CHENNAI/BANGALORE: In the Martian tourney, India won a T20 on Monday. The real test is on Wednesday.The celebration lasted as much as the match – a mere four seconds — when at 2.30pm, Indian Space Research Organisation ( Isro ) scientists ‘woke up’ the main engine of Mars Orbiter Mission (MOM) spacecraft. Having ensured that the 440N engine is in good shape, they got back to preparations for the 24-minute firing early on Wednesday morning that would put the spacecraft in the red planet’s orbit.The liquid apogee motor (LAM) engine has been idle for about 300 days since the spacecraft left the Earth’s orbit on a Martian trajectory on December 1, 2013. MOM executed with precision a set of commands sent from mission control in Bangalore last week and fired the engine.“With this, we have achieved two things,” Isro chairman K Radhakrishnan told TOI. “One, we checked if all is fine with the engine; two, we used the exercise to correct the trajectory to get nearer to Mars.” With this, MOM has also entered Mar’s sphere of influence.There were apprehensions of the long duration of idling would have affected some valves because of the corrosive fuel used. If the main engine doesn’t fire on Wednesday, an alternative plan is to fire the eight thrusters of the spacecraft to capture the Martian orbit. This Plan B, however, would not help MOM achieve a perfect orbit to take up scientific studies during its elliptical journey around Mars.If everything goes fine, Isro aims to put the spacecraft in an orbit with a periapsis (closest point to Mars) of 423km and an apoapsis (farthest point) of 80,000km.The four-second firing used up a little more than half-a-kg of fuel. “Using 564 gram of fuel, we re-fired the engine to achieve the necessary trajectory correction by reducing the speed of the spacecraft by 2.18 metres per second,” said Isro scientific secretary V Koteswara Rao.Isro chairman, K Radhakrishnan showing the miniature of Mars orbiter during interview with TOI in Bangalore.Radhakrishnan said the test firing boosted the scientists’ confidence. “But we cannot be complacent. We now know that we have the best chance since the launch of MOM to acquire the desired orbit. Yet, we know that there are many things that still have to work as precisely as on today. We are now focused on that,” he said.Rao said that everything happened on the dot. “There was not a minor deviation from our plan. We are constantly monitoring the spacecraft,” he said.Rao said that the Mars Colour Camera (MCC) is likely to transmit the first images of the red planet by Wednesday afternoon. MCC was active last in November 2013. On November 19, it sent its first image of Earth from an altitude of more than 67,000km with a resolution of 3.53km.“Soon after the Mars orbit insertion operation on Wednesday, we will have the images transmitted back to earth.” Isro’s Indian Deep Space Network (IDSN) in Byalalu, Karnataka will receive the images. There will be a one-way time gap of more than 12 minutes between MOM and the earth station.