There's been lots of talk about plasma rockets for decades, but the Ad Astra Rocket Company just finished testing the most powerful plasma engine on Earth. It's not just some pipe dream, either — this small-scale prototype actually works, cranking out 201kW in a vacuum chamber. Planning to take the tech out of the lab and into space, the company just signed an agreement with NASA to test its VASMIR (Variable Specific Impulse Magnetoplasma Rocket) engine on the International Space Station in 2013.
The VASMIR technology uses magnetic fields to force the fired-up plasma out the back, sipping cheap argon, hydrogen, argon, and neon fuel. While that 200 kW engine is a good start, Ad Astra vows to create a 10 to 20MW version that can zip humans to Mars in 39 days — that's a whole lot faster than that "unsustainable" idea involving six months of space travel using conventional rockets. Check out this video of the engine's record-breaking test: