''Luna 18'', part of the Ye-8-5 series, was an

unmanned space mission A robotic spacecraft is an uncrewed spacecraft, usually under telerobotic control. A robotic spacecraft designed to make scientific research measurements is often called a space probe. Many space missions are more suited to telerobotic rather ...

of the Luna program.

Overview

''Luna 18'' was placed in an Earth parking orbit after it was launched and was then sent towards the Moon. On 7 September 1971, it entered lunar orbit. The spacecraft completed 85 communications sessions and 54 lunar orbits before it was sent towards the

lunar surface The geology of the Moon (sometimes called selenology, although the latter term can refer more generally to " lunar science") is quite different from that of Earth. The Moon lacks a true atmosphere, which eliminates erosion due to weather. It does ...

by use of braking rockets. It impacted the Moon on 11 September 1971, at 3 degrees 34 minutes N, 56 degrees 30 minutes E (selenographic coordinates) in a rugged mountainous terrain. Signals ceased at the moment of impact. This mission was the seventh Soviet attempt to recover soil samples from the surface of the Moon and the first after the success of ''Luna 16''. After two mid-course corrections on 4 September and 6 September 1971, ''Luna 18'' entered a circular orbit around the Moon on 7 September at 100 kilometers altitude with an inclination of 35°. After several more orbital corrections, on 11 September, the vehicle began its descent to the lunar surface. Contact with the spacecraft was lost at 07:48 UT at the previously determined point of lunar landing. Impact coordinates were 3°34' north latitude and 56°30' east longitude, near the edge of the

Mare Fecunditatis Mare Fecunditatis (Latin ''fēcunditātis'', the "Sea of Fecundity" or "Sea of Fertility") is a lunar mare in the eastern half of the visible Moon. The mare has a maximum diameter of 840 km. __NOTOC__ Description The Fecunditatis basin form ...

("Sea of Fertility"). Officially, the Soviets announced that "the lunar landing in the complex mountainous conditions proved to be unfavorable." Later, in 1975, the Soviets published data from ''Luna 18''s continuous-wave radio altimeter that determined the mean

density Density (volumetric mass density or specific mass) is the substance's mass per unit of volume. The symbol most often used for density is ''ρ'' (the lower case Greek letter rho), although the Latin letter ''D'' can also be used. Mathematicall ...

of the lunar topsoil.

References

External links

Zarya - Luna programme chronology

NASA NSSDC Master Catalog
Luna programme Sample return missions Missions to the Moon 1971 in spaceflight 1971 in the Soviet Union Spacecraft that impacted the Moon Spacecraft that orbited the Moon Spacecraft launched in 1971 1971 on the Moon {{astrobiology-stub

Overview

See also

References

External links