Skip to content

Lagrange points (L-points)

This stunning star-forming region within the Carina Nebula was captured by the Webb Space Telescope from its vantage point in Lagrange Point 2.
This stunning star-forming region within the Carina Nebula was captured by the Webb Space Telescope from its vantage point in Lagrange Point 2. Image: NASA, ESA, CSA, and STScI

For some spacecraft, such as space-based telescopes, it’s not ideal for them to be so close to Earth. Our planet emits visible light and infrared radiation, which can interfere with observations of distant stars and galaxies.

In those cases, we can send spacecraft to one of two Lagrange points—locations in space where the gravitational fields of Earth and the Sun combine to keep an object stable and in a fixed position relative to Earth. Technically speaking, these are solar orbits, but Earth is directly involved in generating these gravitational sweet spots.

Diagram showing the location of five Earth-Sun Lagrange points, with L1 and L2 being particularly useful.
Diagram showing the location of five Earth-Sun Lagrange points, with L1 and L2 being particularly useful. Graphic: NASA/Robert Simmon

The first Lagrange point, L1, is located inside Earth’s orbit, while the second Lagrange point, L2, is behind Earth as viewed from the Sun. Both L1 and L2 are located 932,000 miles (1.5 million km) from Earth.

Spacecraft currently working in Sun-Earth L1 include NASA’s SOHO solar telescope and ESA’s gravitational wave detector, LISA Pathfinder. L2 is currently home to the Webb Space Telescope and ESA’s star-mapping GAIA observatory.

Related Articles