We're speaking, of course, of the first-ever guidance system baked into the US Minuteman 1 nuclear missile. Maximum portability: about 9,700 km (6,000 mi). Target demographic: Commies.

[snip]

Atomic explosions in the atmosphere can disrupt radio communications. Missiles at the time were controlled by ground-based computers, so huge amounts of radio interference made America's ability to direct a second volley of fission sandwiches unreasonably hard. And on the other side of such an exchange, not being able to control your rockets can make mutual assured destruction up to 50 per cent less mutual. What's the fun in that?

The solution developed was to put a digital guidance computer right dab on the missile. (Somewhere in the multiverse, Skynet cackles maliciously in anticipation). Easier said than done at the time, as a computer with dimensions less than that of a family sedan was considered slim and chic.

This is a good funny read.