NASA and the aerospace industry, for the second time this year, are scrambling to determine how to cope with the closure of a sole-source supplier of needed material for the space program.

Solid rocket motor industry officials Friday were huddling behind closed doors in Salt Lake City to figure out how to maintain supplies of a rayon fiber used in boosters for space shuttle and military flights.Meetings Thursday and Friday were attended by representatives from Morton Thiokol, Hercules Aerospace and virtually every heavy-weight firm producing solid rocket motors as officials tried to trouble-shoot the situation.

Avtex Fibers-Front Royal Inc., NASA's sole source of the fiber, announced earlier this week that its Virginia manufacturing facility would cease production of fiber products on Thursday.

Huddling industry officials refused to answer reporters' queries, saying they would "muddle through" the situation and make a comment sometime in the next week. The closure also puts 1,300 Avtex employees in Virginia out of work.

NASA officials, meanwhile, remain optimistic the problem can be resolved.

"First of all, we're hoping that the industry guys will come up with some type of industry deal," said Royce Mitchell, solid rocket motor program manager for NASA's Marshall Space Flight Center in Huntsville, Ala. "We'd prefer not to get involved too heavily."

Avtex said rising costs of rayon's main ingredients, wood pulp and caustic soda, coupled with cheaper South African pulp used by foreign competitors, squeezed it out from the marketplace.

Space and military officials faced a similar problem in May when a fire and explosion at Pacific Engineering Production Co.'s Henderson, Nev., plant, which supplied an oxidizer for rocket fuel, caused a shutdown of the production of ammonium perchlorate.

The difference is that following the PEPCON fire, Kerr-McGee Corp., which supplied ammonium perchlorate to other users, picked up the slack. Avtex has no other U.S. competitor to provide quality-assured rayon for the space program.

"Just because there's another source doesn't mean the quality assurance is known," Morton Thiokol spokesman Rocky Raab said.

Morton Thiokol Inc. is the largest user of the fiber, which is wrapped, coated to make it resistant to the 5,000-degree heat of ignition and used in rocket nozzles for shuttle and military programs.

"We've done an inventory of what's on hand and what's coming down the pipeline and there's sufficient materials for 10 shuttle flights beginning with Atlantis," which is scheduled for lift-off later this month, Raab said.

Still, the amount of approved rayon on hand will take Thiokol and NASA through the end of the decade. The shuttle program uses less than 5 percent of Avtex's production, NASA said in a news release.

"We've got some time but we can't dawdle around," Mitchell said, adding, "we've got to get after it and make sure we protect ourselves."

Avtex currently is negotiating with NASA and the Department of Defense on ways the government could help the firm that is the only supplier of aerospace-grade rayon.

Avtex, along with its financial problems, also has had difficulties complying with Virginia's environmental and worker safety standards.

"We're constantly trying to assess where we might have vulnerabilities like this," Mitchell said in a telephone interview from Alabama. "Nobody likes to be tied to a single source of anything."

In a related action, the Bureau of Land Management will set aside 21,000 acres in northwest Las Vegas for Kerr-McGee to use for storage of ammonium perchlorate. The firm doubled production of the oxidizer after the PEPCON explosion.