Luna 16
First robotic probe to return lunar soil to Earth.
In 1970, the Soviet Union’s Luna 16 became the first robotic spacecraft to land on the Moon and bring back a sample of lunar soil. It was part of the Luna program and marked the Soviet Union’s first successful sample return, though it was the third such mission overall. The probe collected 101 grams (3.56 ounces) of material from Mare Fecunditatis.
The spacecraft had two main parts: a descent stage and an ascent stage mounted on top. The descent stage was a cylinder with four landing legs, fuel tanks, a landing radar, and two engines. A primary engine slowed the craft until an onboard computer cut it off based on altitude and speed; then a set of smaller jets finished the landing. This stage also served as a launch pad for the ascent stage. The ascent stage was a smaller cylinder with a rounded top, carrying a sealed soil-sample container inside a re-entry capsule. The descent stage also held a television camera, radiation and temperature monitors, communications gear, and a drill on an extendable arm.
Launched from Earth orbit, Luna 16 made one mid-course correction on 13 September 1970 and entered a circular 111-kilometer lunar orbit with a 70° inclination on 17 September. From there, it studied lunar gravity. After two orbital adjustments on 18 and 19 September, its perilune was lowered to 15.1 kilometers and its inclination adjusted for landing. At perilune on 20 September at 05:12 UTC, the main braking engine fired, starting the descent. Six minutes later, at 05:18 UTC, the probe soft-landed at 0°41' south latitude and 56°18' east longitude, in the northeast of Mare Fecunditatis, about 100 kilometers west of Webb crater and 150 kilometers north of Langrenus crater. This was the first lunar landing made during lunar night—the Sun had set about 60 hours earlier. The main engine cut off at 20 meters altitude, and the landing jets cut off at 2 meters, with a velocity under 2.4 m/s, followed by a vertical free fall. The landing mass was 1,880 kilograms.
Less than an hour later, at 06:03 UTC, an automatic drill began collecting a soil sample. After seven minutes, it reached a depth of 35 centimeters, then withdrew the sample and lifted it to the top of the spacecraft, depositing the material into a small spherical capsule. The drill tube’s column of regolith was transferred to the sample container. After 26 hours and 25 minutes on the surface, at 07:43 UTC
- Mission type
- Lunar sample return
- Launch date
- 1970
- Landing date
- 20 September 1970
- Sample mass
- 101 grams (3.56 ounces)
- Landing site
- Mare Fecunditatis (0°41' S, 56°18' E)
- Operator
- Soviet Luna program
- Notable achievement
- First robotic lunar sample return
Lore & Background
The spacecraft consisted of two attached stages: a descent stage with four landing legs, fuel tanks, landing radar, and a dual descent-engine complex, and an ascent stage carrying a hermetically sealed soil-sample container inside a re-entry capsule. The descent stage was equipped with a television camera, radiation and temperature monitors, telecommunications equipment, and an extendable arm with a drilling rig. Launched toward the Moon from a preliminary Earth orbit, after one mid-course correction on 13 September it entered a circular 111 km lunar orbit on 17 September 1970. After orbital adjustments on 18 and 19 September, the perilune was decreased to 15.1 km. At perilune on 20 September at 05:12 UTC, the main braking engine fired, and six minutes later at 05:18 UT the spacecraft soft-landed in Mare Fecunditatis, approximately 100 kilometers west of Webb crater and 150 km north of Langrenus crater. This was the first landing made in lunar night, as the Sun had set about 60 hours earlier. The main descent engine cut off at 20 m altitude, landing jets at 2 m at a velocity less than 2.4 m/s, followed by vertical free fall. The landing mass was 1,880 kilograms.
Reader's Guide
Luna 16 was a landmark success for the Soviets in deep-space exploration, accomplishing the first fully automatic recovery of soil samples from the surface of an extraterrestrial body. Less than an hour after landing, an automatic drill penetrated the lunar surface to collect a soil sample, reaching 35 centimeters depth after seven minutes. The column of regolith was transferred to the soil sample container. After 26 hours and 25 minutes on the lunar surface, the upper stage lifted off on 21 September. Three days later, on 24 September, the capsule reentered Earth's atmosphere at 11 km/s and parachuted down 80 kilometers southeast of Jezkazgan in Kazakhstan. Analysis of the dark basalt material indicated a close resemblance to soil recovered by the American Apollo 12 mission. On 10 June 1971, the Soviet Academy of Sciences exchanged Luna 16 samples with NASA in Moscow, receiving samples from Apollo 11 and Apollo 12. A 0.4825 g sample from a depth of 27 cm was sent to Britain. Three tiny samples (0.2 grams) were sold at Sotheby's auction for $442,500 in 1993 and resold for US$855,000 on 29 November 2018. A series of 10-kopeck stamps was issued in 1970 to commemorate the flight. Replicas are on display at the Memorial Museum of Cosmonautics and Tsiolkovsky State Museum of the History of Cosmonautics.
Did You Know?
- Luna 16 was the first robotic probe to land on the Moon and return a sample of lunar soil to Earth.
- The spacecraft landed in lunar night, with the Sun having set about 60 hours earlier.
- The sample of 101 grams was returned from Mare Fecunditatis, approximately 100 km west of Webb crater.
- Three tiny samples (0.2 grams) of Luna 16 soil were sold at Sotheby's auction for $442,500 in 1993.
More in Successful space missions 1-24
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