How do astronauts find their way to the moon?

There are two questions you need to answer when you want to get to the moon: are you going in the right direction, and how far have you already travelled?

Sailors

First: which direction should you choose? The route is always planned carefully before launching a moon mission. And that’s not easy – you have to deal with the Earth spinning on its axis, while the moon spins around the Earth. Fortunately, both the Earth and the moon follow regular paths, so if you get your calculations right you can predict where you need to be.

The nice thing is that you shouldn’t have to make any unexpected turns along the way. You just have to make sure you don’t drift away from the planned route.

When the first astronauts went to the moon, they didn’t have powerful modern computers to help them. They used the same navigation techniques as sailors from history to work out where they were. Their equipment included a telescope and a device called a sextant that measures the angle between the stars and the Earth or the moon. Armed with that information, those early astronauts could be sure they were going in the right direction.

Radio broadcast

OK, so we know we’re still on course. But how can we work out how far we’ve already travelled? The answer is: radio waves. NASA experts on Earth sent a signal, like a radio message, to the rocket. As soon as the message got to the rocket, it was sent back again.

We know how fast a radio signal travels through space, and the people at NASA could see how long it had taken for the message to get there and back. That helped them work out how far the signal had travelled, which revealed the distance between them and the astronauts.

Today, astronauts have a much easier way to find their location: GPS. This ‘global positioning system’ works just the same in space as on Earth. The rocket has a GPS receiver, which picks up signals from different satellites. The receiver calculates the distance between it and each of the satellites and uses that information to work out its location.

Answered by Ans Hekkenberg