astroengine writes "Mission managers of NASA's Dawn asteroid probe had a long Saturday, waiting for news from the asteroid belt. Eventually they got the news they were hoping for: Dawn had entered Vesta orbit. This is the first time in history that an object in the asteroid belt has been orbited by an artificial satellite. It's taken four years for the ion thruster-propelled spacecraft to reach the asteroid and there was some uncertainty as to whether the probe had been captured by the asteroid's gravity at all. But after a long period of waiting, mission managers received the signal after Dawn was able to orientate its antenna toward Earth."