NASA's spacecraft Dawn enters into giant asteroid's orbit

"Dawn's study of the asteroid Vesta marks a major scientific accomplishment and also points the way to the future destinations where people will travel in the coming years," NASA administrator Charles Bolden said.

"Today, we celebrate an incredible exploration milestone as a spacecraft enters orbit around an object in the main asteroid belt for the first time," Bolden said.

The spacecraft Dawn will study the asteroid named Vesta, for a year before departing for a second destination, a dwarf planet named Ceres, in July 2012, he said.

Vesta is 530 kilometres in diameter and the second most massive object in the asteroid belt.

The aim of Dawn's eight-year mission is to compare and contrast the two giant bodies, which NASA says will help scientists "unlock the secrets of our solar system's early history."

"The observations will provide unprecedented data to help scientists understand the earliest chapter of our solar system. The data also will help pave the way for future human," NASA said in a press release.

"With Dawn now in orbit, the science team can take more accurate measurements of Vesta's gravity and gather more accurate timeline information," the release said.

Dawn will start collecting science data in early August at an altitude of approximately 2,700 kilometres above the asteroid's surface. The spacecraft will later orbit at approximately 200 kilometres to perform other measurements and obtain closer shots of parts of the surface.

Dawn was launched in 2007, has a gamma ray and neutron detector instrument, which will gather information on cosmic rays during the approach phase, as well as an infrared mapping spectrometer.