Re: SPACE: New propulsion technologies

Gabriele Betti (lbetti@dinonet.it)
Sun, 15 Aug 1999 20:29:42 +0200

Does anybody knows about anti-matter propulsion? What exactly anti-matter means/is?
Ciao,
Gabriele

At 09.48 15/08/99 -0400, you wrote:
>In increasing order of "mad-scientist factor", here's three interesting
>pieces about promising new propulsion technologies (apologies if these have
>appeared here before; I've been weeding pretty ruthlessly in my in-box and
>may have missed a previous post of these items):
>
> * * *
>
>Sacramento - August 10, 1999 - NASA's Marshall Space Flight Center (MSFC)
has
>awarded GenCorp Aerojet a multimillion dollar extension for continued
>development of the Strutjet Rocket-Based Combined Cycle (RBCC) engine
through
>2001.
>This revolutionary propulsion system combines air-breathing and rocket
engine
>technologies in a single engine for use on future reusable,
>single-stage-to-orbit launch vehicles. This type of engine allows the
vehicle
>to take off horizontally, like an airplane, for greater safety and
>reliability and a dramatic reduction in cost of access to space. The
Strutjet
>RBCC is a candidate as the primary propulsion for a third-generation space
>shuttle engine.
>
>"Aerojet is proud to be working closely with MSFC as it moves forward on
>reusable launch vehicle technology. We believe our technology will provide
>the capability for early demonstration of a vehicle powered by an RBCC
>engine," said Bob Harris, vice president, Strategic and Space Propulsion.
>
>Since 1996, Aerojet has successfully progressed in building the Strutjet
>RBCC, which is part of MSFC's Advanced Reusable Technologies Project. This
>contract extension will refine the Strutjet RBCC into a highly integrated
>engine/vehicle concept, and a new emphasis will be placed on the development
>of flight-type cooled components, including the use of advanced materials
and
>fabrication processes. These flight-type components will be exposed to
engine
>thermal environments in a Component Development Rig at Aerojet's Sacramento
>site.
>
>The Strutjet RBCC is an advanced, hydrogen-fueled engine that combines the
>best elements of air-breathing and rocket propulsion. It operates initially
>as an air-augmented rocket as it accelerates to low supersonic speeds,
>transitions to ramjet operation by turning off the rockets, then converts to
>a scramjet as flight speed increases. The rockets are turned back on as
>atmospheric oxygen diminishes, then the engine transitions to a
>high-expansion rocket for final ascent.
>
>During the initial program phase, the Strutjet RBCC demonstrated superior
>performance and a robust operating capability in wind tunnel tests over the
>entire flight operating range. Also, Aerojet's patented cascade fuel
injector
>efficiency and rocket durability and flexibility have been proven in the
>large number of tests conducted.
>
>Aerojet, a leading proponent of RBCC propulsion, has demonstrated excellent
>performance using both hydrogen and hydrocarbon fuels, providing evidence of
>the flexibility of this engine. Aided by Aerojet technology advances on this
>program, NASA placed recent emphasis on continuing the advancement of this
>promising concept through flight.
>

>Aerojet, a leader in propulsion, electronics and weapon systems, and fine
>chemicals, is a segment of GenCorp, a technology-driven company with strong
>positions in polymer products, automotive, and aerospace and defense
>industries.
>
> * * *
>
>Washington - August 12, 1999 - Researchers at NASA'ss Glenn Research Center
>have made for the first time tiny particles of frozen hydrogen suspended in
>liquid helium, a first step towards new rocket fuels that could
revolutionize
>rocket propulsion technology.
>In the experiments, small amounts of liquid hydrogen were poured onto the
>surface of liquid helium. The liquid hydrogen was at a temperature of 14
>kelvins (minus 435 degrees F), just above freezing point; and the liquid
>helium was held at 4 kelvins (minus 452 degrees F), or just above absolute
>zero.
>
>As the liquid hydrogen fell toward the surface of the helium, small, solid
>hydrogen particles formed and then floated on the surface of the helium.
>
>The suspension will be used to make futuristic atomic fuels that take
>advantage of the chemical recombination of atoms into molecules.
>
>"Atomic fuels will make possible rockets with liftoff weights one-fifth that
>of today's or with payloads three to four times more massive," said Bryan
>Palaszewski, Glenn principal investigator for the experiment.
>
>Using atomic fuels could reduce or eliminate on-orbit assembly of large
space
>vehicles, thereby eliminating multiple launches and years of assembly time
>and making flights to all parts of the solar system less expensive and more
>practicable.
>
>In atomic fuels, atoms of very active elements would be stored in a medium
>that prevents their recombination. Solid molecular hydrogen is a promising
>medium for storing and keeping atoms separate because it becomes solid at
>temperatures just a few degrees above absolute zero, where atomic activity
>due to heat is at a minimum.
>
>Helium, in turn, is the ideal medium for creating and holding the solid
>hydrogen particles because it remains liquid below the freezing point of
>hydrogen. In the rocket's reaction chamber, or engine, the fuel would warm,
>and the atoms would be freed.
>
>In less than an instant, they would recombine into molecules, and
>temperatures would go from 4 to 2000 kelvins (minus 452 to 3140 degrees F).
>Both hydrogen and helium would instantly vaporize and shoot out of the
engine
>at tremendous speed, propelling the rocket forward.
>
>Details about the behavior and characteristics of the particles are
described
>in a paper presented at the U.S. Air Force High Energy Density Materials
>Meeting in Cocoa Beach, FL, in June of this year.
>
>The advanced fuels experiments are part of Glenn's continuing efforts to
>advance the state of the art of propulsion technology. The experiments were
>conducted under the auspices of the NASA Advanced Space Transportation
>Program (ASTP), led by NASA Marshall Space Flight Center, Hunstville, AL.
>Current research is underway with an extensive team that includes
researchers
>from Glenn, Marshall, the U.S. Air Force, the Department of Energy,
>universities and industry.

>
> * * *
>
>Fusion fuels dreams of space travel
>
>Concepts could yield new propulsion techniques in a few years Terry Kammash,
>an astrophysicist and engineer at the University of Michigan, is developing
>a concept for a gas-dynamic mirror fusion propulsion engine.
>
>By Anne Rueter
>NEWHOUSE NEWS SERVICE
>
>ANN ARBOR, Mich., Aug. 11-To Terry Kammash, going to the stars is not sci-fi
>stuff. In the new millennium, the nuclear engineer envisions missions to
>Alpha Centauri, closest star to our solar system. In just the next 20 to 25
>years, he predicts spacecraft will reach one milepost on the route, the Oort
>Cloud, a debris-filled comet belt 932 billion miles away. And heís betting
>the missions will use fusion, the basic energy source of stars themselves.
>
>NEVER MIND that efficient fusion reactors to power industry and light our
>homes have so far eluded scientists and engineers. Kammash has designed two
>propulsion engines that take one of fusionís serious flaws and turn it into
>an asset for space travel. And as scientists search for ways to explore the
>vast distances in space, Kammashís most developed design looks like a
>front-runner.
>
>The physics is well understood, the technology is available, said Kammash, a
>University of Michigan professor emeritus. Itís just a question of putting
>it together.
>
>Thatís what NASA scientists have been doing at the Marshall Space Flight
>Center in Huntsville, Ala., where several alternatives to chemical rockets
>are being explored. Kammashís concept is the furthest along, said Bill
>Emrich, a senior engineer at the center. Heís getting a working model ready
>to test the design the first such test of fusion propulsion for use in
>space.
>
>I think itís a reasonably promising (concept), although there are others
>that look promising too, Emrich said. Itís hard to say at this point which
>one is going to be the winner.
>
>FUSION IN A YEAR OR TWO?
>Kammashís gas-dynamic mirror engine holds promise for faster travel to
>planets such as Mars and Pluto. Emrich and other NASA scientists have
>electromagnets in place in a 2-meter-long model of the engine. In the next
>few months, they hope to start injecting plasma, the superheated fuel that
>the magnets are designed to confine long enough to produce nuclear fusion
>reactions. The scientists hope to achieve fusion during the next year or
>two.
>
>Meanwhile, Kammash is pushing forward with his second engine design, one
>with the thrust needed for more distant interstellar missions. He got a
>boost recently when this design was among a handful of propulsion ideas to
>receive funding from NASAís newly formed Institute for Advanced Concepts.
>
>Both engines, Kammash said, aim to cut to a realistic level the time and
>cost of missions to planets in our solar system and beyond. And time is of
>the essence. Using conventional chemical rockets, missions to Mars are long
>enough to be daunting for humans: At seven to nine months each way, a trip
>might last two years. At a typical shuttle speed of 17,600 mph, it would
>take 168,000 years or more for a robotic mission to reach Alpha Centauri.

>
>Kammash estimates his gas-dynamic mirror fusion propulsion engine would take
>three to four months to travel to Mars and back. He thinks his newer design,
>fast enough for interstellar missions, could reach Alpha Centauri, 259
>trillion miles away, in as little as 213 years. This new engine might take a
>mere 29 years to make a one-way trip to the Oort Cloud.
>
>Now it costs $10,000 to put a kilogram in space, Kammash said. He and other
>space scientists take seriously NASAís challenge to cut this figure to
>$2,000 or less. Alternative propulsion methods are key because conventional
>fuels for long missions are extremely bulky and costly. It takes huge
>amounts of fuel to lift a spacecraft into space if it must carry fuel to
>travel to distant planets or stars.
>
>OTHER OPTIONS
>Fusion energy, produced when the light nuclei of certain atoms fuse together
>under intense heat, is not the only energy source being eyed for
>long-distance space missions. Energy from fission, the splitting of heavy
>atoms, is still a contender. Fission rockets, though they evoke safety
>concerns, havenít been abandoned and could power missions to the relatively
>near moon and Mars. For more distant ones, scientists believe fusion has
>greater potential.
>
>The idea of a robotic mission to explore the environs of Alpha Centauri
>draws many skeptics, but also many restless minds eager to try. If man does
>not explore he becomes stagnant, civilization becomes stagnant, Kammash
>said.
>
>Streams of leaking energy are one reason fusion hasnít lived up to hopes as
>an energy source on Earth. Some fusion reactors have had trouble producing
>more energy than they lose because hot plasma, the systemís fuel, is hard to
>contain. Kammash worked on designs for such fusion reactors for decades.
>Fusion enthusiasm ran high in the late 1970s and early í80s; now Congress
>continues to reduce funds for fusion research.
>
>In the early 1990s, Kammash came to see possibilities in fusionís problems.
>You want to eject hot plasma because thatís propulsion, Kammash said. Fusion
>is inherently leaky, so letís take advantage of it.
>
>The gas-dynamic mirror engine relies on powerful magnets to create
>electromagnetic fields that will confine plasma particles long enough for
>sufficient fusion reactions to occur. Mirror refers to the magnetic fields
>at each end that bounce particles back and forth. The engine retains some of
>the plasma to keep the fusion reaction going, and lets a fraction of it
>escape through a nozzle to produce thrust.
>
>THE ANTIMATTER FACTOR
>The second engine, called MICF (Magnetically Insulated Inertial Confinement
>Fusion), uses a different method to achieve fusion. A laser beam zaps
>BB-sized pellets of fuel, creating a hot plasma contained by a metallic
>shell. The plasma should be contained long enough to lead to large energy
>gains, Kammash writes in Ad Astra, a magazine read by astronauts and other
>space enthusiasts.
>
>His idea is a concept that brings together antimatter and fusion propulsion,
>said Robert Cassanova, director of the Institute for Advanced Concepts. We

>found that intriguing.
>
>Instead of a laser, Kammash ultimately wants to use antimatter, an
>experimental technique, to zap the fuel pellets. Giant particle accelerators
>produce fleeting forms of antimatter. Scientists are trying to find ways to
>trap one form, antiprotons, and use the energy they produce. Using a stream
>of antiprotons instead of a bulky laser apparatus would make Kammashís
>design very attractive in space.
>