I don’t much like the spin-offs argument for why we should have a space program. Here’s a good example of why. It’s a weak justification. If you can damn with a faint praise, the spin-off argument is damning with a weak justification. You don’t justify something like the space program on the basis of its serendipitous spin-offs – they’re just accidental bonuses along the way.
Having said that, the space program spawned at least one pretty big accidental bonus.