Orbiter Mission Out of Earth's Grip, Begins Long Journey to Red Planet - The New Indian Express

Orbiter Mission Out of Earth's Grip, Begins Long Journey to Red Planet

Published: 01st December 2013 07:56 AM

Last Updated: 01st December 2013 07:56 AM

By the time you read this, India’s first interplanetary mission should be on its way to Mars. This would be the first time an Indian spacecraft would have left the Earth’s Sphere of Influence (SOI), which is the zone in which Earth’s gravitational pull holds sway. This would be the beginning of a 300-day journey for ISRO’s ambitious Mars Orbiter Mission.

The Spacecraft Command Centre (SCC) at the Indian Telemetry, Tracking and Command Network (ISTRAC), located at Peenya in Bangalore, is slated to set the main engine of the spacecraft firing for 1351 seconds. The engine burn would increase the velocity by 648 m/second (called delta-v or incremental velocity).

The spacecraft would need about 10.7 km/second to tear itself away from Earth’s gravitational pull. When it was injected into orbit by the PSLV-C25 on November 5, the Mars Orbiter Mission was orbiting the Earth with a velocity of about 9.8 km/second. In five pre-planned and one contingency orbit raising manoeuvres, ISRO has so far added incremental velocity of 873.4 m/second. The manoeuvre set to be carried out at 12.49 am on Sunday is aimed at increasing the velocity of the spacecraft to about 11.32 km/second. This would be the speed required to take the spacecraft outside of Earth’s SOI, which is about 9.25 lakh km.

When ISRO gives the spacecraft the command to fire its engine, the Mars Orbiter Mission would be about 270 km above its home planet. The trip to Mars would not be done in a straight line. After leaving the Earth’s orbit, the Mars Orbiter Mission would enter into an orbit around the Sun. This would be an elliptical path, designed to intersect with Mars’s position on September 24, 2014. This is called the Hohmann Transfer Orbit, which is the most fuel-efficient way to travel to Mars, as the spacecraft’s engine need not be fired in this phase.

This is method being used by NASA as well to get its MAVEN spacecraft to Mars, on a timeline that is very similar to that of ISRO’s Mars Orbiter Mission.

When the Mars Orbiter Mission is set to make its rendezvous with its target planet, the 440 Newton Liquid Apogee Motor, the main engine of the Mars Orbiter Mission, would then be fired after remaining dormant for 10 months, to push the spacecraft into Mars’s orbit.

If Indian Space Research Organisation does manage to successfully pull it off, it would be no mean achievement. It would be the first time that a space agency would have succeeded in getting its first Mars mission to the red planet.

Senior officials at ISRO have said they have used the six orbit raising manoeuvres to test various systems on board the Orbiter.

These have not only included the various instruments that the spacecraft would use to collect data and images from Mars, but also the backup systems that the spacecraft would automatically use in the event of failure of or snag in one of the primary systems.

A senior Indian Space Research Organisation official has said all systems that are required to take the spacecraft to its destination are in order, and that the challenge lies ahead, 10 months from now.

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