Certified space-nerd and all-around retro-tech guru [Fran Blanche] has just outdone herself with a comprehensive look at how NASA ran the Mission Control “Big Boards” that provided flight data for controllers for Apollo and for the next 20 years of manned spaceflight.
We’ve got to admit, [Fran] surprised us with this one. We had always assumed that the graphs and plots displayed in front of the rows of mint-green consoles and their skinny-tie wearing engineers were video projections using eidophor projectors. And to be sure, an eidophor, the tech of which [Jenny] profiled a while back, was used on one of the screens to feed video into Mission Control, either live from the Moon or from coverage of the launch and recovery operations. But even a cursory glance at the other screens in front of “The Pit” shows projections of a crispness and clarity that was far beyond what 1960s video could achieve.
Instead, plots and diagrams were projected into the rear of the massive screens using a completely electromechanical system. Glass and metal stencils were used to project the icons, maps, and grids, building up images layer by layer. Colors for each layer were obtained by the use of dichroic filters, and icons were physically moved to achieve animations. Graphs and plots were created Etch-a-Sketch style, with a servo-controlled stylus cutting through slides made opaque with a thin layer of metal. The whole thing is wonderfully complex, completely hacky, and a great example of engineering around the limits of technology.
Hats off to [Fran] for digging into this forgotten bit of Space Race tech. Seeing something like this makes the Mission Control centers of today look downright boring by comparison.