The Geosynchronous Satellite Launch Vehicle (GLSV) MK III has been fully integrated and is waiting to take off from the second launch pad (SLD) at the Sriharikota High Altitude Range (SHAR), ISRO's rocket launch facility in Andhra Pradesh. This is the first developmental flight of the GSLV MK III, and will make it the heaviest rocket launch by the Indian space agency. This will be the third consecutive flight by ISRO in 2017 considered to be a milestone, following the February launch of 104 satellites on board a single rocket, and the deployment of the South Asia Satellite in May, which was India's gift to countries in the region.
The GSLV MK III has been dubbed the "Fat Boy", but ISRO officials have referred to it as India's "workhorse" rocket of the future. The current "workhorse" rocket is the Polar Satellite Launch Vehicle (PSLV), which is one of the most reliable launch vehicles in the world. The other rocket in the ISRO fleet is the GSLV MK II, known as the "naughty boy" because of its unpredictable nature. The GSLV will be able to take four ton class of satellites into the Geosynchronous Transfer Orbit (GTO), which will allow India to commercialise launch services of this heavier class of satellites. The GSLV MK III or a variant, is expected to be the rocket that will be used for the first Indian manned mission into space.
The GSAT-9 is the first of three communications satellites that will be launched by ISRO by 2018. Each of these satellites will increase the communications capability of the country, and are on the verge of transforming the entertainment and internet landscapes in India. The satellites will allow for high speed broadband access, even in remote and rural areas. Through wi-fi dongles connected to regular television sets, and local antennas for downloading the information from the satellite, internet services will be available to the citizens through conventional television sets. The satellites are being launched to meet the future communication needs of the country, as well as support the smart cities project.
The GSAT-19 is a geostationary communications satellite, that will always be above Indian skies. The lift off mass of the satellite is 3136 kg. The satellite is mainly cuboidal in shape with two solar arrays. There are momentum wheels, magnetic torquers and thrusters on board that will help the satellite maintain its position and orientation. Apart from the communication capabilities, there is a Geostationary Radiation Spectrometer (GRASP) payload on board which will study the effects of space weather on the delicate electronic components on satellites. The satellite uses an indigenous Lithium-ion Battery.
The entire flight is expected to last only sixteen minutes. There are four separation events, the strap on motors, the payload fairing, the core stage, and the satellite itself. There are only two strap on motors, unlike the four used in the PSLV missions flown in the XL configuration. There are three stages on the GSLV MK III. The first stage uses a composite solid propellant, the second stage uses hypergolic liquid fuel, and the third stage has an indigenously developed cryogenic engine. This third stage is a matter of pride for ISRO and the country, and will be the first time it is being used in a launch. The C25 cryogenic stage has 28 tons of propellant stored in very cool conditions.
The 25 hour countdown has started, and it is shorter than usual. The launch will be telecast live on Doordarshan and the ISRO web site. For cord cutters, the live stream will also be available on Doordarshan's YouTube channel. The launch is scheduled for 5:28 PM, but the pre-launch programming will start from 4:55 itself. Viewers can follow along with ISRO scientists through the countdown and the separation events over the sixteen minute flight. Tech2 will be covering the launch in a liveblog, so keep an eye out for that as well.