SlideShare utilise les cookies pour améliorer les fonctionnalités et les performances, et également pour vous montrer des publicités pertinentes. Si vous continuez à naviguer sur ce site, vous acceptez l’utilisation de cookies. Consultez nos Conditions d’utilisation et notre Politique de confidentialité.
SlideShare utilise les cookies pour améliorer les fonctionnalités et les performances, et également pour vous montrer des publicités pertinentes. Si vous continuez à naviguer sur ce site, vous acceptez l’utilisation de cookies. Consultez notre Politique de confidentialité et nos Conditions d’utilisation pour en savoir plus.
Nuclear Propulsion Through Direct Conversion of Fusion Energy
Nova engine powerpoint
The future of manned space exploration and development of space
depends critically on the creation of a vastly more efficient propulsion
architecture for in-space transportation. Nuclear-powered rockets can
provide the large energy density gain required. A small scale, low cost
path to fusion-based propulsion is to be investigated. It is accomplished
by employing the propellant to compress and heat a magnetized plasma
to fusion conditions, and thereby channel the fusion energy released
into heating only the propellant. Passage of the hot propellant through a
magnetic nozzle rapidly converts this thermal energy into both directed
(propulsive) energy and electrical energy.
Fusion-powered rockets could provide longer thrust than chemical
rockets, which burn their fuel quickly. It's believed that fusion propulsion
will allow rapid travel to anywhere in our solar system, and could allow
round trips from Earth to Jupiter in just two years.
My idea of the nuclear propulsion is a fusion reaction between
deuterium plasma and tritium plasma (D-T Fusion, below). In this
reaction the hydrogen isotope, deuterium plasma (with one “extra”
neutron) collides with the hydrogen isotope, tritium plasma (with two
“extra” neutrons), to form an alpha particle (a helium nuclei ) and a
neutron. This is a nuclear reaction: between them, the new alpha and
the neutron possess 17.6 MeV (million electron volts) of energy. The
helium nuclei will be accelerated out of a magnetic nozzle in a very high
speed with the energy made by the nuclear reaction and that produces
high thrust of plasma propulsion with a long duration of gas injection.
the first RF coupler is to convert gas into plasma by
ionizing it, or knocking an electron loose from each
gas atom. It is known as the helicon section, because
its coupler is shaped such that it can ionize gas by
launching helical waves. Helicon couplers are a
common method of generating plasma. After the
helicon section, the gas is now "cold plasma", even
though its temperature is greater than the surface of
the Sun (5800 K). The plasma is a mixture of electrons
and ions (the atoms they were stripped from).
Heating the plasma.
the Ion Cyclotron Heating (ICH) section. ICH is a
technique used in fusion experiments to heat plasma
to temperatures on the order of those in the Sun's
core (10 million K). The ICH waves push only on the
ions as they orbit around the magnetic field lines
resulting in accelerated motion and higher
Confining the plasma.
Since fusion needs a hot plasma held tightly together for long
enough for the fusion reaction to occur, and since the plasma
is so hot it would melt any container you could put it in (like
trying to boil water in a pot made from ice!!) we need to use
We can see this principle is used in the tokamak. The Tokamak
employs many magnetic fields to ensure the plasma stays
tightly confined and away from its walls. The plasma must be
dense for fusion to occur, but the temperature of the plasma
gets so high that anything it touches would melt instantly.
This is why extremely strong magnets are needed to keep it
away from the tokamak walls.
Heating the combustion chamber.
Fusion can only occur in super-heated
environments measuring in the millions of degrees. Stars,
which are made of plasma, are the only natural objects that
are hot enough to create fusion reactions. In this case, the
combustion chamber will be heated using radio-frequency
radiation to create extreme heat and fuse the plasma.
The high level of heat required to create this type of plasma
makes it impossible to contain the components in any known
material. However, plasma is a good conductor of electricity,
which makes it possible to be held, guided and accelerated
using magnetic fields. This is the basis for creating a fusion-
powered spacecraft, which NASA believes is achievable within
The plasma will be inside a quartz tube with spiral
shape so that we get a long way to put the plasma in,
because the longer the tube is, the faster the plasma
will be in the outlet.
Accelerating the plasma.
To accelerate the plasma, we use a solenoid which will
be wrapped around the tube to push the ions into the
combustion chamber in a very high speed.
Injecting the electrons.
Once the gas is converted into plasma, an anode will
absorb the electrons and inject them using a
neutralizing electron gun.
You can understand the process of the gas
injection, producing the plasma, confining it,
heating it up and accelerate it from these two
One of the key challenges in developing the NOVA
engine is supplying power to it. A high-power electric
thruster requires a lot of electricity, and generating
that in space may require some engineering
Solar power can be efficiently used for going to Mars.
Spacecraft operating in the inner solar system usually
rely on the use of photovoltaic solar panels to derive
electricity from sunlight. In the outer solar system.
Recent advances in solar array technology show a
significant increase in solar power utilization (up to an
order of magnitude).
The same principle of the producing and accelerating
plasma is used in the VASIMR engine.
The Variable Specific Impulse Magnetoplasma Rocket
(VASIMR) engine is a new type of electric thruster with
many unique advantages. In a VASIMR engine, gas such as
argon, xenon, or hydrogen is injected into a tube
surrounded by a magnet and a series of two radio wave
(RF) couplers The couplers turn cold gas into superheated
plasma and the rocket’s magnetic nozzle converts the
plasma thermal motion into a directed jet.
Many types of nuclear propulsion have been proposed, and some of
them (e.g. NERVA) tested for spacecraft applications.
Project Orion has to be the most audacious, dangerous and
downright absurd space program ever funded by the US taxpayer.
This 1950s design involved exploding nuclear bombs behind a
spacecraft the size of the Empire State Building to propel it through
space. The Orion’s engine would generate enormous amounts of
energy – and with it lethal doses of radiation.
Plans suggested the spacecraft could take off from Earth and travel to
Mars and back in just three months. The quickest flight using
conventional rockets and the right planetary alignment is 18 months.
Project Orion was a study of a spacecraft intended to be directly
propelled by a series of explosions of atomic bombs behind the craft
(nuclear pulse propulsion). Early versions of this vehicle were
proposed to take off from the ground with significant
associated nuclear fallout; later versions were presented for use only
There were three stated goals for Project Daedalus:
•The spacecraft must use current or near-future technology.
•The spacecraft must reach its destination within a working
•The spacecraft must be designed to allow for a variety of
target stars. The final design solution was published in a
special supplement of the Journal of the British Interplanetary
Society in 1978.