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This Defense Intelligence Reference Document, dated 21 November 2010, was prepared by the Defense Intelligence Agency's Defense Warning Office under its Advanced Aerospace Weapons System Applications (AAWSA) Program. It reviews propulsion concepts that use weakly ionized plasmas and magnetohydrodynamics for hypersonic flight and spacecraft. It concludes that the Ajax MHD energy bypass concept is meaningless below Mach 12. A reverse energy bypass with a Virtual Cowl is judged potentially practical, and electric propulsion is expected to become standard for spacecraft.
From the source:Release of 2026-09-18 Incident: 11/21/10, Las Vegas, Nevada. Released with redactions. This document is a Defense Intelligence Reference Document (DIRD), a technical reference format used by the Defense Intelligence Agency (DIA) to capture baseline knowledge on a specific topic for later analytic use. DIRDs are best understood as reference and synthesis products rather than as original research. It is one of 38 DIRDs produced under the Advanced Aerospace Weapon System Applications Program (AAWSAP) between 2009 and 2011. Because AAWSAP’s scope permitted a broad range of supporting topics, not every DIRD in the series directly concerns aerospace systems or future threat assessment. The following summary reflects the DIRD’s scope and framing at the time of writing and should not be read as implying current validation of the concepts discussed. This DIRD surveys magnetohydrodynamic (MHD) and plasma-based concepts for air-breathing propulsion, onboard power generation, and aerodynamic control, arguing that such systems could in principle extend aerospace performance beyond the limits of conventional chemical propulsion and control surfaces. The report reviews concepts including MHD acceleration, flow control, inlet control, onboard power generation, drag reduction, and plasma-generated “virtual” aerodynamic surfaces, while giving particular attention to hypersonic applications such as scramjet power extraction, reentry vehicles, global-strike gliders, and aero-assisted orbital maneuvers. However, it emphasizes major practical constraints, especially extreme power requirements, system weight and complexity, and the difficulty of achieving useful ionization in colder air at lower hypersonic speeds; on that basis, it argues that Ajax-style MHD bypass concepts, in which energy is extracted from the airflow upstream and reintroduced downstream through an electromagnetic system, are not meaningful below about Mach 12, while treating the “virtual cowl” and related reentry applications as more plausible. The document presents plasma and MHD aerospace systems as a technically serious but highly demanding field whose nearer-term promise lies in specialized hypersonic control, power generation, and reentry applications rather than a fully realized air-breathing propulsion system.
“Mission Control”2 pages
UNCLASSIFIED/ /FOA QFFI@IAL tt91!! Brit I Chapter 3 : Space Applications Electric propulsion systems are currently being used for attitude control, positioning, and primary propulsion. The use of electric propulsion systems on spacecraft was limited by the amount of power available. The thrusters were developed decades before the power systems. Early applications were the replacement of hydrazine monopropellant thrusters with hydrazine resistojet and arcjet thrusters (increasing lsp from 200 seconds to 300 seconds for resistojet thrusters and to 600 seconds for arcjet thrusters). An example is shown in Figure 11. This keeps most spacecraft the same, just changing the thrusters (lower risk and cost). Newer spacecraft are being designed specifically for use with electric thrusters. These are primarily gridded ion engin es and Hall-effect thrusters operating on xenon propellant. Xenon is a unique noble gas that can be stored with densities close to liquids at pressures above 800 psia. As the available electric power has increased, the transition to alt electric spacecraft has increased, as well as the sizes of the electric propulsion systems. Hall thrusters are used for station keeping as well as apogee insertion maneuvers. This trend will continue for decades to come. 50 The high lsp available from electric systems enables new operation concepts for what a spacecraft can do. The amount of propellant that can be stored onboard limits the number and types of maneuvers the spacecraft can perform. Electric systems enable enhanced ability to relocate assets, fly nontraditional or non Kelplerian orbits, and keep spacecraft on station for much longer periods. Although the l sp of electric systems are much higher than chemical systems, the thrust levels are much lower. This results in much lower spacecraft accelerations and longer repositioning times. The availability of higher power levels will allow for higher power thrusters to be used and, therefore, the repositioning times to be lower. For a given power, the lsp and thrust can be traded (Pe1ect = ½ go lsp Fth /17). High-power Hall-effect thrusters are being designed to operate in both a high-thrust (lower l sp) mode for obit insertion and repositioning and high -lsp (tow thrust) for propellant-efficient maneuvers and station keeping. This adds significant flexibility to how the spacecraft is operated and the missions it can perform . Very fine spacecraft positioning and pointing can be accomplished using the low thrust levels associated with some electric systems. For example, fie ld emission electric propulsion (FEEP) and colloid thrusters are capable of thrust levels in the micro-Newton range and can be used to offset small spacecraft perturbations such as solar wind. UNCLASSIFIED/FQA OFFl&lsld:. ~9E 8HLY Figure 11. Electrothermal Arcjet Thruster on Satellite. Lockheed Martin Series 7000 Comsat with Aerojet 1.8-kW Arcjet thrusters (insert photo) for north-south station keeping. 23
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Official release, from the pursue collection. The PDF is mirrored here; the original link is above. 32 pages are in the text index: search them above, or from the library's search.