"Doctor, it may be that common misconception which caused you to check me is why such a catapult has not been constructed before this. I’ve seen those earlier studies. Most assumed that a catapult would be vertical, or that it would have to tilt up at the end to toss the spacecraft into the sky—and neither is feasible nor necessary. I suppose the asswnption arose from the fact that your spaceships do boost straight up, or nearly."