What is ISRO’s GSLV MkIII?

India’s heaviest rocket launcher, GSLV MkIII , is the third-generation rocket from Indian Space Research Organisation (ISRO). The project to develop it was approved in 2002, with a mandate of achieving the capability to launch a four-tonne class satellite to geosynchronous orbit.  

Weighing 641 tonnes, which is equivalent to a large aircraft, GSLV (Geosynchronous Satellite Launch Vehicle) MkIII made its maiden launch on June 5, 2017, from the Satish Dhawan Space Centre in Sriharikota. The launcher is capable of lifting four-tonne class satellites to Geosynchronous Transfer Orbit (GTO) and about 10,000 tonnes to Low Earth Orbit (LEO). The heavy rocket costs around ₹400 crore. In June 2018, the Union Cabinet approved ₹4,338 crore to build 10 such rockets over a five-year period.

What is the rocket’s configuration?

GSLV MkIII is configured as a three-stage vehicle with two solid strap-on motors (S200); one liquid core stage (L110); and a high thrust cryogenic upper stage (C25). The S200 solid motor is among the largest solid boosters in the world with 204 tonnes of solid propellant. The L110 stage uses a twin liquid engine configuration with 115 tonnes of liquid propellant, while the C25 is configured with the fully indigenous high thrust cryogenic engine (CE20) with a propellant loading of 28 tonnes. The overall length of the vehicle is 43.5 m with a gross lift-off weight of 640 tonnes and a 5m-diameter payload fairing. The powerful cryogenic stage enables it to place heavy payloads into LEO of 600 km altitude as was witnessed in the recent launch of 36 satellites of OneWeb. 

What are the other launch vehicles that ISRO has?

India has two operational launchers — the workhorse and most reliable launcher Polar Satellite Launch Vehicle (PSLV), and GSLV. The next variant of GSLV is GSLV MkIII. 

What is the significance of GSLV-MKIII’s recent launches?

The Chandrayaan-2 spacecraft launch on July 22, 2019, into its planned orbit with a perigee (nearest point to Earth) of 169.7 km and an apogee (farthest point to Earth) of 45,475 km, was a highly complex mission. It represented a significant technological leap compared to the previous missions of ISRO, comprising an Orbiter, Lander and Rover to explore the unexplored South Pole of the Moon. The recent successful launch of OneWeb satellites makes India a cost-effective destination to launch commercial satellites.

What’s the next major target for GSLV Mk-III? 

GSLV MkIII is identified as the launch vehicle for Gaganyaan mission, which aims at carrying three crew to LEO and bring them back safely to a predetermined location on Earth. 

Where does India stand today in the satellite launch market?

India has over the last two decades built a solid foundation for rocket launches. The ISRO, through its commercial arms, has earned around $279 million (as per July 2022 data) in foreign exchange by launching satellites for global clients. ISRO has been providing launch services for customer satellites since 1999 — more than 350 customer satellites from over 30 countries have been launched by PSLV. With the recent launch of OneWesb, GSLV has made a grand entry into the commercial launch service market for heavier satellites.

What more should ISRO do to become the ‘go to’ player in the satellite launch business?

India has managed to enter the big league of being a cost-effective destination to launch smaller and lighter satellites. The same cannot be said about the heavier communication satellites. GSLV is yet to prove itself as a reliable launcher of heavy satellites. ISRO needs to establish that first. The challenge going forward is to have re-usable rockets that will help in reducing the cost further. 

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