1.   Astronauts insert a crank handle into the hub and rotate it to move cams and latches on the back side of the door.

2.   At the same time, another astronaut will insert a thin needle with an electronic amplifier into a nerve behind the leg.

3.   The hatch is designed to open when astronauts insert a crank handle into the gear hub and rotate it.

4.   While the procedure was under way, another astronaut inserted a hair-thin needle with an electrode into a nerve in the leg muscle.