[Spaceships] A slide rule will get you to the Moon . . . or will it?

[vicky_molokh]

Greetings, all!

I'm wondering, how serious is the title statement? Is it true that calculations necessary for space flight are mostly doable without computers at all? If so, how hard is it? How would 'retrotechy' TLs 8-10 look in terms of space exploration without computers?

Thanks in advance!