Space exploration is the story of how humans, and our clever robots, have started to visit the rest of the universe. It began less than 70 years ago. In 1957 the Soviet Union launched the first satellite, Sputnik 1. Four years later, Yuri Gagarin became the first human in space. By 1969, two Americans were walking on the Moon. Today we have robotic rovers driving on Mars, telescopes peering across the universe, and crews living on the International Space Station 400 km above your head.
- First satelliteSputnik 1Launched by the USSR in 1957
- First human in spaceYuri GagarinSoviet cosmonaut, 12 April 1961
- First Moon landingApollo 11Neil Armstrong, 20 July 1969
- People on the Moon12All American astronauts, between 1969 and 1972
- ISS launched1998400 km up, always crewed since November 2000
- Furthest spacecraftVoyager 1Over 24 billion km away and still flying
How do rockets work?
To leave Earth a rocket has to reach a speed of about 11 kilometres per second. That is more than 100 times the speed of a fast car. Rockets get there by burning huge amounts of fuel and blasting the hot gas out of the back at high speed. By Newton's third law (for every action there is an equal and opposite reaction), the rocket itself is pushed forwards. Most modern rockets have several "stages" that drop off one by one as their fuel runs out, so the rest of the rocket can keep going.
Why do we explore space?
We send spacecraft for lots of reasons. Some look outwards to study other planets, moons and stars. Telescopes like Hubble and the James Webb Space Telescope have seen further back in time than ever before. Probes like Voyager 1 and 2 have flown past the giant planets and are now leaving the solar system. Some spacecraft look back at Earth to study our weather, climate or oceans. And the International Space Station is a kind of floating laboratory where astronauts run experiments that would be impossible to do down here in gravity.
The race to the Moon
For most of human history, space was just somewhere to look at. Then, in 12 short years between 1957 and 1969, two countries (the United States and the Soviet Union) raced to be the first to do everything: the first satellite, the first animal in space, the first human, the first spacewalk, the first probe to the Moon, and finally the first crewed Moon landing.
- 1957: The Soviet Union launches Sputnik 1, the first artificial satellite.
- 1961: Soviet cosmonaut Yuri Gagarin becomes the first human in space.
- 1962: American astronaut John Glenn orbits the Earth.
- 1969: Apollo 11 lands and Neil Armstrong becomes the first person to walk on the Moon.
- 1972: Apollo 17, the last crewed Moon mission to date, returns to Earth.
Since 1972 no human has been back to the Moon, although NASA's Artemis programme is now working to send the first woman and the next man to walk on the lunar surface, possibly later this decade.
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