Test drive to Mars
2.38 pm, November 5, Sriharikota.
The moment marked a giant leap for Indian science. With a resounding roar, PSLV-C25 took off, beginning the journey of the orbiter to Mars. Within a minute, the great ball of fire turned into a tail of smoke and disappeared in the sky.
Just 15 minutes before the launch, P Kunhikrishnan, mission director for Polar Satellite Launch Vehicle (PSLV), switched on the computer on the orbiter. The computer then took over the controls and launched the rocket. The crowd of excited journalists, stationed eight kilometres from the launch pad at the media centre of Satish Dhawan Space Centre (SDCS) in Sriharikota, Andhra Pradesh, was kept abreast with each step through a public address system.
Forty-three minutes of PSLV’s journey was monitored at Sriharikota and by two Indian ships posted in the South Pacific Sea. Use of ships was necessitated due to extra time taken by the rocket to reach the orbit—scientists wanted the rocket to reach the orbit at a specific angle. After the 43 minutes, PSLV released the orbiter in Earth’s orbit. Monitoring and control of the orbiter was taken over by the Indian Deep Space Network complex at Byalalu, a village near Bengaluru in Karnataka, and ISRO Telemetry Tracking and Command Network at Peenya Industrial Area, also near Bengaluru. The solar panels of the orbiter were successfully deployed and manoeuvered to harness maximum solar energy.
“The spacecraft is in good health. Tests done on it found everything normal,” said S Arunan, project director of Mars Orbiter Mission (MOM). “The journey has just begun,” said K Radhakrishnan, chairperson of the Indian Space Research Organisation (ISRO) after the launch.
For the next 25 days, the orbiter will go round the earth progressively increasing the length of its orbit as well as its velocity. During this time, it will increase the length of its orbit five times (see ‘Out of this world mission’). Two such manoeuvres have already been carried out in the early mornings of November 7 and 8. The sixth orbit increase, on December 1, will be the final send-off of the orbiter to Mars. It is expected to reach there in September 2014. It will be monitored for the next six to 10 months, the orbiter’s expected life.
The mission has placed India among the handful of countries which have attempted the journey to Mars. If the orbiter reaches Mars’ orbit and sends informations from there, the country will be the fourth to achieve the feat. “This is an incredibly exciting, challenging and demanding mission,” says K Kasturirangan, who headed ISRO till 2003. For Yash Pal, the first director of ISRO’s Space Application Centre, Ahmedabad, the orbiter is the organisation’s special gift to the nation. The mission marks the 50th year of ISRO’s existence.
On high speed mode
The mission has moved on a fast track. It took researchers at ISRO about 20 months to ready the Mangalyaan, often called so by scientists. The government allocated budgetary funds for it in March 2012 and on Independence Day that year, Prime Minister Manmohan Singh announced from the ramparts of the Red Fort that India would venture to the Red Planet. By October 2013, the orbiter was ready to go.
With elections round the corner, some critics write off the mission as the ruling party’s effort to give people a reason to cheer through this demonstration of scientific prowess. Others say it is an attempt to defeat China in the race to reach Mars—China’s orbiter, sent in 2011, had failed. Yet another group suggested that this is a way of offsetting the failure to send Chandrayaan-2 on time.
ISRO officials say speed was necessary to ensure that the orbiter was launched when it would take the least energy to reach Mars. By launching it between October 28 and November 19, the space research body ensured that it would need to travel the least distance to reach the Martian orbit. The orbiter will be taken to Mars in two steps. First, PSLV-C25 carries it to Earth’s orbit and releases it. The process takes 25 days. In the second stage, the orbiter, after travelling in space for nearly 300 days, will be injected into Mars’ orbit. This is a novel method.
NASA’s Mars Atmosphere and Volatile EvolutioN orbiter is also expected to be injected in the planet’s orbit in September 2014. It is being launched from the Cape Canaveral Air Force Station, US, on November 18, 2013, using Atlas V 401 rocket.
How info will come home
Till the time the orbiter is still under the earth’s influence, it will be monitored by an 18-metre antenna at the Byalalu station. Once it enters the heliosphere, sphere of Sun’s influence, it would be followed by a 32-metre antenna, also stationed at Byalalu. The signals will be monitored 24x7. Support for ground observation has been taken from NASA’s Jet Propulsion Laboratory, which has stations around the world and has bigger antennas. These signals will be transferred to the Peenya centre through an optic fibre leased from Bharat Sanchar Nigam Limited. Project director S Arunan will monitor the orbiter’s movements and send appropriate signals to control it.
The orbiter is programmed to function independently. This is important as each message from Earth can take between 4 and 20 minutes to reach Mars. If something goes amiss, the satellite should be able to figure out the problem and switch to the safe mode. To ensure autonomy during this time, commands for the orbiter have already been programmed. However, commands over and above the programmed ones will be sent from ground. These could include command such as those to change the course or speed of the orbiter.
The orbiter manufactured by Hindustan Aeronautics Limited is made of aluminium and weighs 1,350 kg. Of this, 850 kg is just the propellant. The payload—instruments that would carry out atmospheric, particle environment and surface imaging studies—weighs around 15 kg. These would start working the moment the orbiter is released from PSLV.
Payload forms the core of the mission. Five instrument will be responsible for sending information about Mars back home (see ‘Payloads’ on facing page). Earlier Mars missions of other countries have carried all these instruments except the one responsible for measuring methane in the atmosphere. With this, India may answer the question on the presence of methane on Mars. On Earth, the gas is largely produced by living organisms. Finding methane could indicate that life existed, or exists, on Mars.
Latest data from NASA’s Curiosity rover, which is presently exploring Mars, shows that methane is not present on the planet’s Gale Crater area. ISRO scientists say their methane study is better as it will give information on the presence of the gas in the atmosphere unlike Curiosity, which gave data in situ, only at a single position.
ISRO scientists generated as many as 30 ideas for the kind of instruments that would best suit this purpose. Nine of these were found feasible and only the best five were finally put on the Mangalyaan. Around 1 terabyte of information is expected from the mission, which would be saved at the Indian Space Science Data Center at Byalalu.
The Indian mission has a well-defined agenda—to demonstrate that it has the capability to reach Mars and that it can carry out studies there. Scientists hope that the mission would help develop applications which would help the common man. For instance, remote sensing became possible only after satellites were sent to the upper atmosphere.
Scientists hope that similar, path-breaking benefits would emerge from missions to space. “India is the leader in space applications,” says Radhakrishnan. ISRO has launched as many as 70 satellites in the past four decades and helped improve mobile communication, weather monitoring, education, telemedicine, education, disaster management, and search and rescue operations. Lessons learnt would enhance autonomy of such satellites.
The mission has cost India Rs 450 crore, thrice of what Shahrukh Khan-starrer Chennai Express earned in its first week (Rs 156.70 crore) of release. “The space programme gets 0.04 per cent of the Centre’s expenditure and the Mars mission represents just 0.34 per cent of our funds,” says Radhakrishnan. The mission would lead to excitement and enrichment of knowledge. This is why we study science, he says.