Helmet, A-4-H

This pressure bubble helmet was designed and constructed by the Hamilton Standard Company, and was a very early use of the highly impact-resistant material polycarbonate. It was the first helmet prototype to integrate the pressure visor into the helmet shell in order to alleviate issues of neck and head discomfort.

The C3 helmet, used in conjunction with A-4-H spacesuits, enabled the astronaut to move his head within it, and a communications carrier was placed on the astronaut's head as well to enable him to communicate. As the helmet had no neck joint or bearing, it was considered to be a roomy "fixed-type" helmet. Oxygen was pumped into the helmet through an opening in the back, which was a change from the previous system of a "spray bar" in the front. The newer system became the standard of oxygen supply for later helmets.

NASA transferred this helmet to the museum towards the end of the Apollo program.