The Rosetta Science Working Team has made the final selection of the asteroids that Rosetta will observe at close quarters during its journey to Comet 67P/Churyumov-Gerasimenko. Steins and Lutetia lie in the asteroid belt between the orbits of Mars and Jupiter.
Read more:
http://www.esa.int/export/SPECIALS/Rosetta/SEM3LY2PGQD_0.html