New Delhi, Nov. 8: The Chandrayaan-1 spacecraft slipped into a lunar orbit this evening in perfect harmony with commands from engineers in Bangalore, yanking India into a small club of nations that have gifted the moon its own satellites.

A now-or-never orbital manoeuvre successfully guided the spacecraft from what was its final Earth-bound orbit into its first moon orbit 504km to 7,502km above the lunar surface, Indian Space Research Organisation engineers said.

“This is a great moment. I’m feeling fantastic,” said T.K. Alex, director of the Isro Satellite Centre, Bangalore, where the spacecraft was designed and built. “It was the most crucial manoeuvre of the mission so far — and we did it,” Alex told The Telegraph shortly after ground observations revealed a perfect lunar orbit.

The success, he said, demonstrates India’s capabilities in spacecraft tracking, orbital dynamics, precision guidance and control. Russia, the US, the European Space Agency, Japan and China have sent spacecraft to the moon.

Chandrayaan-1, launched by Isro on October 22, is on a two-year mission of scientific observations from its final target orbit, 100km above the lunar surface.

The spacecraft is carrying 10 payloads built by scientists in India, Europe and the US, each tasked with extracting new information about the moon relevant for future unmanned or manned missions.

“We had to do this just right today,” Mylswamy Annadurai, project director of Chandrayaan-1, said.

At 4.51pm IST, responding to commands by engineers at the Spacecraft Control Centre, Bangalore, the main thrust engine on Chandrayaan-1 came to life, fired for exactly 817 seconds, and reduced the spacecraft’s speed from about 2km a second to 1.5km a second.

The drop in speed allowed the spacecraft to slip into a highly elliptical lunar orbit — 504km at its closest point, and 7,502km at its farthest point. In this orbit, Chandrayaan-1 takes about 11 hours to go around the moon once.

“It was thrilling to watch all the computations we had made proved correct,” Annadurai said.

In the next few days, four more guided speed reductions will decrease its orbital distances until the craft settles down in its final target orbit 100km above the moon’s surface. Each of these will require high-precision firings.

The next firing of the thrust engine is scheduled for tomorrow night, Annadurai said.

Isro engineers had given themselves a single opportunity for the transition. As the spacecraft approached the moon, about 380,000km from Earth, the tug of lunar gravity shifted its Earth-bound elliptical orbit into a hyperbolic orbit — a path further into deep space.

“Without the speed reduction at the right time, it would have been lost in space,” Annadurai said. Retrieving the craft from its hyperbolic trajectory back into lunar orbit would have been “very difficult”.

Around noon today, engineers at the Spacecraft Control Centre, Bangalore, began a series of pre-manoeuvre checks to determine that everything aboard the spacecraft was in order.

About an hour before the moment of engine activation, the engineers turned the spacecraft a full 180 degrees to allow the nozzle to point in the direction of motion. Only in this new orientation would the thrust engine firing reduce the speed of the spacecraft.

Then, as the spacecraft flew about 500km above the North Pole of the moon, the engine fired. “There was no abrupt turn — the spacecraft just began to go around the moon in an elliptical polar orbit,” a senior Isro engineer said.

Isro engineers said the thrust engine fuel expended so far is well within set limits. The spacecraft had taken off with about 800kg of fuel. “We have enough fuel aboard for each of the rest of the manoeuvres and the two-year science mission,” Alex said.

After Chandrayaan-1 reaches its final 100km orbit, an instrument called the moon impact payload will be hurled toward the moon’s surface for a 20-minute descent and a hard, destructive fall.