THIRUVANANTHAPURAM: For the Indian Space Research Organisation, the year 2019 is significant in many counts. 2019 will witness some crucial preparations to hold the first unmanned (without astronaut) mission of Gaganyaan, slated to be held in December 2020 and the second unmanned mission in July 2021, which will be followed by the first Gaganyaan mission with astronauts in December 2021. Further, the year marks the 100th birth anniversary of its visionary leader Dr Vikram Sarabhai and the 50th year of its first successful test flight of an Indigenous Sounding Rocket RH-75 from Thumba, using in-house developed composite solid propellant.
A landmark achievement in the history of the ISRO and the premier institution then contributed significantly towards enabling the country to fulfil the vision of harnessing space technology for national development from this strong edifice of composite solid propellant technology, a major breakthrough which still helps the R&D institution to hold its untiring pursuit of space research and planetary exploration.
The composite solid propellant for the sounding rocket was named ‘Mrinal’, reportedly after Mrinalini Sarabhai, the classical dancer and wife of Vikram Sarabhai. It was used to launch the sounding rocket, designated as Dynamic Test Vehicle, DTV-75, on February 21, 1969, heralding the development of indigenous solid propellant technology in the country. Sounding rockets are experimental rockets, carrying a scientific payload for conducting research during suborbital flight.
It was under the leadership of R Gowarikar in the Propellant Engineering Division (PED) at Veli then known as SSTC the work on composite propellants was initiated for rockets. According to ISRO officers, the nature of the development being strategic in nature and due to lack of open literature, it was essential to design each experiment with caution.
Several experiments were conducted in the initial phase with the available raw materials consisting of polyester resin, ammonium perchlorate and aluminium powder. Finally a composition was found to work in static firing which had nitroglycerine added to improve its energy and processability. This was a major breakthrough in the nation’s composite propellant programme for processing large solid motors.
In 50 years, the ISRO has progressed to the ‘golden era’ of launch vehicles starting from the humble beginnings of launching small sounding rockets to Launch Vehicles such as PSLV, GSLV Mk 2 & GSLV Mk 3. Today ISRO has the capability to launch 4 Tonne class using GSLV MK3. This has been possible due the development of the mammoth S200 solid booster that powers the initial moments of the flight regime of GSLV MK3.
Colloquium tomorrow To celebrate the 50 year legacy of its solid propellants, the ISRO is holding a colloquium on ‘Solid propellants - Past, Present and Future’ on Wednesday. ISRO chairman K Sivan will inaugurate the function at Dr Srinivasan Auditorium, VSSC, Thiruvananthapuram