Past probes

• International Cometary Explorer, formerly the International Sun–Earth Explorer 3 (ISEE-3), diverted out of L₁ 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 L₁ 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 L₁ 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 L₁ 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 L₁ 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.

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 L₁.^[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)

Proposed

• Vigil (ESA). One spacecraft in L5.

Past probes

• Hiten was the first spacecraft to demonstrate a low energy trajectory, passing by L₄ and L₅ 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 The High Frontier: Human Colonies in Space Dr. Gerard O'Neill proposed the establishment of gigantic Space Islands in L₅. 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.