Damnit, I knew that too. I stopped skimming too early in the Wiki paragraph.

The entire pressure vessel for the crew used five major components: two hemispherical titanium end caps, two matching titanium interface rings, and the 142 cm (56 in) internal diameter, 2.4-meter-long (7.9 ft) carbon fiber-wound cylindrical hull.[15] The forward hemispherical end cap could be detached from its interface ring, becoming a hatch that allowed crew members to enter the crew compartment before a mission, and exit at its conclusion.[3]