National

A powder that will power the nation's strategic capability

By T.S. Subramanian

G. Madhavan Nair, Chairman of the Indian Space Research Organisation, lays the foundation for a project to augment the capacity of the ISRO's Ammonium Perchlorate Experimental Plant (APEP) at Aluva on Thursday. The others in the picture are (from left): N. Vedachalam, Director, Liquid Propulsion Systems Centre, ISRO, K. Kasturirangan, former Chairman, ISRO, and Vasant R. Gowariker, former Director, Vikram Sarabhai Space Centre. - Photo: Mahesh Harilal

ALUVA (KERALA), FEB. 19. When an employee of the Indian Space Research Organisation (ISRO) proudly held a handful of ammonium perchlorate in February 1979, a fine powder of white crystals that look like common salt, a colleague made an unkind cut: "Ah, you must have stolen it from WIMCO" (Western India Match Company). The other man could only mutter to himself, "When ignorance is bliss, it is folly to be wise."

For the manufacture of ammonium perchlorate, which is an important constituent of solid propellant that powers rockets, is a closely guarded secret. This is because solid propellants fuel not only civilian launch vehicles that deploy satellites but also missiles that launch destructive warheads. Thus, the manufacture of ammonium perchlorate lends strategic capability to nations.

It was a proud occasion on February 19 when the ISRO Chairman, G. Madhavan Nair, pulled a lever to unveil the foundation stone for augmenting the capability of ISRO's Ammonium Perchlorate Experimental Plant (APEP) at Aluva, 27 km from Ernakulam, Kerala. In about 12 months, the present production of 300 tonnes of ammonium perchlorate at the APEP will step up to 800 tonnes a year. The day also marked the culmination of the silver jubilee celebrations of the setting up of the APEP.

In its 25 years of its existence, the APEP has metamorphosed from an experimental plant that manufactured 12 tonnes of ammonium perchlorate a year to a full-fledged production facility that produces 300 tonnes now. This led to a demand from speakers at the function that it be renamed as "Ammonium Perchlorate Excellence Plant."

Speakers, including Mr. Nair and the former ISRO Chairman, K. Kasturirangan, paid tributes to the visionary genius of Dr. Vasant R. Gowariker, former Director, Vikram Sarabhai Space Centre, Thiruvananthapuram, whose brainchild is the APEP.

Dr. Gowariker not only envisioned the setting up of the APEP but also made a crucial decision after consulting his VSSC colleagues, that ISRO's launch vehicles would use a solid propellant called hydroxy-terminated poly butadine (HTBP). He made this decision in the mid-1970s but it was in the early 1980s that the United States decided to use the same HTPB to power the solid boosters of its space shuttle. In the 1990s, the Ariane decide to use the HTPB to power its solid boosters of Ariane-5.

The stepping up of the APEP's capacity from 300 tonnes to 800 tonnes is essential because ISRO is getting into the commercial mode. It will launch a minimum of four launch vehicles a year from its spaceport at Sriharikota,

Andhra Pradesh, where a second "universal" second launch pad built at a cost of Rs.400 crores is undergoing final commissioning trials.

When ISRO's giant GSLV- Mark III [Geo-synchronous Satellite Launch Vehicle] blasts off from Sriharikota by 2007, half of its lift-off weight of 600 tonnes will come from ammonium perchlorate. This GSLV- Mark III will have two booster rockets, each of which will be powered by 200 tonnes of solid propellants, that is, HTPB. Of the 400 tonnes of HTPB, ammonium perchlorate will account for 70 per cent, viz 280 tonnes. This GSLV-Mark III will put an indigenous INSAT weighing four tonnes into orbit. The present GSLVs put satellites weighing two tonnes into orbit.

Ammonium perchlorate also accounted for half of the lift-off weight of ISRO's SLV-3, the Augmented Satellite LaunchVehicle (ASLV) and the Polar Satellite Launch Vehicle (PSLV). Since there will be four flights of PSLVs and GSLVs every year from Sriharikota, there is a felt need to increase the capacity of the APEP. In a few years, the capacity will be further boosted to 1,000 tonnes a year. Mr. Nair said ammonium perchlorate formed a vital element in rocket technology. Although information about producing it was available in chemistry textbooks and it looks simple to do it, when it came to practically manufacturing it, it amounted to a man from Aluva making "Mysorepak" compared to a Karnataka man making the same dish.

The innocuous-looking ammonium perchlorate is the workhorse in the HTPB. In rocket engines in flight, ammonium perchlorate decomposes into oxygen and thus provides the oxygen for the engine to absorb. So it is called an oxidiser.

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