Missions to Sun-Mars L1 Lagrange Point Using Bimodal Nuclear Thermal Electric Propulsion

Abstract

For missions into deep space both cost and risk must reach levels below current projections before any such missions will be practical. Unfortunately a decrease in cost will increase the risk for any specific mission scenario and thus a delicate balance needs to be maintained for each scenario. What is needed is a scenario that decreases both cost and risk below current projections. Such a mission is possible using Bimodal Nuclear Thermal Electric Propulsion (BNTEP) and targeting the Lagrange equilibrium points instead of low planetary parking orbits. The use of BNTEP can decrease mission times to Mars to one year; significantly reducing not only the cost but also the risks from cosmic rays, solar flares, weightlessness and isolation. Parking the spacecraft at the unstable Lagrange equilibrium points L1 or L2 by utilizing a high performance electric propulsion system driven by nuclear power significantly reduces the propellant mass required (i.e., the cost) and the also reduces the risk since the spacecraft never enters into orbit about Mars. Parking at a Lagrange equilibrium point also allows for the use of electric propulsion to enter and leave the equilibrium point. High thrust is simply not required once the spacecraft enters deep space. For L1 BNTEP mission scenarios to become a reality, high performance electric propulsion needs to be developed and bimodal nuclear thermal reactors need to be built and tested. List of Symbols C Arbitrary constant e Eccentricity G Newton’s gravitational constant h Orbital altitude J Jacobi integral Sun M Mass of the Sun