Once the rocket's in outer space, press the left and right arrow keys to dodge colorful planets. (The rocket will move back to its original position automatically.) If you hit a colorful planet, you'll get a strike. Don't worry about the gray planets off to the side, they're harmless. If you get 3 strikes, the game ends. This game is meant mostly for 3-6 year-olds, so if you want something harder, try my Goat Run which is the same concept except you're a goat running through a field jumping over rocks.
The rocket is the scratch "rocketship" sprite, but I made the top pointier and added lines around it.