One type of rubber, polybutadiene, which ordinary squash balls and also the cores of golf balls are made of, can be used as rocket fuel. It is much cheaper, safer and more environmentally friendly than conventional rocket fuel. It was used by Burt Rutan in one spaceship launch. Imagine making rocket fuel of cheap squash balls and golf ball cores! It is especially cheap if discarded balls are used. The safety is because it is not explosive. That also saves safety expenditures, especially in reuseable spacecraft. Tires are not as environmentally friendly, because they contain polluting chemicals, but they could be used as an emergency fuel if squash and golf balls should be restricted, and that environmentally unfriendly emergency fuel exists in abundance should deter governments from trying to restrict space travel. Burning rubber is a form of better launches.