The two-year setback in America's space program from the Challenger disaster has not made the Soviets complacent about its lead in space, a University of Utah scientist says.

The successful Sept. 29-Oct. 3 Discovery flight will "place us back in the race, although I don't think the Soviets ever thought we were out of it. They have no doubt we're a major player," said Richard Shorthill, a research associate professor of mechanical engineering.Shorthill, who this summer attended the 28th meeting of COSPAR, an international organization of space scientists, said many Soviet scientists he met have great faith in America's technological capabilities.

The Soviets "respect our skill, our resilience and our experience in building new systems," he said.

The effort to launch the Discovery was not a major point of conversation during the two-week conference in Helsinki, Finland, he said.

"It can be summed up best by saying American scientists seemed to be holding their collective breaths, hoping for a successful launch. But nobody talked about it too much," Shorthill said.

The scientist who worked on the Apollo and Viking space programs in the 1960s and 1970s said the consensus of scientists was that the United States was wise to move cautiously in returning the redesigned shuttle to space.

The USSR's plans for manned and unmanned trips to Mars and U.S. plans for building a space station received the most attention, he said.

The space station would serve as a laboratory for long-term basic research in the almost perfect vacuum and microgravity of space and as a staging base for flights between the planets.