But by nineteen seventy-nine, the world's first nuclear-powered submarine had become an old ship.

VOA: special.2010.06.11

NASA's slice of the pie includes a plan that would improve detection of near-Earth asteroids, send a solar-powered robot ship (like the NASA concept above) to capture one of the space rocks and tow it back to a stable orbit near Earth, where researchers could study it up close.

ENGADGET

At slow speeds, it runs only on an electric motor powered by the ship's auxiliary turbine.

ECONOMIST: Monitor

So surprisingly, the best hope for clean, green ethanol right now is to ship it in diesel-powered trucks.

FORBES: Ethanol: Getting There Is None Of The Fun