Could you be more specific? At face value, I can think of some obvious thing - if you know the distance traveled in a certain time (and how far the object is), you can calculate how long it takes to get there.
um, with knowledge of the equations of motion of a rocket -distance moved at any time ,t to be more specific. soft landing on satelites can be achieved. my questin is, how can such knowledge be useful in soft landing on a satelite?