The redesigned solid rocket boosters built by Morton Thiokol are the best anyone in the industry has come up with, and the firms bidding to build the second-generation shuttle boosters will be hard-pressed to improve them.

Gerald Smith, NASA's Marshall Space Flight Center solid rocket booster program manager, told several hundred Morton Thiokol employees gathered outside the company's main building Friday afternoon that the other firms have formidable competition from the status quo.Smith told the workers he doesn't believe anywhere in the history of the solid rocket motor industry that a better set of boosters than those that lifted Discovery back into space have been flown.

"We've got a big program ahead of us," with flights planned to explore Mars and Jupiter and build the space station, he said.

NASA now is ordering the next set if boosters that will lift shuttles into space through the mid-1990s, Smith said. Thiokol is expected to win the contract.

Teams of contractors are competing to win the estimated $1 billion bid to build, operate and produce the advanced solid rocket motors and its facilities.

Final proposals are due Oct. 31, with a decision expected in early 1989. One of those proposals is from Utah's Hercules Aerospace, which has proposed using graphite boosters to lift the shuttle into space in the next century.

"Those are things on paper. You've got things in this plant that are the best ever built," Smith told the cheering employees.

"We've got to do this thing right every time. I have every confidence that you will do it right every time."

Morton Thiokol workers helped make "the best solid rocket motor program that's ever existed," Smith said, as the cheers and whistles increased in the crowd.

Morton Thiokol did not bid on the NASA contract for the second-generation boosters, preferring to concentrate on resuming flights and improving the rockets used on the shuttle.

Scuttlebutt was the NASA contract, with its requirements the government own and the contractor build and operate the facility in Mississippi, was written to exclude Morton Thiokol. The theory was the national space agency wanted a tighter reign on what is produced for the space program.

But Dave Ewing, Morton Thiokol deputy director of program involvement, said in an interview that the current boosters will be used until the advanced solid rockets prove themselves flight-worthy.

"Also it's my own personal opinion that the final cost for the government-owned, contractor-operated facility hasn't been seen yet," Ewing said. "When it is, and when Congress has to ante up the money, and if we're at that time flying very successfully and have a highly reliable motor, I don't know why Congress would be motivated to pay the bill."