WASHINGTON A space probe that scientists hope will provide new information about the moon ahead of future manned US moon missions entered lunar orbit on Tuesday, four and a half days after it was launched aboard a rocket, NASA said.

The Lunar Reconnaissance Orbiter (LRO) space probe successfully entered orbit around the moon at 1027 GMT, the US space agency said in a statement.

Engineers had to perform a mid-course correction while the probe was enroute, to ensure it would successfully slip into orbit.

The Maryland-based Goddard Space Flight Center overseeing the project said the probe's successful orbit marked a milestone in their attempts to collect new data about the moon.

'Once we enter the moon's orbit, we can begin to build up the dataset needed to understand in greater detail the lunar topography, features and resources,' said Cathy Peddie, LRO deputy project manager at NASA's Goddard Center.

Now the probe is in orbit, it will undergo a series of checks and its instruments will be brought online during a so-called commissioning phase expected to be completed 60 days after the LRO launch.

Scientists hope the LRO's instruments will provide information that can help them produce high-resolution, three-dimension maps of the moon's surface.

The mission will also explore the moon's deepest craters, examining both permanently sunlit and shadowed areas, and provide insights on the way lunar radiation affects human beings.

The LRO was launched Thursday with a second probe, known as the LCROSS, aboard the Atlas V rocket.

The LRO separated from the Atlas V rocket's Centaur upper stage last week, but the LCROSS probe will remain attached until October when it will be launched with the upper stage towards the moon.

It is expected to crash-land into a crater near the south pole of the moon, kicking up lunar material that can be tested for evidence of frozen water.

Both probes are part of NASA's preparations for the return of American astronauts to the moon, tentatively planned for around 2020.

US astronauts were the first to reach the moon and the only ones to walk on the moon's surface, but the United States has not launched a manned lunar mission since 1972.— AFP