Pyro Lab at Thumba was set up in 1967

Every time you read about a space mission, you come across accounts of how the strap-on boosters and rocket stages separate and jettison as planned, how each subsequent stage ignites, and, once the satellite is safely in orbit, how its solar panels are successfully deployed.

But how exactly do these events occur with millisecond precision as the launch vehicle spears its way skyward? That is where space ordnance systems come in. These are a special class of pyrotechnical devices—or informally, pyros—that space agencies across the globe including the Indian Space Research Organisation (ISRO) employ to activate critical functions on board rockets.

Come Monday, ISRO’s Vikram Sarabhai Space Centre (VSSC) here at Thumba will celebrate 50 years of the development of space-ordnance systems in ISRO by honouring scientists who pioneered this critical area of rocketry in the space programme.

Aboard every ISRO rocket, whether it be the Polar Satellite Launch Vehicle (PSLV) or the Geosynchronous Satellite Launch Vehicle (GSLV), there are a number of these explosive devices whose key functions include ignition, separation and, when a mission has to be aborted mid-flight, destruction.

Using pre-set commands programmed into the on-board computer, pyros are electrically triggered to ignite the solid boosters at launch and the engines of the stages during flight.

The ‘duties’ of these single-use devices do not end there. They are required for a host of other tasks including the jettisoning of spent strap-on boosters and stages.

As the mission progresses, these devices help to separate the heat shield, release the satellite, and deploy its solar panels. In extreme circumstances when the destruct mechanism has to be activated to blow up an errant rocket, it is again these specialised ordnance systems that come into play.

Key role

The pyro team plays a key role in every ISRO mission, be it the moon and Mars missions or the upcoming manned Gaganyaan. Being explosives, pyros have to be handled with kid gloves, but the pyro team at the VSSC vouch for their safety and reliability. Their history in ISRO date back to the 1960s, when India began its fledgling forays into space.

The Pyro Lab was set up at Thumba—at the insistence of A. P. J. Abdul Kalam—in 1967. The pioneers included V.V. Babu, Abdul Majeed and C.B. Kartha. The first India-made Centaure rocket was launched with systems developed by the lab in 1974. In mid-1980s, the team was assigned to design and develop ordnance for the PSLV.

As it evolved, the Pyro Lab was variously renamed as the Igniter and Pyrotechnic Division (IPD), the Igniter and Pyrotechnic Group (IPG), and finally, the Space Ordnance Group (SOG). In 2018, it was recognised as an entity of the VSSC—the AeroSpace Ordnance Entity (ASOE).

On Monday, December 30, the VSSC will organise a colloquium, ‘Fifty Years of Space Ordnance Development in ISRO’, at the VSSC where the pioneers will be felicitated.