By R Anil Kumar
‘Samudrayaan’ is a project under the Deep Ocean Mission of the Ministry of Earth Sciences (MoES) which envisages the development of MATSYA-6000, a submersible spherical vessel to carry humans into the sea up to a depth of 6km.
Bengaluru. In a major milestone for India’s Deep Ocean Mission, the Indian Space Research Organisation (ISRO) has successfully developed the personnel sphere for the submersible vessel MATSYA-6000, designed to carry humans up to 6,000 meters below the ocean surface.
India now is a step closer to realising its first crewed deep ocean exploration. Scientists from the National Institute of Ocean Technology (NIOT) and the Indian Space Research Organisation (ISRO) completed a critical welding process on the Matsya-6000—the submersible that will carry out India’s ‘Samudrayaan’ mission.
This human-occupied vehicle (HOV) is part of the ‘Samudrayaan’ project overseen by the Ministry of Earth Sciences (MoES) and aims to strengthen India’s capabilities in deep-sea exploration.
The National Institute of Ocean Technology (NIOT), under MoES, collaborated with ISRO’s Vikram Sarabhai Space Centre (VSSC) to design and fabricate the spherical crew compartment.
Matsya-6000 is the submersible that is being developed as a manned vehicle to send three humans to a depth of over 6,000 meters below sea level. (Photo: NIOT)
The personnel sphere measures 2.26 metre in diameter and features an 80 millimeter-thick wall made from a titanium alloy, known for its superior strength and corrosion resistance. Engineered to withstand extreme pressures up to 600 bar at temperatures as low as -3C, this pressure hull can safely accommodate a three-member crew at great ocean depths.
The successful welding and rigorous testing of a full-scale 7100 mm-long personnel sphere, welded over 32 minutes, marks a national first.
This achievement positions India among a select few nations with the technological prowess to build deep-sea human habitats.
With this critical component ready, the “Samudrayaan” mission moves closer to launching manned explorations of the deep Indian Ocean, promising advancements in marine research, resource utilisation, and underwater technology development.
Towards development of this Human Occupied Vehicle (HOV), National Institute of Ocean Technology (NIOT), MoES signed a Memorandum of Understanding with Vikram Sarabhai Space Centre (VSSC), ISRO for realizing the spherical vessel.
Design of the personnel sphere along with development of the material for realisation was carried out by VSSC. MATSYA-6000 is a sphere of 2260mm diameter with a wall thickness of 80mm, made out of Titanium alloy (Ti6Al4V – ELI grade) and is expected to withstand an external pressure up to 600bar under low temperature conditions of -3°C. This has the capability to carry a three-member crew into the deep ocean.
Major challenge in realizing the spherical vessel is the development of reliable, high penetration (80-102mm thick) Electron Beam Welding (EBW) process and the high-energy (7.5MeV) X-ray radiography facility for the Non-Destructive Evaluation (NDE), which is essential for the certification of the human-rated product. Certification of the facilities, process and the product are planned to be carried out by a third party.
Liquid Propulsion Systems Centre (LPSC) was responsible for developing the process and infrastructure for the welding process and NDE.
LPSC-Bengaluru had the facility and expertise to carry out welding up to 20mm thick. To meet the high power demand for welding, the EBW machine was augmented from 15kW to 40kW rating along with additional facilities for chemical cleaning and handling equipment for the higher size and mass.
For Non-Destructive Evaluation, the existing X-ray facility in kV range was augmented to 7.5MeV range. Multiple NDE techniques were employed which complement each other in ascertaining weld quality, including Time of Flight Diffraction (TOFD) and Dual Linear Array (DLA) Phased Array Ultrasonic Testing (PAUT).
LPSC developed the welding process through extensive weld trials (nearly 700 trials) for optimizing the process parameters. NDE techniques were established through inspecting artificially created defects and calibration standards were created. The welding procedure specification and weld qualification protocols are getting approved by a third party.
Subsequent to the process development and process optimization, the first welding on the actual hardware and detailed evaluation have been successfully completed. High penetration welding of this scale, i.e. 80mm weld thickness over 7100mm length with 32 minutes of weld duration, was carried out for the first time in the country.
Big step for Samudrayaan as ISRO, NIOT complete key weld on deep-sea submersible after ‘700 trials’
Samudrayaan, which is part of government’s larger Deep Ocean Mission, will send humans to a depth of 6,000 metres. Journey will be undertaken in a spherical submersible vessel, Matsya-6000.
India is a step closer to realising its first crewed deep ocean exploration. Scientists from the National Institute of Ocean Technology (NIOT) and the Indian Space Research Organisation (ISRO) completed a critical welding process on the Matsya-6000—the submersible that will carry out India’s ‘Samudrayaan’ mission.
Samudrayaan, which is part of the government’s larger Deep Ocean Mission, will send humans to a depth of 6,000 metres.
This journey into the ocean’s depths will be undertaken in a spherical submersible vessel, the Matsya-6000, which has a diameter of 2,260 mm and a wall thickness of 80 mm. Its titanium-alloy walls can withstand external pressures up to 600 bar and temperatures as low as -3°C.
On July 23, ISRO, which is developing this crew capsule, announced that it had completed a key weld for this capsule. This is the first time in India that such a thick titanium alloy sphere was welded. It was done using electron beam welding (EBW) technology, which is typically used for spacecraft and nuclear energy components. This was achieved after nearly 700 trials.
“High-penetration welding of this scale—80 mm weld thickness over a length of 7,100 mm with a 32-minute weld duration—was carried out for the first time in the country,” a statement by ISRO read.
This achievement is significant because it is India’s first-ever human-rated deep-sea weld on a titanium sphere, using advanced space-grade technology.
Challenging technology
One of the biggest challenges scientists faced in creating this weld lay in the properties of titanium as a metal. While titanium is known for its strength, it can be difficult to weld.
Its high reactivity with oxygen and nitrogen can cause porosity and embrittlement in the weld.
Another challenge, according to ISRO, was to develop a ‘reliable, high penetration (80-102mm thick) electron beam welding (EBW) process and a high-energy (7.5 (mega-electron volts or MeV) X-ray radiography facility for a non-destructive evaluation (NDE), a method of evaluating the properties of materials, components, or systems without causing damage, which is essential for the certification of the human-rated product.’
One other challenge, according to ISRO, was developing a ‘reliable, high-penetration electron beam welding (EBW) process’ for welds 80–102 mm thick. Additionally, a high-energy X-ray radiography facility with a beam energy of 7.5 mega-electron volts (MeV) had to be established for non-destructive evaluation (NDE), a method of assessing materials or systems without causing damage, essential for certifying the human-rated product.
ISRO’s Liquid Propulsion Systems Centre (LPSC) in Bengaluru developed the process and infrastructure for the welding process and NDE. While the LPSC had the expertise to carry out welding up to 20mm thickness, it augmented the EBW machine from a 15kW rating to 40kW, while also making alterations to the chemical cleaning and handling equipment to accommodate the increased size and mass.
For NDE, the existing X-ray facility in the kV range was augmented to the 7.5 MeV range.
‘Multiple NDE techniques were employed which complement each other in ascertaining weld quality, including Time of Flight Diffraction (TOFD) and Dual Linear Array (DLA) Phased Array Ultrasonic Testing (PAUT),’ the statement read.
SAMUDRAYAAN PROJECT The Samudrayaan project, part of India’s Deep Ocean Mission, aims to develop a manned submersible, MATSYA 6000, to carry three researchers to a depth of 6,000 meters (6 kilometers) for deep-sea exploration.
This project will allow for direct observation and understanding of unexplored deep-sea areas and contribute to the sustainable use of ocean resources.
Here is an explanation on the Samudrayaan project, its goals, and its significance:
Key Objectives:
Deep-sea exploration:
The project will enable the study of deep-sea resources, including minerals, and explore the biodiversity of the unexplored ocean depths.
Technological Advancement:
It will facilitate the development of a manned submersible, MATSYA 6000, designed to withstand the extreme pressure at 6,000 meters.
Blue Economy:
The project supports India’s vision of a “Blue Economy,” promoting sustainable use of ocean resources.
Development and Implementation:
National Institute of Ocean Technology (NIOT):
NIOT, under the Ministry of Earth Sciences, is the nodal agency responsible for designing and developing the MATSYA 6000 submersible.
Deep Ocean Mission:
The Samudrayaan project is a key component of India’s Deep Ocean Mission, which was approved by the Cabinet with a total cost of Rs. 4077 crores for the period 2021-2026.
Collaboration:
The project involves collaboration with organizations like the Vikram Sarabhai Space Centre, ISRO, and international partners for specific aspects like the titanium sphere for the submersible.
Significance:
Scientific Advancement:
The manned submersible allows for direct human observation and intervention in deep-sea environments, which is crucial for scientific research.
Resource Assessment:
It will help in assessing the potential of deep-sea resources, including minerals like polymetallic nodules.
National Pride:
The Samudrayaan project is a significant step towards realizing India’s aspirations in deep-sea exploration and technology.
