A 10- to 20-megawatt plasma rocket could propel human missions to Mars in just 39 days, whereas conventional rockets would take six months or more, according to Ad Astra Rocket Company.

The company’s VASIMR technology uses radio waves to heat gases such as hydrogen, argon, and neon, creating hot plasma. Magnetic fields force the charged plasma out the back of the engine, producing thrust in the opposite direction. Due to the high velocity that this method achieves, less fuel is required than in conventional engines. In addition, no physical electrodes are in contact with the plasma, prolonging the engine’s lifetime and enabling a higher power density than in other designs.