As Mars comes closer to Earth, Mangalyaan crosses half-way mark

CHENNAI: As sky gazers across India got ready to peer through telescopes for a view of Mars which comes close to Earth (9.2 crore km from Earth) on Wednesday evening, India's Mars Orbiter Mission (MoM) went past the half-way mark to the red planet.

After escaping earth's influence, MoM, which was launched from Sriharikota onboard PSLV-C25 on November 5, 2013, is now in the Sun's influence region called the helio-centric trajectory.

"On Wednesday at 9:50am, India's Mars Orbiter Spacecraft crossed the half-way mark of its journey to the red planet along the designated helio-centric trajectory," the Indian Space Research Organisation said in a statement.

India's Deep Space Network, aided by Nasa, has been tracking the orbiter since its launch and six orbit raising manoeuvres after which it left the Earth orbit on December 1 last year.

"Some 250 scientists have been working on the last big exercise before the spacecraft left the earth's orbit," Isro chairman K Radhakrishnan told TOI in an earlier interview.

Through six orbit raising exercises, scientists have brought the apogee (the spacecraft's farthest point from Earth) from the initial 25,000km to 1.92 lakh km.

As the spacecraft goes through the spheres of influence of the Sun and Mars, four trajectory correction manoeuvres (TCMs) were planned to keep it on course.

The first such correction happened on December 11 last year, soon after the orbiter crossed the sphere of influence of Earth. Now it looks like the life of the orbiter may be extended from its original five months, as very less fuel has been used for manoeuvres.

"As the spacecraft is on its designated trajectory, the TCM planned for April 2014 is not considered essential. If required, the next TCM is planned to be carried out in June 2014," Isro said.

Originally the TCMs were planned in April, August and September, 2014. The Mars orbiter insertion will be carried out on September 24, 2014.

If all goes fine, MOM will study a range of things including early signs of life or supporting system on the red planet and its atmosphere through five indigenous instruments or for at least five months.

India is among an elite club of nations to take up interplanetary probes. Of the 51 Mars missions by the US and Russia/ USSR, only 21 had been successful. Fourteen days after India's MoM, the US launched a similar mission, MAVEN, which is also on its way to the red planet.

arun.ram@timesgroup.com

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