Bangalore, Dec 11 (IANS)

India's Mars spacecraft was fine tuned early Wednesday in the interplanetary space to stay on course in the 680-million-km sun orbit on way to the Red Planet.

"The onboard computer carried the first mid-course correction of the Mars Orbiter at 6:30 a.m. by firing the 22 Newton thrusters for 40.5 seconds," a senior space agency official told IANS.

The spacecraft was 2.9-million km away from the earth when the trajectory correction was carried and cruising at 32 km/second to reach the Martian orbit in mid-September 2014 for its geological exploration.

"The craft is coasting in the intended solar orbit towards Mars. Three more mid-course corrections will be carried out in April, August and early September next year to ensure that the orbiter stays on course for its interjection into the Martian orbit Sep 24," the official said.

Scientists at the Deep Space Network of the Indian Space Research Organisation (ISRO) at Bylalu, about 40 km from here, are monitoring the orbiter's odyssey and programming its computer for sending and receiving commands for its operations despite a 20-minute delay in the exercise due to the distance between earth and the orbiter in deep space.

The onboard navigators have been monitoring the orbiter's velocity and determining its space path to fine tune its voyage in the intended sun orbit.

"The onboard computer is also getting hands-on experience in handling the commands in spite of the 20-minute delay due to the space distance between the orbiter and our ground network centre," the official said.

The orbiter zoomed out Dec 4 of the earth's sphere of influence, which extends up to 925,000 km in the interplanetary space and freed from its gravitational pull.

After a nine-month journey, the spacecraft will enter the Mars sphere of influence, which is around 573,473 km from its surface, in a hyperbolic trajectory.

When the spacecraft is closest to the Red Planet, it will be captured into the Martian orbit through a crucial manoeuvre, which involves slowing its speed.

Transition from the earth's final orbit to solar orbit has been programmed in line with sun's gravity and laws of the universe to ensure the orbiter reaches precisely on time to be slung into Martian orbit.

The 1,337 kg orbiter was launched Nov 5 from Sriharikota off the Bay of Bengal, about 80 km from Chennai, onboard a 350-tonne rocket with five scientific instruments -- MarsColour Camera, Methane Sensor, Thermal Infrared Imaging Spectrometer, Lyman Alpha Photometer, and Mars exospheric Netural Composition Analyser.

India became the first Asian country and the fourth nation in the world to leap into the interplanetary space with its Rs.450-crore exploratory mission to Mars, about 400-million km (250 million miles) from earth.

So far, only Russia, US and the European Space Agency (ESA) have undertaken such missions to Mars.