================================================== ==========
From: Robert Clark )
Subject: Microwave powered ion drive.
Newsgroups: sci.astro, sci.physics, sci.space.policy
Date: 2000/07/30


Found this site while looking up info on microwaves:

Physics inside a Microwave Oven
http://home.earthlink.net/~marutgers...microwave.html

One of the demonstrations on this page appears to show plasmas being
generated by heating grapes with a microwave oven. Nice Quicktime
movies here. It's also described on the page:

HOW THINGS WORK: Microwave Ovens
http://rabi.phys.virginia.edu/HTW//microwave_ovens.html

Would this provide a low energy means of creating the plasma required
for ion engines? One means of creating the required plasma is by
irradiating the propellent gas with intense laser or x-ray beams to
strip off the electrons of the atoms of the gas, producing an ionized
plasma. However, these are both high-frequency forms of EM radiation
and therefore require high energy to produce. Microwaves being longer
wavelengths require less energy to produce.
Another means that is actually used for the Deep Space 1 probe is to
use electrons emitted by a cathode to irradiate the gas, ionizing it.
How does the energy requirement for the heating element of a cathode
compare to the energy requirement for producing the microwaves?

If this can be exploited as a low energy means of producing plasmas
then this might be used not only for low thrust engines as on DS 1 but
also for lauching ships into space by beaming the microwaves into a
reaction chamber of a rocket lined with, er, grapes.

--
________________________________________________

"In order for a scientific revolution to occur,
most scientists have to be wrong"
-- Bob Clark
________________________________________________

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Another recent story discusses the applications of using cold plasmas:

Force Fields and 'Plasma' Shields Get Closer to Reality,
http://www.space.com/businesstechnol...ma_000724.html

An advantage of the cold plasmas is the low power required to generate
them. However the article mentions that hot plasmas can be generated
with higher densities. Perhaps the microwave plasma generation method
can match the efficiency of the cold generation system while allowing
the high densities of the hot plasmas.


From: Robert Clark )
Subject: Plasma propulsion for access to space?
Newsgroups: sci.astro, sci.physics, sci.space.policy, rec.arts.sf.science
Date: 2002-11-05 21:21:09 PST
http://groups.google.com/groups?th=87680963df54e46c


Bob Clark

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(Ron Baalke) wrote in message ...
Dwayne Brown
Headquarters, Washington November 20, 2003
(Phone: 202/358-1726)

Lori J. Rachul
Glenn Research Center, Cleveland
(Phone: 216/433-8806)

RELEASE: 03-377

NASA SUCCESSFULLY TESTS ION ENGINE

NASA's Project Prometheus recently reached an important
milestone with the first successful test of an engine that
could lead to revolutionary propulsion capabilities for space
exploration missions throughout the solar system and beyond.

The test involved a High Power Electric Propulsion (HiPEP)
ion engine. The event marked the first in a series of
performance tests to demonstrate new high-velocity and high-
power thrust needed for use in nuclear electric propulsion
(NEP) applications.

"The initial test went extremely well," said Dr. John Foster,
the primary investigator of the HiPEP ion engine at NASA's
Glenn Research Center (GRC), Cleveland. "The test involved
the largest microwave ion thruster ever built. The use of
microwaves for ionization would enable very long-life
thrusters for probing the universe," he said.

The test was conducted in a vacuum chamber at GRC. The HiPEP
ion engine was operated at power levels up to 12 kilowatts
and over an equivalent range of exhaust velocities from
60,000 to 80,000 meters per second. The thruster is being
designed to provide seven-to-ten-year lifetimes at high fuel
efficiencies of more than 6,000-seconds specific impulse; a
measure of how much thrust is generated per pound of fuel.
This is a contrast to Space Shuttle main engines, which have
a specific impulse of 460 seconds.

The HiPEP thruster operates by ionizing xenon gas with
microwaves. At the rear of the engine is a pair of
rectangular metal grids that are charged with 6,000 volts of
electric potential. The force of this electric field exerts a
strong electrostatic pull on the xenon ions, accelerating
them and producing the thrust that propels the spacecraft.
The rectangular shape, a departure from the cylindrical ion
thrusters used before, was designed to allow for an increase
in engine power and performance by means of stretching the
engine. The use of microwaves should provide much longer life
and ion-production capability compared to current state-of-
the-art technologies.

This new class of NEP thrusters will offer substantial
performance advantages over the ion engine flown on Deep
Space 1 in 1999. Overall improvements include up to a factor
of 10 or more in power; a factor of two to three in fuel
efficiency; a factor of four to five in grid voltage; a
factor of five to eight in thruster lifetime; and a 30
percent improvement in overall thruster efficiency. GRC
engineers will continue testing and development of this
particular thruster model, culminating in performance tests
at full power levels of 25 kilowatts.

"This test represents a huge leap in demonstrating the
potential for advanced ion technologies, which could propel
flagship space exploration missions throughout the solar
system and beyond," said Alan Newhouse, Director, Project
Prometheus. "We commend the work of Glenn and the other NASA
Centers supporting this ambitious program."

HiPEP is one of several candidate propulsion technologies
under study by Project Prometheus for possible use on the
first proposed flight mission, the Jupiter Icy Moons Orbiter
(JIMO). Powered by a small nuclear reactor, electric
thrusters would propel the JIMO spacecraft as it conducts
close-range observations of Jupiter's three icy moons,
Ganymede, Callisto and Europa. The three moons could contain
water, and where there is water, there is the possibility of
life.

Development of the HiPEP ion engine is being carried out by a
team of engineers from GRC; Aerojet, Redmond, Wash.; Boeing
Electron Dynamic Devices, Torrance, Calif.; Ohio Aerospace
Institute, Cleveland; University of Michigan, Ann Arbor,
Mich.; Colorado State University, Fort Collins, Colo.; and
the University of Wisconsin, Madison, Wis.

For information about NASA on the Internet, visit:

http://www.nasa.gov

For more information about NASA's Glenn Research Center,
visit:

www.grc.nasa.gov

For more information about Project Prometheus on the
Internet, visit:

http://spacescience.nasa.gov/missions/prometheus.htm

Information about JIMO is available on the Internet at:

http://spacescience.nasa.gov/missions/JIMO.pdf


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