Thursday, 12 December 2019

Mangalyaan: India Scripts History In Space Odyssey

Updated: October 11, 2014 3:27 pm

Mangalyaan—which has traversed a distance of 660 million kms (65 crore kms)—got into Mars Orbit exactly at 8.15.21 AM. The three-hour cliff-hanger task of Mars Orbiter Mission started as early as 4.17 AM

India scripted its own grand chapter in the history of space odyssey by successfully placing its satellite in Mars orbit on September 24, 2014, in what is being described by the space scientific community as most complex, complicated and delicate exercise ever achieved. “What is of paramount importance is that we have achieved this success in our first attempt, never heard in the annals of space history. This is what makes ISRO scientists deserve all credit,” said beaming Prime Minister Narendra Modi who watched every intricate exercise with bated breath in ISRO’s telemetry Centre at Peenya in Bengaluru. “I am proud to be a witness for the history in the making,” he said, when he shook hands of Dr K.Radhakrishnan, chairman of ISRO.

The excitement of the Prime Minister was so overwhelming and visible—not less than that of the ISRO staff—that unmindful of propriety and protocol, Modi hugged Dr Radhakrishnan, much to the amusement of hundreds of ISRO personnel.

The atmosphere at ISRO’s telemetry centre in the rain-soaked early morning was tense as apprehension gripped the air. “I have started my day at 1 AM with prayer on my lips; hope in the heart; dream in my eyes; confidence in my mind & thought,” said a middle-level engineer, requesting anonymity, as he was not authorised to speak to the media. The atmosphere in the entire sprawling telemetry complex in the industrial hub at Peenya was reflected in the words of that engineer.

The complex manoeuvre on September 24—achieved successfully to the mathematical precision—was to place Mars Orbiter Mission (Mangalyaan) into Mars Orbit. “The Mars orbit insertion is the most complicated task which we have achieved today. Over 100 scientists and engineers are directly involved in this mission that was launched on November 5 last year. The entire nation’s support, blessings and prayers have brought us here today,” modest, mild-mannered and soft-spoken Dr Radhakrishnan said, whose day started at 2 AM.

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In its Mars Orbiter Mission (MOM)—Mangalyaan—ISRO had three major challenges. The first one was the launch of MOM using PSLV-XL on November 05, 2013; then the next challenge was Trans-Mars Injection (TMI) of December 2013, where required velocity had to be given to MOM in specific periods in order to enable it continue its journey towards the Red Planet. The third challenge was on September 24, when the speed of MOM had to be reduced and placed in the Mars orbit.


Second To Second Journey Towards Scripting History


 

  • 17.32—Change over to Medium Gain Antenna
  • 56.32—Forward Rotation Starts
  • 12.19—Eclipse starts
  • 14.32—Attitude Control with Thrusters
  • 17.32—Engine Burn Starts
  • 21.50—Mars Occult Starts
  • 22.32—Telemetry Off
  • 30.02—Ground Control Staff receives confirmation of Burn start
  • 37.01—Eclipse Ends
  • 41.46—Liquid Engine Burn Ends
  • 42.46 to 8.04.32—Reverse manoeuvre starts
  • 45.10—Occult Ends
  • 45.10—Occult Ends
  • 47.46—Telemetry resumes an Doppler measurement to provide first information about total burn performance.
  • 52.46—Reverse manoeuvre Ends; MOM placed in Mars Orbit.

 


As planned by the scientists, Mangalyaan—which has traversed a distance of 660 million kms (65 crore kms) —got into Mars orbit exactly at 8.15.21 AM. The three-hour cliff-hanger task of Mars Orbiter Mission started as early as 4.17 AM. “We first had to slow down the speed of the cruising spacecraft, Mangalyaan. Then the spacecraft had to be reversed so that its two antennas will face the earth. All these manoeuvres required precision,” ISRO officials said. Yet another crucial aspect was that the spacecraft went out of sight behind mars between 7.22 AM and 7.45 AM soon after the engine started firing. The waiting of those 23 minutes was like eternity for many scientists and especially the command team which waited with bated breath to know the outcome based on recorded actions. This communication blackout of about 23 minutes is due to the radio link between MOM and the ground station getting blocked by Mars. The operations during this vital 23-minutes was carried out autonomously. The link was re-established at 8.16 AM.­

When at 8.43 AM the command team received data that the MOM has been placed rightly and firmly in Mars Orbit, there was a thunderous applause from the hundreds of staff sitting in front of their computers from as early as 3 AM. The heave of the sigh of relief was audible and palpable. Dr Radhakrishnan immediately went to the enclave where Modi was sitting but even before the ISRO chairman went to the Prime Minister, Modi was already seen walking towards the Scientific Community in ISTRAC to greet them.

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“This inter-planetary accomplishment will enable ISRO to venture into much greater tasks. You have made our forefathers proud and inspired the future generations,” Modi said, while addressing the emotionally-charged but relaxed-looking ISRO engineers, scientists and other personnel. True to his nature of being a real leader, Modi said, “I was told that the task is very complicated and delicate. I was also told that ISRO was hesitant to invite me to this historic event. I told the officials that I will be the first and the last person to take responsibility if the mission failed. Do not worry.” These words made every staff feel proud of themselves, going by their body language.


Technological Terminology


  • MOM—Mars Orbiter Mission. It is the official name given by ISRO for its project of putting a spacecraft into Mars Orbit.
  • TCM—Tragectory Correction Manoeuvre. It is a procedure by which ISRO uses the MOM thrusters to steady its course en-route to the Red Planet. Four TCM’s performed ever since the spacecraft was launched on November 5, 2013.
  • MCC—Mars Colour Camera. It is a scientific payload on board the orbiter to monitor the events on Mars and its satellites—Phobes, Deimos, etc, etc.
  • LAP—Lyman Alpha Photometer. It is another payload on board the orbiter which will be useful to understand the process of loss of water from Mars.
  • MOI—Mars Orbit Insertion. It is a set of complex procedures which ISRO implemented to slow down MOM and put it into an orbit around Mars.
  • OCCULT—Occultation is an event which an object is hidden by another that passes between it and the observer. For the Mars Mission, the orbiter was in Mars Occult for around 24 minutes.
  • LAM—Liquid Apogee Motor. It is the main engine of MOM which was dormant for 300 days after it was launched on November 5, 2013. It was tested for around four seconds on Monday.
  • AOCS—Attitude Control and Orbit System. The eight smaller thrusters on MOM are for operating the AOCS in the event of main engine failing to operate. ISRO scientists would have used these AOCS thrusters to slow down the orbiter for insertion. AOCS is a stand-by for main engine.

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According to Dr Radhakrishnan, Mangalyaan will have a total life of about six months (180 days) during which ISRO has planned a number of explorations including its quest for methane. Now that the technology demonstration has been proved successful, the focus will now shift towards scientific experiments including to get detailed understanding of the evolution of the Red Planet, possibility of any existence of life and other geological studies. MOM carries a camera, two spectrometers, a radiometer and a photometer, which all put together weighs about 15 kgs. According to the technical details made available by the ISRO, the heaviest payload weighing 3.56 kgs is the Mars Exospheric Neutral Composition Analyser (MENCA) to study the neutral composition of Mars upper atmosphere.

By S A Hemantha Kumar from Bengaluru

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