Imagine that you are an asstronut orbiting Earth at a certain altitude and velocity and that you must suddenly orbit the Moon at another altitude and velocity, i.e, you must jump from one orbit (of the Earth) to another orbit (of the Moon). If you can do it, you might win my Challenge. So when and where and how in the orbit around Earth do you do something (what?), so you later when, where and how start in another orbit around the Moon? Or with other words - you ride one merry-go-round around Earth and want to ride another merry-go-round around the Moon, when and where do you jump???