The Soviet Union yesterday resumed testing its hunter-killer satellite in Earth orbit, ending a two-year silence that had been prompted at least in part by pressure from the Carter administration to slow the military space race.

Sources said it was "virtually certain" that the 12 hours spent yesterday in Earth orbit by a Soviet satellite called Cosmos 1174 was a test of the hunter-killer satellite the Soviets have tested on and off for 12 years. Cosmos 1174 was maneuvered in orbit to intercept a target satellite called Cosmos 1171, then brought back yesterday to a crash landing in the Pacific.

Talks began two years ago between the United States and the Soviet Union, aimed at banning hunter-killer satellites. The talks were first held in Helsinki in June 1978 and resumed before being suspended late last year.

The Soviets had last tested their hunter-killer satellite May 19, 1978, a month before the antisatellite talks began. On that date, a Soviet target satellite named Cosmos 1006 was intercepted by a hunter-killer satellite dubbed Cosmos 1009 that was put into Earth orbit a few days after the target satellite was flown.

Space experts say they believe the Soviets use their hunter-killer satellite in two ways, one where it swoops by its target and the other where it actually intercepts it and flies alongside it. Either way, the killer satellite works by exploding near the target satellite and destroying it in a hail of shrapnel.

The Soviets have conducted 16 tests where their antisatellite intercepted a target satellite before yesterday's test. At times, the Soviets flew the antisatellite alongside the target, then withdrew it before blowing it up so they could test a second antisatellite against the same target.

It was not clear whether yesterday's test was a success or failure. One source at the Pentagon said the test was an "apparent failure," in part because the killer satellite may not have come close enough to the target to destroy it. The killer satellite may have been no close to its target than eight miles.

Another intelligence source suggested that the Soviets may have deliberately flown the killer satellite no closer than eight miles, either because they were satisfied that that was close enough or because they may have been testing a laser-beam weapon aboard the killer satellite.

"They might also be saving the target satellite for another test," the source said.