The videos in this collection highlight some of these moments, the achievements and the sacrifices.
Watch videos about triumphs and tragedies in space exploration.
A Russian probe sends back the first pictures taken from the Moon's surface.
Luna 9, the first Moon probe to achieve a soft landing and send back photos of the lunar surface, caught the West by surprise in 1966. The Russian spacecraft's data transmissions were intercepted by Jodrell Bank Observatory, and the pictures were published in a British newspaper before they were published in Russia.
Apollo 8 orbits the Moon as NASA prepares for a manned landing.
Apollo 8 orbited the Moon on Christmas Eve in 1968 and temporarily lost contact with mission controllers when the spacecraft went behind the Moon. This mission was one of the final test flights before the 1969 Apollo 11 lunar landing.
Twin probes take close-up pictures of the planet's rock strewn surface.
The unmanned Mars probes Viking 1 and 2 landed on the Red Planet's surface in 1976 and returned photographs of a world littered with volcanic rock. Seismometers aboard the craft suggested that the planet is no longer geologically active.
The Russians take the first photograph of the planet's surface.
After a series of Venera missions, the Russians built Venera 9, a craft capable of withstanding Venus's searing temperatures and crushing pressures long enough to send back a picture of the surface. Venera 9's 1975 photograph of Venus showed a surface strewn with volcanic rocks.
The US probe sees ancient craters on Mars.
The Mariner 4 probe arrived at Mars in July of 1965, returning the first close-up photographs of the planet's surface as it flew by. The spacecraft showed scientists a barren, cratered area on Mars devoid of any signs of life.
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