India's Chandrayaan 2 spacecraft entered lunar orbit on Tuesday, executing one of the trickiest maneuvers on its historic mission to the moon.

After four weeks in space, the craft completed its lunar orbit insertion as planned, the Indian Space Research Organization (ISRO) said in a statement.

The insertion "was completed successfully today at 0902 hrs IST (3:32 GMT) as planned, using the onboard propulsion system. The duration of maneuver was 1738 seconds," the national space agency said.

India is seeking to become just the fourth nation after Russia, the US and China to land a spacecraft on the moon. 

If the rest of the mission goes to plan, the Indian probe will land on the lunar south pole on September 7. 

To enter the final orbit over the lunar poles, Chandrayaan 2 will undergo four more similar maneuvers, with the next scheduled for Wednesday.

ISRO chief K. Sivan said the maneuver was a key milestone for the mission, adding he was hoping for a perfect landing next month.

"On September 7, the lander will land on the moon. Whatever is humanly possible, has been done by us," Sivan told reporters.

Tuesday's insertion was one of the trickiest operations in the mission because if the satellite had approached the moon at a higher velocity it would have bounced off and got lost in deep space. 

And had it approached at a slow velocity, the moon's gravity would have pulled it in, causing a crash. "The approach velocity had to be just right and the altitude over the moon precise. Even a small error would have killed the mission," Sivan said.