Two cosmonauts safely rode their Soviet spacecraft back to earth tonight after a malfunction of direction control rockets forced them to abandon a linkup with a manned orbiting space station.

The Soyuz 33 capsule, commanded by a Soviet civilian, Nikolai Rukavishnikov, and carrying a Bulgarian Air Force major, Georgi Ivanov, as flight engineer, landed without mishap in Kazakhstan, Moscow Radio said.

The two, who were launched Tuesday from Baikonur, the Soviet Central Asian cosmodrone, had been scheduled to dock Wednesday night with the Salyut 6 space station, in which in all-Soviet crew has been orbiting for 47 days. The docking would have coincided with the 18th anniversary of history's first manned orbital flight, by Yuri Gagarin in 1961.

But, said Tass, "In the process of approach there arose deviations from the regular mode of operations of the approach-correction power unit and the linkup was canceled."

In the soviet space program, much of the docking approach is controlled from ground stations.

The Salyut was launched in September 1977, and six crews have been aboard, including two that set world space endurance records of 96 and 140 days. Visiting crews have included a Czech, a Pole and an East german. Rukavishnikov, a veteran of two previous successful Soyuz missions, and Ivanov were scheduled to spend a week aboard with Vladimir Lyakhov and Valery Ryumin.

The mission failure, while embarrassing to the Soviets, is not expected to have major adverse impact on their manned orbital station program.