Luna 16 — first robotic sample return from another world

When Luna 16 dropped toward Mare Fecunditatis on 20 September 1970, the Sun had already set on its landing site. The spacecraft descended through the lunar night and settled onto the basalt plain in darkness, with no astronaut aboard and no audience, a machine working alone on the night side of the terminator. Moscow had been chasing this feat for years; Luna 15 had crashed attempting it fourteen months earlier, even as Apollo 11's astronauts were still working on the surface.

On command from Earth, a drill at the end of an articulated arm bored into the regolith, stopping 35 centimetres down, and the arm swung the core up in an arc to deposit it inside a small sealed sphere atop the ascent stage. The entire visit lasted 26 hours and 25 minutes. At 07:43 UT on 21 September the upper stage fired straight up off the back of the lander, leaving the descent stage as a permanent launch pad on the Moon, and carried its 101 grams of cargo onto a path for home.

Three days later, on 24 September 1970, the capsule made a ballistic plunge into Earth's atmosphere and parachuted down about 80 kilometres southeast of Dzhezkazgan in Kazakhstan, carrying the first pieces of another world ever fetched home by a machine. The Soviet program had its answer to Apollo: a robot could sample the Moon without risking a single life. Decades on, three tiny grains from those 101 grams became the only documented Moon samples ever legally sold privately, fetching 855,000 dollars at Sotheby's in 2018.