The Luna 16 Robotic Probe was the first unmanned spacecraft to land on the Moon, robotically scoop up a small amount of lunar soil and then launch the sample back into space to return to Earth. The 12-day mission by the Soviet Union took place months after the Apollo 11 and Apollo 12 missions that had already returned lunar samples to Earth.
When the unmanned Luna 16 Robotic Probe set down in the Sea of Fertility in September 1970, it was the first time a spacecraft had landed on the Moon during the gloomy two-week lunar night. Within an hour of landing, a drill onboard the probe collected a sample of lunar soil. Then, mission controllers in Kazakhstan verified the collection and transmitted the order to fire the ascent stage of Luna 16. Three days later, the soil sample was returned to the Earth, marking the first time a sample from another world had been retrieved purely by machine.
Scientists were fascinated to learn of slight differences in the chemical composition of lunar soil returned by Luna 16 compared to the Apollo material. The dark, powdery basalt material (pictured, left) was found to be very similar to that obtained from another mare site by Apollo 12, but differed slightly from Apollo 11's samples in the levels of titanium and zirconium oxide.
The Luna 16 spacecraft consisted of two attached stages, an ascent stage mounted on top of a descent stage.
The descent stage was a cylindrical body with four protruding landing legs, fuel tanks, landing radar and a dual descent engine complex and was equipped with a television camera, radiation and temperature monitors, telecommunications equipment and an extendable arm with a drilling rig.
The ascent stage was a smaller cylinder with a rounded top that carried a cylindrical hermetically sealed soil sample container inside a re-entry capsule. The actual Luna 16 Robotic Probe was 10 ft. (3.1 m) tall and, with its legs extended, 11 ft. (3.3 m) in diameter. It weighed 4,145 lbs. (1,880 kg). The model on display in the El Pomar Space Gallery is half-scale and was constructed in the Soviet Union.
Two additional missions by the Soviets - Luna 20 in 1972 and Luna 24 in 1976 - also returned samples from the Moon.
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