The docking of the Space Shuttle Atlantis/STS 71 to the Russian space station, the Mir 1, originally scheduled for 12 June, is likely to be delayed until 26 June (Flight International, 29 March-4 April).
Russia will not be able to launch its new Mir module, the Spektr towards the space station on a Proton booster until after 21 May and needs at least a month to ensure that it is fully operational before the Atlantis mission.
Other preparations for the mission include the repositioning of a solar array during a series of space walks by two Soyuz TM21 resident Russian cosmonauts.
As a result, NASA has officially scheduled the Atlantis/STS 71 for a launch, "no earlier" than 19 June but unoffically for 24 June and have made plans to launch the Discovery/STS 72 mission, to deploy a Tracking and Data Relay Satellite before the Atlantis, on a launch date no earlier than 8 June, as an option against further delays.
If launched on 8 June, the Discovery would land on 16 June, but if it was delayed by several days, the Atlantis again would have take priority.
The Atlantis/STS 71 is scheduled for a five-day joint mission at the Mir, delivering a new Russian two-man crew and returning the TM21 Russians and NASA astronaut Norman Thagard, who was launched with them on 14 March.
Source: Flight International