The Moon: Lunar Exploration
More than 50 missions to the Moon have been launched by the USA and Russia (formerly the USSR) since 1959. Lunik 3, which flew past the Moon in 1959, was the first to photograph its far side. The ambitious Apollo project sent 27 astronauts to the Moon between 1968 and 1972, twelve of whom landed on the surface. During the last three Apollo missions, more than 50 tonnes of men and equipment were transported from Earth to the lunar bases at Hadley Rille, Cayley Plain and Taurus-Littrow. A total of 381.7kg of rock samples were brought back. Three quarters of it is still preserved for future researchers.
Apollo 17 astronaut Harrison Schmitt working next to a huge boulder with the Lunar Roving Vehicle nearby. Since there is no atmosphere or weather on the Moon, the imprints of the astronauts’ boots and the tracks made by the lunar rover will remain unchanged for many millions of years, until they are gradually obliterated by the impacts of micro-meteorites.
The astronauts found the Moon a barren and forbidding place. Because there is no atmosphere, the sky is permanently black and starry. However, to see the stars during lunar daytime would be difficult because of the direct sunlight and the sunlight scattered from the surface. The lunar night lasts a little over two weeks because the Moon takes 27.3 days to rotate once on its axis and another two days to catch up with its motion around the Sun.
The temperature at night drops to –190°C – so cold that oxygen would liquefy. In contrast, during the lunar day the surface can get as hot as 120°C, above the boiling point of water. The surface is very dry. Any water would immediately boil off into the vacuum of space. As a result, there is no trace whatsoever of life on the surface.
The Earth in the sky over the Moon’s horizon as the Apollo 11 ascent stage approaches the orbiter.