What is the difference between escape velocity and orbital speed?
Orbital speed is the speed you need to obtain orbit. Note that by definition, since you are in orbit, you still have not ‘escaped’ Earth. You need an even higher velocity to get beyond Earth orbit. A good example of the difference between orbital speed and escape velocity is when Apollo went to the moon. First the Saturn V rocket boosted the astronauts into near Earth orbit which required a speed of about 18,000 mph. Then once everything checked out, they re-lit the third stage of the Saturn V to gain speed to break out of Earth orbit and head towards the Moon. This required a higher speed of about 25,000 mph. Upon reaching the Moon, they would fire the spacecraft’s engine to ‘slow down’ to orbit the Moon. Without this ‘braking’ maneuver, they would have too much speed and been swung around the Moon and flung back to Earth (too fast for orbit). Upon leaving Lunar orbit, they had to again fire their spacecraft’s engine to gain speed and break out of their lunar orbit (escape the Moon’s
