ISRO develops cryogenic engine
After two decades of development, India developed the cryogenic technology, giving it the much-needed capability to launch medium-sized satellites in a geostationary orbit, and joined an exclusive club of six nations.
When it flew, the GSLV put the satellite into orbit with a precision never possible with the Russian engines. We take a look at the difficulties that ISRO faced while developing the engine:
It all began in 1987
The year was 1987. V Gnanagandhi, head of the cryogenic engine project at ISRO, wanted to set up a high-pressure hydrogen plant in Mahendragiri near Thiruvanathapuram. But an official from the supplier of the machinery, a German company called Messers Grieshem, suddenly threw a spanner in the works. 'There are snakes and elephants on the roads in India,' he told them. 'How can I come there?'
Gnanagandhi reached a compromise with the Grieshem executive. He need come only as far as Mumbai; the entire ISRO team would meet him there. He agreed. The German—his name is now forgotten—agreed to sell the machinery, but was also inquisitive. 'Why do you need a high-pressure hydrogen facility?' he asked. 'We are using it to launch rockets,' came the answer. 'You cannot just fill an engine tank with high-pressure hydrogen,' he told the ISRO team. 'It will evaporate in no time.' The ISRO engineers, thus, learned a thing or two about dealing with hydrogen at high pressure.
What ISRO engineers learnt
On that day in 1987, at their Mumbai Guest House, ISRO engineers, led by Gnanagandhi, were taught a thing or two about hydrogen under pressure by their German guest.
Brought into the nascent cryogenic engine team in 1984, Gnanagandhi had begun his job with clean slate. He had not even heard about the cryogenic engine. He didn't know how to get liquid oxygen or liquid hydrogen, let alone how to use them in an engine. But he learned quickly, set up the facilities, and made a one-tonne prototype engine by 1988. It blew up during a test.
Cryogenic engines absolutely essential
Cryogenic engines were absolutely essential to put satellites in geostationary orbit, but the technology was difficult and a closely guarded secret. India had offers of engines.
US firm General Dynamics offered first at a high price, and so did the French. It was then that Russia, which was going through difficult times, offered it at a reasonable price. India signed a deal in 1991 for two engines and the technology.
Everything looked good, but soon wasn't. The Americans pressurised the Russians into reneging on the deal, saying its engines will be used for nuclear missiles.
ISRO got seven engines
Eventually ISRO got seven engines. However, flying them was not a simple matter as there were no data about their performance. The engines that ISRO got hadn't been flown yet in any rocket.
ISRO engineers discovered they had to work hard to make the engines fly in their launch vehicle
Developing the technology
If flying the Russian engines was hard, copying the engine design was harder. The Russians had designed these engines in the 1960s but not flown them, probably because they were still not flight ready.
Moreover, they used a technology— called stage combustion—that was efficient but difficult. It made the engine a bit heavy but gave the highest efficiencies for a specific amount of propellant. The indigenous engines had to be exactly like the Russian engines: the GSLV has already been planned based on them.
Cryogenic Upper Stage project
The Indian government gave a formal approval to the Cryogenic Upper Stage (CUS) project in 1994. The budget was Rs 300 crore. ISRO then made a key decision quite in keeping with its tradition: involve the private industry from the beginning.
The two major partners were Godrej and the MTAR Technologies. Godrej set up the rotary vacuum brazing facility in Mumbai. Brazing was a key and difficult technology, and setting up the facility took more than a year. MTAR made the turbo pump and some other components.
Few simple facts
The sophistication of the cryogenic engine would be obvious from a few simple facts. The liquid hydrogen is kept at -253 degree centigrade. The turbo pump operates at 500 degree centigrade and rotates 40,000 times a minute. The combustion temperature is around 3,000 degree centigrade.
The pressure inside the combustion chamber is 60 times the atmospheric pressure. The chamber wall has to withstand the high pressure and temperature. No material can withstand a temperature of 3,000 degree centigrade, and so the combustion chamber wall has to be cooled.
Lift Off
ISRO's cryogenic team made the first 7.5-tonne engine in 2000. It blew up while being tested. The hydrogen valve had prematurely closed, affecting the oxygenhydrogen ratio in the combustion chamber.
They succeeded finally in 2002. The indigenous cryogenic engine was qualified in 2003. It took another four years to integrate it with the GSLV. But the first flight failed in 2010, as the engine shut down three seconds after ignition.
Thorough review
ISRO then conducted a thorough review of the entire GSLV project. For the cryogenic engine, special vacuum testing facilities were created at Mahendragiri. By 2013 end, every likely cause of failure was looked into.
A few days before the GSLV flew on January 5, ISRO officials conducted a review meeting to clear the vehicle for launch. Such meetings usually take several hours. This one ended in 45 minutes. Every possibility had been analysed, and project leaders were quietly confident.
To view the pictures, kindly visit the below link
Thorough review - Challenges ISRO faced while developing cryogenic engine | The Economic Times
After two decades of development, India developed the cryogenic technology, giving it the much-needed capability to launch medium-sized satellites in a geostationary orbit, and joined an exclusive club of six nations.
When it flew, the GSLV put the satellite into orbit with a precision never possible with the Russian engines. We take a look at the difficulties that ISRO faced while developing the engine:
It all began in 1987
The year was 1987. V Gnanagandhi, head of the cryogenic engine project at ISRO, wanted to set up a high-pressure hydrogen plant in Mahendragiri near Thiruvanathapuram. But an official from the supplier of the machinery, a German company called Messers Grieshem, suddenly threw a spanner in the works. 'There are snakes and elephants on the roads in India,' he told them. 'How can I come there?'
Gnanagandhi reached a compromise with the Grieshem executive. He need come only as far as Mumbai; the entire ISRO team would meet him there. He agreed. The German—his name is now forgotten—agreed to sell the machinery, but was also inquisitive. 'Why do you need a high-pressure hydrogen facility?' he asked. 'We are using it to launch rockets,' came the answer. 'You cannot just fill an engine tank with high-pressure hydrogen,' he told the ISRO team. 'It will evaporate in no time.' The ISRO engineers, thus, learned a thing or two about dealing with hydrogen at high pressure.
What ISRO engineers learnt
On that day in 1987, at their Mumbai Guest House, ISRO engineers, led by Gnanagandhi, were taught a thing or two about hydrogen under pressure by their German guest.
Brought into the nascent cryogenic engine team in 1984, Gnanagandhi had begun his job with clean slate. He had not even heard about the cryogenic engine. He didn't know how to get liquid oxygen or liquid hydrogen, let alone how to use them in an engine. But he learned quickly, set up the facilities, and made a one-tonne prototype engine by 1988. It blew up during a test.
Cryogenic engines absolutely essential
Cryogenic engines were absolutely essential to put satellites in geostationary orbit, but the technology was difficult and a closely guarded secret. India had offers of engines.
US firm General Dynamics offered first at a high price, and so did the French. It was then that Russia, which was going through difficult times, offered it at a reasonable price. India signed a deal in 1991 for two engines and the technology.
Everything looked good, but soon wasn't. The Americans pressurised the Russians into reneging on the deal, saying its engines will be used for nuclear missiles.
ISRO got seven engines
Eventually ISRO got seven engines. However, flying them was not a simple matter as there were no data about their performance. The engines that ISRO got hadn't been flown yet in any rocket.
ISRO engineers discovered they had to work hard to make the engines fly in their launch vehicle
Developing the technology
If flying the Russian engines was hard, copying the engine design was harder. The Russians had designed these engines in the 1960s but not flown them, probably because they were still not flight ready.
Moreover, they used a technology— called stage combustion—that was efficient but difficult. It made the engine a bit heavy but gave the highest efficiencies for a specific amount of propellant. The indigenous engines had to be exactly like the Russian engines: the GSLV has already been planned based on them.
Cryogenic Upper Stage project
The Indian government gave a formal approval to the Cryogenic Upper Stage (CUS) project in 1994. The budget was Rs 300 crore. ISRO then made a key decision quite in keeping with its tradition: involve the private industry from the beginning.
The two major partners were Godrej and the MTAR Technologies. Godrej set up the rotary vacuum brazing facility in Mumbai. Brazing was a key and difficult technology, and setting up the facility took more than a year. MTAR made the turbo pump and some other components.
Few simple facts
The sophistication of the cryogenic engine would be obvious from a few simple facts. The liquid hydrogen is kept at -253 degree centigrade. The turbo pump operates at 500 degree centigrade and rotates 40,000 times a minute. The combustion temperature is around 3,000 degree centigrade.
The pressure inside the combustion chamber is 60 times the atmospheric pressure. The chamber wall has to withstand the high pressure and temperature. No material can withstand a temperature of 3,000 degree centigrade, and so the combustion chamber wall has to be cooled.
Lift Off
ISRO's cryogenic team made the first 7.5-tonne engine in 2000. It blew up while being tested. The hydrogen valve had prematurely closed, affecting the oxygenhydrogen ratio in the combustion chamber.
They succeeded finally in 2002. The indigenous cryogenic engine was qualified in 2003. It took another four years to integrate it with the GSLV. But the first flight failed in 2010, as the engine shut down three seconds after ignition.
Thorough review
ISRO then conducted a thorough review of the entire GSLV project. For the cryogenic engine, special vacuum testing facilities were created at Mahendragiri. By 2013 end, every likely cause of failure was looked into.
A few days before the GSLV flew on January 5, ISRO officials conducted a review meeting to clear the vehicle for launch. Such meetings usually take several hours. This one ended in 45 minutes. Every possibility had been analysed, and project leaders were quietly confident.
To view the pictures, kindly visit the below link
Thorough review - Challenges ISRO faced while developing cryogenic engine | The Economic Times
