The Soviet Union attempted to upstage the Apollo program by sending a robot to fetch Moon rocks back to Earth. Soviet scientists boasted they could achieve the same results as Apollo at a fraction of the cost. The 5,800-kg Luna 15 was launched three days before Apollo 11 on July 13, 1969, and made orbital changes while Neil Armstrong and Buzz Aldrin walked on the surface. Two hours before the U.S. pair blasted off for home, the Soviet spacecraft descended toward the surface. It crashed into the Seas of Crises, unable to drill for samples as intended and send them back in a capsule.
Luna 16
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The 5,800-kg Luna 16 performed the mission the Soviet Union had intended to carry out just prior to the Apollo 11 landing. After going into lunar orbit, the spacecraft descended to the Sea of Fertility on September 20, 1970. A mechanical arm lowered a drill to the surface and took 101 grams of soil. The arm then raised the drill to the top of the spacecraft and placed the soil into a return rocket. The return craft launched itself back to Earth where it was recovered in Kazakhstan on September 24.
Luna 18
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Signals from the 5,800-kg Luna 18 stopped at touchdown on September 11, 1971, in a highlands area of the Sea of Fertility. It was probably meant to return another soil sample to Earth.
Luna 20
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The Soviet Union's second successful soil return was accomplished by the 5,800-kg Luna 20. It landed in the Sea of Fertility on February 21, 1971 with a mechanical arm holding a hollow rotary/percussive drill. This apparatus penetrated down a meter or more to capture 50 grams of soil. Then the arm lifted the drill up to the top of the craft and poured the soil into a return capsule. The sample was rocketed back toward Earth on February 22 and recovered from an island in the Karakingir River in Kazakhstan on February 25.
Luna 23
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The 5,800-kg Luna 23 was intended to return soil samples to Earth, but it landed November 6, 1974, in the Sea of Crises in a jagged region. The drill intended for gathering samples was damaged and no sample return was possible.
Luna 24
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The 5,800-kg Luna 24 was the Soviet Union's last lunar probe. It landed on August 18, 1976, in the southeast part of the Sea of Crises. A drilling rig gathered 170 grams of soil from a depth of 2.5 meters, filling a flexible tube 1.6 meters long. The tube was placed in the top return capsule, and launched back to Earth on August 19. Portions of the sample were given to U.S. and British researchers, who found the most common rock type at the Luna 24 site was a basalt that was low in titanium and high in iron. In total, the Soviet program return about 330 grams of lunar soil compared to 380 kilograms for the U.S. Apollo program.
