“Courage” is only necessary when you have fear. So, they both spring from the same drive. If you don’t fear anything, you don’t need courage. Curiosity is detached. A detached mind is able to distinguish questions that are answerable (that is, legitimate questions) from those that aren’t. Questions driven by fear are attached; as such, most of them are nonsensical. Science in general is driven by our fear of phenomena that our minds cannot explain (therefore cannot control).