Electric Propulsion Tug Modeling Improvements and Application to the NASA/DARPA Manned Geosynchronous Servicing Study

摘要

This paper describes the improvements that have been made to design tools involved in vehicle and mission modeling of electric propulsion vehicles and inter/intra-orbit relocation vehicles i.e. space tugs. The integration of advanced solar array technology, in-development propulsion systems, rendezvous and capture mechanisms and sensors, and orbital maneuvering trajectories into the Modular Concurrent Engineering Methodology (Mod CEM) design tool has been investigated. These improvements have supported tasks for both the USAF Space and Missile Command (SMC) Materiel Innovation Working Group (MIWG) and the NASA/DARPA Manned Geosynchronous Servicing Study. The effort incorporated power and sizing information for the Boeing Fast Access Spacecraft Testbed (FAST) concentrator and Integrated Blanket/Interconnect System (IBIS) planar solar arrays. Engineering models, technology trends, and specific performance and design information were also incorporated for Hall-effect thrusters, ion engines, and variable specific impulse magnetoplasma rockets (VASIMR). In addition, a model of a smart rendezvous and capture package that includes systems to enable autonomous rendezvous and docking with arbitrarily design satellites was incorporated for payload mass, power, and system effects. These hardware modeling advancements have also been coupled with trajectory analysis and concept of operations development. This allowed system studies to be performed assessing the impact of each technology advancement, system effects for tug reusability, and mission applications including: within-geosynchronous Earth orbit (GEO) transfer, low Earth orbit (LEO)-to-GEO transfer, GEO-to-High Earth Orbit (HEO) transfer, and servicing operations. Vehicle masses, phasing requirements, fuel use and refueling needs were analyzed and reported for each technology and mission class. For most of the applications explored the results showed clear benefits to the development of electric propulsion based tug systems in comparison to chemical propulsion based tug systems.