How fast should fly a rocket to leave the earth?

If the moons gravity is one sixth that of the earths how did they launch off of the moon without a rocket one sixth the size used to leave earth?

• Answer:

  The 'Saturn V' rocket that launched the moon mission from earth was as tall as a 40 story building. It weighted almost 7 million pounds and had to carry fuel and supplies for the complete round trip. More than half that fuel was expended just to get everything else into Earth orbit. The 2 astronauts landed on the moon in a tiny, lightweight craft called an LEM - it weighed about 10,000 lbs when it took off (part of it stayed on the surface of the moon). When it took off it had to carry only enough fuel to reach the Lunar Module then orbiting the earth. So the rocket for liftoff from the moon could be very much smaller than the one needed to liftoff from the earth at the start of the mission.