Isro to Test-Fire MOM Engine on Sept 22

On September 22, about 48 hours prior to its crucial orbit insertion, the Mars Orbiter Mission's (MOM) 440N liquid apogee motor (LAM) will be test-fired for five seconds.

The engine's test-firing will result in the spacecraft deviating from its trajectory, which will be corrected later.

Isro chairman K Radhakrishnan told TOI on Friday that should there be a problem with the motor, the space agency will resort to its 'Plan B' for the Mars orbit insertion. This backup plan involves firing of the eight 22 Newton thrusters for the insertion.

When asked whether the mission profile would change in case Isro has to fall back on its 'Plan B', Radhakrishnan acknowledged that "it will not be the original mission", but it will mark the end of an uncertain period. He said 'Plan B' would essentially be a "salvaging exercise".

The Isro chief said that commands for the orbit insertion will be uploaded on September 14.

During the orbit insertion, which starts at 7.18am on September 24, the engine will be fired for 28 minutes. The success of the mission will only be confirmed around 8.15am, as the spacecraft will be on the other side of Mars during the insertion.

The MOM, travelling at a speed of 22km/second, is now less than 6 million km away from Mars.