For a car to move the wheels turn, plus the friction on the road and it goes. For a shuttle to enter orbit, rockets fire and the propelent pushes it off the ground and into the air. If an space craft is in deep space, it then fires its rockets how does it move?? there is no friction in space.. i know of newtons law every action has an equal and oposite reaction but i cant see how it works here. I understand how a solar sail would work because that is being given a push from the photons which are already traveling into it from the sun. Is it rockets do work but not very much because there isnt much matter in space voids to push off of, hence you dont see space crafts or probes using them to go to mars say, do they just glide there????