Astronomy:Luna 20

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Short description: 1972 lunar sample retrieval mission as part of the USSR's Luna program


Luna 20
Luna 20 descent stage.png
Luna 20 descent stage as seen from orbit by Lunar Reconnaissance Orbiter in 2010
Mission typeLunar sample return
COSPAR ID1972-007A
SATCAT no.5835
Mission duration11 days (day of launch to day of landing)
Spacecraft properties
BusYe-8-5
ManufacturerGSMZ Lavochkin
Launch mass5,725 kilograms (12,621 lb)[1]
Dry mass5,600 kilograms (12,300 lb)
Start of mission
Launch date14 February 1972, 03:27:58 (1972-02-14UTC03:27:58Z) UTC[2]
RocketProton-K/D
Launch siteBaikonur 81/24
End of mission
Landing date25 February 1972, 19:19 (1972-02-25UTC19:20Z) UTC
Landing site [ ⚑ ] 47°24′N 68°36′E / 47.4°N 68.6°E / 47.4; 68.6,[3] 40 km north of Dzhezkazgan, Kazakhstan
Orbital parameters
Reference systemSelenocentric
Semi-major axis6,477.8 kilometres (4,025.1 mi)
Eccentricity0.0
Periselene altitude100 kilometres (62 mi)
Aposelene altitude100 kilometres (62 mi)
Inclination65 degrees
Period119 minutes
Lunar orbiter
Orbits~36
Lunar lander
Landing date21 February 1972,
19:19 UTC
Return launch22 February 1972,
22:58 UTC
Landing site [ ⚑ ] : 3°47′11″N 56°37′27″E / 3.7863°N 56.6242°E / 3.7863; 56.6242[4]
Sample mass55 grams
 

Luna 20 was the second of three successful Soviet lunar sample return missions. It was flown as part of the Luna program as a robotic competitor to the six successful Apollo lunar sample return missions.

Luna 20 was placed in an intermediate Earth parking orbit and from this orbit was sent towards the Moon. It entered lunar orbit on 18 February 1972. On 21 February 1972, Luna 20 soft landed on the Moon in a mountainous area known as the Terra Apollonius (or Apollonius highlands) near Mare Fecunditatis (Sea of Fertility), 120 km from where Luna 16 had landed.

While on the lunar surface, the panoramic television system was operated. Lunar samples were obtained by means of an extendable drilling apparatus. The ascent stage of Luna 20 was launched from the lunar surface on 22 February 1972 carrying 1.9 ounces (55 grams) of collected lunar samples in a sealed capsule.[5] It landed in the Soviet Union on 25 February 1972. The lunar samples were recovered the following day.

Overview

Model of the Luna sample return lander with soil sample scoop - the ascent stage is the smaller cylinder with spherical Earth-return capsule on top.

This was the eighth Soviet spacecraft launched with the intent of returning lunar soil to Earth. It was evidently sent to complete the mission that Luna 18 had failed to accomplish. After a 4.5-day flight to the Moon, which included a single midcourse correction on 15 February, Luna 20 entered orbit around the Moon on 18 February. Initial orbital parameters were 100 x 100 kilometers at 65° inclination.

Three days later, at 19:13 UT, the spacecraft fired its main engine for 267 seconds to begin descent to the lunar surface. A second firing further reduced velocity before Luna 20 set down safely on the Moon at 19:19 UT on 21 February 1972 at coordinates 3.7863 North and 56.6242 East,[4] only 1.8 kilometers from the crash site of Luna 18.

After collecting a small sample of lunar soil, the spacecraft's ascent stage lifted off at 22:58 UT on 22 February and quickly accelerated to 2.7 kilometers per second velocity—sufficient to return to Earth. The small spherical capsule eventually parachuted down safely on an island in the Karkingir River, 40 kilometers north of the town of Jezkazgan in Kazakhstan, at 19:19 UT on 25 February 1972.

The 55-gram soil sample differed from that collected by Luna 16 in that the majority (50 to 60%) of the rock particles in the newer sample were ancient lunar highlands anorthosite (which consists largely of feldspar) rather than the basalt of the earlier one (which contained about 1 to 2% of anorthosite).[6] The American Apollo 16 mission returned similar highlands material two months later.

Like the Luna 16 soil, samples of the Luna 20 collection were shared with American and French scientists. A 0.4983g sample of material from a depth of 27and 32 cm was sent to Britain.[7]

Lunar Mission Sample Returned Year
Luna 16 101 g[8] 1970
Luna 20 30 g[8] 1972
Luna 24 170.1 g[8] 1976

In March 2010, NASA reported that its Lunar Reconnaissance Orbiter satellite had spotted Luna 20 on the lunar surface.[9][10]

See also

References

  1. Siddiqi, Asif (2018). Beyond Earth: A Chronicle of Deep Space Exploration, 1958–2016 (second ed.). NASA History Program Office. https://www.nasa.gov/sites/default/files/atoms/files/beyond-earth-tagged.pdf. 
  2. Siddiqi, Asif (2018). Beyond Earth: A Chronicle of Deep Space Exploration, 1958–2016 (second ed.). NASA History Program Office. https://www.nasa.gov/sites/default/files/atoms/files/beyond-earth-tagged.pdf. 
  3. "Soviet and Russian Lunar Exploration". p. 314. http://epizodsspace.airbase.ru/bibl/inostr-yazyki/sov-luna/sovets-luna.pdf. 
  4. 4.0 4.1 "Table of Anthropogenic Impacts and Spacecraft on the Moon". https://nssdc.gsfc.nasa.gov/planetary/lunar/lunar_artifact_impacts.html. 
  5. "In Depth | Luna 20". https://solarsystem.nasa.gov/missions/luna-20/in-depth. 
  6. "In Depth | Luna 20". 15 March 2018. https://solarsystem.nasa.gov/missions/luna-20/in-depth. 
  7. Pillinger, Colin Trevor; Gowar, A.P (4 January 1977). "The separation and subdivision of two 0.5g samples of lunar soil collected by the Luna 16 and 20 missions". Philosophical Transactions of the Royal Society of London. Series A, Mathematical and Physical Sciences 284 (1319): 137–143. doi:10.1098/rsta.1977.0003. Bibcode1977RSPTA.284..137P. https://royalsocietypublishing.org/doi/10.1098/rsta.1977.0003. 
  8. 8.0 8.1 8.2 "NASA - NSSDC - Spacecraft - Details". https://nssdc.gsfc.nasa.gov/nmc/spacecraft/display.action?id=1970-072A. 
  9. David, Leonard (18 March 2010). "NASA Lunar Orbiter Spots Old Soviet Moon Landers". http://www.space.com/missionlaunches/moon-orbiter-spots-Soviet-landers-100318.html. 
  10. "Luna-20 surface photos". Lunar Reconnaissance Orbiter Camera. http://www.lroc.asu.edu/featured_sites/lroc_features/Luna%2020/feature_highlights. 

External links