Lunar probe Chang'e-2 is more than 60 million kilometers away from Earth and has become China's first man-made asteroid, a spokesperson said Tuesday.

Still in good condition, Chang'e-2 is heading for deep space and is expected to travel as far as 300 million km from Earth, the longest voyage of any Chinese spacecraft, Wu Zhijian of the State Administration for Science, Technology and Industry for National Defence (SASTIND) told reporters at a press conference.

In comparison, the shortest distance between Earth and the Mars is about 55 million km, and the longest 400 million km. NASA confirmed in September that Voyager-1, launched in 1977, had left the solar system and was over 18.7 billion km away from Earth.

Launched on October 1, 2010, Chang'e-2 was designed for half a year of service but has kept working for over three years. The probe verified some crucial technologies for Chang'e-3 and reconnoitered the landing area. It also made the world's first lunar holographic image with a resolution of 7 meters, Wu said.

Chang'e-2 and Chang'e-3 are part of the second stage of China's three-stage lunar mission: orbiting, landing, and return.