Original Apollo 11 guidance computer (AGC) source code on GitHub

So that's about 1500 pages of source code for each of the two modules. That's incredibly small, it would literally fit into a thick book.

It's often claimed that a modern car contains more program code than early spacecraft. Obviously that's true, but what an understatement! I doubt that even the hardware abstraction layer provided by 2021 Toyota models' embedded operating systems could fit into 1500 pages – and that's just the tip of a huge iceberg that includes everything from ECU firmware to the entertainment system to the built-in web browser, navigation, countless sensors and monitoring systems, protocols like Bluetooth LE, file systems so the music from your USB drive can be read, audio codecs so it can be played, the list goes on and on and on.

And it still cannot lift itself even an inch above the ground, much less to outer space...