ISRO launching its biggest rocket ever, GSLV-Mk III, is a bold move by India

The successful launch of GSLV from the spaceport at Sriharikota on Monday, June 5, evening marks a major landmark in India’s space journey that began with the firing of sounding rockets from Kerala coast half a century ago.

Both the rocket that took off from the second launch pad of the Satish Dhawan Space Station and the satellite it carried were the heaviest to lift-off from Indian soil. Named GSLV-Mark III, the rocket is a technological successor to two of its earlier versions – Mark I and Mark II – but is entirely different from them in terms of structure, size and stages.

Mark I used Russian cryogenic upperstage, while Mark II was powered by an indigenous cryogenic engine. The structure of GSLV-Mark III was tested during a suborbital flight in December 2014.

A cryogenic engine is the holy grail of rocket technology and a must to possess for any space agency aspiring to execute complex and large missions. This rocket stager is more efficient as it provides more thrust for every kilogram of propellant it burns compared to solid and liquid propellant stages.

Its "specific impulse" –  factor that represents efficiency of an engine - that can be achieved with cryogenic propellants (liquid hydrogen and liquid oxygen) is much higher that achievable by liquid and solid propellants.

This means that with cryogenic on can pack heavier payloads on rocket. It is technically extremely challenging because it requires maintaining propellants at very low temperatures – liquid oxygen at -183 degree centigrade and hydrogen at -253 degree centigrade.

The use of cryogenic upper stage in GSLV makes it capable of lifting payloads up to 4000kg into Geosynchronous Transfer Orbit (GTO) and 10,000kg into Low Earth Orbits. Till now, India depended on foreign launchers for putting heavy communication satellites into space.

After "man rating", this rocket can attain the capability of sending a manned mission in future. Right now, India has no approved plan for a manned mission but whenever that happens, GSLV-Mark III will come handy.

GSLV-Mark III makes a solid technological, strategic and geopolitical statement for India and the national space agency – the Indian Space Research Organisation (ISRO). Technologically speaking, it represents cumulative expertise developed by the agency in handling solid, liquid and cryogenic rocket propulsion technologies as well as mastery over design and development of heavy world class communication satellites.

In addition, the agency is fully capable of all associated ground control and tracking technologies. Overall, ISRO is now ready to be counted among the best space agencies of the world. For an outfit which came into existence when NASA had already sent man to the moon, this is a truly remarkable achievement.

It is a strategic move for India as all the technologies involved in making the rocket and its cryogenic upper stage are proprietary and holders of all such technologies do not part of with them. Both Americans and Russians have played tricks with India when it came to cryogenic technology in the 1990s, virtually holding up the rocket development programme.

When the Russians agreed to provide the technology to Indians, Americans pressurised them and ultimately Russia only sold its engines to India without any technology transfer. The cryogenic engine that flew on Monday morning is fully indigenous. Not just this, ISRO was blacklisted by America to prevent it from buying even commercially available parts and components.

GSLV-Mark III also marks a bold geopolitical statement in the wake of the rise of China in the space sector. India has deliberately chosen to develop its space programme stage-wise, beginning from SLV, then testing ASLV in early 1990s and establishing PSLV as its workhorse in the past two decades. Having done this, ISRO went in for the next stage of development in the form of GSLV.

It has taken almost 15 years for GSLV-Mark III to be developed. The project was approved by the government in 2002 and the configuration of three-stage rocket with capacity to place into GTO a four-tonne class satellite was fixed. The experience of managing PSLV and earlier GSLV projects, involving multiple teams and institutions, was used in the GSLV-Mark III project. New facilities like Thrust Chamber Test facility with High Altitude Test (HAT) were established.

While Monday’s flight has been successful, a few  more flights of the vehicle will help ISRO establish GSLV-Mark III as the new reliable and cost-effective workhorse for the requirement of launching large satellites, including manned mission as and when it happens, over the next couple of years. In this sense, with GSLV-Mark III the space agency has begun its next phase of journey.

Capturing a part of the growing market for commercial satellites would also be possible with this robust vehicle.

In all this, the stated and real goals of the Indian space programme have remained the same: peaceful application of space technology for national development. On the other hand, China which entered space arena much later than India, rapidly scaled up its programme but its focus has been high visibility goals like manned missions and setting up a space station.

By remaining firm on the path chosen by its founder, Vikram Sarabhai, ISRO has once again affirmed that it's mission in the space sector is to achieve self-reliance, technological excellence and use space technology for the benefit of common people.

Also read: Why ISRO's biggest rocket, GSLV Mark III, is a big deal