Mangalyaan successfully passes critical engine test: Why was it important

Mars Orbiter’s main liquid engine test firing was succesful, according to reports. “Main Liquid Engine test firing on Mars orbiter spacecraft was successful,” said an ISRO official, according to PTI. India’s Mars Orbiter Mission Mangalyaan underwent the first crucial test of its fourth and final maneuver ahead of entering the orbit of the red planet on Wednesday. According to Isro, the main liquid engine of the spacecraft, which has been dormant so far, was expected to fire for four seconds in preparation for it being placed into orbit at around 2.30 pm IST. As a result, it was put in action along with eight thrusters to slow down the craft, so that it could be injected into a safe orbit around Mars. https://twitter.com/isro/status/513704771249664000 M Annadurai, programme director at Isro, told Hindustan Times: “The test firing is like a trial. The dormant engine has to be brought back to life. It is a challenge but if one is prepared well for the exam, the confidence for success is higher.” [caption id=“attachment_1724015” align=“alignleft” width=“380”]  Image from Isro[/caption] “We are confident the engine will work. But just in case it doesn’t, we have a Plan B that involves firing the eight thrusters for a longer time but this will need more fuel". Isro chairman Dr K Radhakrishnan explained further in this interview with The Hindu: Why four seconds? There are two considerations. There is a minimum time of firing necessary and four seconds are good enough to get at least 3 or 4 good points to know that the fluid flow is proper and also to measure the acceleration imparted correctly. So we will measure once in 520 milliseconds. The two Mars Transfer Trajectory (MTT) mid-course corrections that were done on December 11, 2013, and June 11, 2014, were done only with the small thrusters. Small thrusters are working; there is no issue. What we are now looking at is the working of the main engine. Now that the engines are tested, the Mangalyaan craft is pretty much be on its own. Isro says that the radio link between Mangalyaan and the ground mission will be blocked by Mars, which means that the craft will have to execute commands autonomously. The commands were uploaded by Isro on 14 and 15 September. If successful, then India will be the first country to successfully launch a Mars mission on its first go. It will also be only the fourth country after US, Russia and Europe to reach the Red planet. Once in orbit, the craft’s five payloads will take pictures and collect data for the next six months. Take a look at the payloads of the Mars mission here: