The Soviet Union's space program has suffered two major failures involving products it is attempting to sell to Western customers: the Proton rocket and highly detailed satellite images of Earth.

On Jan. 31, the Soviets destroyed a Cosmos 1,906, an imaging satellite, after it malfunctioned, in order to prevent it from reentering the Earth's atmosphere out of control and possibly falling into U.S. hands, the magazine Aviation Week & Space Technology reports in the issue to be published Monday. The failure was confirmed by Air Force and other Soviet watchers in the United States.

Explosion of the imaging satellite, which was not announced by the Soviets, reportedly cost them $50 million to $100 million and scattered more than 100 pieces of debris in orbit.

The Cosmos craft was taking pictures of Earth for sale by the new marketing organization Soyuzkarta, whose highly detailed offerings have attracted the interest of scientists in the United States, including some at the U.S. Geological Survey who have asked for government approval to purchase them.

The craft was launched on Dec. 26 and usually would have remained aloft about two weeks before being returned to Earth with a load of film.

The other failure, disclosed Thursday by the official Soviet news agency Tass, occurred Wednesday when a Proton rocket's fourth stage failed to boost three Glonass advanced military navigation satellites into their planned 12,000-mile orbit. The satellites, which reached an altitude of 100 miles, "entered dense layers of the atmosphere and ceased their existence," Tass said.

The Space Surveillance Center in Colorado Springs, Colo., reported that some debris from the disintegrated rocket's third stage had plunged into the atmosphere south of Australia Wednesday. A spokesman for the U.S. Space Command said yesterday that debris from the satellites and the Proton fourth stage was expected to reenter the atmosphere over the eastern Soviet Union last evening.