Two Soviet cosmonauts launched to the Mir space station 326 days ago sailed toward a new space endurance record Friday with no word on when a second attempt will be made to launch the first Soviet shuttle.

A promised announcement of a new launch date for the shuttle had not materialized as of 11:50 p.m. Moscow time and sources at Tass and Radio Moscow said they did not expect one Friday.As commander Vladimir Titov and flight engineer Musa Manarov orbited overhead, there was confusion in the Soviet media as to whether the duo had already broken the record of 326 days set by cosmonaut Yuri Romanenko in December 1987.

Both Radio Moscow and the daily Komsomolskaya Pravda said they had already passed the mark, but it was thought that Romanenko's record would not be exceeded until 1:55 a.m. Saturday Moscow time - 5:55 p.m. EST Friday in the United States.

"The Mir veterans tomorrow will break the record of Yuri Romanenko who remained in space (until last December) for 326 days, 11 hours and 38 minutes," the Tass news agency said in a brief dispatch from mission control at Star City outside Moscow.

Titov and Manarov were launched to Mir on Dec. 21, 1987, and while their time aloft exceeded Romanenko's, an official record will not be recognized by the Federation Aeronautique Internationale in Paris, the body that sanctions such records, until the old mark has been exceeded by 10 pdroent, which will happen Dec. 14.

In any case, the achievement is viewed by Soviet space authorities as a minor milestone on the road toward an eventual manned flight to Mars, an otherwise routine event in a multi-faceted space program that now includes a manned reuseable space shuttle like the U.S. has.

The Soviets attempted to launch their first shuttle, Buran, Oct. 29 on an unmanned two-orbit flight but trouble with ground equipment forced a computer to interrupt the countdown at the T-minus 51-second mark.

A second launch attempt is thought to be close at hand, and Alexander Dunayev, head of the Soviet space agency Glavkosmos, told a news conference Thursday a new launch date was expected Friday. But as the day wore on, there was no word from Soviet space officials on when Buran might be launched.

Dunayev said Titov, 41, and Manarov, 37, will return to Earth from Mir Dec. 21 after a full year aloft, an endurance record that will dwarf the 84-day American record but one that falls far short of what will be required for a manned flight to Mars in the next century.

Soviet space officials said the long stays are aimed at gathering data about the psychological and physiological effects of prolonged exposure to weightlessness.

A 21st century trip to Mars would take about 30 months roundtrip, so the data also will assist in improving orbiting stations like Mir.