The space agency says the comet-chaser Rosetta flew by Lutetia (loo-TEE'-shee-uh) as close as 1,900 miles and had about two hours to capture images of the asteroid with its high-tech cameras.
Though Lutetia was discovered some 150 years ago, for a long time it was little more than a point of light to those on Earth. Only recent high-resolution ground-based imaging has given a vague view of the asteroid.
Scientists hope to find in the information and images gathered by Rosetta clues to the history of comets and asteroids and of the solar system.
For Rosetta, examining Lutetia and other asteroids is only an event on its long journey to another comet (67P/Churyumov-Gerasimenko).
Rosetta was launched in 2004 and is expected to reach its target in 2014.