The evolution of the Jupiter 2 hull contour. Top to bottom: The original Fox blueprint, the “Gemini 12” single-level concept from the unaired pilot, the revised “Jupiter 2” design (upon which several models were based), and the distinctive four-foot articulated miniature with working landing gear

Reconciliation for scale with respect to the revised hull contour. The top diagram depicts the original studio set with selected internal appointments. The dotted line on the right indicates a final exterior revision which allowed for the construction of the airlock and porthole, and also resulted in a deep recess for the primary viewport. Note that in the original pilot version, the astrogator dome could be elevated to the position of the top “blister.” In the final version, the finished roof top gave way to an elevated sound stage, and filming was done below a designated crop line. The bottom diagram illustrates the necessary scale adjustment for the miniature to insure a comfortable fit for the same hardware components.

via