Rosetta's images of the asteroid Steins
Rosetta's images of the asteroid Steins
For the first time ever, a European spacecraft performed a fly-by of an asteroid. On the evening of 5 September 2008, the European Space Agency ESA's Rosetta spacecraft passed the small celestial body at a distance of just 800 kilometres.
The first images received show an irregularly shaped asteroid with a diameter of 4.6 kilometres, which confirms calculations made in the run-up to the observations. In Steins’ north polar region, a circular impact crater of about 1.5 kilometres across is visible; north is at the top of the image.
The crater is so large relative to the Steins' overall size that it is very likely that the collision that created it was so severe as to almost shatter it. Also striking is a chain of at least six smaller impact craters extending from north to south across the asteroid’s day side with the craters decreasing in size along the chain. Such a chain of craters has never been observed on any other asteroid. Through investigating small Solar System bodies, such as asteroids and comets, the researchers hope to gain an insight into the first few million years in the history of the Solar System, which is 4.6 billion years old.
