Electric propulsion on Isro satellites

Business Standard India | January 10, 2016

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Indian Space Research Organisation (Isro) plans to use electric propulsion to power satellites, thereby increasing their ability to carry heavier communication satellites by its home-grown rockets. The first of the few satellites would be hurled into space in 2017.

Nearly a third of the weight of a satellite is liquid fuel, which is used to power the spacecraft to its orbital slot once it is in space. On the other hand, electric or ion propulsion uses electricity generated from solar energy and releases positive atoms to create the force required to push the satellite to its slot. It weighs significantly lighter and is 10 times more efficient than liquid fuelled satellites.

“Using electric propulsion, we can send a four-tonne satellite, which is equivalent to a six-tonne satellite. Instead of chemical fuel, we save on weight and pack it with more transponders,” said A S Kiran Kumar, chairman of Isro. “With electric propulsion, we can add more transponders into space on our own.”

India’s geosynchronous satellite launch vehicle (GSLV) can carry two-tonne satellites into space. It is building a more powerful rocket, GSLV Mk-III, which can carry four-tonne communication satellites.

Isro’s attempt to use electric propulsion technology has been a decade-old idea. But, it could not test electric propulsion technology after an experiment satellite GSAT-4 in April 2010 did not take off after the GSLV rocket exploded soon after launch. With Isro successfully mastering the cryogenic engine technology, which helps in powering rockets that can carry heavier communication satellites into space, the space agency now has concrete plans to use the electric propulsion power plant in its satellites.

“We are planning a couple of satellites that will have electric propulsion,” said Kumar.

Isro is not the only space agency experimenting with this technology for communication satellites, which has been used in deep space missions by National Aeronautics and Space Administration (Nasa). In March 2015, Boeing said two communication satellites were hurled into space powered by ion propulsion.

The fixed satellite service (FSS) industry is currently in a transition phase. According to a September 2015 report of Euroconsult, a global consulting firm specialising in space markets, the overall direction is that of higher cost effectiveness of satellite infrastructure. This is achieved through larger payloads, lower launch costs and other cost optimisation options such as electric propulsion offered by the recent streams of innovation.