Saturn V Instrument Ring & Guidance Computer

[FlyingPenguin]

There's a ring at the top of the 3rd stage that contains all the gyros, computers, batteries, and a very sophisticated cooling system. This controls the rocket stack throughout launch until the command module detaches from the stack.

Despite the title of this video in goes into great detail on the design of the entire instrument ring. It's amazing how the power and cooling worked considering the primitive state of technology at the time.

Very interesting video.