Author: Parveen Kaswan ( Author is an Aerospace Engineer and currently working on his Masters in Engineering Designs at Indian Institute of Science, Bangalore. He is the founder of SimplyDecoded Group)
The current GSLV-D5 mission lasted about 17 minutes, the cryogenic engine was fired for twelve minutes. At the end of seventeenth minute, the rocket put the GSAT-14 satellite into orbit, with a good precision, marking a historical moment for Indian Scientific community. With this achievement India became the sixth space agency in the world after U.S., Russia, Japan, China and France. Now when super-cool cryogenic engine has delivered, it is high time to talk about: what it holds for India and its future space and strategic affairs.
Space Launch vehicles are the medium of transport for parking satellites into the desired orbits around the earth. For the most satellites launch, the scheduled launch rocket is aimed straight up at first. This is to get the rocket through the dense part of the atmosphere quickly and it minimizes fuel consumption. Then rocket’s guidance system, say, inertial guidance system do the necessary adjustments and further tilt the rocket path according to the plan path. In most cases, the flight plan calls for the rocket to head east because Earth rotates towards the east, giving the launch vehicle a free boost. ISRO’s Launch facility is located at Satish Dhavan Space Centre SHAR and Thumba Equatorial Rocket Launching Station (TERLS) from where Launch Vehicles and Sounding Rockets are launched.
India placed Rohini satellite in its orbit in 1980 by the first Indian-made launch vehicle, SLV-3. In subsequent years ISRO has developed two other major launch vehicles, the Polar Satellite Launch Vehicle (PSLV) for launching satellites into polar orbits and the Geosynchronous Satellite Launch Vehicle (GSLV) for placing satellites into geostationary orbits. The difference between these two rockets is in their capabilities to park the satellites in their planned orbits. These rockets have launched numerous communication satellites and earth observation satellites and specially PSLV is called as workhorse for Indian Space Programme.
Polar Satellite Launch Vehicle (PSLV) is capable to launch small satellites into geostationary transfer orbit (GTO). PSLV has launched 55 satellites / spacecraft ( 26 Indian and 29 Foreign Satellites) into a variety of orbits so far, which provide ample evidence for its success. Its only failure in 22 flights was its maiden voyage in September 1993, so rocket has a success rate of 95 percent .
The Geosynchronous Satellite Launch Vehicle, is an expendable launch system developed to enable India to launch its INSAT-type satellites into geostationary orbit and to make India less dependent on foreign rockets. At present, GSLV is ISRO’s heaviest launch vehicle and is capable of putting a total payload of up to 5000 Kg to Low Earth Orbit or 2,000 to 2,500 kilograms to geostationary transfer orbit (GTO).
These launch vehicles use a variety of propulsion system – for example solid rocket motors, liquid rocket motors, cryogenic engines, plasma, hybrid rocket engines, pulsed plasma thrusters, nuclear thermal rockets etc. But widely used types are Chemical, Solid and Cryogenic as others are still in development stage. It depends on the mission profile which propulsion system will be utilized by a particular launch vehicle. Interesting part is, somewhat same propulsion technology is used by missiles also, say in case of Intercontinental ballistic missiles.
The differences in these different propulsion system are, one is obviously the fuel material which is acting as input and the other important factors are specific impulse and thrust profile. The specific impulse is the most important factor in choosing the rocket and is measured in seconds. In simple terms it is impulse per unit of propellant so it tells us the efficiency of a particular engine. An engine that gives a large specific impulse is normally highly desirable, for example cryogenic engine has more specific impulse than liquid engine. So specific impulse is giving information about how much thrust an engine can produce per unit of propellant utilization. So India is looking forward for its own cryogenic engine that can be used in GSLV for heavier satellite launches.
If we go into the details of cryogenic engine technology, by simple physics definition, cryogenics is the study of the production of very low temperature (below −150 °C, −238 °F or 123 K) and the behaviour of materials at those temperatures. This technology is very complex and used in various fields like medical research, space and food processing.
While using it in the propulsion system, liquid oxygen at minus 183 degrees Centigrade and liquid hydrogen at minus 253 degrees Centigrade are utilized. The fuel is supplied to the combustion chamber by a turbo pump where it is ignited and here the proportion of fuel and oxidiser plays an important part. This is different than any other engine, like in solid engine the solid fuel grain profile is very important or say in hypergolic type the mixing itself will ignite the fuel.
It is very difficult to master this technology as very complex issues are involved in developing the insulation to keep the liquid oxygen and liquid hydrogen at their low temperatures so they should not boil off, their movement from storage tank to combustion chamber, mixing of fuel and oxidizer in right proportion and designing the nozzle cooling system etc.
ISRO called off its August 19, 2013 launch 75 minutes before the lift-off because of the leakage in second stage which is a liquid stage. After that complete vehicle was dismantled and all stages are new including four strap-on booster motors. Also it is using a new propellant tank in the second stage, made of an aluminium alloy different from the one used in August. Earlier in 2006 and 2010, two continues launches were failed so this time there are high hopes.
As we have discussed earlier because of cryogenic engine’s capability, it is much desired to master this sophisticated technology. So there is no need to explain the importance of various communication, weather forecasting and spy satellites and the role played by space programmes in socioeconomic and technological development. The successful launch of GSLV with indigenous cryogenic engine will now provide a boost to Indian space launch programme as now we need not to be dependent on foreign launch vehicles to park our satellites in higher orbits or say parking heavier satellites. These days space is a very important commercial sector also, as after mastering this technology it will help India in projecting itself in international market as a provider of viable and cost effective satellite launch facilities to other countries. Therefore, it will also play an important role in strategic fields as the matter is about mastering the high-end rocket technologies. Subsequently after two successful launches it can be used for Chandrayaan-2 mission. Mrs. Rajeswari Pillai Rajagopalan, who is a well known researcher in areas of space and security, sees this attempt as very significant both from the commercial and strategic perspectives.
As India has already proven its iron in other scientific projects including Mars Mission and Chandrayaan-1, and also the cost effectiveness of its projects is worth mentioning. Undoubtedly India is a big player in space field, generally on global horizon, and particularly in Asia with others like China and Japan. Thus by providing the cost effective and reliable services India can tap the Asian and African space market, which are looking towards India on this front.
It took plenty of time to India for reaching this stage of cryogenic development and lots of hard work by thousands of scientists and engineers. Initially Russia provided these engines for GSLV’s but due to international sanctions (specially pressure from United States) they were further denied to India. Even there are many reports which show the dubious character of international powers which never wanted India to have this technology with possible strategic warfare applications. One of the widely recognized international columnist Mr. Rakesh Krishnan Simha has written in detail how the Indian cryogenic team was systematically targeted.
Remember, we have successfully developed the technology which was once denied to us and message is quite clear to the superpowers !!