“Dhanush” weighs 700 Kg more than the 155mm/39 Calibre BOFORS and has an 877mm longer barrel. It has a larger chamber volume of 23 liters as compared to 19 liters of the BOFORS.

Some of the important functional differences and the underlying technologies are as under :

What makes this test-firing of the K-4 missile more significant is the fact that a recent launch of the missile, conducted from a submerged platform in December 2017, had ended in a failure. The launch was not successful due to “a failure in the missile’s ignition following its ejection from the submerged pontoon.”

SLBMs are test-fired from submerged platforms not only to collect data to analyse its performance, but also to ensure safety. A failed launch from an active ballistic missile submarine would cause massive damage to its hull.

Developmental testing of the missile, which has an estimated maximum range of 3,500 kilometers and can be fitted with a 2,000-kilogram sub-kiloton nuclear or conventional payload, began in 2010.

The K-4 was last successfully test fired in full  operational configuration from India’s first domestically developed and built nuclear-powered ballistic missile submarine (SSBN), the INS Arihant, in April 2016. Notably, the K-4 has been tested using depressed trajectories.

The INS Arihant, the first-of-class of a planned fleet of four to five SSBNs based on the Russian Project 971 Akula I-class nuclear-powered attack submarine (SSN), has been designed to carry up to four K4s or 12 K-15 (B-05) short-range ballistic missiles (SLBM).

With the 3,500-km range K-4, INS Arihant and future SSBNs will be able to target parts of China, including Beijing, and all of Pakistan, from the northern parts of the Bay of Bengal. Not ideal, but better than the K-15.

Given India’s position of ‘No-First-Use’ (NFU) in launching nuclear weapons, the SSBN is the most dependable platform for a second-strike. Because they are powered by nuclear reactors, these submarines can stay underwater indefinitely without the adversary detecting it. The other two platforms — land based and air launched are far easier to detect.

The Advanced Technology Project (ATV) began in the 1980s and the first of them, Arihant, was launched in 2009. Since then it underwent extensive sea trials and the reactor on board went critical in 2013. In 1998, India conducted nuclear tests under Phokran-II and in 2003, declared its nuclear doctrine based on credible minimum deterrence and an NFU policy while reserving the right of massive retaliation if struck with nuclear weapons first.

Given the  Arihant’s primary role as a technology demonstrator, it will likely take the Indian Navy at least until 2021–when the second Arihant-class SSBN the future INS Arihant (originally assumed to be named Aridhaman) is set to enter service — to achieve an operational long-range nuclear strike capability.

For a credible at-sea deterrence, a country’s SSBNs must be capable of, among other things, targeting population and industrial centres of the adversary. In India’s case, this means that the Indian Navy’s SSBNs must be capable of holding at risk cities not only in Pakistan but also in the Chinese mainland.

With the K-15’s 750-km range, targeting Pakistani cities would be possible only from the Arabian Sea, which lowers down the area the Pakistan Navy would have to keep watch over if it was trying to locate an Indian SSBN. This becomes more problematic when one factors in the fact that India has only one SSBN as of now.

Cities in the Chinese mainland would remain outside the range of the missile even if the boat was at the north-eastern edge of the Bay of Bengal. Therefore, in the event of a crisis with Beijing, New Delhi would not have the option of threatening a nuclear attack on a target of consequence in China. (Theoretically, the SSBN can reach closer to China to make up for the short-range of the missile, but it will be at an increased risk of detection or worse — an attack).

Therefore, India may have operationalised its triad, but the naval leg or the at-sea deterrent is not credible given the limited range of the missile it uses.

The DRDO, reports say, is already working on 5,000-km range K-5 and 6,000-km range K-6 SLBMs.

In 2004, The cost of the project was revised to Rs.2839.00 crore with PDC of December 2009. Almost Rs 2100 crore have been spent so far.

The Comptroller and Auditor General (CAG) in its 2010-11 report said that Rs 1,892 crores had been spent over two decades on the project, but the country ended up buying General Electric (GE) engines at a cost of Rs 883 crore to power the LCAs.

The project had overshot its budget by 642 per cent without any perceptible results.The project underwent five revisions of cost, and saw a 1,013 per cent rise in its foreign exchange element since inception.

The CAG report had criticised Gas Turbine Research Establishment (GTRE) for having finally opted for a joint venture (JV) with a foreign partner, when the purpose of the Kaveri project was to indigenously develop a high performance jet engine for use on fighters.

Kaveri engine (K-9) was flight tested for the first time on November 3, 2010 by DRDO during the Flying Test Bed (FTB) trials (on board IL-76 aircraft) at Gromov Flight Research Institute (GFRI), Moscow, Russia.

The engine remains under development but has been dropped as a prospective power plant for the LCA. It is now a technology demonstrator engine for the LCA. A dry thrust only variant of the Kaveri maybe used to power the Indian Unmanned Combat Aerial Vehicle (UCAV). Also, more into the future, the Kaveri could be developed as the K-10 with the help of a foreign collaborator to power the Advanced Medium Combat Aircraft (AMCA).

Reasons for Non-completion

The following are some of the major reasons for non-completion of project within the time-schedule (as stated by defence minister Manohar Parrikar in Parliament on 30 July 2015):

• Technological difficulties faced during development due to complexities of engine system.
• Non-availability of raw materials/ critical components.
• Lack of infrastructure/ manufacturing/ test facilities within the country.
• Non-availability of skilled/ technical manpower in the field of aero-engine technology.
• Increase in scope during development.

Core Technologies

DRDO hasnot been successful so far in developing the nickel and cobalt superalloys for the Kaveri turbine capable of withstanding temperatures of 1,600^oC without warping.

Shaping the alloys into engine parts is an equal challenge. GTRE has learned how to make "directionally solidified" turbine blades, but it has not mastered the making of "single-crystal blades," which are now standard.

Indian Eco-system

The Indian aircraft industry is dominated by one big public sector player – Hindustan Aeronautics Ltd (HAL). It is supported by DRDO’s several establishments and laboratories, notably GTRE and Aircraft Development Authority (ADA) as well as National Aeronautics Laboratory (NAL).

HAL’s engine division has a long history of licenced-production of various imported designs. HAL has been making aero engines under licence from Russia for its MiG-21 and Sukhoi-30 fighters, with Britain's Rolls Royce for Jaguars and advanced jet trainer (AJT) Hawk and Shakti aero engines for its advanced light helicopter (ALH) Dhruv.

Assembling and overhauling are the same thing as designing and developing aeroengines. It has not taken up jet engines for fighters so far.HAL has taken up the design and development of the following aero engines:

2018. 25 kN Turbofan Engine: The design and development of 25 kN Turbo fan Engine are expected to meet the requirement of engines for basic/ advanced military trainers, small business jets and also for large UAV applications. Core-2 engine run was successfully carried out in January 2018. Development effort of this engine will enable the country to achieve self-reliance in design of this class of engines and technologies thus mastered would be further leveraged to design and develop higher thrust engines for modern fighter aircraft.
2019. 1200 KW Turboshaft Engine: HAL has also taken up the design and development of 1200KW Turboshaft engine which would be used as power plant for three to six-ton category helicopters. HTSE-1200 engine technology demonstrator is assembled and inaugural test run successfully carried out on February 12, 2018. Maximum speed archived so far is 76% of the RPM. Engine light up under hot and cold conditions was successful.

Until 1991, private companies were not permitted to operate in the aircraft industry. HAL has grown but being government-owned and run, it has suffered from the ills of bureaucracy and reliance on government funds and orders.

The mistake was that world over aircraft were designed around a proven engine. The user would first decide on the class of the fighter, say 10 or 15 tons and select a suitable, tested and reliable engine with the required thrust and then design the airframe around it with weight to spare and space to cater for later developments. Our designers placed the cart before the horse - they went about designing the plane with no suitable engine in mind.

In the 1960s, the very successful 'Sabre killer' Gnat was inducted into the IAF. It was powered by a Rolls Royce Orpheus 703 engine with dry thrust of 20.9 kN (??). Rolls Royce was also developing an improved version of the engine that would provide a thrust of 35.6 kN to power the improved Gnat for the RAF. When the RAF decided not to go for the improved Gnat, the Rolls Royce project was also in limbo. Rolls Royce offered to jointly develop it with India for the HF-24 for a reported cost of $3 mn. This option was rejected. Meanwhile, the Eqyptian effort to produce a suitable engine for the HF-24 Marut failed. India looked at the Russian Tumansky engine, which was suitable, but rejected it on flimsy grounds.

With no other choice, the HF-24 Marut got the Orpheus 703, which was being assembled in India for the Gnat. It was the death knell of the HF-24 Marut. It remained underpowered and was phased out, all because of lack of synergy and understanding between the military, bureaucracy, politicians and scientists.

The plan to build six new submarines as part of Project 75I(I for India) is a follow-on of the Project 75 Kalvari-class submarines. Under this project, the Indian Navy intends to acquire six diesel-electric submarines, which will also feature advanced air-independent propulsion systems to enable them to stay submerged for longer duration and substantially increase their operational range.

Project 75I is based on the Scorpene-class submarine designed by the French Company Naval Group that could be built in India by Mazagon Dock in Mumbai, India, using the technology and training provided by Naval Group.

The submarines in the P75I Scorpene-class are powered by conventional diesel-electric propulsion systems. The last two submarines are expected to be equipped with AIP technology, which is developed by DRDO to provide long-range and extended endurance capabilities. The submarines are also installed with batteries.

The P75I Scorpene class submarines will be armed with six torpedo launching tubes, 18 heavy weapons, tube-launched MBDA SM-39 Exocet anti-ship missiles and precision-guided weapons. The weapons are carried in weapon launching tubes and can be easily reloaded at sea.

The initial Expression of Interest to foreign vendors willing to take part in the mega programme, the Navy wants the submarines to be equipped with heavy-duty firepower as it wants the boats to have at least 12 Land Attack Cruise Missiles (LACM) along with Anti-Ship cruise missiles (ASCM). The Navy specified that the submarines should also be able to carry and launch 18 heavyweight torpedoes in the sea. Compared with the Scorpene, the firepower required in the next line of submarines is many times more than what is being put on the Scorpenes which have the heavyweight torpedoes and the Exocet surface to surface missiles as their main weapons.

It is necessary for the P-75I programme to make concrete contribution to submarine building capacity in India but in a way that also helps us towards indigenisation as has been achieved for nuclear submarines.

The army has launched a hunt for image intensifier and thermal imaging-based night sights for a total of 56,000 7.62X51 mm assault rifles, according to the RFIs. Image intensifier-based night sights amplify ambient light for detecting targets, while thermal imaging sights spot targets by their body heat.The army wants 40,000 image intensifier-based night sights and 16,000 thermal imaging-based night sights.

This is part of the Army’s effort to make up huge deficiencies in night fighting capabilities

Requirements of NVDs and EO Devices

An essential requirement is for the soldier to use his weapon sight for surveillance. The power source for the II sights should preferably provide for continuous surveillance, whereas, for the TI-based sights power would be required for confirmatory and not continuous role. Detachment of soldiers should also be able to estimate range, wind speed and altitude.

Recent Developments

* SIG 716 assault rifles are under delivery. They require reflex, telescopic, image intensifier (II) and thermal imaging (TI) sights.

* Reflex, telescopic, II and TI scopes are required for 5.56x45mm carbines and 7.62x51mm light machine guns (LMG), whose procurement process through fast track procedure (FTP) is under progress.

* Telescopic sights and night scopes are required for balance quantity of LMGs for which Request for Proposals (RfP) has been issued.

* Night scopes are required for .338 sniper rifles, whose procurement process is under progress.

* Acceptance of necessity (AoN) for telescopic sights for assault rifles and thermal sights for medium machine guns has been granted by the Defence Acquisition Council.

* A case for night sights (TI) for ASG 30 automatic grenade launcher is at the pore-AoN stage.

* A case for TI sights for 84mm rocket launcher (RL) is at the pre-AoN stage.

Requirements for Small Arms

In the case of close quarter battle (CQB) weapons, ie, for ranges under 300 metres, the Infantry is looking for reflex sights with magnifier (3x) for employment during day and II-based 'clip on' sights for night fighting (with Figure of Merit (FOM) > 1700).

For longer range weapons, ie 300-800 metres, the Infantry is looking for telescopic sights (4x or 5x) for daylight employment and TI sights 9'clip on' or standalone) for night fighting. Specifications should be FPA minimum 640x480 pixels and pitch 17/12 microns.

For support weapons like LMGs, MMGs, etc, the Infantry is looking for Integrated Day (CMOS) & Night (TI) sights, ballistic computers, GPs, Laser range finder and DMC, requiring minimum or no modification to the weapon to bring it into use.

Night Fighting Enablement Road Map

Passive night sights (PNS) for small arms (SA) which are in service have a FOM of 950. Their maximum range is 200 metres with moonlight conditions. For SWs in use CSWS/ Darshak is available????. There are bulky and Data Record??? For surveillance, the PNVGs and PNVBs which are in service have poor ergonomics and performance. The HHTIs in use are bulky and noisy.

In the short term, Infantry wants to increase the scales of TI and II devices by 10 times; go for increase in the FOM of short-range II devices to 1700 and of long range TI devices to 12 microns. For SW too, it would like to go scale the TI devices and opt for 'clip on' and indigenous FCS. In the case of surveillance devices, it wants substantial increase in their scaling, besides silent and light HHTI (UC), integrated LRF, GPS and DMC.

In the long term, the as far as night sights go, Infantry plans to review the QRs (min 2200 ??), explore SMART sights and increase the level of indigenisation through R&D. For SW, Infantry wants customised solutions through R&D, aiming for development of network integration and use of artificial intelligence (AI). For surveillance devices, Infantry wants industry to provide data transmission and networking options as well as AI enhanced devices.

Overall Requirements

The infantry's requirements, based on scaling of devices is huge. The following table shows the enormity of the requirements and the numbers for which procurement action has been initiated:

Night Weapon Sights

Type                      Required             Procurement Initiated

Carbine (II)         130,000                  40,000

Rifle (TI)               90,000                   19,000

Rifle (II)               180,000                 40,000

LMG (TI)              27,000                   5,000

LMG (II)               12,000                   2,300

RL (TI)                 15,000                   3,500

MMG (TI)            5,000                     1,500

EO Devices

PNVG (II)             100,000 17,000

PNVB (II)             30,000                   20,000

HHTI (C)               8,000                   7,500

HHTI (UC)            12,000                   0

Israel, Germany, Spain are among the other users of 4th-generation Spike LR ATGM system. China has developed a 3rd-generation ATGM System while Pakistan does not have such a capability yet.