Op amp on the Moon: Reverse-engineering a hybrid op amp module

I recently obtained a mysterious electronic component in a metal can, flatter and slightly larger than a typical integrated circuit.1 After opening it up and reverse engineering the circuit, I determined that this was an op amp built for NASA in the 1960s using hybrid technology. The commercial history of the op amp started in 1952 when Philbrick introduced the K2-W op amp, a two-tube module that made op amps popular.3

I’ll now jump to Jean Hoerni, who founded Amelco. Interestingly, the transistors in the op amp module (below) look identical to Hoerni’s original teardrop-shaped planar transistors.

Source: www.righto.com