Ask an Explainer


When traveling to the moon does your spacecraft orbit around the sun with the Earth or must it account for the movement of the Moon around the sun?


When working with any physics problem, you need to know what system to work with. While the sun is a huge part of our solar system, we don't have to take it into account when sending a rocket to the moon. We can work with just a Moon/Earth system.


The rocket we send up is already travelling with the Earth around the sun. It's already got a huge amount of velocity. Think of thorowing a tennis ball up in the air in a moving train. It will land in your hand, not three feet behind you, because it's already going at the same speed as the train. It's the same for rockets. 

Categories: Flight Dynamics