Mars orbiter exits Earth's orbit

Clears key hurdle as Isro's slingshot sets off its 300-day voyage to the red planet

India's vision to join the league of global space agencies on Mars exploration turned brighter on Sunday, with a major milestone - the slingshot of the Mars Orbiter Mission (MOM) to the solar orbit - being completed.

The spacecraft would reach the Mars orbit on September 24, 2014, after a 10-month journey around the sun and travelling 440 million km.

The Indian Space Research Organisation (Isro) conducted the critical manoeuvre to place the Mars orbiter in the trajectory concerned almost an hour past midnight on November 30. The slingshot required precise calculations to eliminate the risk of missing the new orbit.

With this, India has become the first Asian nation, and the fourth globally, to leap into interplanetary space. Only about half the 50-odd spacecraft sent by other countries to Mars have been able to complete the journey so far. Most countries failed at the point of moving away from the Earth's orbit. The spacecraft of the previous one, China's Mars probe in November 2011, had disintegrated before leaving the Earth's orbit.

Minutes after the trans-Mars injection (code name for the slingshot operation), Isro Chairman K Radhakrishnan told Business Standard: "The injection operation was performed successfully at 1.19 am and everything is fine."

Soon, Isro wrote to its followers on its Facebook page: "While Mangalyaan takes 1.2 billion dreams to Mars, we wish you sweet dreams!"

The orbiter was given an incremental velocity of 648 metres a second for the crucial manoeuvre on its 680-million-km voyage to the Mars. The slingshot was to give the spacecraft a specific velocity, so that it could be closer to the Mars (about 500 km, plus or minus 50 km) in September 2014, said Radhakrishnan.

The success of the spacecraft, scheduled to orbit the Mars in September 2014, would put India in the elite club of the US, Europe, and Russia, the probes of which have so far been successful in orbiting the Mars or landing on it.

"Of the three important events, two have been completed successfully," Radhakrishnan said. The first was the launch of the orbiter (November 5) and the second injecting it in the trans-Mars orbit (December 1). The third important event would be placing MOM in the Mars' orbit in September 2014. "If we are able to reduce the velocity precisely at that particular point of time, we would get into the orbit and, finally, the instruments would be operated," he said.

The challenge before Sunday's operation was placing the craft in the precise orbit. "To get thrown out of the Earth's orbit, towards the Mars, with the right velocity, in the right direction and at the right time - that's MOM's escape challenge," said Isro.

There would be three or more mid-course corrections, based on the orbit determination, added Radhakrishnan.

NAIL-BITING MOMENTS

Nov 30

11.50 pm: MOM's on-board computer takes over operations

Dec 1

12.30 am: Forward rotation to put spacecraft in the right direction for the slingshot successful

12.49 am: The 440-N liquid engine begins 23-minute firing for trans-Mars injection

1.00 am: Isro says performance normal

1.02 am: Last perigee achieved

1.19 am: Isro says trans-Mars injection completed