Space has no drag, so I added some

The boot.dev Asteroids course gives you a ship that moves while you hold a key and stops when you let go. It works, it is simple, and it feels nothing like being in space. What I wanted was continuous motion: you thrust, and then you keep going, because nothing out there is slowing you down. That is a small change to describe and a surprisingly interesting one to build, because the honest version of it is unplayable.