How far away/close are satellites?

Distances in space can range from hundreds to millions of kilometres and more. This makes it very difficult to get an idea of just how big it is. This activity is aimed at getting to grips with the distances involved in satellite orbits, both natural and artificial.

Sense of scale

It is incredibly easy to underestimate how big space is. A useful tool to aid our understanding of large distances can be a scale model. While this doesn’t accurately depict the enormous distances being dealt with, it can give us an insight into the relative positioning of things. This activity will help you set up a model that can be assembled beforehand, or you could give it to volunteers and guide them in the construction. A set of picture arrows depicting objects at each orbital distance is available as an additional digital resource.

Satellites at different distances

For this activity we first must start by scaling down our Earth. This reduction can be tailored to your space. We suggest using a model of Earth that is 35cm in diameter, and have based the measurements on that.

With the Earth set at this scale, each centimetre of distance is roughly equivalent to 350km.

• 1cm above Earth’s surface – International Space Station – 350km
• 2cm above Earth’s surface – Iridium satellite phone constellation – 770km
• 6cm above Earth’s surface – highest altitude considered ‘low Earth orbit’ – 2,000km
• 47cm above Earth’s surface – average altitude considered ‘medium Earth orbit’ – 16,500km
• 66cm above Earth’s surface – Galileo satellite navigation constellation – 23 000km
• 102cm above Earth’s surface – geostationary orbit – 35,800km
• 102cm above Earth’s surface – Meteosat weather satellite – 35,800km
• 1000cm above Earth’s surface – the Moon – 384,400km
• 4290cm above Earth’s surface – James Webb Space Telescope – 1,500,000km