Overall view of the forward tunnel hatch.
This is a pressure hatch, sealing the forward docking tunnel against the vacuum
After the Command Module and Lunar Module have docked (providing an air-tight
seal between the CM and LM docking tunnels) and astronauts need to access the
LM, the Command Module Pilot equalizes the pressure in tunnel using the pressure equalization valve at center,
disengages the six latch assemblies holding
the hatch in place using the actuator
handle on the face of the hatch, removes the hatch, collapses and removes
probe, and removes the LM drogue,
finally gaining access to the LM upper hatch.