The Discovery astronauts donned their bright orange spacesuits and went to the launch pad Friday to board the space shuttle for a countdown dress rehearsal and emergency evacuation training.

Commander Alan Poindexter, pilot Jim Dutton, spacewalkers Rick Mastracchio and Clay Anderson, and mission specialists Dotty Metcalf-Lindenburger, Stephanie Wilson and Naoko Yamazaki of the Japan Aerospace Exploration Agency conducted the simulation in preparation for the April 5 launch to the International Space Station.

The Astrovan delivered the astronauts to the seaside pad around 8 a.m. EST to begin entering the orbiter and taking their assigned seats just like the actual countdown.

Clocks ticked down to T-minus 4 seconds before ending with a mock abort at about 11:05 a.m.

The Terminal Countdown Demonstration Test concluded with the astronauts exiting the shuttle to practice evacuation procedures and jumping in the escape baskets hanging on the launch tower.

Here's a collection of NASA-KSC photos from the day's activities:

Photo credit: NASA-KSC