Advances in Technologies for High Power SEP Missions

Abstract

NASA has always been interested in advanced propulsion technologies that would enable safe and affordable interplanetary exploratory missions that are of high scientific value. In the past, radioisotope power systems were used to conduct such missions. Although such mission were very successful and provided interesting and useful scientific data, they were very expensive and had limited capability. About a decade ago, NASA was interested in developing high power (>100kW) Nuclear Electric Propulsion (NEP) system for exploring Jupiter and its Icy moons (JIMO). NASA later abandoned 1 the program because of high risk, cost and safety concerns. Recent advances in solar cell technologies, lightweight structures, high voltage systems are enabling NASA to achieve its exploration goals using Solar Electric Propulsion (SEP) systems. The ability to get SEP spacecraft that provides very high Delta-V while being safe, reliable, affordable and compatible to an affordable launch vehicle, has opened a variety of new and exciting space exploration opportunities for NASA and other stakeholders. This paper discusses the SEP exploratory missions that are of interest to NASA and other stakeholders. These include missions to high-energy orbits, missions between Earth and moon (Cis lunar space), Mars and its asteroids; Phobos & Mars sample return, along with deep space mission to Jupiter, Europa, Saturn, Titan and beyond. These mission will require a family of high power (>300kW) SEP spacecraft that could be used as reusable space tugs. The technologies that enable such high power spacecrafts range from advanced solar cells, lightweight and compact solar arrays, deployable structures, high voltage power management and distribution system (PMAD), solar wing drive assemblies, low impedance harness, advanced electric thrusters, high voltage power processing units (PPU’s). Some of the key SEP technologies, which relate to power systems, are also discussed in this paper.