The US space agency's Dawn probe has gone into orbit around Ceres, the largest object in the Solar System between Mars and Jupiter.
A signal from the satellite confirming its status was received by ground stations at 13:36 GMT.
Ceres is the first of the dwarf planets to be visited by a spacecraft.
Scientists hope to glean information from the object that can tell them about the Solar System's beginnings, four and a half billion years ago.
Dawn has taken 7.5 years to reach its destination. Its arrival has seen it pass behind the dwarf to its 'dark side'.
Over the next month, controllers will re-shape the orbit to get it ready to begin the prime science phase.
And over time, the intention is to progressively lower the orbit until the probe is just a few hundred km above the surface.
'We feel exhilarated,' said Chris Russell, the mission's principal investigator from the University of California, Los Angeles (UCLA).
'We have much to do over the next year and a half, but we are now on station with ample reserves, and a robust plan to obtain our science objectives.'.