30/12/2014 8:19 AM IST | Updated 15/07/2016 8:24 AM IST

ISRO's Milestone GSLV Flight Carries India's First Human Spacecraft

And this is where India's USP lies. ISRO has till date, on average, charged only around 75 percent for commercial launches of smaller satellites as compared to total costs borne by customers of satellite launch service providers in Europe and US.

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SRIHARIKOTA, INDIA - JUNE 30: India's Polar Satellite Launch Vehicle PSLV-C23 launched by Indian Space Research Organization (ISRO) from the Satish Dhawan Space Centre on June 30, 2014 in Sriharikota, India. India today launched five foreign satellites on board an indigenous rocket, prompting Prime Minister Narendra Modi to asks Indian scientists to develop a SAARC satellite which can be dedicated as a gift to the neighbours. (Photo by Subrata Biswas/Hindustan Times via Getty Images)

GSLV Mk III takes off from Satish Dhawan Space Center at Sriharikota, Dec 18, 2014; Courtesy: ISRO

Indian Space Research Organisation (ISRO) has hit two birds with a single shot. On December 18, 2014, ISRO successfully launched the maiden flight of its next generation launch vehicle, the Geosynchronous Satellite Launch Vehicle (GSLV) Mark III from its Satish Dhawan Space Centre spaceport at Sriharikota (SDSC SHAR).

And the flight carried the first prototype of a crew module aimed at carrying the first ever Indian human mission to space in future. On both fronts, ISRO passed the tests with flying colours.

Firstly, GSLV Mk III flight is a major step towards attaining home-grown capability to launch communication satellites weighing above 4000kg (four tonnes). This will one day open up the huge global communication satellite launch and services market for ISRO.

As per Satellite Industry Association's (SIA) State of the Satellite Industry Report 2014, satellite industry revenues were US $195 billion in 2013 with satellite launch market forming 3 percent at US $5.4 billion. This may appear minuscule but any nation mastering capability to launch four tonne plus communication satellites goes on to become a one-stop shop for providing satellite services, satellite manufacturing and ground based equipment, the three larger revenue segments of the satellite industry respectively.

And this is where India's USP lies. ISRO has till date, on average, charged only around 75 percent for commercial launches of smaller satellites as compared to total costs borne by customers of satellite launch service providers in Europe and US. In the last two calendar years alone, India has garnered $17 million from commercial satellite launches of foreign clients.

However, GSLV needs to be 'commercially ready' before this market can be tapped. Thus, the December 18 experimental flight, officially called Launch Vehicle Mk III - Experimental (LVM3-X) was a test bed for certain critical technologies and two full scale 'developmental flights' are in pipeline in coming years.

GSLV Mark III contained only 4 propulsion modules as against 7 in earlier GSLV versions. The launch vehicle is divided into three stages. The first stage consists of two solid propellant boosters called the S200. The S200 contained 207 tonnes of propellant, fourth highest globally after the Ariane 5 from Europe and the Titan IVB and space shuttle launchers from the US.

Following the solid stage is the L110 liquid core stage. The third and final stage is the C25 upper cryogenic one consisting of hydrogen and oxygen stored in liquid form. Upper Cryogenic Stage is used by all major space launchers because of its much higher efficiency than solid and liquid propellant stages.

ISRO achieved a milestone when it successfully tested its indigenous developed upper cryogenic stage for GSLV Mark II in January 2014 but GSLV Mark III requires a bigger and more complex cryogenics system. Thus this flight contained a passive cryogenic stage simulating the actual one in weight and geometry.

And it was on top of this passive stage that the crowning glory of the December 18 flight was mounted. India tested the prototype human module, the 3,775 kgCrew module Atmospheric Re-entry Experiment (CARE) which will hopefully one day carry three Indian astronauts into space. While the government has not officially cleared a human mission, preliminary preparations are on for years.

In 2006-07, an ISRO study concluded that a human mission in low earth orbit (LEO) could be carried out in next seven to eight years costing Rs. 12,400 crore (slightly above $2 billion in current dollars). The government has till now sanctioned only Rs. 145 crore for the human spaceflight program in last eight years but ISRO's frugal engineering expertise has achieved mini feats with that fund only. In 2007, ISRO tested an experimental spacecraft which, for the first time, tested the most critical element of any human space mission--the re-entry and descent of a spacecraft into the earth's atmosphere.

The Human Crew Module after landing in Bay of Bengal; Courtesy: ISRO

On the December 18 flight, the human spacecraft prototype was mounted upside down than what will be in an actual human flight. This ensured that the heat shield of the spacecraft at the bottom did not have to face the core stages of the rocket during flight. Also, it eliminated the need for complex maneuvering of the spacecraft during re-entry so that the heat shield already faced the atmosphere.

Since the actual cryogenic stage was not present in this flight, GSLV Mark III jettisoned the crew module at a height of 126 km and a velocity close to 19,000 km per hour. The spacecraft re-entered earth's atmosphere at an altitude of about 80 km and its temperature soared to 1000 degrees Celsius. In an actual human flight in low earth orbit (LEO), temperature will hit 1600 degrees Celsius. For comparison, NASA's Orion spacecraft aimed to carry the first humans to Mars made re-entry during its recent December 05 experimental flight at 2200 degrees Celsius.

The crew module hit the Bay of Bengal as expected 1600 km from Srikarikota. It had sensors fitted all over its body to measure values of 200 variables including temperature, acoustics, pressure and stresses throughout the crew module. At a height of 15 km, the second objective of the crew module flight was successfully achieved, decelerating the spacecraft using two sets of parachutes. The major parachutes are 31 meters in diameter, the biggest ever manufactured in India.

Thus, while the December 18 launch did not contain the hype and glamour of Mangalyaan (Mars Orbiter Mission) or Chandrayaan-1 (moon mission), it is one in a series of small yet critical steps before ISRO's next major leap.