All systems were pronounced go for Thursday's launch of the first of two unmanned probes to Mars and its moon Phobos in the boldest assault yet on the red planet. The probes will pick out sites for a possible manned landing next century.

Phobos I, followed by Phobos II on July 12, are the first probes to be sent to the mysterious planet in more than a decade. The successful U.S. Viking series landed in July and September 1976."The two Soviet unmanned probes, Phobos I and Phobos II, are waiting for their hour of triumph at Baiknour" Cosmodrome in Soviet Central Asia, the official Tass news agency said Wednesday.

"No other planet of the solar system has so many hypotheses - fantastic, audacious and imaginative - as (those) attached to Mars," Tass said. "People's imaginations were fired by the fascinating prospect of finding life there."

The two probes will take 200 days to reach a stationary orbit around Mars, some 120 million miles from Earth.

After their January arrival near Mars, the probes will remain there for 60 to 90 days, then enter the orbit of Phobos, one of Mars's two irregularly shaped moons.