View source for Luna 20

{{Short description|1972 lunar sample retrieval mission as part of the USSR's Luna program}}
{{Use dmy dates|date=May 2020|cs1-dates=ly}}
{{italic title}}
{{one source|date=April 2015}}
{{Infobox spaceflight
| name               = ''Luna 20''
| image              = Luna 20 descent stage.png
| image_caption      = Luna 20 as seen from orbit by the [[Lunar Reconnaissance Orbiter|LRO]] in 2010
| mission_type       = [[Planetary Science|Lunar sample return]]
| operator           = Soviet space program
| COSPAR_ID          = 1972-007A
| SATCAT             = 5835
| mission_duration   = 11 days (day of launch to day of landing)
| spacecraft_bus     = [[Ye-8-5]]
| manufacturer       = [[NPO Lavochkin|GSMZ Lavochkin]]
| dry_mass           = {{convert|5600|kg|lb}}
| launch_mass        = {{convert|5725|kg|lb}}<ref name=beyond>{{cite book|url=https://www.nasa.gov/sites/default/files/atoms/files/beyond-earth-tagged.pdf|title=Beyond Earth: A Chronicle of Deep Space Exploration, 1958–2016|last1=Siddiqi|first1=Asif|publisher=NASA History Program Office|edition=second|year=2018|isbn=9781626830431}}</ref>
| launch_date        = {{start-date|14 February 1972, 03:27:58|timezone=yes}}&nbsp;[[Coordinated Universal Time|UTC]]<ref name=beyond/>
| launch_rocket      = [[Proton-K]]/[[Blok D|D]]
| launch_site        = [[Baikonur Cosmodrome|Baikonur]] [[Baikonur Cosmodrome Site 81|81/24]]
| launch_contractor  = 
| landing_date       = {{end-date|25 February 1972, 19:19|timezone=yes}}&nbsp;UTC
| landing_site       = {{coords|47|24|N|68|36|E}},<ref>{{Cite web|url=http://epizodsspace.airbase.ru/bibl/inostr-yazyki/sov-luna/sovets-luna.pdf|title=Soviet and Russian Lunar Exploration|page=314}}</ref> <small>40 km north of Dzhezkazgan, [[Kazakhstan]]</small>
| orbit_reference    = [[Selenocentric orbit|Selenocentric]]
| orbit_regime       = 
| orbit_periapsis    = {{convert|100|km}}
| orbit_apoapsis     = {{convert|100|km}}
| orbit_inclination  = 65&nbsp;degrees
| orbit_semimajor    = {{convert|6477.8|km}}
| orbit_eccentricity = 0.0
| orbit_period       = 119&nbsp;minutes
| apsis              = selene
| interplanetary     = {{Infobox spaceflight/IP
 | type             = orbiter
 | object           = [[Moon|Lunar]]
 | orbits           = ~36
 | arrival_date     = 
 }} 
{{Infobox spaceflight/IP
 | type             = lander
 | object           = [[Moon|Lunar]]
 | arrival_date     = 21 February 1972, <br /> 19:19 UTC
 | departure_date   = 22 February 1972,<br />22:58 UTC
 | location         = {{coord|3.7863|N|56.6242|E|globe:moon|display=inline,title}}<ref name="nssdc.gsfc.nasa.gov">{{Cite web|url=https://nssdc.gsfc.nasa.gov/planetary/lunar/lunar_artifact_impacts.html|title = Table of Anthropogenic Impacts and Spacecraft on the Moon}}</ref>
 | sample_mass      = 30 grams
 }}

| programme          = '''[[Luna programme]]'''
| previous_mission   = [[Luna 19]]
| next_mission       = [[Luna 21]]
}}

'''''Luna 20'''''  was the second of three successful [[Soviet Union|Soviet]] lunar [[sample return mission]]s. It was flown as part of the [[Luna program]] as a robotic competitor to the six successful [[Apollo program|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&nbsp;km from where ''[[Luna 16]]'' had landed. 

While on the lunar surface, the panoramic television system was operated. [[Lunar sample]]s 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.<ref>{{Cite web |title=In Depth {{!}} Luna 20 |url=https://solarsystem.nasa.gov/missions/luna-20/in-depth |url-status=dead |archive-url=https://web.archive.org/web/20221105170528/https://solarsystem.nasa.gov/missions/luna-20/in-depth/ |archive-date=2022-11-05 |access-date=5 February 2020 |website=NASA Solar System Exploration}}</ref> It landed in the [[Soviet Union]] on 25 February 1972. The lunar samples were recovered the following day.

==Overview==
[[File:Luna sample return and Lunokhod lunar rover models.jpg|left|thumb|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,<ref name="nssdc.gsfc.nasa.gov">{{Cite web|url=https://nssdc.gsfc.nasa.gov/planetary/lunar/lunar_artifact_impacts.html|title = Table of Anthropogenic Impacts and Spacecraft on the Moon}}</ref> 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 30-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).<ref>{{Cite web|url=https://solarsystem.nasa.gov/missions/luna-20/in-depth|title=In Depth {{!}} Luna 20|date=15 March 2018|website=NASA Solar System Exploration|access-date=5 February 2020|archive-date=2022-11-05 |archive-url=https://web.archive.org/web/20221105170528/https://solarsystem.nasa.gov/missions/luna-20/in-depth/|url-status=dead}}</ref> 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 27 and 32&nbsp;cm was sent to Britain.<ref name="pillingersamp">{{cite journal |last1=Pillinger |first1= Colin Trevor |last2=Gowar |first2=A.P |date=4 January 1977 |title=The separation and subdivision of two 0.5g samples of lunar soil collected by the Luna 16 and 20 missions |journal= Philosophical Transactions of the Royal Society of London. Series A, Mathematical and Physical Sciences |url=https://royalsocietypublishing.org/doi/10.1098/rsta.1977.0003 |volume=284 |issue=1319 |pages=137–143|doi=10.1098/rsta.1977.0003|bibcode= 1977RSPTA.284..137P |s2cid= 119730403 |url-access=subscription }}</ref>

{| class="wikitable" 
!Lunar Mission
!Sample Returned
!Year
|-
|''[[Luna 16]]''
|align="center"|101 g<ref name="NSSDC">{{Cite web|title = NASA – NSSDC – Spacecraft – Details|url = https://nssdc.gsfc.nasa.gov/nmc/spacecraft/display.action?id=1970-072A|website = nssdc.gsfc.nasa.gov|access-date = 8 November 2015}}</ref>
|align="right"|1970
|-
|''Luna 20''
|align="center"|30 g<ref name="NSSDC"/>
|align="right"|1972
|-
|''[[Luna 24]]''
|align="center"|170.1 g<ref name="NSSDC"/>
|align="right"|1976
|-
|}

In March 2010, NASA reported that its [[Lunar Reconnaissance Orbiter]] satellite had spotted ''Luna 20'' on the lunar surface.<ref>{{cite news | url = http://www.space.com/missionlaunches/moon-orbiter-spots-Soviet-landers-100318.html  | title = NASA Lunar Orbiter Spots Old Soviet Moon Landers | first = Leonard | last = David | date = 18 March 2010 }}</ref><ref>{{cite web|url=http://www.lroc.asu.edu/featured_sites/lroc_features/Luna%2020/feature_highlights|title=Luna-20 surface photos|access-date=November 30, 2022|publisher=Lunar Reconnaissance Orbiter Camera}}</ref>

==See also==
{{Portal|Spaceflight}}
* [[Timeline of artificial satellites and space probes]]
* [[List of artificial objects on the Moon]] (descent stage)
* [[List of missions to the Moon]]

==References==
<references/>

==External links==
* [http://www.zarya.info/Diaries/Luna/Luna.php Zarya – Luna program chronology]
* [https://nssdc.gsfc.nasa.gov/nmc/spacecraft/display.action?id=1972-007A NASA NSSDC Master Catalog]

{{Luna programme}}
{{Moon spacecraft}}
{{Orbital launches in 1972}}

[[Category:Luna programme]]
[[Category:Sample return missions]]
[[Category:Missions to the Moon]]
[[Category:Soft landings on the Moon]]
[[Category:1972 in the Soviet Union]]
[[Category:Spacecraft launched in 1972]]
[[Category:1972 on the Moon]]