Lutetia: The Largest Asteroid Yet Visited . ... Credit Copyright: ESA , NASA , JAXA ; Montage: Emily Lakdawalla ( Planetary Society ) Explanation: As humans explore the universe, the record for largest asteroid visited by a spacecraft has increased yet again. Earlier this month, ESA's robotic Rosetta spacecraft zipped past the asteroid 21 Lutetia taking data and snapping images in an effort to better determine the history of the asteroid and the origin of its unusual colors . ...