JOIN USMars Orbiter clears crucial manoeuvre
After 300 days of dormant flight, the main engine of Isro’s Mars Orbiter came to life for a designated four seconds at 666 million km away from the earth on Monday, setting the trajectory for the final manoeuvre that will place the spacecraft in the Martian orbit.
Monday’s manoeuvre was crucial as it confirmed that the spacecraft’s 440 Newton Liquid Apogee Motor (LAM) engine would function as planned. The engine has to fire for 24 minutes during the final manoeuvre scheduled for Wednesday. Isro is one step away from making history as India will be the first country to enter the Martian orbit on a maiden mission if it succeeds.
Probes to Mars have a high failure rate. Of the 51 missions so far, only 21 have succeeded. A similar mission by China failed in 2011. The success will also make India the first Asian country, and Isro the fourth space agency, to send a satellite to the Red Planet.
European, the US and Russian probes have managed to orbit or land on the planet but only after initial failures and repeated attempts.
In a warm gesture, Nasa, also tracking the spacecraft, wished Isro the best even as its MAVEN spacecraft began orbiting the Red Planet on Monday. “We are not the only show that is happening on Mars this week,” said Gary Napier, a spokesman for Lockheed Martin, during a television broadcast of the MAVEEN orbital insertion. “Everyone at Nasa and its partners wishes that (Indian) team all the best.”
Isro said: “The Main Liquid Engine test firing on Mars orbiter spacecraft was successful. We had perfect burn for four seconds as programmed. The trajectory has been corrected. Mars Orbiter Mission (MOM) will now go ahead with the normal plan for Mars Orbit Insertion.”
Space agency’s chairman K Radhakrishnan was joyous. “The spacecraft is healthy. It has completed 98 per cent of its journey to Mars and we are now prepared for that crucial operation to take place on September 24 morning.” The critical operation of inserting the spacecraft into the Martian orbit will take place sometime around 7:30 am on Wednesday and the results would be known by 8:15 am.
“Our navigators’ calculations show that MOM has entered the gravitational sphere of Influence of Mars,” Isro said. The spacecraft was within 5.4 lakh km radius of the Mars’ Gravitational Sphere of Influence,” it added.
In the last lap on September 24, the orbiter has to be slowed down from 22.1 km per second to 4.4 km per second to be captured by the Martian orbit. The engine will be fired for 24 minutes on that day to reduce its velocity and insert it into the Martian orbit. Isro already uploaded commands on September 14 and 15 to help the spacecraft enter the orbit.
The MOM was launched from Isro's spaceport of Sriharikota on Nov 5, 2013. It escaped the earth’s gravitational pull on Dec 1 and has travelled 666 mn km over the last nine months. If everything goes as per plan, the orbiter may circle around Mars for the next six months.
There is a theoretical possibility of making the orbiter last for a month more or two, but that depends on the fuel position and performance of the spacecraft .