LUNA 16
The Luna 16 automatic station was launched toward the Moon from a preliminary Earth orbit and after one mid-course correction on 13 September it entered a circular 111km with 70° inclination lunar orbit on 17 September 1970.
The lunar gravity was studied from this orbit. After two orbital adjustments were performed on 18 September and 19 September the perilune was decreased to 15.1km, as well as the inclination altered in preparation for landing. At perilune at 05:12 UT on 20 September, the main braking engine was fired, initiating the descent to the lunar surface. Six minutes later at 05:18 UT, the spacecraft safely soft-landed in its target area at 0°41' south latitude and 56°18' east longitude, in the northeast area of the Mare Fecunditatis Sea of Fertility approximately 100 kilometers east of Webb crater. This was the first landing made in the lunar night side, as the Sun had set about 60 hours earlier. The main descent engine cut off at an altitude of 20 m and the landing jets cut off at 2 m height at a velocity less than 2.4;m/s, followed by vertical free fall. The mass of the spacecraft at landing was 1,880 kilograms. Less than an hour after landing, at 06:03 UT, an automatic drill penetrated the lunar surface to collect a soil sample. After drilling for 7 minutes, the drill reached a stop at 35 centimeters depth and then withdrew its sample and lifted it in an arc to the top of the spacecraft, depositing the lunar material in a small spherical capsule mounted on the main spacecraft bus. The column of regolith in the drill tube was then transferred to the soil sample container.
Finally, after 26 hours and 25 minutes on the lunar surface at 07:43 UT on 21 September, the spacecraft's upper stage lifted off from the Moon. The lower stage of Luna 16 remained on the lunar surface and continued transmission of lunar temperature and radiation data. Three days later on 24 September, after a direct ascent traverse with no mid-course corrections, the capsule, with its 101 grams of lunar soil, reentered Earth's atmosphere at a velocity of 11 kilometers per second. The capsule parachuted down 80 kilometers southeast of the town of Jezkazganin Kazakhstan at 05:25 UT on 24 September 1970. Analysis of the dark basalt material indicated a close resemblance to soil recovered by the American Apollo 12 mission.
According to the Bochum Observatory in Germany strong and good quality television pictures were returned by the spacecraft. Luna 16 was a landmark success for the Soviets in their deep space exploration program; the mission accomplished the first fully automatic recovery of soil samples from the surface of an extraterrestrial body.
Read more about this topic: Luna 16