The Dyna-4's central body was constructed of Tomasite in movable, overlapping segments for compactness, but it could be expanded into a long cigar-shaped vehicle for maneuverability in narrow places. The four labs, also cigar-shaped, would fit snugly against the central body when the struts were retracted. Fully equipped with its own pilot-control unit, each capsule was self-operating and could be detached for individual research projects. Passageways in the struts provided easy access to and from the main capsule and smaller labs.