Propellant Savings from Using a Tether System for Mars Flight

We investigated the possibility of using a tether system for Mars flight. After the spacecraft is inserted in the reference orbit at an altitude of 200 km, it uses its engine to fly to an orbital station located at the orbit at an altitude of 400 km. The spacecraft docks with the module of the orbital station where the folded cable is located. After the scheduled tasks arc done, the tether system is deployed. When the cable reaches the permissible length from the strength viewpoint, the spacecraft detaches. Then the spacecraft uses its engines to transfer to the elliptical Hohmann trajectory for Mars flight. In this paper we consider a way of reducing the characteristic velocity and propellant consumption for Mars flight by additional speed increment using a near-Earth tether system. We obtained the analytical relations allowing to evaluate the propellant savings and reduction of the characteristic velocity when the tether system is used. It is assumed that the position of the center of gravity of the tether system in the radial direction does not change and all orbits are in the same plane. The center of gravity of the tether system moves on a circular orbit. The tether is radial with respect to the Earth. All points of the tether have the same angular speed.