(1) Newton's Third Law Explanation: The modern science of spaceflight and rockets rest on Newton's Three Laws of Motion, a set of ideas and equations developed in the 1600s. In particular, the Third Law, which relates the action and reaction of forces, is essential to explain how a rocket accelerates. To make a rocket move forward, its engines point rearward. The action of the engine thrust produces a reaction on the rocket, accelerating it.