It's my understanding that everything in space is in some sort of "free fall", which is pretty much what an orbit is. So, if you were in a space ship and applied some thrusters, you are pretty much changing the orientation and speed of your "free fall", right? So, lets say I wanted to get to Mars. If I turned my thrusters on full blast would I keep constantly accelerating (as long as the thrusters are active)? Would the gravitational pull of Earth cause a slight deceleration? Because I'm closer to Earth, Earth wants to pull me back, but when I cross over the 50% distance mark then Mars's pull will be more influential and will start pulling me in. Of course this 'threshold' wouldn't be 50% because Mars and Earth are not exactly the same size, and would not have the same GP. My main question is: Could you simply apply thrusters to reach a certain velocity, and then turn them off (to save fuel) and maintain that velocity until you reached your destination?