In October 1957, a beeping sphere streaked across the sky, striking terror in the hearts of unsuspecting Americans. Sputnik I, the first artificial satellite, had been launched by the Russians.

For the next decade, American schoolchildren were inundated with lessons on the space program, and it was intimated that if the United States lost the space race, and the Soviets landed first on the moon, the free world was doomed.Today those children can bring their children to see and touch the technology that once seemed so terrifying - a full-size replica of Sputnik hangs in an exhibit opening Friday at Boston's Museum of Science.

"Soviet Space" is the first major U.S. exhibit of Soviet space technology. It tears down yet another wall between East and West.

The exhibit represents "a new age in space," said Dana Wilson, the museum official who helped organize the show. "The new space age is cooperative."

Visitors through Sept. 23 can see working models of probes sent to Mars and Venus, a Soyuz space capsule, Soviet spacesuits, a returned moon probe, even Soviet space food. There's a fetching portrait of Laika, the first dog in space.

Cosmonauts Valentin Lebedev and Aleksei Leonov, the first man to walk in space, will visit during the opening week, and artifacts and history once shrouded in secrecy will be available for comparison with the U.S. program.

The exhibit brings to light Soviet failures along with successes. Included is a full-size model of the Phobos probe to Mars. An incorrect radio command caused Phobos I to lose contact with Earth in 1988 about six weeks after launch. Phobos 2 orbited Mars in 1989, gathering data for two months until it, too, was lost.

To create the exhibit, Wilson and J. Kelly Beatty, who covers the Soviet space program for the magazine Sky and Telescope, made two trips to the Soviet Union. All doors were opened to them, Wilson said, including those of a rocket factory.

"The feeling now is cooperation," Wilson said. "No one country can afford to have its own space program. Space belongs to all of us. You hear that over and over."

Despite the alarm caused by Sputnik and by cosmonaut Yuri Gagarin's becoming the first human in space in 1961, the superpowers have long collaborated on space, including the Soyuz-Apollo mission of 1975.

Today, Soviet and American scientists are cooperating on unmanned travel to Mars and hope some day to send a manned mission to the planet.

Although Americans "won" the race to the moon, the Soviets have racked up a long list of firsts, including the first human in space, the first spacewalk and the first woman in space (Valentina Tereshkova, 1963), Beatty noted.

Most impressive is their work in conditioning cosmonauts to long space stints, something necessary for flights to Mars or other planets, Beatty said.