The five top NASA executives at the Marshall Space Flight Center here involved in the decision to launch the shuttle Challenger a month ago said today they see nothing wrong with the agency's decision-making process, despite Thursday's conclusion by the presidential investigating commission that it is "flawed."

The National Aeronautics and Space Administration executives, in separate comments, said that nothing the investigation has revealed causes them to question anything they did prior to the Jan. 28 launch.

At Cape Canaveral, meanwhile, space agency officials announced that 1,100 shuttle workers there will be laid off or transferred and thousands will lose overtime in the largest cutback since 1970.

Only one of the five executives at Marshall, Judson A. Lovingood, deputy manager of the space center's shuttle projects office, hinted that there might have been a problem.

"All of us know," he said, "that there are risks in this hardware, that the equipment has failure modes. I think one thing perhaps we didn't realize is that there are also failure modes in ourselves." He did not elaborate.

William R. Lucas, director of the Marshall center, said: "I don't know what my people knew, but given what they say they knew, what they testified they knew, I think it was a sound decision to launch."

Lucas said nothing he has heard causes him to question the adequacy of the O-ring seals on the rocket boosters, which are the leading candidate as a cause of the accident.

"To my knowledge, we do not have evidence yet if the booster was the principal cause of the explosion and, if so, which aspect of that gave rise to the failure," he said.

"I'm not sure what Mr. Rogers means in terms of saying the decision-making process is 'flawed,' " Lucas added. "In my judgment, the process was not flawed."

Lucas spoke at a press conference on the 10th floor of the center headquarters here. The others, Lawrence B. Mulloy, manager of NASA's solid rocket booster program, George B. Hardy, deputy director of science and engineering at Marshall, Stanley R. Reinartz, manager of shuttle projects, and Lovingood spoke in separate interviews. All were key witnesses this week before the investigating commission, chaired by former secretary of state William P. Rogers.

"I think everything was done properly," said Mulloy.

"I know of nothing now that I should have done differently," said Hardy.

"Obviously, if I could have said, 'Hey, stop the launch,' I would have. But I had no reason to say that. I had a reason to proceed," said Lovingood.

Mulloy, Hardy and Lovingood participated in a prelaunch telephone conference with engineers from Morton Thiokol Inc. in which the Thiokol engineers initially expressed strong reservations about a cold-weather launch.

Thiokol makes the solid rocket boosters that help power the shuttle into orbit, and the design and operation of those boosters is supervised by Mulloy, Hardy, Lovingood and others at Marshall.

The Thiokol engineers were concerned that any launch below 53 degrees Fahrenheit might cause the seals on the booster to malfunction, causing the shuttle to explode. Those reservations, known to officials here, were subsequently overruled by Thiokol's managers.

The four engineers interviewed said that they had been watching the Challenger launch at control consoles, either at Marshall or Cape Canaveral, on Jan. 28.

"I just sat in disbelief," said Lovingood. "It took me several minutes to realize what had happened. In fact, I think I said, 'What happened?' and somebody said, 'It exploded.' I guess I just had a difficult time accepting that."

Lovingood added that "for two days, I couldn't watch the explosion on TV. I just couldn't."

Mulloy, who has assumed a central role in the investigation because Thiokol engineers testified he had pressured them to reconsider their recommendation against the launch, was at Cape Canaveral.

"It was just a shock . . . . I had a very sinking feeling," he said. "But from what I could see from that point, there was no way I could tell what happened. I thought about a lot of things in the booster system but, while I was thinking, I was watching the boosters fly intact down range."

All four said it was several days after the explosion before they recalled the prelaunch conference on the seals and the cold weather.

"It was at least two or three days later, after we started getting information on the possible involvement of the solid rocket booster," Hardy said.

"I don't think I started thinking about it until I saw that film, which showed an indication of fire" in the right-hand booster rocket, said Lovingood.

Several of the men said they thought that they had trouble conveying their version of events to members of the presidential commission and that this may have contributed to the testy tone of some of the questions the commissioners addressed to them.

"We're engineers. I've got a PhD in math," Lovingood said, "and that makes me tend to think one way and try to communicate one way. I found it difficult to communicate with some members of the commission. And that's not critical of them. But . . . . an engineeer does not think like a lawyer might think."

"We at NASA have never considered ourselves infallible," Lucas said. "We've had a long history of success. We've been very fortunate in that regard. I think the public came to expect that we wouldn't have any problems at all. Certainly, when that happens, then you disappoint people."