The next part of the Viking '75 Mars lander’s High Gain Antenna (HGA) that I’ve modeled is one of the electrical connector receptacles used to link the antenna to electronics within the lander. Available on the 3D Warehouse.
This is a Malco Microdot MARC 63 series connector receptacle type MD63-00E9-19P (shell size 9, with 19 pins). The right-center photograph shows one of these connectors on the interface bracket of the HGA mast (see the right-most connector; the connector with red-taped cover is a Radio Frequency coax connector for pre-launch testing). This multi-pin connector supplies electric power and signal lines to the antenna’s altitude-azimuth drive head.
Photographed in the upper right is a similar unit with larger diameter shell size 15, supporting 61 pins (compared to 19 pins in the modeled unit). There are four sizes of MARC 63 series connector: shell size 9, 12, 15, and 18 (smallest to largest). Size 18 supports 91 pins. I was able to purchase an unused unit surplus on eBay recently. It is a little treasure. The main body or shell of the unit is just over one and a quarter inches long.
The customer who uses the connector (in this case RCA Astro Electronics, maker of the lander’s radio subsystem) installs their wiring into each pin and then threads the pins through the red and black “inserts”, first through the taller rear insert and then the front insert. The inserts are keyed to orient within the shell in just one way. The inserts are locked into place by a five-piece closure (the left-most components in the exploded view) which threads into the hex-end of the shell, behind the inserts. This is an extremely tight fit; the internally-tapered sleeve of the closure squeezes the tapered red rubber rear insert. It is so tight that I have not attempted to fully assemble my unit for fear of causing damage.
The SketchUp model has more detail than might be warranted for inclusion in the overall Viking lander model; most of it becomes hidden when the connector is installed. However, it was enjoyable to model it fairly completely - and with an actual unit in-hand, I could not resist. Even so, the actual hardware is yet more complicated. The gold pins, for example, have some features I decided not to model. The hollow end of each pin (where the customer’s wire is inserted) has two shoulders each just a few thousandths of an inch high. There is also a tiny inspection hole bored sideways through each pin near the base of the hollow wire-insert end.