The Zarya control module went up Nov. 20.
Unity is the first piece delivered by space shuttle.
The Zarya and Unity modules of the International Space Station are currently in orbit. The Service Module is scheduled for launch in September, and under a revised plan, the first crew may follow a few weeks later. In the rushed hope of manning the International Space Station before the end of the millennium, American space officials have agreed to a Russian proposal to move the launch of the first crew to October, four months earlier than previously planned. Scheduling Conflict That could lead to a cosmic clash of priorities, because the Russians will have only one Soyuz spacecraft available for the latter half of this year. Mir has been orbiting Earth for 13 years, and the Russians don't want to say goodbye yet.