COLORADO SPRINGS, AUG. 9 -- U.S. military and space officials today tracked a mysterious Soviet satellite that was expected to plunge to Earth in the South Pacific early Monday morning.

Officials of the U.S. Space Command here predicted that the giant satellite, said by the Soviet Union to weigh 10 tons, would reenter the atmosphere about 3:13 a.m. (EDT), about 1,500 miles east of New Zealand.

The official Soviet news agency Tass reported today that the satellite, launched Aug. 1, will reenter the atmosphere Monday and fall to Earth in the southern Pacific, most likely near Antarctica.

It was unclear how much debris from the satellite, called Cosmos 1871, would survive reentry to strike the Earth.

"It's a danger because this is a big piece of space hardware," James Oberg, an expert on the Soviet space program, said in a recent interview. "There's a lot of metal that's going to survive reentry."

But Tass said the satellite poses no danger. "The area of the scattering of separate parts is large and the possibility of danger on the Earth's surface is insignificant . . . . Cosmos 1871 has no load constituting additional danger to life," it said.

Cosmos 1871 is in the type of polar orbit favored for spy satellites. Tass said it carries scientific equipment for space exploration.