The centenary monument at the HEMRL.
A WONDERFUL monument with a plaque reading “HEMRL Centenary Monument – 1908-2008…” occupies the foyer of the High Energy Materials Research Laboratory (HEMRL), Pune. On top of it is a metal sculpture of the chemical structure of China Lake-20, or CL-20, a molecule that can be incorporated into both propellants and explosives. On its sides are wooden models of missiles developed by the Defence Research and Development Organisation (DRDO). Manish Bharadwaj, Scientist, and J.R. Peshave, Technical Officer, at the HEMRL, reading this correspondent’s thoughts, said: “This monument is our pride.”
Everyone at the laboratory, from A. Subhananda Rao, its Director, to the junior-most skilled worker is proud of its 100-year-old heritage. Way back in 1908, the HEMRL began functioning as the Chemical Examiner’s Office at Nainital (now in Uttarakhand). In the decades that followed, it underwent radical changes in its charter of duties, shifted locations and finally got established in Pune in 1936. In 1995, it was rechristened HEMRL.
Today HEMRL is the only laboratory of its kind in the country dealing with high-energy materials such as propellants and ammunition required for missiles, rockets, battle tanks, artillery, guns, rifles and carbines. It has developed warheads for missiles; liquid fuel for torpedoes; explosive reactive armour for battle tanks; mine inflammables to set waterways on fire; powerful explosives to demolish buildings; fuel-air explosives to clear landmines; smokeless propellants, anti-laser grenades and illuminating flares. It makes the lethal ammunition for Pinaka, the indigenously developed multi-barrel rocket launching system. It is developing nanotechnology in seven types of high explosives, including RDX (Research Department Explosive), HMX (Her Majesty’s Explosive) and ammonium perchlorate.
Most importantly, the HEMRL has developed diverse rocket motors that power a variety of missiles, including Agni-I and Agni-II, Akash, Nag and Trishul. Its latest achievement is the production of powerful motors that propel the K-15 missile. K-15 will be fired from under water, from the nuclear-powered submarine Arihant. The HEMRL also makes motors that help missiles perform manoeuvres to avoid detection by radars. It has developed motors that jettison the missile’s spent stages.
Subhananda Rao said: “Wherever explosives and propellants are there, we are there. Our quest is to provide ammunition for all the armaments of the Army, the Navy and the Indian Air Force. That is why our motto is ‘Power Behind the Systems.’ Self-reliance is our forte. We emphasise safety and quality.” The HEMRL’s thrust area is solid rocket propellants. “We have developed an entire range of propellants for missiles such as ram-jet Akash, Trishul, Nag, Agni systems, Shourya and Prithvi Air Defence Systems,” said Subhananda Rao, who has designed and developed more than 30 propulsion systems for India’s tactical and strategic missiles.
S.N. Asthana, Associate Director, said: “Propellants developed by the HEMRL provide thrust to missiles and tank/gun munitions whereas explosives developed by it impart lethal power to warheads and projectiles.” B. Bhattacharya, Associate Director, said: “Name any missile system in India and it is linked to the HEMRL through motors, propellants or explosives.”
It is the propulsion system that makes a missile either a tactical one or a strategic one, such as an intermediate range ballistic missile (IRBM) or an inter-continental ballistic missile (ICBM). The propulsion systems for strategic missiles and K-15 missiles were developed by the DRDO’s largest laboratory.
The HEMRL has made important contributions to the development of India’s ballistic missile defence shield, the Advanced Air Defence System (AADS). In this system, an incoming “enemy” ballistic missile is knocked out in mid-flight by the DRDO’s interceptor missile. Three tests of such interceptor missile have been successful in a row.
Developing motors and propellants for missiles is quite different from making them for civilian launch vehicles. While launch vehicles for civilian applications can afford to have a slow lift-off, the DRDO’s missiles should accelerate fast. While the propellants on board civilian launch vehicles have a burn rate of 8 mm per second, the HEMRL-developed propellants have a burn-rate of 40 mm per second.
A. SUBHANANDA RAO, Director of the laboratory.
While rockets for civilian applications are launched in normal temperatures, DRDO-developed missiles function effectively at -40°0 Celsius at Siachen or +50°0 C in the deserts of Rajasthan. “So the propellants need a special casting,” said Subhananda Rao.
“We need to ensure 10 to 15 years of life for the missiles. We make motors with a high margin of safety and the capability for quick reaction too. They are high-acceleration motors,” he added. The DRDO’s missiles should withstand rigours and vibrations because they are moved from place to place. “So this class of missile motors have to be extremely robust and operate at extreme temperatures,” explained Bhattacharya.
For the canister-launched Shourya missile, the HEMRL has developed a generator that produces gas to push it out of the canister. The U.S., Russia and India are the only countries to develop the total technology needed for the gas generators.
The HEMRL was using RDX or HMX for missile warheads. It has now shifted entirely to HMX. It has developed the HMX composition for Akash and Nag. The laboratory had developed advanced demolition charges for use by the Army, Asthana said. These charges have civil applications, too. The laboratory has provided explosive cords to cut open the canopy of the Light Combat Aircraft, Tejas, to enable the pilot to eject in an emergency.
The HEMRL has embarked on the modernisation of gun ammunition. Its thrust is the modular charge system for gun propellants, which has an edge over the charge housed in cloth bags. The laboratory is mastering the technology of low-vulnerability (LOVA) propellants for gun ammunition. Amarjit Singh, Associate Director, said it had developed enhanced-energy LOVA propellants. This made them safer to use.
It has also developed the technology for making combustible cartridge cases (CCC) for gun ammunition. The CCCs are produced in partnership with a private industry. “The indigenous CCC technology has not only replaced costly imported brass cartridge cases, saving foreign exchange, but reduced logistic problems,” said Amarjit Singh.
The laboratory has synthesised CL-20. “It is a wonderful chemical. It can change the scenario of conventional explosives. We have given the licence to a private industry to produce it,” said Subhananda Rao. The HEMRL has developed FOX-7 (Field Ordnance Explosive) and also amorphous boron. “This [amorphous boron] is one of the greatest things to be produced here,” said Bhattacharya. The technology for developing amorphous boron was known only to a few countries.
A nanotechnology centre is coming up on the 340-hectare HEMRL campus. The laboratory has set up an Advanced Research Centre in High Energy Materials, funded by the DRDO, on the University of Hyderabad campus.
It has embarked on an ambitious programme in the area of insensitive explosives to overcome the problem of explosion by unplanned stimuli. “It will be of great advantage from the logistics point of view,” said Manish Bharadwaj.
EXPLOSIVE REACTOR ARMOUR
A visible success of the HEMRL is in developing the explosive reactor armour (ERA) for battle tanks. The ERA is a novel concept wherein the explosive reaction disrupts and defeats even the latest anti-tank missiles. A. Appa Rao, Associate Director, explained: “While the normal armour is passive, the ERA will react to the penetration of the incoming missile with the help of explosives sandwiched between armour plates. The explosives generate sufficient energy to destroy the incoming missile. The missile does not penetrate the entire thickness of the armour. The missile is deflected by an explosive force.”
More than 600 T-72 (CI Ajeya) tanks of the Army have been refurbished with the ERA. “We have developed a hybrid armour that can take care of tandem warheads and kinetic energy projectiles,” Appa Rao said.
A big facility of the HEMRL is coming up at Nashik. It will process propellants for large-sized case-bonded rocket motors. The facility, with more than 80 technical buildings and critical equipment, will process 100 tonnes of propellants a year. The processing will involve a new technology called pressure casting, which will improve the mechanical properties and energy of the propellants.
“The plant will meet the futuristic requirements of our missile programme,” said Subhananda Rao.
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