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Ion Propulsion
Ion Propulsion - Transport System to the Planets
The efficiency of a rocket engine can be described by its specific impulse, which is the change of momentum gained from a 1 kilogram weight of propellent.
The Space Shuttle main engines have a specific impulse of 453 seconds which is typical of a liquid fuelled rocket engine.
An Ion thruster has a specific impulse of more than 3000 seconds and so requires less than a sixth of the fuel of a liquid fuelled engine.
Gridded electrostatic ion thrusters commonly utilize Xenon gas. The gas is first ionized by bombarding it with electrons. The positively charged ions then diffuse through the positive grid and enter a potential difference between the positive and negative grids. The potential difference accelerates the ions to high velocities, which then leave the engine to create thrust. An electron emitter, on the exterior of the engine, neutralizes the ion beam to prevent charge build-up.
The typical thrust of an ion engine is equivalent to a weight of 10 grams - about the weight of a sheet of paper.
This means ion thrusters need to provide continuous thrust for a very long time in order to achieve a reasonable change in velocity. Electrostatic ion engines have been tested for 3.5 years of continuous thrust at full power. Collision of ions with the charged grids causes their erosion and will lead to eventual failure.
Ion engines consume more than 2 kilowatts of electrical power, which may be generated by solar arrays or nuclear generator.
NASA has developed a Xenon ion thruster called NSTAR for use in their inter-planetary missions. This thruster was tested in the space probe Deep Space 1, launched in 1998.
The Dawn mission was launched in September 2007 to explore the dwarf planet Ceres and the asteroid Vesta. To cruise from Earth to its targets it will use three Deep Space 1, heritage, NSTAR thrusters, firing only one at a time, to take it in a long outward spiral. The three thrusters are required to meet the lifespan requirement of the engine.
Length: 244
Rating: 4.70 (35 ratings)
Tags: Ion Propulsion
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LightCraft Launch Oct 2000 - laserbeam powered propulsion
Prior to liftoff, a jet of compressed air is used to spin the lightcraft to about 10,000 revolutions per minute (RPMs). The spin is needed to stabilize the craft gyroscopically.
Once the lightcraft is spinning at an optimal speed, the laser is turned on, blasting the lightcraft into the air. The 10-kilowatt laser pulses at a rate of 25-28 times per second. By pulsing, the laser continues to push the craft upward. The light beam is focused by the parabolic mirror on the bottom of the lightcraft, which heats the air to between 18,000 and 54,000 degrees Fahrenheit (9,982 and 29,982 degrees Celsius) -- that's several times hotter than the surface of the sun. When you heat air to these high temperatures, it is converted to a plasma state -- this plasma then explodes to propel the craft upward.
(note: the Lightcraft here actually employed a plastic ablative propellant. So the "it burns air" statement is not entirely correct - the laser is igniting air AND PROPELLANT)
Lightcraft Technologies uses a Pulsed Laser Vulnerability Test System (PLVTS), an offspring of the Star Wars defense program. The 10 kw Carbon-dioxide pulsed laser being used for the experimental lightcraft is among the most powerful in the world.
more info:
http://science.howstuffworks.com/light-propulsion.htm
http://www.lightcrafttechnologies.com
Length: 249
Rating: 4.50 (15 ratings)
Tags: Beamed Energy Propulsion Light Microsatellite laser launch space lightcraft satellite test Carbon-dioxide CO2 PLVTS
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Electromagnetic Inertial Propulsion System
Initial report on project aimed to develop new way of space travel. This engine is based on electromagnetism. It utilizes a delay between two moments: when force field is created and when it acts on object. Currently there is a attempt to build levitator using proper oscillator/impulsator, coil and permanent magnet.
This is not a science fiction idea. There are other teams trying to achieve the same by different methods. Here is short scientific abstract from adsabs.harvard.edu
Experiments performed by independent research teams, suggesting that ``propellantless'' propulsion without external assistance is being achieved by means of electromagnetic inertia manipulation, are discussed here and compared within the framework of competing theoretical formulations. The authors' theory relies upon the fact that the electromagnetic (EM) field can exhibit a whole non-vanishing momentum in the ``matter'' frame, even for stationary regimes, provided Minkowski's energy-momentum tensor holds for EM fields in matter. In a closed system this EM momentum can be converted into mechanical momentum, so that electromagnetic inertia intervenes to modify the inertial properties of the generating device. Another theory, set forth by Corum and based on Slepian's works, states that the inertia manipulation effect stems from the Heaviside force density in vacuum, which is shown to lead to a zero instantaneous volume integrated force on a closed system. Although the system momentum is not conserved in the reported experiments, the propulsion effect is shown to be consistent with an alternative formulation of Minkowski's EM force density that correctly predicts former peer-reviewed experimental results. A fourth theory by J. Woodward, based on ``Machian'' mass/inertia fluctuations due to transient mass modifications, purportedly predicts the observed results but flaws are found in the predictions which, when corrected, considerably disagree with the experimental data. Finally, recent developments in vacuum physics allow building a conceptual framework with the potential of resolving the apparent violation of momentum conservation, closely connected to Minkowski's energy momentum tensor and its lack of symmetry.
Length: 368
Rating: 3.40 (8 ratings)
Tags: levitation space travel spacecraft rocket shuttle antigravity inertial propulsion engine magnet aerospace
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Ion propulsion
This is a piece of tin foil shaped to direct high voltage arcs in the same rotational direction.
Length: 16
Rating: 4.10 (9 ratings)
Tags: ion propulsion tesla coil physics
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CSU - Space Lab (Ion Propulsion)
This video highlights the work being done at Colorado State University's Space Lab working with Ion Propulsion. If you would like to know more about CSU's Engineering programs please go to www.engr.colostate.edu.
Length: 158
Rating: 0.00 (0 ratings)
Tags: Engineering Colorado State University Space Science Ion Propulsion
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