.. on room-sized computers. VLSI hadn't been achieved yet, so Apollo flew with a suitcase-sized computer made from discrete gates and core memory programmed in assembler by Margaret Hamilton and others. https://github.com/chrislgarry/Apollo-11
Not trying to be pedantic or a dick, but you should refer to that language as assembly, not assembler. It is a non trivial difference as assembly refers to the language and assembler refers to the software written to parse assembly commands into machine code (binary strings defined in the given machine's instruction set that are meaningful to the processor).
Otherwise it's similar to referring to the language C as Compiler, which is just silly :)
Also, to your point, agreed. It took several years before we could actually fly high level, compiled languages in space, the first being HAL/S on the Shuttle (completed in 1975).
I dunno how other !English languages handle it, but in German both are simply called Assembler. It would also seem that this distinction isn't generally made, due to the human ability to deduce meaning from context.
Although a few high-level languages existed at the time, compilers back then were not capable of code optimization. The only way to write code tight enough to operate a spacecraft would have been Assembly language.
EDIT: As I can’t answer to comments due to the retarded "you are submitting too fast" rule, here is a source: https://en.wikipedia.org/wiki/Plankalk%C3%BCl