Few space propulsion technologies have generated as much recent interest as the ion engine. This weekend, the ESA announced it will it an advanced ion thruster to propel an upcoming probe to study the planet Mercury.

The mission is named BepiColumbo after Giuseppe Columbo, a pioneering scientist in the study of Mercury. It will launch in 2013 and arrive six years later. BepiColumbo will be the ESA's first mission to the hot regions of the solar system well inside the Earth's orbit. While approaching Mercury, the spacecraft will have to endure extremely hot temperatures on its sun-facing side, and extremely cold temperatures on the side facing away from the sun.

One of the primary goals of the mission is to discover whether pockets of water ice exist on Mercury's cold, shadowed side.

The ion engine will be built by Astrium, a subsidiary of the European Aeronautic Defense and Space Company (EADS). It uses an electric field to propel ions, or electrically-charged atoms of xenon gas to extremely high velocities, giving it an efficiency far above that of chemical-based engines. Its performance, if converted into earthly units, would equate to 17.8 million miles per gallon.

Electro-propulsion specialist Howard Gray says, "Ion propulsion will be a key technology for a series of future long-distance exploration missions. Today's agreement puts British scientists and engineers in a strong position in Europe to take a lead role in adopting these systems for future spacecraft."