You won't get much thrust out of an ion thruster: compared to a chemical rocket engine, they're not all that impressive. What makes ion thrusters so great is their ability to put out small amounts of thrust very efficiently and for a very long time, and NASA's Evolutionary Xenon Thruster has now been operating for 43,000 hours. That's nearly five years straight.

Everything from big budget science fiction films to very real ancient texts have primed us for any number of doomsday scenarios promising to bring an end to civilization as we know it. But none have gained more traction in recent years than the Mayan calendar end-of-days prophecy. To address these concerns, NASA has released a new video in which the agency seeks to debunk any fears of a cosmic catastrophe.

For the past year, two spacecraft the size of washing machines have been orbiting the Moon in formation, mapping out gravitational anomalies by precisely measuring the distance between them. Now they're all done, and to celebrate, NASA is about to slam 'em both into a lunar mountain at a couple thousand miles an hour.

While we'll never really be happy about the retirement of the space shuttle, NASA is completely over it and looking towards the future of space transportation, which is going to be commercial. The agency announced today its selection of three companies which it hopes to certify to take its astronauts up to the ISS and back within the next five years.