38 Esoteric propulsion schemes part2 (solar sails, lasers, fusion...)
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This article is from the Space FAQ, by Jon Leech leech@cs.unc.edu and Mark Bradford tla@surly.org with numerous contributions by others.
38 Esoteric propulsion schemes part2 (solar sails, lasers, fusion...)
FUSION
"A Laser Fusion Rocket for Interplanetary Propulsion", Roderick Hyde,
LLNL report UCRL-88857. (Contact the Technical Information Dept. at
Livermore)
Fusion Pellet design: Fuel selection. Energy loss mechanisms.
Pellet compression metrics. Thrust Chamber: Magnetic nozzle.
Shielding. Tritium breeding. Thermal modeling. Fusion Driver
(lasers, particle beams, etc): Heat rejection. Vehicle Summary:
Mass estimates. Vehicle Performance: Interstellar travel
required exhaust velocities at the limit of fusion's capability.
Interplanetary missions are limited by power/weight ratio.
Trajectory modeling. Typical mission profiles. References,
including the 1978 report in JBIS, "Project Daedalus", and
several on ICF and driver technology.
"Fusion as Electric Propulsion", Robert W. Bussard, Journal of
Propulsion and Power, Vol. 6, No. 5, Sept.-Oct. 1990
Fusion rocket engines are analyzed as electric propulsion
systems, with propulsion thrust-power-input-power ratio (the
thrust-power "gain" G(t)) much greater than unity. Gain values
of conventional (solar, fission) electric propulsion systems are
always quite small (e.g., G(t)<0.8). With these, "high-thrust"
interplanetary flight is not possible, because system
acceleration (a(t)) capabilities are always less than the local
gravitational acceleration. In contrast, gain values 50-100
times higher are found for some fusion concepts, which offer
"high-thrust" flight capability. One performance example shows a
53.3 day (34.4 powered; 18.9 coast), one-way transit time with
19% payload for a single-stage Earth/Mars vehicle. Another shows
the potential for high acceleration (a(t)=0.55g(o)) flight in
Earth/moon space.
"The QED Engine System: Direct Electric Fusion-Powered Systems for
Aerospace Flight Propulsion" by Robert W. Bussard, EMC2-1190-03,
available from Energy/Matter Conversion Corp., 9100 A. Center
Street, Manassas, VA 22110.
[This is an introduction to the application of Bussard's version
of the Farnsworth/Hirsch electrostatic confinement fusion
technology to propulsion. 1500<Isp<5000 sec. Farnsworth/Hirsch
demonstrated a 10**10 neutron flux with their device back in
1969 but it was dropped when panic ensued over the surprising
stability of the Soviet Tokamak. Hirsch, responsible for the
panic, has recently recanted and is back working on QED. -- Jim
Bowery]
"PLASMAKtm Star Power for Energy Intensive Space Applications", by
Paul M. Koloc, Eight ANS Topical Meeting on Technology of Fusion
Energy, special issue FUSION TECHNOLOGY, March 1989.
Aneutronic energy (fusion with little or negligible neutron
flux) requires plasma pressures and stable confinement times
larger than can be delivered by current approaches. If plasma
pressures appropriate to burn times on the order of milliseconds
could be achieved in aneutronic fuels, then high power densities
and very compact, realtively clean burning engines for space and
other special applications would be at hand. The PLASMAKtm
innovation will make this possible; its unique pressure
efficient structure, exceptional stability, fluid-mechanically
compressible Mantle and direct inductive MHD electric power
conversion advantages are described. Peak burn densities of tens
of megawats per cc give it compactness even in the
multi-gigawatt electric output size. Engineering advantages
indicate a rapid development schedule at very modest cost. [I
strongly recommend that people take this guy seriously. Bob
Hirsch, the primary proponent of the Tokamak, has recently
declared Koloc's PLASMAKtm precursor, the spheromak, to be one
of 3 promising fusion technologies that should be pursued rather
than Tokamak. Aside from the preceeding appeal to authority, the
PLASMAKtm looks like it finally models ball-lightning with solid
MHD physics. -- Jim Bowery]
GAS GUNS
There's a good article (replete with pictures) in the August 10,
1992 issue of Aviation Week entitled "World's Largest Light Gas Gun
Nears Completion at Livermore." In addition, that article refers to
another article on the same subject in their July 23, 1990 issue.
GUN LAUNCHERS (GENERAL)
"Battle of the Big Shots" Frank Kuznik, "Air"&"Space",
August/September, 1993, pp. 54-61.
Discusses all the current gun-launch-to-space concepts as well
as the concept's checkered history (G.V. Bull).
ION DRIVES
NASA Spacelink carries material covering many aspects of ion drives
and describing the SERT I and II missions, which flight-tested
cesium ion thrusters in the 1960s and 70s. There are numerous
references.
http://spacelink.msfc.nasa.gov:80/NASA.Projects/NASA.Launch.Vehicles/Proposed.Systems/Ion.Propulsion.Engine/
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