(04/29/1997) --- STS-84 Pilot Eileen Marie Collins participates in Terminal Countdown Demonstration Test (TCDT) activities at Launch Pad 39A. Behind her is Commander Charles J. Precourt. TCDT is a dress rehearsal for the launch, which is scheduled May 15. STS-84 aboard Atlantis will be the sixth docking of the Space Shuttle with the Russian Space Station Mir. After docking, STS-84 Mission Specialist C. Michael Foale will transfer to the space station and become a member of the Mir 23 crew, replacing U.S. astronaut Jerry M. Linenger, who will return to Earth aboard Atlantis. Foale will live and work on Mir until mid-September when his replacement is expected to arrive on the STS-86 mission