Expedition Three Commander Frank Culbertson left and Scott Horowitz hold the sign for their mission.

Expedition Three Commander Frank Culbertson (left) and STS-105 Commander Scott Horowitz (right), in the White Room at Launch Pad 39A, hold the sign for their mission. Both crews are at KSC to take part in Terminal Countdown Demonstration Test activities, which include emergency egress training, a simulated launch countdown and familiarization with the payload. Mission STS-105 will be transporting the Expedition Three crew, several payloads and scientific experiments to the International Space Station aboard Discovery. The current Expedition Two crew members on the Station will return to Earth on Discovery. Launch of Discovery is scheduled no earlier than Aug. 9, 2001