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What are space probes for?

Pioneer 10 space probePioneer 10 space probeSpace probes are unmanned, remote-controlled spacecraft. They are sent to explore other planets and moons—even comets and asteroids—in the Solar System. Often, they are steered to "fly by" or go into orbit around one of these worlds. Sometimes, they are landed on a planet or moon’s surface. Space probes are equipped with cameras and sensing equipment, so they can transmit information back to Earth by radio.

Voyager 2 space probe. Voyager 2 space probe.

Voyager 2's image of Neptune's moon, TritonVoyager 2's image of Neptune's moon, Triton


The twin space probes, Voyager 1 and Voyager 2, were launched in 1977. They visited the outer planets, Jupiter, Saturn, Uranus and Neptune. The probes carried out a “fly by” of each planet, taking pictures and send back information about the planets and some of their moons. Voyager 2 captured this image (left) of Neptune's moon Triton in 1989.

After their successful missions, both probes were left to travel on out of the Solar System. Should aliens come across them one day, they would find messages and information about Earth on board.

US spacecraft Mariner 2 became the first space probe successfully to reach another planet when it flew by Venus in December 1962.

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