Luna 9

In the evening hours of 3 February 1966, an egg-shaped capsule slammed into the Ocean of Storms, bounced, rolled, and went still. Four petals unfolded like a flower, antennas sprang upright, and a small camera began to scan the grey desolation around it. For the first time in history, a machine built by human hands was working on the surface of another world, and it had survived the moment engineers feared most: the landing itself.

Luna 9 was, by most counts, the Soviet Union's twelfth attempt to soft-land on the Moon, after three years of crashes and misses. The winning solution was brutally pragmatic: moments before the carrier bus struck the surface, it threw clear a 99-kilogram landing capsule swaddled in airbags. The capsule came to rest tilted about 15 degrees, near the rim of a 25-metre crater in Oceanus Procellarum, photographing rocks at its feet and a horizon just 1.4 kilometres away.

The world saw the pictures before Moscow chose to show them. At Jodrell Bank in England, radio astronomers realised Luna 9 was transmitting in the same format used to wire newspaper photographs, borrowed a facsimile receiver from the Daily Express, and decoded the Moon's surface in time for the next morning's front pages. Over the following days the lander completed seven radio sessions totalling eight hours and five minutes, returning three series of pictures as the shifting Sun re-lit the landscape, before its batteries faded on 6 February.

Quietly, Luna 9 retired one of the great anxieties of the space age. Some scientists had warned that landers, and the astronauts who would follow, might simply sink into a deep ocean of dust; the little capsule sat firmly on solid ground. Four months later NASA's Surveyor 1 repeated the feat, and the path to a human bootprint, three and a half years away, suddenly looked real.