(04/28/1997) --- STS-84 Pilot Eileen Marie Collins practices using a gas mask during Terminal Countdown Demonstration Test (TCDT) activities at Launch Pad 39A. STS-84 will be the sixth docking of the Space Shuttle with the Russian Space Station Mir. It will be second space flight for Collins, who was the first woman Shuttle pilot on her initial mission, STS-63 in 1995. 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. STS-84 is targeted for a May 15 liftoff