| PSLV takes off from the space centre at Sriharikota. (PTI)
Sept. 12: India today took a giant leap towards weather forecasting and the small step towards a lunar adventure.
An Indian Space Research Organisation (Isro) rocket blasted off from Sriharikota, 100 km from Chennai, and placed into orbit a one-tonne Metsat – the country’s first dedicated weather satellite.
The satellite will sharpen weather forecasting and cyclone warnings since the data will be more accurate. Metsat is expected to get images over the Indian subcontinent once in half-an-hour instead of the current once in three hours.
But the launch stoked wider interest because the launch vehicle – a modified version of Isro’s warhorse rocket – also crossed a crucial threshold today.
The satellite the modified Polar Satellite Launch Vehicle (PSLV) today lobbed into a geostationary orbit -- a parking slot 36,000 km above the Earth – weighed over 1,000 kg. The PSLV was originally intended to carry 900-kg satellites into 900-km orbits.
The new weight and reach has implications for India’s moon mission, which has been proposed by a national task force. The launch might also serve as a test of the first sequence of operations during a lunar mission.
Asked if the PSLV will be used as a platform for the moon mission probe also, a jubilant Isro chairman K. Kasturirangan said today’s achievement, in terms of the weight of the payload and the fuel carried by it, was such that it would “enable us to put this craft into a lunar orbit”.
The national committee on lunar probe has submitted a report. Subject to scientists preparing a positive project report, it would take another four to five years for the proposed mission to come through, he added.
In a report submitted to Isro last month, the task force proposed that a modified PSLV could launch a 450-kg satellite into an elliptical GTO from where the satellite would be manoeuvred towards the moon. The proposal is yet to be approved by the government.
“What we hope to see tomorrow is one possible option in which the PSLV could be used to take a spacecraft towards the moon,” George Joseph, a senior space scientist at the Space Applications Centre, Ahmedabad, and chairman of the task force, had told The Telegraph yesterday.
“This launch is intended to prove the versatility of the PSLV,” a space department official said.
This is the first time Isro is using an entirely indigenous launch vehicle to carry a satellite into geostationary orbit. Although Isro’s Geostationary Satellite Launch Vehicle flew into space last year, its crucial cryogenic engine came from Russia.
Three key changes in the multi-stage PSLV are behind its ability to carry its heavier payload into higher orbit. Isro scientists have added 500 kg of extra liquid propellant in PSLV’s fourth stage and improved the performance of its third stage.
They have also replaced the traditional alumina structure that holds the satellite in place on the launch vehicle with a novel structure constructed out of lighter composite material, reducing its weight by 70 kg.
The Metsat itself is a unique weather satellite, a precursor to future generations of Insats that will be used exclusively for either meteorology, telecommunications, or broadcasting.
Almost all the Insats have until now served as multi-purpose satellites for combinations of meteorology, telecommunications and broadcasting applications.