AAWSAP DIRD, Aneutronic Fusion Propulsion I, November 2010

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using D-Li6 fuel pellets. The estimated travel time of this system to Alpha Centauri was
100 years at an average velocity of about 0.5% of the speed of light.
OTHER ANEUTRONIC ROCKET DESIGNS
Antimatter-Catalyzed Fusion
In the 1990s, Pennsylvania State University worked on a fusion rocket design that
employed antimatter to catalyze fission reactions in uranium. As a comparison, in
order to make a nuclear fission bomb for space propulsion, approximately 12 kg of
uranium-235 is required to generate the three critical masses required. Using
antimatter, this can be achieved with gram-quantities of uranium.
Magnetized Target Fusion
Plasma guns are used instead of lasers to generate heat in a low-density fusion fuel
mixture confined by magnetic fields. The fuel is rapidly compressed to ignite fusion.
The NASA/MSFC HOPE (Human Outer Planets Exploration) Group estimates that this
propulsion system could transport payloads to Jupiter within about 300 days.
Ion Drives
The VASMIR engine is a highly efficient ion thruster that uses an RF resonant cavity to
accelerate ionized argon or xenon gas as a propellant. One concept is to generate
electricity from aneutronic fusion by capturing the energy of the emitted ions in a
magnetohydrodynamic generator. The electricity would then be used to power the
VISMIR ion drive.
This direct conversion drive could capture useful energy from aneutronic fusion or from
D-T fusion which is easy to ignite, but loses about 80% of its energy to neutrons. The
neutrons can be used to generate secondary ions through impact on a target and the
ion energy can be collected in the MHD generator.
COMMERCIAL DEVELOPMENT
In addition to teams from universities and national laboratories, several companies
have been formed to develop aneutronic fusion propulsion systems. Several are
discussed below .
1. EMC2 Fusion Development Corporation
A prolific designer and author, Dr. Robert Bussard has explored inertial
electrostatic confinement fusion as used in the Farnsworth-Hirsh Fusor .13, 14, 15, 16,
17 He and his colleagues formed EMC2, a private company based in Santa Fe,
New Mexico, to test components of a practical fusion drive. Their work has been
funded by DARPA, NASA, and the U.S. Navy.
Outlined in Figure 11, his QED (charged particle electric discharge engine) is
based on the Farnsworth-Hirsch Fusor, an ion accelerator patented in 1968. This
accelerator works through the use of spherical electrodes that force ions toward
the center of a spherical chamber by Lorentz forces. By injecting preheated ions
of deuterium and helium-3 or boron-11 into the fusor core, the resulting fusion
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