By means of steel cables and iron brackets anchored into rock faces, climbers reach a high-altitude world that would otherwise be seen only by hardened alpinists.
Unlike any other asteroid known today, Vesta has an iron core surrounded by layers of mantle rock and crust, similar to Earth and Mars, preliminary gravity and density measurements suggest.
Based on what we knew about the way our Solar System behaved, Dr Murray said most of this iron would have come from lumps of rock like asteroids being hurled into the stars by the gravitational disturbance of orbiting planets.
The grey stands in contrast to the weathered red outer-coating of the Sheepbed unit, and the darker colour hints at a different oxidation state for iron (Fe) minerals that might be inside the rock.