I'll let that sink in for a second.
The innovative rocket uses radio waves to ionize cold gas – such as argon, xenon or hydrogen – and heat the resulting plasma to temperatures 20 times hotter than the surface of the sun. VASIMR then employs magnetic fields instead of metal tubes to control the direction of the plasma exhaust, making it one of the most innovative technologies in rocket propulsion.
VASIMR could get us to Mars so much quicker because the rocket has a much higher specific impulse – the amount of speed obtainable from a unit mass of propellant – than conventional chemical and electric rockets. In other words, the plasma propulsion system employed by VASIMR can go much faster on less fuel so, in a way, it could be very useful simply because it has better "gas mileage" than other rockets.
There is a drawback to this type of propulsion, however, in that VASIMR does not produce an adequate thrust to weight ratio in order to launch payloads from the surface of the earth and requires a vacuum to operate in. Thus, the rocket is suited for upper-stage cargo transportation, after a payload has been launched from earth with a chemical rocket.
VASIMR, which is being developed by former NASA shuttle flier Dr. Franklin Chang-Diaz and his Houston-based Ad Astra Rocket Company, has already operated at full capacity inside a vacuum chamber and is supposed to be taken to the International Space Station in 2014. From there, the rocket may be used for exploring other parts of our solar system, such as visiting an asteroid or (crosses fingers) Mars.
Since VASIMR would greatly reduce the amount of time that astronauts are subject to dangerous cosmic and solar radiation – currently one of the main issues preventing us from flitting around the solar system and placing footprints on the Martian surface – we really hope that we will see much more of it.
Want to learn more? Check out the VASIMR page on Ad Astra's website.