Question by Rob: Can some one tell me about VASIMR Variable Specific Impulse Magnetoplasma Rocket?
The only thing I can dig up is
((( The Variable Specific Impulse Magnetoplasma Rocket (VASIMR) is an electro-magnetic thruster for spacecraft propulsion. It uses radio waves to ionize and heat a propellant and magnetic fields to accelerate the resulting plasma to generate thrust. It is one of several types of spacecraft electric propulsion systems. )))
It sounds like it uses radio waves to heat a propellant and magnetic fields.Does this have high thrust and high and high-specific impulse> Can this go almost the speed of light ?
Can this take up 10 or 15 people to the space station? How many people can this hold?
I hear there 3 types of VASIMR a plane/ rocket combo and rocket type and may be a SSTO.
Best answer:
Answer by lithiumdeuteride
Ion engine exhaust velocity is very high, giving it very good efficiency (as measured by specific impulse). However, the thrust is very low, making the engine totally useless for getting out of an atmosphere such as Earth’s. Ion engines like these are only good for orbital maneuvers, but they are much better than chemical rockets for such maneuvers.
Chemical rockets have very high thrust, but their specific impulse is low, so they run out of fuel more quickly (or alternatively, they must more fuel mass to accomplish the same maneuver).
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VASIMR has high specific impulse (meaning fuel efficiency), but low thrust. Therefore, it cannot get off the ground on its own. It must either be built in space or launched via some other type of propulsion. Magnetic fields confine the plasma, which is heated to around 50,000 degrees using radio waves. This is much hotter than even the surface of the sun, and will vaporize any matter it comes into contact with, which is why the magnetic restriction is needed. A choke-point in the magnetic field at one end allows the plasma to escape when the temperature becomes high enough, turning it into a rocket. This choke can be opened or narrowed in order to exchange efficiency for higher thrust. This is ideal for space flight because there are some points in an orbit which require higher thrust (such as close to a gravitational source), and others that require high efficiency (such as mid-trip). VASIMRs are so fuel efficent that one could be used to accelerate all the way to Mars, turning a normally 6 month trip into a 3 month one. However, nothing near the speed of light is possible with one. They are still in the experimental stage and are not being used, but supposedly there is a major test of one scheduled for 2010, or so I’ve heard a few years ago.