How Far Will Artemis Go?

Even with the numbers at hand, it can be hard to visualise the sheer distances involved in interplanetary space travel

Artemis 1 has successfully launched towards the Moon. At the time of writing, it is about 135,000 km from Earth, after around 15 hours of flight. Despite having lost speed as it climbed out of our planets gravity well, it is still travelling at almost 2 kilometres per second. Even at this speed, it will not arrive at the Moon for several days. NASA has a nice page to track the progress of the spacecraft here.

But looking at the Moon from Earth, it is difficult to comprehend just how far away it is, even when you know the numbers involved.

A photo I took on a recent holiday when the Moon was looking especially striking. My phone camera doesn’t do it justice at all.

The Earth has an average radius of around 6,3870km and the Moon has an average radius of around 1,740km. The orbit of the Moon is not circular, but the semi-major axis of its orbit (half the length of the longest axis of an ellipse, analogous to radius) is around 384,000km. I have plotted the Earth and Moon to scale below - scr…