And check out that engine name:
...Ad Astra's Variable Specific Impulse Magnetoplasma Rocket (VASIMR) ionizes gases such as xenon or hydrogen to create superheated plasma stream for thrust. ...
New Rocket Engine Could Reach Mars in 40 Days
By Jeremy Hsu—SPACE.com Contributor
Future Mars outposts or colonies may seem more distant than ever with NASA's exploration plans in flux, but the rocket technology that could someday propel a human mission to the red planet in as little as 40 days may already exist.
A company founded by former NASA astronaut Franklin Chang-Diaz has been developing a new rocket engine that draws upon electric power and magnetic fields to channel superheated plasma out the back. That stream of plasma generates steady, efficient thrust that uses low amounts of propellant and builds up speed over time.
....VASIMR and the necessary power sources could get a boost in the coming years. NASA's new five-year budget includes more than $3 billion for developing heavy-lift and propulsion technologies, as well as a Game Changing Innovation program that similarly targets next-gen propulsion and power sources. ...
Image: VASIMIR installed on ISS (NASA concept art)