New Delhi:
In an ambitious mission India today will be attempting to launch a communications satellite using its smaller rocket the Polar Satellite Launch Vehicle. Woefully short of transponders, this is a crisis response to hurriedly augment satellite capacity. In an interview to NDTV's Science Editor Pallava Bagla, ISRO chief K Radhakrishnan explains the rationale for this unique mission.
NDTV: Dr Radhakrishnan you have a launch of the polar satellite launch vehicle. What is unique about that mission?
K RADHAKRISHNAN: Yes we have a launch of the PSLV or the Polar Satellite Launch Vehicle. We designate that mission as PSLV C-17 and this is basically to launch a communication satellite G-SAT 12. What is unique in this is we are using a PSLV which normally is used for sending remote sensing satellite to polar orbits of 1000 kilometer (km) altitude. Here it is for a geostationary transfer orbit mission.
NDTV: So a small vehicle for sending a large satellite?
K RADHAKRISHNAN: And a different type of orbit. For a communication satellite we normally go to an elliptical orbit. And finally through ground controlled mission operations using the satellite propulsion systems we raise it to the 36,000 km circular orbit and bring it in the equatorial plane. But here with the PSLV we will not be able to reach 36,000 (km) in the first go. We go up to 21,000 km and then again raise it. This means complexity on the mission operations. Since a PSLV is being used for this type of mission there are variations in the guidance scheme and the associated changes.
NDTV: So it is a more complex mission than the other PSLV's?
K RADHAKRISHNAN: It is a new type of mission and this requires a lot of changes in the algorithms, software's and the associated simulations, testing on the ground, all that we have gone through. Now we are getting ready for the launch.
NDTV: But why are you using smaller rocket which you normally don't use to send communication satellites?
K RADHAKRISHNAN: See essentially what happens is we need to augment the transponder capacity. We have with the G-SAT 8 which started operation a few days ago, 175 transponders in KU band, in C band, in extended C band. But there is a lot of demand. While it is a very positive thing that we have a large demand for satellite transponders in the country which is a hallmark of the space application and its success in the country, we need to build that capacity. So one part of the strategy is to use PSLV and put a few communication transponders. Second one is to use heavy satellite platforms like G-SAT 8 and G-SAT 10 to build up again capacity. That of course requires launch from the outside [India] for the time being. Third thing is to lease out a few transponders from the foreign operators or lease a whole satellite. So we are going through all these routes at the moment. So these 175 what we have today it has to be doubled in the next 1 year, that's the target.
NDTV: Will that be able to meet the large demand of the Indian broadcast industry, cable industry, DTH industry has?
K RADHAKRISHNAN: Yes, certainly and we do have at the moment a few of the leased transponder capacity that also would continue for some more time.