The satellite itself is a hollow sphere 80 cm in diameter. The sphere is engraved with a map of Earth and surrounded by an aluminium layer, a thermal layer and several layers of titanium and other heavy materials intertwined with vacuum. The sphere is resistant to cosmic radiation, atmosphere re-entry, space junk impacts, etc. For its first few years in orbit, KEO will sport a pair of wings 10 meters across that will aid in its spotting from Earth. As the satellite enters the atmosphere, the thermal layer will produce an artificial aurora to give a signal of the satellite's re-entry. The passive satellite will not carry any communications or propulsion systems. It will be launched by an Ariane 5 rocket into an orbit 1,800 km high, an altitude that will bring it back to Earth in 500 centuries, the same amount of time that has elapsed since early humans started to draw on cavern walls.