For the first time in weeks, there were smiles today along with the pot roast at The Idle Isle, which bills itself as "Utah's Fourth Oldest Restaurant."

"We were dead in the water till old Al got up there," said Ernie Apodaca, draped in an oversized blue "Thiokol Space Shuttle Team" windbreaker.

"We've been an easy target and I'm glad some people got to set the record straight," he said.

The dramatic testimony of Allan McDonald before the presidential commission investigating the destruction of the shuttle Challenger brought new cheer to this city. Morton Thiokol Inc. workers here made the solid rocket booster that appears to have played a role in the Challenger explosion.

McDonald, Thiokol's senior representative at the Kennedy Space Center at the time of the Jan. 28 launch, told the commission that no Thiokol engineer agreed to put the space shuttle aloft on that unusually cold day.

For more than a week, McDonald was the most sought-after man in the region when he let word seep out that he refused to sign off on the launch -- the first time a Thiokol chief engineer has done that.

Born in Montana and trained as a chemical and administrative engineer, McDonald, 48, has been with Thiokol for 26 years. He is known as a loner and an iconoclast.

"I have the highest regard for him as a professional and as a man," said Harold W. Ritchey, a longtime friend and former Thiokol president. "His integrity cannot be questioned, but he is not a conformist and sometimes that can be a cause of trouble in a large organization."

For many of the workers at the Thiokol plant, shock had turned to rage as they watched previous commission sessions.

Today, some of the testimony backed up what employes here have contended all along: that Thiokol engineers would never have allowed Challenger to fly if its safety was in jeopardy.

"Safety was always the first, second and last words they told us," said Robbie Johnson, a 26-year-old Thoikol worker who mixed propellant for the solid rocket booster.

"I think it's NASA's fault," he said. "We told them what they needed to know. They went ahead with the launch."

A senior management official, however, said that he was not sure the pressure would ever shift completely away from the company.

"Let's face it," he said, "NASA decides whether to launch but the bottom line is we signed off on it. We make these things and our signature is on a piece of paper that says it's okay to fly. Everything else is moot."

To the people of this predominantly Mormon town of 17,000 on the flat edge of the Rockies, the aftermath of Jan. 28 has been ugly at times.

Last week, after Thiokol announced that it would lay off 200 employes and put another 1,400 on four-day weeks, vandals painted the words "Morton Thiokol Murderers" on bridges leading to the 20,000-acre plant west of town.

Threatening phone calls to the company switchboard have prompted local police to patrol around the homes of Thiokol executives.

More than a third of Thiokol's employes are assigned to shuttle-related work, and its contract to build rockets for the shuttle brings several hundred million dollars each year to the business, which opened its plant here in 1957.

The initial booster contract covers the first 37 launches. Thiokol was negotiating a contract for 60 more launches when the 25th ended in disaster.

"We're just holding our breath now," said Mark A. Walker, an engineering administrator at Thiokol and a member of the City Council. "The thing that is so frightening is to see the Senate and the Congress posturing, raising the public fear. Some people are just getting a desperate feeling."