List of objects at Lagrange points explained

This is a list of known objects which occupy, have occupied, or are planned to occupy any of the five Lagrange points of two-body systems in space.

Sun–Earth Lagrange points

Sun–Earth L₁

is the Lagrange point located approximately 1.5 million kilometers from Earth towards the Sun.

Past probes

• International Cometary Explorer, formerly the International Sun–Earth Explorer 3 (ISEE-3), diverted out of in 1983 for a comet rendezvous mission. Currently in heliocentric orbit. The Sun–Earth L₁ is also the point to which the Reboot ISEE-3 mission was attempting to return the craft as the first phase of a recovery mission (as of September 25, 2014 all efforts have failed and contact was lost).^[1]
• NASA's Genesis probe collected solar wind samples at from December 3, 2001, to April 1, 2004, when it returned the sample capsule to Earth. It returned briefly in late 2004 before being pushed into heliocentric orbit in early 2005.
• LISA Pathfinder (LPF) was launched on 3 December 2015, and arrived at on 22 January 2016, where, among other experiments, it tested the technology needed by (e)LISA to detect gravitational waves. LISA Pathfinder used an instrument consisting of two small gold alloy cubes.
• The Chang'e 5 orbiter^[2] (during extended mission. After ferrying lunar samples back to Earth in 2020, the transport module was sent to where it is permanently stationed to conduct limited Earth-Sun observations.)

Present probes

• The Solar and Heliospheric Observatory (SOHO) in a halo orbit around L1
  • Mission: Investigation of the outer layer of the Sun, making observations of solar wind and associated phenomena in the vicinity of L1, probing the interior structure of the Sun.
  • Launched: 2 December 1995
  • Arrival: Operational orbit in May 1996
  • Institution: ESA
• The Advanced Composition Explorer (ACE) in a Lissajous orbit
• WIND (At since 2004)

• The Deep Space Climate Observatory (DSCOVR), designed to image the sunlit Earth in 10 wavelengths (EPIC) and monitor total reflected radiation (NISTAR). Launched on 11 February 2015, began orbiting L₁ on 8 June 2015 to study the solar wind and its effects on Earth.^[3] DSCOVR is unofficially known as GORESAT, because it carries a camera always oriented to Earth and capturing full-frame photos of the planet similar to the Blue Marble. This concept was proposed by then-Vice President of the United States Al Gore in 1998^[4] and was a centerpiece in his 2006 film An Inconvenient Truth.^[5]
• Aditya-L1 was successfully launched on 2 September 2023 and entered the halo orbit around the lagrange point on 6 January 2024.^[6] It's a Solar observation mission by ISRO. It will study solar atmosphere, solar magnetic storms, and their impact on the environment around the Earth.^[7]

Planned probes

• Interstellar Mapping and Acceleration Probe slated for launch in late 2024
• NEO Surveyor
• SWFO-L1
• Vigil (ESA). One spacecraft in L1 and one in L5.

Sun–Earth L₂

is the Lagrange point located approximately 1.5 million kilometers from Earth in the direction opposite the Sun. Spacecraft at the Sun–Earth L₂ point are in a Lissajous orbit until decommissioned, when they are sent into a heliocentric graveyard orbit.

Past probes

• 2001 – 2010: NASA's Wilkinson Microwave Anisotropy Probe (WMAP)^[8] observed the cosmic microwave background. It was moved to a heliocentric orbit to avoid posing a hazard to future missions.
• 2003 – 2004: NASA's WIND. The spacecraft then went to Earth orbit, before heading to .^[9]
• 2009 – 2013:^[10] The ESA Herschel Space Observatory exhausted its supply of liquid helium and was moved from the Lagrangian point in June 2013.
• 2009 – 2013: At the end of its mission ESA's Planck spacecraft was put into a heliocentric orbit and passivated to prevent it from endangering any future missions.
• 2011 – 2012: CNSA's Chang'e 2.^{[11] [12]} Chang'e 2 was then placed onto a heliocentric orbit that took it past the near-Earth asteroid 4179 Toutatis.

Present probes

• The ESA Gaia probe
• The joint Russian-German high-energy astrophysics observatory Spektr-RG
• The joint NASA, ESA and CSA James Webb Space Telescope (JWST)
• The ESA Euclid mission

Planned probes

• The NASA Nancy Grace Roman Space Telescope (WFIRST)
• The ESA PLATO mission, which will find and characterize rocky exoplanets.
• The JAXA LiteBIRD mission.
• The ESA Advanced Telescope for High ENergy Astrophysics (ATHENA)
• The ESA ARIEL mission, which will observe the atmospheres of exoplanets.
• The joint ESA-JAXA Comet Interceptor
• The NASA Large Ultraviolet Optical Infrared Surveyor (LUVOIR) which would replace the Hubble Space Telescope.

Cancelled probes

• The ESA Eddington mission
• The NASA Terrestrial Planet Finder mission (may be placed in an Earth-trailing orbit instead)

Sun–Earth L₃

is the Sun–Earth Lagrange point located on the side of the Sun opposite Earth, slightly outside the Earth's orbit. Direct communication with spacecraft in this position is blocked by the sun.

• There are no known objects in this orbital location.

Sun–Earth L₄

is the Sun–Earth Lagrange point located close to the Earth's orbit 60° ahead of Earth.

• Asteroid is the first discovered tadpole orbit companion to Earth, orbiting ; like Earth, its mean distance to the Sun is about one astronomical unit.
• Asteroid is the second Earth trojan, confirmed in November 2021, oscillating around in a tadpole orbit and expected to remain there for at least 4000 years, until destabilized by Venus.^[13]
• STEREO A (Solar TErrestrial RElations Observatory – Ahead) made its closest pass to in September 2009, on its orbit around the Sun, slightly faster than Earth.^[14]
• OSIRIS-REx passed near the L4 point and performed a survey for asteroids between 9 and 20 February 2017.

Sun–Earth L₅

is the Sun–Earth Lagrange point located close to the Earth's orbit 60° behind Earth.

• Asteroid, in a horseshoe companion orbit with Earth, is currently proximal to but at a high inclination.
• STEREO B (Solar TErrestrial RElations Observatory – Behind) made its closest pass to in October 2009, on its orbit around the Sun, slightly slower than Earth.^[14]
• The Spitzer Space Telescope is in an Earth-trailing heliocentric orbit drifting away c. 0.1 AU per year. In c. 2013–15 it has passed in its orbit.
• Hayabusa2 passed near during the spring of 2017, and imaged the surrounding area to search for Earth trojans on 18 April 2018.^[15]

Proposed

• Vigil (ESA). One spacecraft in L5.

Earth–Moon Lagrange points

Earth–Moon L2

• THEMIS
  • Chang'e 5-T1 Queqiao relay satellite
• EQUULEUS nanosat.

Earth–Moon L4 and L5

• Kordylewski clouds^[16]
• Future location of TDRS-style communication satellites to support satellite and further regions on the Moon.^{[17] [18]}

Past probes

• Hiten was the first spacecraft to demonstrate a low energy trajectory, passing by and to achieve lunar orbit at a very low fuel expense, compared to usual orbital techniques. Hiten did not find any conclusive increase in dust density at Lagrange points.^[19]

Proposed objects

• Exploration Gateway Platform
• In his 1976 book Dr. Gerard O'Neill proposed the establishment of gigantic Space Islands in . The inhabitants of the L5 Society should convert lunar material to huge solar power satellites. Many works of fiction, most notably the Gundam series, involve colonies at these locations.

Sun–Venus Lagrange points

L4

Sun–Mars Lagrange points

Asteroids in the and Sun–Mars Lagrangian points are sometimes called Mars trojans, with a lower-case t, as "Trojan asteroid" was originally defined as a term for Lagrangian asteroids of Jupiter. They may also be called Mars Lagrangian asteroids.

L5

• 5261 Eureka
  • • ,, (not confirmed as true Lagrangian asteroids)

Source: Minor Planet Center http://www.minorplanetcenter.org/iau/lists/MarsTrojans.html

Sun–Ceres Lagrange points

• 1372 Haremari

Sun–Jupiter Lagrange points

Asteroids in the and Sun–Jupiter Lagrangian points are known as Jupiter Trojan asteroids or simply Trojan asteroids.

L4

• Trojan asteroids, Greek camp

L5

• Trojan asteroids, Trojan camp

Planned

• Lucy (spacecraft)

Saturn–Tethys Lagrange points

L4

• Telesto

L5

• Calypso

Saturn–Dione Lagrange points

L4

• Helene

L5

• Polydeuces, follows a "tadpole" orbit around L₅

Sun–Uranus Lagrange points

L3

• 83982 Crantor, follows a horseshoe orbit around L₃

L4

• ^[20]

Sun–Neptune Lagrange points

Minor planets in the and Sun–Neptune Lagrangian points are called Neptune trojans, with a lower-case t, as "Trojan asteroid" was originally defined as a term for Lagrangian asteroids of Jupiter.

Data from: Minor Planet Center http://www.minorplanetcenter.org/iau/lists/NeptuneTrojans.html

L4

• 385571 Otrera
• 385695 Clete

L5

Tables of missions

Color key:

Lagrangian point missions

scope=col	Mission	scope=col	Lagrangian point	scope=col	Agency	scope=col class="unsortable"	Description
scope=row	International Sun–Earth Explorer 3 (ISEE-3)	Sun–Earth		Launched in 1978, it was the first spacecraft to be put into orbit around a libration point, where it operated for four years in a halo orbit about the Sun–Earth point. After the original mission ended, it was commanded to leave in September 1982 in order to investigate comets and the Sun.^[21] Now in a heliocentric orbit, an unsuccessful attempt to return to halo orbit was made in 2014 when it made a flyby of the Earth–Moon system.^[22] ^[23]
scope=row	Advanced Composition Explorer (ACE)	Sun–Earth	NASA	Launched 1997. Has fuel to orbit near L1 until 2024. Operational .^[24]
scope=row	Deep Space Climate Observatory (DSCOVR)	Sun–Earth	NASA	Launched on 11 February 2015. Planned successor of the Advanced Composition Explorer (ACE) satellite.
scope=row	LISA Pathfinder (LPF)	Sun–Earth	ESA, NASA	Launched one day behind revised schedule (planned for the 100th anniversary of the publication of Einstein's General Theory of Relativity), on 3 December 2015. Arrived at L1 on 22 January 2016.^[25] LISA Pathfinder was deactivated on 30 June 2017.^[26]
scope=row	Solar and Heliospheric Observatory (SOHO)	Sun–Earth	ESA, NASA	Orbiting near L1 since 1996. Operational .^[27]
scope=row		Sun–Earth	NASA	Arrived at L1 in 2004 with fuel for 60 years. Operational .^[28]
scope=row	Wilkinson Microwave Anisotropy Probe (WMAP)	Sun–Earth	NASA	Arrived at L2 in 2001. Mission ended 2010,^[29] then sent to solar orbit outside L2.^[30]
scope=row		Sun–Earth	ESA	Arrived at L2 July 2009. Ceased operation on 29 April 2013; will be moved to a heliocentric orbit.^[31] ^[32]
scope=row	Planck Space Observatory	Sun–Earth	ESA	Arrived at L2 July 2009. Mission ended on 23 October 2013; Planck has been moved to a heliocentric parking orbit.^[33]
scope=row		Sun–Earth	CNSA	Arrived in August 2011 after completing a lunar mission before departing en route to asteroid 4179 Toutatis in April 2012.
scope=row		Earth–Moon and	NASA	Mission consists of two spacecraft, which were the first spacecraft to reach Earth–Moon Lagrangian points. Both moved through Earth–Moon Lagrangian points, and are now in lunar orbit.^[34] ^[35]
scope=row		Sun–Earth	NASA	Arrived at L2 in November 2003 and departed April 2004.
scope=row		Sun–Earth	ESA	Launched 19 December 2013.^[36] Operational .^[37]
scope=row		Earth–Moon		Launched on 23 October 2014, arrived at L2 halo orbit on 13 January 2015.
scope=row		Earth–Moon		Launched on 21 May 2018, arrived at L2 halo orbit on June 14 for Chang'e 4 mission.^[38] Queqiao is the first ever communication relay and radio astronomy satellite at operating its location.^[39]
scope=row		Sun–Earth		Launched 13 July 2019. Roentgen and Gamma space observatory. Operational as of June 2020.^[40]
scope=row	James Webb Space Telescope (JWST)	Sun–Earth	NASA, ESA, CSA	Launched on 25 December 2021, arrived at L2 point on 24 January 2022. Operational as of 2022.^[41]
scope=row	Euclid	Sun–Earth	ESA, NASA	Launched on 1 July 2023, arrived at L2 point on 28 July 2023. Currently in testing phase as of September 2023.^[42]
scope=row	Aditya-L1	Sun–Earth		Launched on 2 September 2023^[43] and was successfully inserted into an orbit about Sun-Earth L1 point on 6 January 2024.^[44]

Future and proposed missions

scope=col	Mission	scope=col	Lagrangian point	scope=col	Agency	scope=col	Description
scope=row	"Lunar Far-Side Communication Satellites"	Earth–Moon	NASA	Proposed in 1968 for communications on the far side of the Moon during the Apollo program, mainly to enable an Apollo landing on the far side—neither the satellites nor the landing were ever realized.^[45]
scope=row	Space colonization and manufacturing	Earth–Moon or	—	First proposed in 1974 by Gerard K. O'Neill^[46] and subsequently advocated by the L5 Society.
scope=row	EQUULEUS	Earth–Moon	University of Tokyo, JAXA	6U CubeSat, launch planned in 2021 as a secondary payload onboard SLS Artemis 1.^[47]
scope=row	DESTINY+	Earth–Moon	JAXA	JAXA "Medium-Sized Focused Mission"; launch planned for 2025.^[48]
scope=row	Exploration Gateway Platform	Earth–Moon ^[49]	NASA	Proposed in 2011.^[50]
scope=row	Nancy Grace Roman Space Telescope (WFIRST)	Sun–Earth	NASA, USDOE	Launch planned for 2026.^[51]
scope=row	LiteBIRD	Sun–Earth ^[52]	JAXA, NASA	JAXA's next "Strategic Large Mission"; launch planned for 2032.^[53] ^[54]
scope=row	Interstellar Mapping and Acceleration Probe (IMAP)	Sun–Earth	NASA	Planned for launch in early 2025.
scope=row	Space Weather Follow On - Lagrange 1 (SWFO-L1)	Sun–Earth	NOAA	Planned for launch in early 2025 as a rideshare to IMAP.
scope=row	Planetary Transits and Oscillations of stars (PLATO)	Sun–Earth	ESA	Planned for launch in 2026 for an initial six-year mission.^[55]
scope=row	Space Infrared Telescope for Cosmology and Astrophysics (SPICA)	Sun–Earth	JAXA, ESA, SRON	, awaiting approval from both Japanese and European side, launch proposed for 2032.
scope=row	Advanced Telescope for High Energy Astrophysics (ATHENA)	Sun–Earth	ESA	Launch planned for 2035.^[56]
scope=row	ESA Vigil	Sun–Earth	ESA	Observatory for early warning of increased solar activity. Launch planned for 2029.
scope=row	Sun Chaser^[57]	Sun–Earth	—	Observatory for early warning of solar particle events. Early proposal phase.
scope=row	Spektr-M	Sun–Earth		Possible launch after 2030.^[58]

See also

• Trojan (celestial body)
• Co-orbital configuration

Notes and References

1. "ISEE-3 is in Safe Mode". Space College. 25 September 2014. "The ground stations listening to ISEE-3 have not been able to obtain a signal since Tuesday the 16th"
2. Web site: Chang'e 5 Test Mission Updates. Spaceflight 101. 14 December 2014.
3. Web site: NOAA's Satellite and Information Service (NESDIS). US Department of Commerce, NOAA Satellites and Information Service. dead. https://web.archive.org/web/20150608182042/http://www.nesdis.noaa.gov/news_archives/DSCOVR_L1_orbit.html. 2015-06-08.
4. Web site: At long last: Al Gore's satellite dream blasts off. 7 February 2015. USA TODAY.
5. Mellow, Craig (August 2014). "Al Gore's Satellite". Air & Space/Smithsonian. Retrieved December 12, 2014.
6. Web site: Kumar . Chethan . Aditya reaches halo orbit around L1 point, Sun study to begin soon . 6 January 2024 . 6 January 2024 . The Times of India.
7. Web site: 2 September 2023 . Aditya L1 Mission: Aditya L1 Launch LIVE Updates: Aditya L1 spacecraft successfully separated from PSLV rocket, now en route to Sun-Earth L1 point. ISRO says mission accomplished . live . https://web.archive.org/web/20230903115715/https://economictimes.indiatimes.com/news/newsblogs/aditya-l1-live-news-updates-isro-first-solar-mission-launch-02-september-2023/liveblog/103297403.cms . 3 September 2023 . 2 September 2023 . The Economic Times . en.
8. Web site: Mission Complete! WMAP Fires Its Thrusters For The Last Time . 2022-01-11 . 2012-07-14 . https://web.archive.org/web/20120714021615/http://news.discovery.com/space/mission-complete-wmap-fires-its-thrusters-for-the-last-time.html . dead .
9. Web site: WIND Solar-Terrestrial Mission. ESA Earth Observation Portal. December 31, 2021.
10. News: Herschel Space Telescope Shut Down For Good, ESA Announces . Huffington Post . Adam. Toobin. 2013-06-19.
11. Web site: China's Moon orbiter Chang'e-2 travels 1.5 km into outer space. 2011-08-30. 2011-08-31. The Economic Times.
12. Web site: Update on yesterday's post about Chang'e 2 going to Toutatis. Planetary Society. 15 June 2012. 26 June 2012. Lakdawalla. Emily. Emily Lakdawalla.
13. Man-To . Hui . Paul A. . Wiegert . David J. . Tholen . Dora . Föhring . The Second Earth Trojan 2020 XL5 . The Astrophysical Journal Letters . November 2021 . 922 . 2 . L25 . 10.3847/2041-8213/ac37bf . 2111.05058 . 2021ApJ...922L..25H . 243860678 . free .
14. http://www.nasa.gov/mission_pages/stereo/news/gravity_parking.html NASA - Join STEREO and Explore Gravitational "Parking Lots" That May Hold Secret of Moon's Origin
15. Web site: 太陽−地球系のL5点付近の観測の結果について . . 23 August 2017 . 2018-06-22 . ja.
16. Slíz-Balogh . Judith . Barta . András . Horváth . Gábor . Celestial mechanics and polarization optics of the Kordylewski dust cloud in the Earth–Moon Lagrange point L5 – I. Three-dimensional celestial mechanical modelling of dust cloud formation . 11 November 2018 . . 480 . 4 . 5550–5559 . 10.1093/mnras/sty2049 . free . 1910.07466 . 2018MNRAS.480.5550S .
17. Hornig . Andreas . TYCHO: Supporting Permanently Crewed Lunar Exploration with High-Speed Optical Communication from Everywhere . ESA . 2022-05-01.
18. Hornig . Andreas . TYCHO mission to Earth-Moon libration point EML-4 @ IAC 2013 . IAC2013 . 2013-10-06.
19. "Hiten", NSSDC.GSFC.NASA.gov.
20. 1303.5774 . 10.1126/science.1238072 . A Uranian Trojan and the Frequency of Temporary Giant-Planet Co-Orbitals . 2013 . Alexandersen . Mike . Gladman . Brett . Greenstreet . Sarah . Kavelaars . J. J. . Petit . Jean-Marc . Gwyn . Stephen . Science . 341 . 6149 . 994–997 . 23990557 . 2013Sci...341..994A .
21. Web site: Solar System Exploration: ISEE-3/ICE . NASA . 2010-09-28 . https://web.archive.org/web/20110614064824/http://solarsystem.nasa.gov/missions/profile.cfm?MCode=ISEEICE&Display=ReadMore . 2011-06-14 . dead .
22. Web site: Emily . Lakdawalla . Emily Lakdawalla . It's Alive! . The Planetary Science Weblog . October 3, 2008 . January 11, 2022 . February 20, 2012 . https://web.archive.org/web/20120220052909/http://www.planetary.org/blog/article/00001673/ . dead .
23. News: Rudderless Craft to Get Glimpse of Home Before Sinking Into Space's Depths . . Kenneth . Chang . August 8, 2014.
24. Web site: ACE MAG Spectrograms: 1 day starting 2019/3/15 (2019 074). www.srl.caltech.edu. 2020-02-12.
25. Web site: LISA Pathfinder factsheet . . 11 June 2012. 26 June 2012.
26. Web site: LISA Pathfinder Will Concludee Trailblazing Mission . 20 June 2017 . ESA Science and Technology . ESA . 17 August 2017 .
27. Web site: The Very Latest SOHO Images. sohowww.nascom.nasa.gov. 2020-02-12.
28. Web site: 25 Years of Science in the Solar Wind. Tran. Lina. 2019-10-31. NASA. 2020-02-12.
29. Web site: WMAP Facts . NASA . 2013-03-18 .
30. http://map.gsfc.nasa.gov/news/events.html WMAP Ceases Communications
31. Web site: Herschel Factsheet . European Space Agency . 2009-05-12 . 17 April 2009.
32. News: Herschel space telescope finishes mission . BBC News . 29 April 2013.
33. Web site: Last command sent to ESA's Planck space telescope. European Space Agency. October 23, 2013. October 23, 2013.
34. Web site: Fox. Karen C.. First ARTEMIS Spacecraft Successfully Enters Lunar Orbit. The Sun-Earth Connection: Heliophysics. 25 March 2015 . NASA.
35. Web site: Hendrix. Susan. Second ARTEMIS Spacecraft Successfully Enters Lunar Orbit. The Sun-Earth Connection: Heliophysics. 25 March 2015 . NASA.
36. Web site: Worldwide launch schedule . Spaceflight Now . 27 November 2013 . dead . https://web.archive.org/web/20100530232910/http://www.spaceflightnow.com/tracking/index.html . 30 May 2010 .
37. Web site: ESA Science & Technology - Fact Sheet. sci.esa.int. 2020-02-12.
38. Web site: China launches Queqiao relay satellite to support Chang'e 4 lunar far side landing mission . . Andrew . Jones . 21 May 2018 . 22 May 2018 . 22 May 2018 . https://web.archive.org/web/20180522112109/https://gbtimes.com/china-launches-queqiao-relay-satellite-to-support-change-4-lunar-far-side-landing-mission . dead .
39. News: Xu . Luyuan . How China's lunar relay satellite arrived in its final orbit . The Planetary Society . 15 June 2018 . https://web.archive.org/web/20181017123833/http://www.planetary.org/blogs/guest-blogs/2018/20180615-queqiao-orbit-explainer.html . 17 October 2018.
40. Web site: Illustration of the Spektr-RG spacecraft . 24 June 2020. 25 December 2021.
41. News: James Webb Space Telescope lifts off on historic mission. BBC News . 25 December 2021 . en. 2021-12-25.
42. Web site: Follow Euclid's first months in space . 25 August 2023 . 2 September 2023 . ESA.
43. Web site: Graham . William . India launches first solar research mission, Aditya-L1, aboard PSLV . 2 September 2023 . 2 September 2023 . NASASpaceFlight.
44. Web site: Halo-Orbit Insertion of Aditya-L1 Successfully Accomplished . 2024-01-06 . www.isro.gov.in.
45. Web site: Lunar far-side communication satellites . P.E. . Schmid . July 28, 1967 . . 2020-09-14 .
46. The Colonization of Space. O'Neill. Gerard K.. Physics Today. 27. 9. 32–40. September 1974. 10.1063/1.3128863. 1974PhT....27i..32O. free.
47. Web site: Extended Tisserand graph and multiple lunar swing-by design with Sun perturbation . JAXA . 3 March 2016 . 2016-06-07.
48. Web site: DESTINYについて . 2015-10-23. ja. https://web.archive.org/web/20151007050659/http://destiny.isas.jaxa.jp/about.html. 2015-10-07. dead.
49. Web site: NASA teams evaluating ISS-built Exploration Platform roadmap. June 15, 2012.
50. Web site: Exploration Gateway Platform hosting Reusable Lunar Lander proposed . Chris . Bergin . December 2011. NASA Spaceflight.com . 2011-12-05 .
51. Web site: The Nancy Grace Roman Space Telescope . . . 21 August 2021.
52. Web site: LiteBIRD . Masahashi . Hazumi . indico.cern . 1 September 2015 . PDF . 2015-10-23.
53. Web site: The origin of the Universe will be unveiled by the LiteBIRD cryogenic satellite . . 3 July 2023 . 26 December 2023.
54. Web site: Montier . L. . LiteBIRD Overview . . 10 July 2019 . 21 August 2021.
55. Web site: ESA selects planet-hunting PLATO mission. ESA. 19 February 2014. 25 April 2016.
56. Web site: ESA Science & Technology: Athena to study the hot and energetic Universe. ESA. 27 June 2014. 23 August 2014.
57. Web site: Sun Chaser - A Mission to the Earth-Sun Lagrangian Point 4. NASA. 7 September 2022. 20 October 2023.
58. Web site: В РАН рассказали, когда состоится запуск космического телескопа "Спектр-М". РИА Новости. 2019-06-29. 2019-07-13.