Washington: The Lunar Atmosphere and Dust Environment Explorer (LADEE) was "on a perfect trajectory" to reach the Moon in 30 days, US space agency NASA has said.

The NASA said Saturday its engineers have fixed mechanical problems the explorer encountered shortly after Friday night's launch, reported Xinhua.

Although NASA described the launch of the LADEE as successful, the small car-sized spacecraft commanded itself to shut down the reaction wheels, used to position and stabilise the spacecraft, after its separation from the rocket.

On Saturday, NASA determined this was the result of fault protection limits put in place prior to launch to safeguard the reaction wheels.

Engineers have since disabled the limits that caused the powering off soon after activation and would selectively re-enable them.

"Our engineers will determine the appropriate means of managing the reaction wheel fault protection program. Answers will be developed over time and will not hold up checkout activities," said LADEE project manager Butler Hine.

"The reaction wheel issue noted soon after launch was resolved a few hours later. The LADEE spacecraft is healthy and communicating with mission operators," said Pete Worden, director of NASA's Ames Research Center, which is leading the LADEE mission.

The $280-million spacecraft is expected to spend about 100 days exploring moon's atmosphere and the role of dust in the lunar sky before running out of fuel and crashing into the moon's surface.

src:IANS