A space elevator deployed at the L1 Mars–Phobos libration point

The paper investigates the feasibility of designing and deploying a space elevator fixed at the L1 libration point in the Mars–Phobos system in the framework of the planar circular restricted three-body problem. Two configurations of the space elevator are discussed. One is directed towards Phobos and the other towards Mars. In the first case, the length of the elevator is limited by the distance to the surface of Phobos (about 3.4 km), and in the second by the distance to the surface of Mars (about 7800 km). The law of motion of the climber is proposed, including the acceleration part, the braking part and the main part of the climbing (or descending) of the climber at constant velocity. The influence of the mass ratio of the climber and the end body is analyzed. It is also shown that it is possible to turn the elevator 180 degrees from the direction of Phobos to the direction of Mars and back when the climber is at the end point of the elevator. This is achieved using the well-known control law of the elevator length. This is the first preliminary study on the design of the Mars–Phobos space elevator using the L1 libration point, based on theoretical statements and numerical simulation results.