I've got the Planet Hopper available for crafting as soon as a I start a new game. That seems premature. Seems like the recipe unlock should happen at a point where you can't use the Planet Hopper to wind up on another planet with no way to use a platform to get supplies down to you so you can get back off.

I agree that the recipe should probably be hidden until you can actually space travel, but I'd also like to state that with default settings you can't travel to ungenerated surfaces, meaning that you need to have already been there normally.