Mars orbiter mission enters last leg

India is awaiting the dawn of September 24 with fingers crossed. The day will be engraved in golden letters if the Indian Space Research Organisation (Isro) is able to put its satellite into the Mars orbit. As the clock ticks, excitement has enveloped the country with ordinary Indians and the scientific community wishing for a breakthrough.

With 48 hours left for the insertion, India will be the first country to enter the Mars orbit on a maiden mission if it succeeds. India will also be the first Asian country and Isro the fourth space agency to send a satellite to the red planet. European, US and Russian probes have managed to orbit or land on the planet, but after several attempts.

 

Isro scientists are confident the mission will succeed. A successful Mars mission will also boost the standing of Isro's launch vehicles, the PSLV and GSLV, and payloads for other countries to use at lower cost. India's $74 million Mars orbiter mission Mangalyaan costs roughly a 10th of Nasa's mission Maven.

At Isro's Bangalore ground station, officials have been busy for the past couple of days taking readings and conducting procedures. On September 17, command uplinks were uploaded and two days later Isro powered on major sensors and electrical subsystems required for inserting the spacecraft into orbit.

On Monday, Isro scientists will run a test of a main engine and make a small course correction. This is crucial because the engine has been idle for nearly 10 months.

"If you get tense, you tend to make mistakes. So far, things are going fine," said Isro Chairman K Radhakrishnan. The engine will be fired for four seconds and almost half a kg of fuel will be needed for this operation.

If there is a problem in test firing, Isro will use eight small thrusters for altitude control and orientation, which may not offer the original target but will salvage the mission.

On November 5, 2013, Isro's Polar Satellite Launch Vehicle C25 took off from the Sriharikota space station, near Chennai, with five scientific payloads to observe the Martian surface.

NOT JUST A WEDNESDAY

• 4.17 am: Operations to insert the spacecraft into Mars’ orbit will start. The three antennas of the spacecraft will be activated
• 6.56 am: The craft will be rotated towards Mars. The craft’s insertion into Mars orbit will be from the dark side
• 7.12 am: The craft will enter eclipse
• 7.17 am: The liquid engine burn will start. The total burn duration is expected to be 24.14 minutes, consuming 249.5 kg of liquid propellant
• 7.21 am: The Mars occult will begin. Mars will be between Earth and the spacecraft, and the radio link with the ground station will be lost
• 7.22 am: Telemetry will switch off. The craft will execute all operations on its own
• 7.37 am: The eclipse will end, the Mars occult will continue
• 7.41 am: The liquid engine burn will end
• 7.42-8.04 am: A reverse manoeuvre will reorient the spacecraft’s antenna towards Earth
• 7.45 am: The Mars occult will end and 2 minutes later telemetry will resume. Scientists will get information about the burn performance
• 8.15 am: First information about the mission will be available from Australia. After an hour, India will be able to get data on its own

An objective of the mission is to develop technologies for design, planning, management and operations of an interplanetary mission. The technological objectives include design and realisation of a Mars orbiter with a capability to survive and perform Earth-bound manoeuvres, test a cruise phase of 300 days, Mars orbit insertion, and on-orbit phase around Mars, deep space communication, and navigation, among other things. The scientific objectives of the mission are exploration of Mars surface features, morphology, mineralogy and Martian atmosphere.

The launch was followed by six Earth-bound manoeuvres between November 7 and November 16, 2013, to bring the spacecraft closer to exit the sphere of influence of Earth. The trans-Mars injection was carried out on December 1, 2013, and the spacecraft left the sphere of influence of Earth on December 4, 2013. After that, there was no coming back, whether the mission would succeed or fail.

From Earth's orbit, the spacecraft was moved in a heliocentric path to a destination around 224 million km away, where the craft meets Mars.

Events that will happen 224 million km away from Earth on September 24 will be watched and controlled by Isro's ground stations the Indian Deep Space Network in Bangalore, Goldstone in the US, Madrid, Spain and Canberra, Australia.

Once inserted in orbit, the spacecraft will complete one rotation around Mars in 3.2 Earth days taking pictures and sending data back to Isro for around 6-10 months. The life of the mission will depend on the quantity of fuel left in the craft.