List of retroreflectors on the Moon

Retroreflectors are devices which reflect light back to its source. Five were left at five sites on the Moon by three crews of the Apollo program and two remote landers of the Lunokhod program.[1] Lunar reflectors have enabled precise measurement of the Earth–Moon distance since 1969 using lunar laser ranging.[2]

The locations of lunar retroreflectors left by Apollo (A) and Lunokhod (L) missions.
The Lunar Laser Ranging Experiment from the Apollo 11 mission.
Lunokhod reflector (hexagon in front)

Successfully placed reflectors
Nation Mission Name Date Location Status Comment
United States Apollo 11 ALSEP LRRR 21 July 1969[3] 0.67337°N 23.47293°E / 0.67337; 23.47293[4] Operational 46x46 cm[5]
Soviet Union Luna 17 Lunokhod 1 17 November 1970[6] 38.315°N 35.008°W / 38.315; -35.008[7][8] Operational 44x19 cm,[1] location rediscovered in 2010[9]
United States Apollo 14 ALSEP LRRR 31 January 1971[10] 3.6453°S 17.471361°W / -3.6453; -17.471361[10] Operational 46x46 cm
United States Apollo 15 ALSEP LRRR 31 July 1971[11] 26.1°N 3.6°E / 26.1; 3.6[11] Operational Larger than previous ones, 105x65 cm
Soviet Union Luna 21 Lunokhod 2 15 January 1973[12] 25.8323°N 30.9221°E / 25.8323; 30.9221[13][14] Operational 44x19 cm[1]

Attempted and planned reflectors
Operator Mission Name Date Location Status Comment
Israel SpaceIL mission Beresheet lander[15] 11 April 2019[16] 32.5956°N 19.3496°E / 32.5956; 19.3496[17] (Mare Serenitatis) Crashed
India Chandrayaan-2 Vikram lander[18] 6 September 2019[19] 70.9°S 22.7°E / -70.9; 22.7 (Planned)[20] Crashed
Moon Express MX-1E lander Flight 1 MoonLIGHT[21] July 2020 (cancelled) 84.9°S 12.9°E / -84.9; 12.9 (Malapert Mountain near the lunar south pole)[22] Cancelled

See also

Notes

    References
    1. Lunar Retroreflectors
    2. Slava G. Turyshev: From Quantum to Cosmos: Fundamental Physics Research in Space (2009) - Page 300
    3. "What Neil & Buzz Left on the Moon: A cutting-edge science experiment left behind in the Sea of Tranquility by Apollo 11 astronauts is still running today". National Aeronautics and Space Administration. 20 July 2004. Retrieved 1 August 2012.
    4. "Landing Site Coordinates". hq.nasa.gov. Retrieved 26 July 2017.
    5. Newman, Michael E. (26 September 2017). "To the Moon and Back … in 2.5 Seconds". NIST. Retrieved 27 January 2021.
    6. http://www.zarya.info/Diaries/Luna/Luna17.php
    7. "LROC Observation M114185541R". Arizona State University. Retrieved 8 August 2012.
    8. "Lunokhod 1 Revisited | Lunar Reconnaissance Orbiter Camera". lroc.sese.asu.edu. Retrieved 8 October 2019.
    9. Space.com Staff (27 April 2010). "Lost Soviet Reflecting Device Rediscovered on the Moon". Space.com. Retrieved 26 January 2021.
    10. "APOLLO 14: The Eighth Mission: The Third Lunar Landing: 31 January–09 February 1971". National Aeronautics and Space Administration. Archived from the original on 14 November 2004. Retrieved 8 August 2012.
    11. Archinal, Brent (13 April 2010). "The Apollo 15 Lunar Laser Ranging Retroreflector - A Fundamental Point on the Moon!". Arizona State University. Archived from the original on 13 January 2013. Retrieved 1 August 2012.
    12. http://www.zarya.info/Diaries/Luna/Luna21.php
    13. "LROC Coordinates of Robotic Spacecraft | Lunar Reconnaissance Orbiter Camera". lroc.sese.asu.edu. Retrieved 8 October 2019.
    14. "NASA - NSSDCA - Spacecraft - Details". nssdc.gsfc.nasa.gov. Retrieved 8 October 2019.
    15. Warner, Cheryl (10 April 2019). "Update on First Private Robotic Spacecraft Attempt at Moon Landing". NASA. Retrieved 12 April 2019.
    16. Beresheet crash caused by manual command, but reflector device may have survived. Georgina Torbet, Digital Trends. 21 April 2019.
    17. Israeli spacecraft Beresheet crash site spotted on moon, 15 May 2019
    18. Bartels, Meghan (24 March 2019). "How NASA Scrambled to Add Science Experiments to Israeli, Indian Moon Probes". Retrieved 25 March 2019.
    19. Sep 8, PTI | Updated; 2019; Ist, 21:06. "Vikram lander located on lunar surface, wasn't a soft landing: Isro". The Times of India. Retrieved 8 October 2019.CS1 maint: numeric names: authors list (link)
    20. Amitabh, S.; Srinivasan, T. P.; Suresh, K. (2018). Potential Landing Sites for Chandrayaan-2 Lander in Southern Hemisphere of Moon (PDF). 49th Lunar and Planetary Science Conference. 19-23 March 2018. The Woodlands, Texas. Bibcode:2018LPI....49.1975A. Archived from the original (PDF) on 22 August 2018.
    21. UMD, Italy & MoonEx Join to Put New Laser-Reflecting Arrays on Moon. Lee Tune, University of Maryland. 10 June 2015.
    22. Internatioinal Lunar Observatory to offer a new astrophysical perspective. Tonasz Nowakowski. Spaceflight Insider. 12 August 2017.
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