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AAWSAP DIRD, Aneutronic Fusion Propulsion I, November 2010

U.S. Department of War · 2010-11-01 · 50 pages · text from the file's own layer

This Defense Intelligence Reference Document, prepared in fiscal year 2010 by the Defense Intelligence Agency's Defense Warning Office under the Advanced Aerospace Weapon System Applications (AAWSA) Program, reviews aneutronic fusion as a way to propel spacecraft. It compares chemical, ion, fission, fusion and antimatter propulsion, and it also covers radiation shielding and relativistic rocket calculations. It looks at research needs over the next 30 years for missions from low Earth orbit to Mars, Jupiter and Alpha Centauri.

From the source:Release of 2026-09-18 Incident: 11/1/10, 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 aneutronic fusion as a possible advanced space-propulsion method, focusing on fusion reactions that release most of their energy in charged particles rather than neutrons and therefore offer potential advantages over more neutron-intensive fusion concepts, especially in radiation shielding, direct energy conversion, and thrust generation. The report reviews the underlying rocket physics, compares candidate fusion fuels and ignition conditions, and gives particular attention to proton-boron and related schemes, while also discussing Bussard’s concepts and other fusion projects as representative development paths. It also makes clear that the central obstacle remains ignition and sustained net-energy fusion under practical conditions, and it notes additional problems such as x-ray energy losses from the hot plasma, extreme temperature requirements, and the gap between theoretical specific impulse and what proposed systems had demonstrated experimentally. Overall, the document presents aneutronic fusion propulsion as an attractive long-range concept for deep-space travel, but one whose practical realization still depended on major unresolved advances in fusion engineering.

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doubled that of typical chemical rocket designs. The largest NERVA rocket tested
generated 867 kN of thrust using liqu id hydrogen propellant. NERVA rockets were
proposed for the Manned Mars Mission using a tethered cabin to protect the crew from
reactor radiation. The NERVA project was cancelled in 1972.
LEO TO THE MOONS OF JUPITER AND SATURN (460 TO 940 MILLION
MILES)
Project Prometheus, 2003-2005, concentrated on nuclear electric and nuclear thermal
propulsion for unmanned missions to the moons of Jupiter. For manned flight, the
nuclear t hermal systems based on NERVA still provide high thrust, reasonable values of
specific impulse, and a technology that requires no major breakthroughs in order to be
achieved. For manned flights, tethered systems will likely be necessary to minimize
radiation exposure to the crew from the reactor. For the next 30 years, nuclear
thermal propulsion can be used to explore locations throughout the solar system based
on new engineered designs with no unresolved scientific hurdles.
Fusion reactors or fus ion propulsion can be developed for missions throughout the solar
system, but there are many unresolved issues in their use. The fusion propu lsion
technology that may show promise in the far-term are pulsed propulsion systems.
These concept designs include large sails or collectors that absorb the energy from
thermonuclear explosions in itiated at a specific distance from the collector. Each
explosion generates a pulse that accelerates the vehicle forward. Design challenges
include protection of the crew from the radiation of the nuclear blast, cushioning the
crew from the incredible "jerk" or change in acceleration that occurs during each blast,
and t he design of a suitable collector.
LEO TO ALPHA CENTAUR! (4.22 LIGHT- YEARS OR 24.8 TRILLION
MILES)
Alpha Centauri contains three of the closest stars to our solar system. Alpha Centauri A
and B are binary stars orbiting one another, yet each one is approximately the same
size as the Sun. Alpha Centauri C, or Proxima Centauri, is the closest at 4.22 light
years and is a red dwarf. There is a limited possibility that Alpha Centauri has Earth
like planets.
Rockets optimal for flights to these stars and destinations of similar distance would
require high specific impulse propulsion. Depending on other mission requirements, the
thrust may be kept low since the application of a small, but continuous thrust over a
long period of time leads to high velocities. Since aerobraking may not be possible, the
spacecraft can accelerate for half the trip and must decelerate for the second half.
Spacecraft acceleration can be low, and most designs for human flight focus on a
continuous acceleration of 1 g (Earth gravity) to provide optimal crew conditions.
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Official release, from the pursue collection. The PDF is mirrored here; the original link is above. 50 pages are in the text index: search them above, or from the library's search.