It's a mechanical sequence timer. Developed by Lockheed for the Agena flight vehicle

Missiles and rockets are controlled by sequence timers... valves have to open at specific times and operations have to be carried out in a specific order, many of them time-specific from other certain events (such as liftoff, hence T-0 or liftoff and "the clock has started" call in the early space program days.) For such events that are strictly time-critical or have to be done in order, (such as opening valves, engine startup, etc) these are controlled by event timers which are all set to slightly different times... say for the Atlas dropping of the half stage-- the butterfly valves had to close in the propellant lines to shut down the engines, so a timer would set that off at a given time mark after liftoff, then the separation explosive bolts had to fire to separate the booster section so many seconds (or fraction of a second(s) later) and so that was controlled by another timer... gimbal inhibit of the center sustainer might be controlled by another timer as staging occurred momentarily and then re-enabled (perhaps I'm just using this as an example not sure it did that) by yet another timer, etc. Today it would all be done by a master electronic digital timer and programming to activate relays or send signals to control devices to do the operations; but back then it was all done by mechanical timers... they were "programmed" by setting each specific timer to the correct "time setting" in relationship to each other before flight-- think of it like a bank of alarm clocks, with each one set to a slightly different time, each one doing a separate event in a sequence or series of events... Kinda like at the beginning of the movie "Back to the Future" where a sequence timer sets off the alarm clock, starts the coffee, breaks an egg into the skillet, toasts the bread, activates a robot arm to operate a can opener to open the dog food, dumps it in the bowl, then drops the can in the trash bin... Exact same thing but controlling different things in the rocket to make it fly. Instead of having multiple "alarm clocks" all running off separate motors or whatever, which means they could develop timing errors due to slight differences in the rate of rotation of the gears within them, these sequence timers were all mechanically run TOGETHER via small gears and a single drive motor, ensuring they all stayed synchronized perfectly with each other, SO setting up the timer you'd wire each event in sequence to sequential timers, and then align them by presetting each to different "times" as they counted down-- say to drop Atlas's half-stage-- the first timer would close the butterfly valves, say it'd be set for 200 seconds after liftoff (can't recall the actual number but that will do for example) then the next timer would say inhibit the center engine gimbal and would be set at say 203 seconds to allow the booster engines to burn out, then say the explosive bolts are fired at say 203.5 seconds to cast off the half-stage, and give it say 2 seconds to fall free, at which point the next timer would enable the center engine gimbal again so that timer would be set to 205.5 seconds, etc. Interestingly enough the first "event sequencers" were developed way back in ancient Greece (IIRC, or was it Rome) to control various 'automatic' functions for devices that would open curtains, cause marionette performers to dance, then close the curtains, etc... these sequence timers were constructed of a round log turned by a pendulum or weight, with pegs drilled and driven into the surface of it in various locations, around which a rope was wrapped and folded over the pegs, each doing a different thing... as the log turned on its axle, the pegs would rotate with it and release the ropes or strings in sequence, triggering the different operations of the device... all of which was timed or "programmed" by how the rope was wound around the pegs on the log... sorta like how a music box works... Later! OL J R :)

@@lukestrawwalker Oh I get it, astro physics is just a big Rube Goldberg device. Easy money! :)

@@minirock000 This isn't what you'd call "astro physics". This is astronautics. Engineering for space flight.