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Dr PV Venkitakrishnan, Distinguished Scientist & Director,
“With the recent space reforms, more private players and entrepreneurs are expected to take up launch vehicle and satellite manufacturing. The aerospace welding market is bound to expand multi fold, compared to the current state.”
Dr PV Venkitakrishnan,
Distinguished Scientist & Director,
Capacity Building Program Office,
ISRO Headquarters, Bangalore
Indian Space Research Organization, formed in 1969, has become one of the six largest space agencies in the world. How has been ISRO’s journey so far?
First of all, let me thank WeldFab for giving me this opportunity to interact with welding professionals and I wish all the readers a very happy new year. Coming to ISRO’s journey so far, as it can be seen, it is so open and transparent, I would like to rate it as fabulous, fantastic, inspiring and enjoying. Starting from sounding rockets for meteorological purposes, we have today reached a level of maturity in space technology for handling interplanetary missions and human-in-space program. Hope you will all agree that ISRO has been the fame of India in the international scene, when it comes to science and technology.
You are a Distinguished Scientist, Director, CBPO, ISRO HQ. Can you share some of the interesting anecdotes while working with ISRO?
One important thing I would like to note here is that ISRO has energised, motivated and inspired any institution or industry, with whom ISRO has worked, to the same level that of ISRO. The sense of ownership among the employees is very famous and ISRO has been able to impart the same level of pride and ownership for its partners also, with whom ISRO is associated with. Two incidents come to mind in this context.
I don’t remember the exact year, but it was just one day prior to Vinayaka Chaturthi. The entire ISRO team, led by me, was in Walchandnagar Industries Ltd. [WIL], Pune for conducting the proof pressure test of Flex Nozzle Control (FNC) tank of GSLV MkIII launch vehicle. The test was scheduled during daytime and we started the activities as early as 5:30 in morning, keeping in mind the uncertainties of test, which was being done for the first time. The test was slated to be over by 3 pm. Then, we found that the pressure was not building up. It was supposed to be just above 400 bars. By the time we found the anomaly, had done the troubleshooting and rectified it, completed the test successfully, it was around early morning next day. Even after being Vinayaka Chaturthi, a grand festival day in the whole of Maharashtra, the entire employees of WIL cooperated whole-heartedly, without any murmur or unhappiness. They all mentioned that we are working for the country and working for ISRO. When you all are here, we are happy to contribute. We will be here to see that it is done successfully. It was assuring to note that the entire team was prepared to stay back, whole next day Vianyaka Chaturthi also, if required.
Another incident of similar nature, which I would like to narrate here, is the heat treatment of L40 aluminium nose caps of GSLV MkII launch vehicle. This was carried out on August 15th (year I don’t remember here). This was done in a small scale industry – Ramakrishna Engg Works, Chennai. The nose cap made of aluminium was to be heat treated to a specific temperature, and to be quenched in water, in a drop tank furnace, within 15 sec quench delay. The industry was not having a drop tank furnace and we created a water tank very near to the furnace and rehearsed with a dummy several times to see that the test article was immersed in water within 15 seconds. The whole exercise went continuously for 3 days and the actual heat treatment/quenching was finally conducted on August 15th. The entire industry and employees whole-heartedly and joyfully participated in the whole process and in realizing he component successfully,
These two incidents I just narrated here are some of the many events, which just came to mind right now, that reinforce the statement I made above, to what level ISRO motivates and inspires their counterparts.
You had been the Deputy Project Director for materials and manufacturing in GSLV Mk III project in VSSC from 2002. Please elaborate more on the project? How has been your experience?
GSLV MkIII was the 3rd generation launch vehicle of ISRO, enabling a quantum jump in payload capability to upto 4 tonnes. The diameter of the core stage itself is 4m and we were not having machining facility, rolling facility of 4m class in the country. Right from the scratch, industry infrastructure creation had to be addressed and we could complete the project within 10 years time frame. This has been a thrilling experience in terms of new technologies and speed of execution.
From 2010 onwards, you were working as Deputy Director (Materials and Manufacturing Entity) in Liquid Propulsions Systems Centre (LPSC), ISRO, Trivandrum, Kerala. LPSC is responsible for design, development and system engineering of high performance space propulsion systems employing earth storable and cryogenic propellants for ISRO’s launch vehicles and satellites. Can you elaborate on some of the latest major developments into this section?
The most challenging job I came across in LPSC is realisation of cryogenic engines for GSLV MKIII as well as MkII launch vehicles, along with stepping up the production rate of earth storable liquid engines for 2nd and 4th stage of PSLV. We could successfully accomplish this and demonstrated through successful launch of GSLV MkII and MkIII vehicles.
Indigenisation of almost all alloys used in cryogenic stages, including the strategic Cu-Cr-Zr-Ti alloy through NFTDC, Hyderabad was accomplished within a short span of 5 years. Looking back, it gives me immense satisfaction to be the founding deputy director of MME, LPSC.
You were leading the Materials and Mechanical Entity of VIkram Sarabhai Space Centre [VSSC] as its Deputy Director, since 2015. Firstly, can you brief us more on VSSC? What type of mega projects has been undertaken?
Vikram Sarabhai Space Centre is the lead centre of ISRO for launch vehicles. The centre deals with design and development of various launch vehicles. It is situated in Trivandrum and the centre has so far executed various launch vehicle projects viz. SLV-3, ASLV, PSLV, GSLV MkII and GSLV MkIII, apart from experimental projects like RLV and Air Breathing Propulsion Project [ABPP].
We are keen to understand the kind of projects that you have worked upon?
I am an in-and-out materials and manufacturing professional. I have worked with metallic and non-metallic materials and their manufacturing. I have been associated so far with ASLV, PSLV, GSLV MkII, GSLV MkIII, RLV and ABPP.
What is your say on aerospace welding market?
Now, with the recent space reforms on and hopefully, more private players and entrepreneurs expected to take up launch vehicle and satellite manufacturing, the aerospace welding market is bound to expand multi fold, compared to the current state.
Also, share your view on the current aerospace materials and manufacturing segment in India?
As regards to aerospace materials, almost 90% of metallic materials are indigenised. When it comes to composites, carbon fibre still continues to be imported. With a stiff competition expected in future, we will have to still reduce our inert mass of launch vehicle, which will force us to rely on composite more and more. In this context, carbon fibre indigenisation assumes topmost priority. The only problem so far has been the low volume consumption of metallic materials. With the opening up of space sector and new players expected to step-in, this volume hopefully will increase to a level, where industry will be comfortable.
Regarding manufacturing, Indian industry has got all the ingredients and technical know-how and competency to make India the aerospace manufacturing hub of the world. The new reforms will accelerate this and take us to numero uno position.
What are the major challenges that the aerospace industry in India faces?
New and unconventional technologies, customised machine & processes and low volume production.
Is the availability of skilled manpower an add-on challenge? If yes, elaborate?
Definitely. Skills required for aerospace manufacturing – welding, sheet metal machining, surface treatment or interpretation/evaluation of non-destructive test results are all specialised. Continuous updation and sustenance of skill is warranted in all these areas. Erosion of trained manpower in these areas is also an added challenge. Again, now with the new reforms, requirement of skilled manpower will be multifold.
What is your say on the involvement of welding activities into the successful completion of any project?
All pressure vessels, including booster motor cases, propellant tanks, depends on the quality of defect-free weld achieved. All these welding are carried out on special materials and alloys and any rejection will prove to be very costly. Also, cryogenic engines are all welded, monolithic construction and rejection at any level on the value-added components/subsystems will prove to be very costly. This shows the importance of skilled welding in aerospace manufacturing and fabrication. Right from the design of weld joints, testing, qualification and evaluation of repair scheme, my team is involved. We have all types of metal joining processes like DCSP –TIG welding, pulsed TIG arc welding, MIG welding, electron beam welding, laser welding, ultrasonic welding, sheet metal arc welding, brazing and soldering in our launch vehicles manufacturing process. Also, we introduced friction welding and friction stir welding, apart from diffusion bonding. To be frank, almost all metal joining processes are used in the realization of a launch vehicle, including diffusion bonding and explosive welding. We also use all types of joints, like butt, lap, fillet weld, etc.
Can your brief us on a project along with welding challenges it faced and how was it resolved?
The most challenging work was the welding of M250 maraging steel. This is a brittle material, which requires meeting of an extra parameter for fracture toughness, apart from other mechanical properties. This calls for almost no inclusion, no porosity welds, which continue to be a challenge, even now. Another important challenge we could introduce was to migrate to DCSP for deep penetration to reduce number of passes as compared to DCRP in Aluminium Alloy AA2219 propellant tank welding of Cryogenic and liquid stages. 9-pass welding of thick Maraging steel plate for GSLV MKIII FNC tank was also a challenge with very stringent requirement of inter-pass cleaning.
Also, 11-pass welding of 15-5PH material for FNC tank was a challenge. Another important process change was migrating to Friction Stir welding in propellant tanks to increase the efficiency of welding, thereby reducing the joint thickness, enabling weight reduction.
What is ISRO’s effort towards the skill development of welders?
We are currently in the process of initiating a skill development training program for aerospace quality welders under the aegis of Aerospace and Aviation Skill Development Council [AASDC], under Ministry of Skill Development. This is contemplated to be a fully residential program for about 4 weeks duration.
National Institute of technology Karnataka, Surathkal and ISRO has recently signed an MOU to carry out advanced joint R&D activities in the area of space technology applications at NIT-K Surathkal. Please elaborate. What has been the motive for partnership?
NIT-K is one among the six Regional Academic Centres for Space [RAC-S]. NIT-K is the regional centre for southern region. Other centres being – NIT Agartala for North-east, NIT Jaipur for North, NIT Patna for East, IT-BHU for Central and NIT Nagpur for West. Here joint research activities for space technology, including advanced welding, will be taken up at these centres, with the help of academia, faculty and students.
‘Safety at site’ is one of the key factors. What are your efforts towards safety?
ISRO gives utmost importance for safety and we leave no stone unturned when it comes to ultimate safety. Safety of the equipment, safety of test stands, safety of launch station, safety of gas storage tanks, safety during transportation, safety of human beings during explosive handling – are all separate specialised areas and handled by qualified personnel in safety engineering. I myself was heading the Centre Safety Committee of VSSC.
According to you, how would be the scenario after Covid-19 situation, especially for space industry.
Post Covid situation, as being pointed out by everybody, has set new normals for ISRO also. The recent launch of PSLV C49 is a sterling example. The entire checkout and control was carried out remotely from VSSC and URSC, instead of at Sriharikota. This has led to development of new technologies of remote control and has considerably reduced movement of people and resources. Even, launch campaign to some extent and inspection after integration was carried out remotely this time. All our review mechanisms were done on virtual platforms.
What has been the impact of lockdown on ISRO?
As in any other front, the sudden unexpected lockdown impacted ISRO also for a brief period. This is due to impact of lockdown of industries also, which supply component subsystems to ISRO. Also, movement of hardware got affected due to lockdown. As usual, ISRO has utilised this time period fruitfully to migrate, create remote/virtual control centres and checkout systems and also tested/qualified it. The satellite tracking as well as control commands were also remotely executed first time during this period. Now that the systems are established, following new normals, we are back to the scene actively.
We have known that ISRO staff has contributed Rs 5 Cr to PM fund. Besides, the scientists are also researching on best methods to provide essential medical devices that will help treat Covid-19 patients. On behalf of the nation, I would like to thank ISRO for the support. Please elaborate more on ISRO’s role in this situation.
Apart from designing customised masks, production and distribution of sanitizers in large scale, contributing to design of more economical ventilators, ISRO also contributed by distributing Covid test kiosks to healthcare workers.
What about the demand and supply scenario, globally? Due to the outbreak of Covid-19, most of the sectors will face a shortage of spare parts, especially those imported. Will this scenario also affect ISRO? Explain. How can we overcome this mega challenge?
As expected, shortage of any imported material, will definitely impact our activities. Taking this as a challenge, ISRO is more rigorously pursuing indigenisation in full thrust. The accelerated thrust in this area is expected to yield results in a very short span of time. ATHMA NIRBHAR ISRO and Baharat is given full thrust.
Any expectations from the government?
Government has clearly been supporting scientists and scientific activities in the country. Post-Covid, government has been so considerate to ISRO. Being involved in high risk activity, which is very capital intensive, government support is very crucial and we are always able to get it.
I hope this interview has given some insight into activities of ISRO as well as importance of welding in aerospace manufacturing of Launch Vehicles and Satellites. Hope the post Covid-19 scenario will catapult India into a higher orbit with a much accelerated velocity. We the generation will be definitely known as successful survivors of these testing times and fruitfully utilising the opportunities thrown by the pandemic to our advantage. I am happy that as usual, ISRO has been leading this by launching PSLV even during the tough times, with innovative technologies. Thank you and wishing all safe times ahead!