The 33st International Electric Propulsion Conference, The George Washington University, USA October 6 – 10, 2013 1 Solar Electric Propulsion Demonstration Mission Trajectory Trades IEPC-2013-456 Presented at the 33rd International Electric Propulsion Conference, The George Washington University • Washington, D.C. • USA October 6 – 10, 2013 William D Deininger, 1 Scott Mitchell, 2 and Bryce Unruh 3 Ball Aerospace, Boulder, CO, 80301, USA John Dankanich 4 NASA Marshall Space Flight Center, Huntsville, AL, USA Abstract: The SEPTD mission is a stepping stone leading to a reusable electric propulsion stage by demonstrating transfers from LEO to GEO and back to LEO. This set of high V trajectories demonstrates long-term SEP operations and flies the SEPTD space vehicle through the radiation belts, sustained plasma environments, diverse distributed inertia Space Vehicle control environments and repeated Space Vehicle occultations. A large number of trades cases and point designs have been analyzed for requirements development, system sizing, and concept of operations definition. The trades and point designs have been completed using various methods and tools at ranging levels of fidelity. The focus was to find high V solutions that fit within the budget (and hence mass) constraints of the SEPTD Mission requirements. Mass is purposefully constrained to constrain cost. The Baseline Mission begins in LEO, performs a low-thrust transit to GEO, transits back down to an equatorial LEO orbit, and then optionally spirals out from LEO to L1. There are a wide range of mission variants including EP system selection, and the Baseline Mission provides the performance capability for flexibility; including extended missions to NEOs, low lunar orbit, or the moons of Mars. Nomenclature ADCS = Attitude Determination and Control ATP = Authorization to Proceed BAA = Broad Area Announcement BPT = Busek Primex Thruster CONOPS = Concept of Operations EM = Earth-Moon EP = Electric propulsion GEO = Geostationary Earth Orbit GTO = Geostationary Transfer Orbit HET = Hall Effect Thruster IEPC = International Electric Propulsion Conference Isp = Specific Impulse km = Kilometers 1 Staff Consultant, Mission Systems Engineering, Associate Fellow AIAA, wdeining@ball.com. 2 Staff Consultant, Mission Systems Engineering, Member AIAA. 3 Business Development, Civil Space and Technologies. bunruh@ball.com. 4 Project Manager, Technology Development and Transfer Office.