ISRO successfully tested a hybrid motor at ISRO Propulsion Complex (IPRC), Mahendragiri, supported by Liquid Propulsion Systems Centre (LPSC/ISRO). The motor used Hydroxyl-terminated polybutadiene (HTPB) as fuel and liquid oxygen (LOX) as the oxidizer. Unlike solid-solid or liquid-liquid combinations, a hybrid motor uses solid fuel and liquid oxidizer.
A hybrid rocket consists of a pressure tank containing the liquid propellant, the combustion chamber containing the solid propellant, and a valve isolating the two. After the ignition process, the liquid gas is propelled into the combustion chamber where it is vaporized. Subsequently, it reacts with the solid propellant.
ISRO’s scientist benchmarked test of a flight equivalent 30 kN hybrid motor demonstrated ignition and sustained combustion for the intended duration of 15 seconds.
According to the ISRO officials, the motor performance was satisfactory.
The basic advantage of Hybrid Rocket Propulsion
A hybrid rocket propulsion, uses two different and distinct type of matter which could be either solid and the other either gas or liquid.
The basic advantages of Hybrid rockets are derived from the fact that solid rockets it avoids the propellant handling. Hybrid works seamlessly unlike the liquid rockets which is based on mechanical maneuvering and poses complex challenges.
The Hybrid systems avoid significant hazards of manufacturing, shipping and handling solid rocket motors by storing the oxidizer and the fuel separately.
Also, hybrid rocket motors can be shut down easily and it is throttleable. Hybrid motor is scalable and stackable, potentially paving the way for a new propulsion system for the futuristic vehicle. In case of Solid rockets have also no possibilities of shutting down without having took risk of failure and almost never have throttling or restart capabilities.
But it is the sustained combustion capabilities that work for Hybrid rockets. Unlike the liquid rockets which run through combustion instabilities, the hybrid rocket show consistence and regular combustion. It leads to high degree of performance and thrust capacity in a secured manner.
biggest advantage rests on the cooling mechanism which is the most vital aspect of due to the high heat and possibilities of the weakening and cracking of metal walls. This is because Hybrid rockets have combustion chambers that are lined with the solid propellant and are coated with graphite materials.
Test takes place in the midst of 36 satellites part of a constellation by UK-based One Web which is planned for the Low Earth Orbit on a GSLV-MkIII.
The launch is part of an agreement signed between the United Kingdom-based firm and the NewSpace India Limited (NSIL).