The South Asia Satellite

The ISRO will launch the GSLV tomorrow carrying the South Asian Satellite on board. ISRO calls it the GSAT-9. It will carry Indian transponders that will be used by India, Nepal, Bangladesh, Bhutan, Sri Lanka and the Maldives. The Wire has a short video describing the significance of the launch and some prior history.

11a8gsat-9seenwithtwohalvesofpayloadfaringofgslv-f09

GSAT-9 seen with the two halves of the payload fairing of the GSLV-F09. Image Credit: ISRO

I think this launch will be important for India for two things. One is to prove, further, the reliability of the GSLV as a launch vehicle capable of regularly delivering communication satellites into orbit. This improves with each launch. As this reliability improves, it brings in business in communication satellite launches as well as reduces India’s dependence on foreign launch vehicles. The second is to improve availability of transponders for users on the ground. Indian transponders can thence be leased and commercialized after meeting India’s requirements.

It would be interesting to see if the use of the transponders by some of our neighboring countries provides them with sufficiently good experience that they will continue using Indian transponders or even ask for multiple transponders. This would make it important again to improve the reliability of the GSLV and the GSLV Mk-III to put enough communication satellites into orbit to service these future requirements. Could then India wean off South East Asian countries from American and European transponders to Indian ones?

Interestingly, this satellite also carries with it an electric propulsion experiment. This satellite is expected to stay in orbit for 12 years. Communication satellites usually  last around 10 years. They have to carry as much fuel for what is known as station keeping. The satellites begin to drift from orbit like kites that we fly. We tug at the kite to keep it at one place and prevent it from drifting too far away. The satellite has no strings attached and hence the satellite will have to use fuel on-board to reach its orbit as well as to stay there.

Using electric propulsion completely for doing station keeping would reduce the amount of fuel the satellite would have to carry. This means we can add more transponders which in turn would mean fewer satellites could meet the requirements. But, this is an experiment and hence ISRO is still carrying the fuel it normally would had the electric propulsion system had not been there. I am also delighted to hear that the GSAT-20 mission flying next year will also carry an electric propulsion system on board. The lessons we learn from the experiment on the GSAT-9 would be incorporated.

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