Martian orbit on Indian spacecraft's radar Wednesday

Bangalore: India's tryst with Mars begins early Wednesday when its inter-planetary spacecraft readies to enter the Martian orbit in a maiden attempt to study the red planet's atmosphere and search for life-sustaining elements.

"We are bracing up for the crucial operation to insert the spacecraft into the Martian orbit by firing the main engine at 7.17 a.m. and receive a confirmation signal of its insertion by 8.15 a.m.," mission's programme director M. Annadurai told IANS Tuesday.

Buoyed by the test-firing of the 440 Newton liquid apogee motor (LAM) engine Monday, about 300 days after it was shut off following the spacecraft's trans-Mars injection into the Sun's orbit Dec 1, 2013, for its voyage to the red planet, the scientists also corrected its trajectory (direction) for the final manoeuvre.

"Everything is going on smoothly as programmed and the spacecraft's health is normal. We are waiting for the final move," the senior scientist said.

Excitement is building up at the Mars Mission control centre in the space agency's telemetry, tracking and command network (Istrac) in this tech hub for the historic event, which Prime Minister Narendra Modi will also witness, as he heads the department of space too.

The operation will begin at 4.17 a.m. with the spacecraft (Orbiter) switching over to the medium gain antenna for receiving and emitting radio signals.

After rotating the Orbiter towards Mars at 6.57 a.m., the main engine will be fired 24 minutes from 7.17 a.m. to 7.41 a.m. to enter the Martian orbit, which will be about 500 km from its surface and 215 million km away from the Earth in radio distance.

The spacecraft will consume about 250 kg of liquid fuel with oxidiser.

"During the fourth course (trajectory) correction Monday, we have reduced the Orbiter's speed by 2.18 metres per second from 22.2 km per second for enabling the insertion into the Martian orbit from the sub-orbit," Annadurai pointed out.

In the absence of sunlight on the Martian surface from 7.12 a.m. causing eclipse, eight thrusters (smaller engines) on board the spacecraft will control its attitude due to lack of solar energy during the operation.

"As the spacecraft will pass through the eclipsed region during the firing, radars at the four earth stations will not receive telemetry (radio) signals till 7.53 a.m.," the director noted.

In the event of the engine not firing at the designated time (7.17 a.m.), the mission control will give commands to fire the eight thrusters for sustaining the momentum.

The deep space networks of America's National Aeronautics and Space Administration (NASA) at California in the US, Madrid in Spain and Canberra in Australia will coordinate with ISRO's deep space network at Baylalu, about 40 km from Bangalore, for receiving the signals from the spacecraft after its insertion into the Martian orbit.

The five scientific instruments on board the 475-kg Orbiter will study the Martian surface and its mineral composition and scan its atmosphere for methane gas.

India became the first Asian country to enter the Martian gravity or sphere of its influence Monday.

The Rs.450-crore ($70 million) ambitious Mars Orbiter Mission (MOM) was launched Nov 5, 2013, on board a polar rocket from the country's only spaceport at Sriharikota off the Bay of Bengal, about 80 km northeast of Chennai.

The state-run Indian Space Research Organisation (ISRO) is the fourth international space agency after National Aeronautics and Space Administration (NASA) of the US, Russian Federal Space Agency (RFSA) and European Space Agency to undertake a mission to Mars.

As the second smallest celestial body in the solar system, Mars is also known as the red planet due to the presence of iron oxide in abundance, giving it a reddish appearance.

Though both the planets have equal period of revolution around their axis, Mars takes 24 hours and 37 minutes to complete a revolution. Earth takes 365 days to orbit the sun while Mars takes 687 days to move around sun.

India launched its space programme five decades ago and developed rockets after sanctions were imposed on it for conducting two nuclear tests in 1974 and 1998.

ISRO has so far launched 40 foreign satellites, many of them for developed countries like Britain, Canada, Germany and France.