Morton Thiokol officials were being tight-lipped - perhaps suppressing smiles - about a new report by the congressional Aerospace Safety Advisory Panel.

The congressional safety panel will recommend in the report, to be released Tuesday in Washington, D.C., that NASA reconsider a $1.3 billion program to build a more powerful solid-rocket booster for the space shuttle, saying a new-generation rocket would be costly, time-consuming and less reliable.That's good news for Morton Thiokol.

But, said Morton Thiokol spokesman Rocky Raab, "We pledged not to try to influence NASA's decision at all."

Raab said Thiokol will support whatever decision NASA and Congress make about the future of the solid-rocket booster program, even if that means building a new booster factory in Yellow Creek, Miss.

Thiokol is tied to its ethical and moral commitment to build the current rocket motors as safely as possible and, because of that, determined not to bid on NASA's contract of reusable boosters, scheduled to be awarded next month.

But in an interview published a year ago in the Deseret News, John Thirkill, vice president of space operations, said he was stunned when he first heard of NASA's plans to build its own shuttle booster plant, and he questioned the wisdom of the announcement. "It's just not a smart thing to do," he said. "I think it would be a step toward nationalizing our industry."

He said he couldn't see the government investing hundreds of millions of dollars to duplicate facilities that already exist.

The recommendation from the Aerospace Safety Advisory Panel, coming only weeks before NASA is to award a contract for building an advanced-booster factory, has the space agency's managers scrambling to defend the program.

Members of the safety panel concluded that NASA could save money by further improving the existing shuttle boosters rather than building a new version, according to one member who spoke only on condition of anonymity.

An upgraded booster would require many years of testing and trial to prove its reliability, the panel member said.

With Congress looking to save money to meet deficit-reduction targets set by law, the panel's recommendation could threaten a program NASA considers crucial to improving the shuttle's performance and payload capacity.

The Aerospace Safety Advisory Panel was created by Congress after a 1967 Apollo launch-pad fire killed three astronauts. Its job is to review NASA's safety programs and issue a report once a year. Members were scheduled to release their recommendations during a meeting with space-agency officials.