Washington: The space probe Dawn on the weekend finally rendezvouse with the asteroid Vesta, which circles the Sun between the orbits of Mars and Jupiter, after a four-year journey, NASA announced.

NASA director Charles Bolden confirmed in a communique on Sunday that the feat is an 'incredible exploration milestone' given that this is the first time that a spacecraft has gone into orbit around a body within the Solar System's main asteroid belt.

President Barack Obama has tasked NASA with sending astronauts to an asteroid in 2025 and Dawn is gathering crucial information that will be useful in preparing that mission, Bolden added.

Dawn, which neared Vesta on Saturday, will study the asteroid for a year before departing for its second destination, the dwarf planet Ceres, which it is expected to reach in 2012.

Dawn, launched in September 2007, will become the first spacecraft to orbit two destination bodies in the Solar System beyond Earth and its observations will help scientists understand the 'first chapters' in the history of the Solar System.

In addition, the US space agency said that Dawn's data will allow NASA to move farther along the road toward future crewed missions, with Mars as the big objective in the coming decades.

Dawn's science is being directed from the University of California, Los Angeles and the mission is being run with the cooperation of the German and Italian national space agencies and the Max Planck Institute for Solar System Research.

Vesta and Ceres are two of the largest bodies within the asteroid belt. In that region between Mars and Jupiter, scientists estimate that there are some 100,000 asteroids, both large and relatively small, which are considered to be the 'rubble' left over from the formation of the Solar System some 4.6 billion years ago.