Session
Technical Session XI: Propulsion
Abstract
Some of the major space operational capabilities desired for modernizing and transforming our existing space infrastructure include: 1) in-space robotic assembly of modular structures, 2) routine spacecraft repositioning and rescue services, 3) use of formations of satellites that can perform functions not possible with traditional single large structures. All of these applications can make use of a new generation of highly capable micro-satellites. Advantages inherent with the use of small satellite formations include: - enhanced launch flexibility; on-orbit adaptability and reconfigurability; multi-mission capability; and mission longevity. These characteristics equate to greater responsiveness and increased performance requirements at lower costs. Specific applications well suited to small satellites include; space-based navigation and guidance for precision target tracking; high-bandwidth global communications for military forces utilizing space-to-space or space-to-ground laser communications; detection, and precise positional knowledge of enemy weapons of mass destruction (geolocation) using formation flying detector systems; formation satellite support of synthetic aperture radars; and precision proximity operations, to name but a few. Mobilizing these micro-satellites will require revolutionary propulsion systems designed for critical performance needs such as long-term maneuvers and precision control. The operational metrics to consider include reliability, safety, simplicity, and weight-constraints. The Hybrid Electric-Laser Propulsion (HELP) system responds to these needs. Modularity, compactness, use of a chemically-benign propellant, and the absence of pressurized tanks, valves, and high voltage supplies, make it an operationally preferable companion to small satellites for a wide range of on-orbit applications. The objective of our work is to demonstrate the feasibility of a HELP system combining features from current state-of-the-art electric and laser thruster technology with several new features developed by Design_Net Engineering. Short pulse-width Qswitched lasers have the ability to create super hot plasmas from a readily available, inexpensive, and environmentally benign propellant. The resulting plasma is contained and directed to provide uniquely high and scalable specific impulse and variable thrust. It also enables superior minimum impulse bit (MIB) and noise levels. The HELP system feeds propellant using a patent-pending system that ensures repeatability and efficient propellant usage. A simple “plug-in” interface to the host spacecraft bus can be easily integrated and robotically serviced onorbit. These features provide modularity, serviceability, and flexibility. The production of the HELP system will fill the current shortfall of cost effective enabling propulsion technologies for small satellite applications. Although some technological hurdles exist, they do not collectively appear to be “show stoppers”. This paper provides an overview of the status of current micro-propulsion systems, discusses associated problems and limitations of these systems in terms of key performance metrics and finally describes the HELP system, which is currently under development with support from DARPA.
Presentation Slides
Advancing the Utility of Small Satellites with the Development of a Hybrid Electric-Laser Propulsion (HELP) System
Some of the major space operational capabilities desired for modernizing and transforming our existing space infrastructure include: 1) in-space robotic assembly of modular structures, 2) routine spacecraft repositioning and rescue services, 3) use of formations of satellites that can perform functions not possible with traditional single large structures. All of these applications can make use of a new generation of highly capable micro-satellites. Advantages inherent with the use of small satellite formations include: - enhanced launch flexibility; on-orbit adaptability and reconfigurability; multi-mission capability; and mission longevity. These characteristics equate to greater responsiveness and increased performance requirements at lower costs. Specific applications well suited to small satellites include; space-based navigation and guidance for precision target tracking; high-bandwidth global communications for military forces utilizing space-to-space or space-to-ground laser communications; detection, and precise positional knowledge of enemy weapons of mass destruction (geolocation) using formation flying detector systems; formation satellite support of synthetic aperture radars; and precision proximity operations, to name but a few. Mobilizing these micro-satellites will require revolutionary propulsion systems designed for critical performance needs such as long-term maneuvers and precision control. The operational metrics to consider include reliability, safety, simplicity, and weight-constraints. The Hybrid Electric-Laser Propulsion (HELP) system responds to these needs. Modularity, compactness, use of a chemically-benign propellant, and the absence of pressurized tanks, valves, and high voltage supplies, make it an operationally preferable companion to small satellites for a wide range of on-orbit applications. The objective of our work is to demonstrate the feasibility of a HELP system combining features from current state-of-the-art electric and laser thruster technology with several new features developed by Design_Net Engineering. Short pulse-width Qswitched lasers have the ability to create super hot plasmas from a readily available, inexpensive, and environmentally benign propellant. The resulting plasma is contained and directed to provide uniquely high and scalable specific impulse and variable thrust. It also enables superior minimum impulse bit (MIB) and noise levels. The HELP system feeds propellant using a patent-pending system that ensures repeatability and efficient propellant usage. A simple “plug-in” interface to the host spacecraft bus can be easily integrated and robotically serviced onorbit. These features provide modularity, serviceability, and flexibility. The production of the HELP system will fill the current shortfall of cost effective enabling propulsion technologies for small satellite applications. Although some technological hurdles exist, they do not collectively appear to be “show stoppers”. This paper provides an overview of the status of current micro-propulsion systems, discusses associated problems and limitations of these systems in terms of key performance metrics and finally describes the HELP system, which is currently under development with support from DARPA.
