[themadturk]

"A handful of actual successful designs"? Perhaps we should get the definition clear: a spacecraft in this context is any human-built vehicle flying in space, not just those that carry humans. There are thousands of earth satellites, extra-terrestrial orbiters, landers, rovers, and now even interstellar spacecraft that are very successful. They all needed launch vehicles.

[jameshart]

“If you screw up the engineering, somebody dies” does not apply to unmanned spacecraft. In fact, unmanned spacecraft generally operate further away from humans than anything else does. When they go wrong the last thing that’s likely to happen is a human getting hurt.

[themadturk]

That’s the only thing on the list that applies specifically to human spaceflight. It certainly doesn’t invalidate my point.