NASA's Messenger spacecraft has become the first to enter orbit of Mercury, the space agency said on its website on Friday.
At 03:45 Moscow time [0:45 GMT] Messenger turned on its main thruster and started 15-minute orbit insertion maneuver.
"NASA's Messenger spacecraft successfully achieved orbit around Mercury," NASA said. "This marks the first time a spacecraft has accomplished this engineering and scientific milestone at our solar system's innermost planet."
In the next several weeks, engineers will check how the spacecraft's systems are sustaining Mercury's harsh thermal environment, and equipment will be turned on March 23. The scientific mission will begin on April 4.
It took the spacecraft more than six years to enter the orbit of Mercury, the least explored terrestrial planet of the inner Solar system. About 31% of the spacecraft's original allotment of propellant is required to slow it down so that it could remain in the orbit.
To reach its destination point, the spacecraft, launched in 2004, covered more than 7.8 billion km. It followed a complicated route through the inner solar system, which included one flyby of Earth, two flybys of Venus, and three flybys of Mercury.
Mercury is the smallest and the densest planet among the four terrestrial planets. It also has the oldest surface and the largest daily variations in surface temperature. Before the Messenger mission, only 45% of the surface of Mercury had been photographed by a spacecraft. The previous mission was Mariner-10, launched in the 1970s.
MOSCOW, March 18 (RIA Novosti)
