Lagrange Point Distance

Lagrange points are positions in a two‑body system where the combined gravitational forces and the orbital motion of a small object balance, allowing it to remain in a fixed configuration relative to the two larger bodies.

For the collinear points L1 and L2, which lie on the line connecting the planet and its star, the distance from the planet can be approximated by ( r approx aleft(frac{M_{p}}{3M_{s}}right)^{1/3} ), where (a) is the planet‑star separation, (M_{p}) the planet’s mass and (M_{s}) the star’s mass.

This approximation is accurate when the planet’s mass is much smaller than the star’s, as is the case for Earth‑Sun or Mars‑Sun systems, and it provides a quick way to estimate where spacecraft can be positioned for continuous observation or communication.