Braking into orbit with a pulse of thrust from an on-board engine, China's first deep space probe arrived in lunar orbit Monday to begin a one-year mission surveying the moon.

An artist's impression of the Chang'e-1 spacecraft. Credit: CNSA

The Chang'e 1 spacecraft entered lunar orbit at about 0337 GMT Monday (10:37 p.m. EST Sunday), capping off a 12-day voyage from planet Earth that began with an Oct. 24 blastoff from the Xichang space base in southwestern China.

The spacecraft circled Earth several times after launch, gradually raising its orbit before embarking on a course last week to intercept the moon early Monday.

The 5,000-pound probe fired a maneuvering engine for about 22 minutes for the critical insertion burn, slowing the spacecraft's velocity by about 800 miles per hour. The change in speed was enough to allow the moon's weak gravity to capture the spacecraft in a preliminary orbit stretching from an altitude of 124 miles to a high point of about 5,344 miles, according to China's state-run Xinhua news agency.

Further thruster firings will circularize Chang'e 1's orbit at a distance of 124 miles from the moon's surface, Xinhua reported.

The first images of the moon from Chang'e 1 are expected by the end of this month. Controllers plan to transition the mission into an operational phase by December.

One of the craft's sensors was switched on a day after launch to collect data on high-energy solar particles between the Earth and the moon. Others were gradually activated later, and engineers expect to test all of the probe's instruments by November 18.

The $187 million mission is a key stepping stone in China's quest to develop a lunar exploration program that includes a lunar rover and a probe to return soil samples from the moon's surface. Those missions could be realized by 2012 and 2017, respectively, according to Chinese space officials.

Chang'e 1's arrival in lunar orbit comes just one month after a Japanese spacecraft began circling the moon. Both missions aim to map the lunar surface and chart mineral distributions on the moon in hopes of finding evidence of water ice, which could be trapped in cold pockets deep within craters near the moon's poles.

Chang'e 1 will also probe the lunar subsurface and study the space environment around the moon, according to Xinhua.

India plans to launch a similar probe to the moon in April, followed in October by the start of a NASA mission that will begin to lay the groundwork for a resumption of human exploration in the next decade.

Chinese officials have dismissed declarations of a budding regional space race between the nations, saying they seek international cooperation in the high frontier. In a report last month, Xinhua said some government leaders hoped to become a partner in the international space station project.

China has also vowed to share science data from the Chang'e 1 mission with international researchers, according to state media reports. Domestic institutions will get to see the data first, followed a year later by a public release.