Indian Probe Leaves Earth Orbit, Begins 10-month Cruise to Mars


BANGALORE, India — A crucial predawn maneuver successfully freed India’s Mangalyaan Mars orbiter from Earth’s gravity, sending it on a 680 million-kilometer, 10-month-long journey to the red planet, the Indian Space Research Organisation (ISRO) announced Dec 1.

Mangalyaan, India’s first interplanetary probe, was launched Nov. 5 aboard an ISRO Polar Satellite Launch Vehicle from Sriharikota in southeastern India. Since then the spacecraft, also called the Mars Orbiter Mission, had been orbiting Earth, progressively gaining in apogee with firings of its on-board liquid-fueled engine. After the fifth orbit-raising exercise Nov. 16, Mangalyaan was in an orbit with an apogee of about 19,280 kilometers.

The Dec. 1 trans-Mars injection maneuver entailed firing the engine for about 22 minutes, giving the spacecraft sufficient velocity to escape Earth’s gravity and begin its heliocentric cruise phase, ISRO said.

“Following the completion of this [maneuver], the Earth orbiting phase of the spacecraft ended. The spacecraft is now on a course to encounter Mars after a journey of about 10 months around the Sun,” ISRO said in a statement.

If everything goes according to plan, Mangalyaan will arrive in the vicinity of Mars Sept. 24, 2014 — two days after the expected arrival of NASA’s Mars Atmosphere and Volatile Evolution spacecraft, which was launched Nov. 18.

During a Nov. 27 press briefing, Koteswara Rao, ISRO’s scientific secretary, said there will be three midcourse corrections between now and Mangalyaan’s arrival at Mars. These course corrections, the first of which is slated for Dec. 11, will utilize the probe’s eight 5-pound-thrust engines, as opposed to the larger 100-pound-thrust engine that sent Mangalyaan on its way to the red planet and will be used for Mars orbit insertion.  

The Mars orbit insertion is scheduled to take place Sept. 24 at 7:14 a.m. local time. In this maneuver the larger engine will be fired for nearly 29 minutes in reverse mode to slow the spacecraft, allowing it to be captured into Mars orbit, Rao said. ISRO said Mangalyaan will be placed in a Mars orbit with a perigee of 365 kilometers, an apogee of 80,000 kilometers and a period of about 77 hours.