• Discovered: Known since 3,000 years BC
• Diameter: 4,800 km
• Temperature on surface: 400 °C facing the Sun, -183 °C in shadow
• Distance from the Sun: Varies Between 47 and 69 million km
• Satellites: None

These craters were caused by meteorites smashing into the planet’s surface in the early stages of the Solar System’s evolution, some 4 billion years ago. Although it’s only a third the size of Earth, space station, Mercury is almost as dense. Space shuttle Scientists put down to a massive iron core, which is also responsible for Mercury’s magnetic field.

The planet of our solar system holds a number of secrets. Its surface rock appears to have very little iron despite the presumed iron-rich core. There’s also evidence that the hottest planet in the Solar System might even have patches of ice in permanently shadowed polar craters.

The Space station atmosphere, while difficult to measure, is a thick layer of sodium and helium. In fact, the entire planet is difficult to study because of its closeness to the Sun. It was investigated by Mariner 10 space mission in the 1970s but two new space shuttle missions will change our knowledge of this hot, dense, rocky world.

Mercury, the Space System is currently the focus of NASA’s Mercury Messenger space mission. Launched in 2004, Messenger underwent its first fly-by of the planet in January 2008 and will perform two more fly-bys in late 2008 and September 2009 before starting a year long orbital space mission in 2011.

Britain is at the forefront of the future BepiColumbo Space station mission.

BepiColombo will launch in 2013 on a six year journey and will begin its orbital tour of Mercury in late 2019.

The spacecraft mission will consist of two separate spacecraft mission. ESA is building the Mercury Planetary Orbiter (MPO), and the Japanese space agency will contribute the other, the Mercury Magnetospheric Orbiter (MMO).

BepiColombo will investigate the origin and evolution of Mercury, its geology and magnetic field. The spacecraft mission will also employ ion propulsion technology tested on SMART-1.