Mars Mission passes crucial stage as Isro test-fires main engine

A failure would have compromised the target orbit and sent the mission into 'salvage' mode

The India's Mars Orbiter Mission (MOM) today passed a crucial test. The Indian Space Research Organisation (Isro) today successfully conducted the test firing of its Main Liquid Engine, which was idle for nearly 300 days, inside the spacecraft.

 

This crucial Trajectory Correction Manoeuver (TCM) was configured for verifying the performance of the Main Liquid Engine to determine the strategy for Mars Orbit Insertion (MOI) on September 24.

At 2.47 pm, Isro said that test firing was successful and that there was a perfect burn for four seconds as programmed. "The trajectory has been corrected. Mom will now go ahead with the nominal plan for Mars Orbit Insertion," it stated.

Commenting on today's development, Isro's Chairman K Radhakrishnan told Business Standard: "Test firing performed as expected and the space craft is in good health. Confidence level (to make the Mission success) has gone up."

Isro in a statement said that the 440 Newton Liquid Apogee Motor (LAM) of India’s Mars Orbiter Spacecraft was successfully fired for a duration of 3.968 seconds at 1430 Hrs IST today (September 22, 2014). This operation of the spacecraft’s main liquid engine was also used for the spacecraft’s trajectory correction and changed its velocity by  2.18 metre/second.

With this successful test firing, Mars Orbiter Insertion (MOI) operation of the spacecraft is scheduled to be performed on the morning of September 24, 2014 at 07:17:32 hrs IST by firing the LAM along with eight smaller liquid engines for a duration of about 24 minutes.

 

Earlier in the Day, Isro said that MOM has entered the Gravitational Sphere Of Influence of Mars.

 

Today's event was crucial considering the fact that Isro’s Plan B, in case the test firing had failed, would have been to salvage the mission rather than achieve the original target. 

 

“Plan B is using the small eight 22N thrusters for attitude control or orientation, which will not give you this original target. It will be salvaging of the mission,” Radhakrishnan said earlier.

Though the backup plan would get Isro Mangalyaan into orbit, how close it would have been was questionable. Since these thrusters have less power (22 Newton), they would have had to be fired for a much longer duration. In spite of this, the orbit achieved would not have been ideal to carry out studies of the Martian atmosphere and morphology.