Mercury in focus

The geology of Mercury, the innermost and smallest planet in our solar system, remains a mystery to astronomers. But a diode laser module designed by German researchers may one day map the hills and valleys of the Earth-like planet.

The

(ILT) in Aachen was asked by German satellite parts manufacturer

to build a prototype diode pump to excite light energy into a laser altimeter, for measuring altitudes on Mercury. If it wins the full contract, the lasers will be launched in 2013 as part of ESA's

.

The knowledge of the planet's landscape is limited to a single NASA spacecraft flyby from 1974-1975, which mapped only 40-45 per cent of its surface. The space probe showed the surface of Mercury to be similar in appearance to the Moon, with extensive, volcanic rock plains and deep craters, indicating that it has been geologically inactive for billions of years.

In the new mission, diode lasers will orbit Mercury and map its geology by directing a beam of light to a point on the planet's surface. The time it takes for the beam to reflect back determines the distance. By scanning the landscape in this way, the researchers believe it will be possible to form an accurate 3D map of the planet, detailing the size and depth of craters and mountains.