Luna 18

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Luna 18
Luna 18
Organization: Soviet Union
Major Contractors: GSMZ Lavochkin
Mission Type: Planetary Science
Lunar Sample Return
Satellite of: Moon
Launch: September 2, 1971 at 13:40:40 UTC
Launch Vehicle: Proton 8K82K + Blok D
Mission Highlight: Lunar impact on
September 11, 1971, 07:48 UTC
at 3° 34' N, - 56° 30' E.
Mission Duration: 9-days
Mass: 5,750 kg
NSSDC ID: 1971-073A
Webpage: NASA NSSDC Master Catalog
Orbital elements
Semimajor Axis: 6,477.8 km
Eccentricity: .001361
Inclination: 35°
Orbital Period: 119 minutes
Aposelene: 100 km
Periselene: 100 km
Orbits: ~48 - then attempted landing and Lunar impact
Instruments
Stereo imaging system : Lunar photography
Remote arm for sample collection : collect lunar material
Radiation detector : Lunar radiation environment
Radio altimeter : Density of lunar topsoil

Luna 18 (Ye-8-5 series) was an unmanned space mission of the Luna program, also called Lunik 18. Luna 18 was placed in an earth parking orbit after it was launched and was then sent towards the Moon. On September 7, 1971, it entered lunar orbit. The spacecraft completed 85 communications sessions and 54 lunar orbits before it was sent towards the lunar surface by use of braking rockets. It impacted the Moon on September 11, 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 midcourse 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. Unfortunately, contact with the spacecraft was abruptly 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 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 of the lunar topsoil.

  • Launch Date/Time: 1971-09-02 at 13:40:40 UTC
  • On-orbit dry mass: 5600 kg

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Preceded by
Luna 17
Luna programme Succeeded by
Luna 19