Rosetta: Cool science at a rare target
Steins, a rare E-type asteroid, holds clues on how the planets formed.
Steins is Rosetta's first nominal scientific target. Based upon ground-based observations, it has been classified as an 'E-type' asteroid, composed mainly of silicates and basalts, but its properties are not known in detail. For these reasons, it has been selected as one of the two asteroids that Rosetta will study, from among those that were within reach of the mission.
The study of asteroids is extremely important as they represent a sample of Solar System material at different stages of evolution – key to understanding the origin of our own planet and of our planetary neighbourhood. The spacecraft will rendezvous with the asteroid in the course of its first incursion into the asteroid belt, while on its way to comet 67/P Churyumov-Gerasimenko.