GSAT-15 set to replace dying INSAT-3A and 4B

GSAT-15, which will be put in space shortly, will replace two older spacecraft-INSAT 3A and 4B- that will likely expire in the coming months.

• According to the ISRO, the transponders of GSAT are solely in the Ku band and will cater to DTH (direct-to-home) television needs, besides supporting the thousands of VSAT operators who provide broadband services and DSNG (digital satellite news gathering) for TV news channels.
• ISRO is also focusing on bridging the Ku-band shortage in the country. Currently, Indian D2H broadcasters are heavily dependent on external transponders.

GSAT 15:

• GSAT-15, weighing 3,164 kg, will be launched in on November 11 from Kourou in French Guiana (in South America) on the European Arianespace’s Ariane-5 launcher.
• The satellite cost and the launch fee are around Rs. 860 crore.
• GSAT-15 will be flown along with Saudi Arabia’s Arabsat-6B/Badr-7.
• It will be stationed over India at a slot at 93.5 degrees East longitude.
• GSAT will also carry the third GAGAN satellite navigation transponder as a back-up for airlines and other users of augmented GPS-based systems.

Why can’t we use Indian launch vehicles?

The two Indian rockets — PSLV and GSLV — cannot pitch the weight of GSAT-15 to its slot 36,000 km high.

INSAT 3A and 4B:

INSAT-3A, launched in April 2003, has completed its 12-year life. INSAT-4B, flown in March 2007, got reduced to half its functions in 2010 after one of its two power-generating solar panels developed a snag.

sources: the hindu, isro.