ISRO successfully tests hybrid propulsion system, to aid future technologies

#GS-03 Science and Technology

About Hybrid Propulsion System:

HTPB-based (hydroxyl-terminated polybutadiene) aluminised solid fuel and liquid oxygen (LOX) as oxidiser.

Conventional HTPB-based solid propellant motors used in rockets use ammonium perchlorate as oxidiser.
While both HTPB and LOX are environment friendly, the cryogenic LOX is safer to handle.
Unlike conventional solid motors, the hybrid technology imparts restarting and throttling capabilities on the motor.
The use of liquids facilitates throttling and control over the flow rate of LOX.

The Indian Space Research Organisation (ISRO) conventionally uses the fuel UDMH (Unsymmetrical Di-Methyl Hydrazine), which is highly toxic and corrosive, along with the nitrogen Tetroxide as the oxidiser. This combination is called a “dirty combination.”
Due to the pollution and toxicity of these materials, most of the countries across the world are shifting to cleaner fuels such as liquid methane or kerosene.

Rockets work under Newton’s third law of motion which states that “To every action there is always opposed an equal reaction; or the mutual actions of two bodies upon each other are always equal and directed to contrary parts.”
When the fuel explodes out of the rocket engine, the outward going fuel exerts a force which is equal in magnitude but opposite in direction to the force of the exploding fuel. This is what propels the rocket.
However, since rockets are designed to work in outer space, where there is a lack of oxygen, it must carry its on oxidizer in order to allow the fuel to burn.

VSSC was founded at Thumba, a coastal village at Thiruvananthapuram, the capital city of Kerala, in 1962.
The Centre is named after Dr Vikram A Sarabhai, who is celebrated as the father of Indian Space Programme.
VSSC is the lead centre of ISRO responsible for the design and development of launch vehicle technology.

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