This is the third AX (Ames Experimental) hard suit developed by NASA, following two between 1964 and 1968. California's Ames Research Center (ARC), founded in 1939, is a primary NASA research center.
Unlike the soft-shell suit, hard-shell space suits like the AX-3 enable movement by using ball bearings and wedges at the joints. The suits also hold their position without effort from the wearer, and can function at higher pressures, meaning the wearer does not need to pre-breathe oxygen in order to adjust their internal pressure moving from cabin to suit.
The man inside the suit is Vic Vykukal, the NASA engineer responsible for designing the suit, its predecessors and its final mode, the AX-5 in the 1980s.
All pictures: Retronaut