Terms of Reference

Earth-Moon Lagrange Points

  • The Lagrange “points” are locations within the Earth-Moon system where a body of small mass, compared with the masses of the Earth and Moon system, will remain fixed relative to the Earth and Moon with minimal station-keeping. Noting that all of these “points” are in orbit about the Earth, what happens at these locations is that the combined gravitational attraction of the Earth and Moon and the centrifugal force acting on the object in orbit about the Earth are in balance. For details see here.
  • Points L1 and L2 are useful for conducting logistics support in lunar orbit and on the lunar surface. They provide intermediate locations for the temporary storage of materiel en route to the Moon. Transportation routes to the Moon from LEO are also enhanced by routing the spaceships through one of these two points. While travel time is increased in doing this, payload performance is also increased.
  • The L4 and L5 points, while shown in the figure above as points, are actually substantial regions. Objects placed in proximity of the theoretical point (meaning within hundreds of kilometers) will orbit about the theoretical point in a kidney-shaped orbit. This has the advantage that, with proper station-keeping for safety separation, a substantial quantity of materiel can be located at these points.