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Why the Moon?

American astronauts orbited and landed on the Moon over 50 years ago. So why are we going back?

Since , the American, Canadian, European, Japanese and Russian space agencies have learned how to live and work in space aboard the ISS. But while we may think that the ISS is located very far from Earth, it orbits a mere 400 km above our planet. It's roughly the driving distance between:

Now don't get us wrong! While the distance isn't that great, the challenges are countless. And we have learned a lot from our time on the ISS about how the body works and adapts to microgravity; how to live and work efficiently in space; how to grow food, perform science and provide medical care; how to maintain good physical and mental health; and so much more!

Distances between Earth and the ISS, the Moon and Mars

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The distances between Earth, the ISS, the Moon and Mars. (Credit: Canadian Space Agency)

Exploring beyond the ISS

Countries from around the world are getting ready to send humans farther into our solar system, beyond the ISS. Nearly 400,000 km away from our planet, the Moon represents a crucial stepping stone in our quest to travel a million times further, onwards to Mars.

Greater distances mean long-duration missions. They also mean bigger health risks for humans living without Earth's protective atmosphere and longer communication delays.

In other words, crews and missions travelling farther from Earth will require more independence and autonomy.

The Canadian Space Agency is preparing for future missions by advancing technologies in areas of strength for Canada, like artificial intelligence, robotics and medical healthcare technologies.

Comparative table – ISS, Moon and Mars

Comparative data between ISS, Moon and Mars
ISS Moon Mars
Distance from Earth 400 km Close to 400,000 km
  • 225,000,000 km (average)
  • 400,000,000 km (farthest)
Communications delay (one way) Less than 1 second 2.4 to 2.7 seconds, with an average of 2.56 seconds 6 to 44 minutes depending on where Mars is located
Time to get there 6 hours to 3 days 3 days 9 months; launch is only possible approximately every two years due to the different orbits of Earth and Mars
Duration of a mission 6 months on average
  • Artemis: up to 3 weeks
  • Gateway: about 3 months
21 months (3 months on Mars)
Time to get back to Earth 3 hours 3 days 9 months

There are many other reasons to go back to the Moon before travelling to Mars. Here are a few:

The exploration of the Moon will inspire the next generation of scientists, engineers and astronauts.

Why do you think we should go back to the Moon? If you could travel there, what would you explore?

Check out NASA's "Why the Moon" video to learn more.

Explore further

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