Indian Probe Leaves Earth Orbit, Begins 10-month Cruise to Mars
BANGALORE, India — A crucial pre-dawn 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 had been orbiting the Earth, progressively gaining in apogee with firings of its onboard liquid-fueled engine. After the fifth orbit raising exercise Nov. 16, Mangalyaan’s 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 mid-course corrections between now and Mangalyaan's arrival at Mars.
The Mars orbit insertion is scheduled to take place Sept. 24 7:14 a.m. local time. In this maneuver the onboard 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.