is to be launched next February, and while working on that satellite’s propulsion system Monday, engineers here discovered a small cut in one of the O-rings used to seal the nose of the small satellite rocket.

If the seal failed, the rocket would not reach its proper orbit and the $100-million satellite would almost certainly be lost.

Failure of the satellite’s rocket would not pose any danger to the shuttle’s five-man crew because the shuttle drifts about 50 miles away from the satellite before the rocket is fired. But officials were concerned for a while that “the problem could be generic” and the rocket on the satellite aboard Discovery could be similarly flawed, said Parker Counts of NASA’s Marshall Space Flight Center in Huntsville, Ala.

However, that concern was eased when workers examining the rocket that will be used in February found a small “burr” on the rim where the O-ring fits. Engineers are reasonably satisfied that the ring was cut by the burr during assembly, said Air Force Col. Dennis E. Beebe, who supervises part of the program.

Manufacturing Defect

The burr, he added, is believed to be a “manufacturing defect” and there is no reason to believe that the rocket in Discovery’s cargo bay is similarly flawed, and engineers do not plan to physically examine it, a procedure that would delay the flight.

Weather forecasters were still predicting favorable weather for Thursday’s launch, although the Kennedy Space Center was repeatedly subjected to “lightning alerts” and intermittent thundershowers Tuesday.

“We had lightning within 5 miles of the pad” Tuesday morning, said Chuck Henschel, a NASA test supervisor. The lightning forced a brief suspension of some operations at the launch pad, but officials expected to have little trouble making up that time. The weather was sufficiently inclement, however, to have prevented a shuttle launch Tuesday morning.

But it was not foul enough to keep two of the crewmen on the ground. Discovery commander Frederick H. Hauck, 47, and co-pilot Richard O. Covey, 42, spent part of the day flying an aircraft that has been designed to handle like the shuttle. The weather, however, kept them from flying it as long as they had hoped.

Meanwhile, crewmen John M. Lounge, 42, David C. Hilmers, 38, and George D. Nelson, 38, spent most of the day checking out the equipment they will use during the four-day mission, which is scheduled to begin with liftoff at 6:59 a.m. PDT on Thursday. The countdown will begin early this evening.