How far away does an astronaut need to be to see the whole of planet Earth?

How far away does an astronaut need to be to see the whole of planet Earth?

ISS images show zoomed-in detail; Apollo images show a distant blue disc. How far do you have to be in space to see Earth in one go?

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Published: January 17, 2024 at 12:24 pm

Astronauts never fail to point out the beauty of seeing planet Earth from space, and it must be a surreal experience watching entire continents drift by as they orbit in the International Space Station.

Images of Earth from space from Apollo missions, Space Shuttle flights, the International Space Station and numerous uncrewed satellites are breathtaking.

But these images vary considerably in terms of how much of the entire globe of planet Earth is seen in one shot.

The famous Earthrise picture was taken by Apollo 8 lunar module pilot Bill Anders on Christmas Eve 1968 after the crew spotted our planet coming up over the horizon. Credit: NASA
The famous Earthrise picture was taken by Apollo 8 lunar module pilot Bill Anders on Christmas Eve 1968, about 230,000 miles from Earth. Credit: NASA

Depending on during which mission the image of Earth was captured, you might be able to make out the intricate detail of lakes and rivers, towns and cities, or simply the whole blue disc of our planet set against the inky backdrop of deepest, darkest space.

Unsurprisingly, the Apollo images of Earth from space show the whole blue disc, given they were captured about 230,000 miles away.

So how far away does an astronaut need to be in order to observe the whole of planet Earth in one go?

To see the whole of our planet in one view, an astronaut would have to be further away than you may imagine.

As an example, from 300km (200 miles) above 52ºN 0ºW, only Europe is seen, and at 1,000km (600 miles) much of northern Africa becomes visible, but with less surface detail.

A satellite image showing Europe from space. Credit: NASA/Goddard Space Flight Center
A satellite image showing Europe from space. Credit: NASA/Goddard Space Flight Center

By 36,000km (22,000 miles) above the ground, the full disc of planet Earth could be seen by a human being.

This latter altitude is the position of a geostationary satellite, a satellite that appears to be in a fixed position because it revolves around the equator once per day, and it needs three of these satellites to give a full view of the planet.

To put this into perspective, the International Space Station orbits Earth from a distance of about 250 miles (400km), which is why images of Earth captured from the Space Station reveal so much detail.

An astronaut’s view of the Caribbean from space. The land mass in the centre is Cuba; on the far right is Florida. In between is the Bahamas. Credit: NASA
An astronaut’s view of the Caribbean from space. The land mass in the centre is Cuba; on the far right is Florida. In between is the Bahamas. Credit: NASA

You can experiment with this yourself by using the website Fourmilab, where you can get a view of Earth from any point of altitude, latitude or longitude.

And Google Earth of course helpfully tells you how far its 'camera' is from ground level, meaning you can zoom in and out to see what the perspective is from different distances.

Zoom into 400km and you'll get an idea of how ISS astronauts see Earth; you'll realise it's much closer than you might have imagined.

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