Advanced Solar Electric Propulsion Research Articles

Asteroid Redirect Mission concept: A bold approach for utilizing space resources

The utilization of natural resources from asteroids is an idea that is older than the Space Age. The technologies are now available to transform this endeavor from an idea into reality. The Asteroid Redirect Mission (ARM) is a mission concept which includes the goal of robotically returning a small Near-Earth Asteroid (NEA) or a multi-ton boulder from a large NEA to cislunar space in the mid-2020s using an advanced Solar Electric Propulsion (SEP) vehicle and currently available technologies. The paradigm shift enabled by the ARM concept would allow in-situ resource utilization (ISRU) to be used at the human mission departure location (i.e., cislunar space) versus exclusively at the deep-space mission destination. This approach drastically reduces the barriers associated with utilizing ISRU for human deep-space missions. The successful testing of ISRU techniques and associated equipment could enable large-scale commercial ISRU operations to become a reality and enable a future space-based economy utilizing processed asteroidal materials. This paper provides an overview of the ARM concept and discusses the mission objectives, key technologies, and capabilities associated with the mission, as well as how the ARM and associated operations would benefit humanity׳s quest for the exploration and settlement of space.

Spacecraft for Hypervelocity Impact Research – An Overview of Capabilities, Constraints and the Challenges of Getting There

We present an introductory overview of the capabilities, constraints and challenges to be taken into account in the design of space missions for HVI research and application, focusing on related planetary defence applications, small spacecraft approaches, using our activities and projects as examples. Large lightweight deployable structure applications are discussed, for large-scale photovoltaic arrays in advanced solar-electric propulsion missions, and for solar sailing as a non-fuel-constrained method of achieving high-energy or retrograde orbit and multiple target missions. Small asteroid landers are discussed as vehicles for precursor exploration of impact target asteroids, precision target orbit determination, and for impact process monitoring that also can be deployed from sail-based missions.

Electric Propulsion for Solar System Exploration

The use of ion propulsion for deep-space missions will become a reality in 1998 with the  ight of the ion-propelled, New Millennium Deep Space 1 (DS1) spacecraft. The anticipation of this event is stimulating the call for improved ion propulsion technologies, a trend that is expected to continue. This paper describes the evaluation of possible advanced solar electric propulsion technologies and their potential beneŽ ts to projected near-term and midterm solar system exploration missions. The advanced technologies include high-performance derivatives of the DS1 ion propulsion technology, scaled-down DS1 systems, and direct-drive Hall-effect thruster systems. The results of this study indicate that signiŽ cant near-term beneŽ ts can be obtained by the development of improved versions of the DS1 ion propulsion system (IPSs) components. In addition, if the current trend to smaller planetary spacecraft continues, then missions  ying these smaller future spacecraft will beneŽ t substantially from the development of scaled-down IPSs that incorporate advanced technologies in the ion engines and the propellant feed systems. The performance of the direct-drive Hall thruster systems is potentially superior to that of all other midterm options, but this technology has the highest development risk. SigniŽ cantly reduced trip times to small bodies and the outer planets may be possible if technology programs work to retire these risks.

Electric propulsion: An evolutionary technology

The NASA Lewis Research Center (LeRC) conducts and directs an electric propulsion research and technology program aimed at providing high-performance electric propulsion system options for a broad range of near and far-term missions. This evolutionary program emphasizes the development of propulsion systems for three classes of missions: (1) near term auxiliary propulsion applications such as North-South Stationkeeping for next generation communications satellites and orbit maintainence for orbiting platforms such as Space Station Freedom; (2) advanced solar electric propulsion and SP-100-class nuclear electric propulsion for Earth-space orbit transfer and robotic planetary missions; and (3) very high power systems to support major space missions including the Space Exploration Initiative. To cover widely disparate mission requirements, the LeRC program includes research on electrothermal, electrostatic, and electromagnetic systems. This paper provides an overview of the LeRC program with a focus on recent progress.

Spacecraft-Generated Plasma Interaction with High-Voltage Solar Array

Calculations are made of the effect of interactions of spacecraft-generated plasmas and high voltage solar array components on an advanced Solar Electric Propulsion system. The plasma consists of mercury ions and electrons resulting from the operation of ion thrusters and associated hollow cathode neutralizers. Because large areas of the solar array are at high potential and not completely insulated from the surrounding plasma, the array can, under some conditions, collect excessive electron currents. Results are given for the parasitic currents collected by the solar arrays and means for reducing these currents are considered.