Recently, Hindustan Aeronautics Ltd (HAL) has been the focus of numerous headlines for its impressive contribution to the Indian Space Research Organization (ISRO). Specifically, HAL has achieved the impressive feat of delivering the heaviest semi-cryogenic propellant tank (SC120- LOX) to ISRO. This follows their 2020 delivery of the largest ever cryogenic Liquid Hydrogen tank (C32-LH2) to the same organization. Here, we delve into the details of this achievement, providing an overview of the technology and importance of these developments.
About the Semi Cryo-Liquid Oxygen (LOX) Tank
The semi cryo-liquid oxygen (LOX) tank is the first developmental welded hardware. Its purpose is to form part of the SC120 stage. The intention behind this technology is to enhance payload through replacing the L110 stage in the existing Mk-III launch vehicle. The GSLV Mk III, a three-stage heavy-lift launch vehicle, was developed by the ISRO. This vehicle includes two solid strap-ons, a core liquid booster, and an upper stage powered by a cryogenic engine.
Understanding Cryogenic Engines
A cryogenic engine, often referred to as a cryogenic stage, forms the final stage of space launch vehicles. This technology utilizes the principles of cryogenics – a branch of science studying the production and behavior of materials at incredibly low temperatures (below -150 degree Centigrade). The primary focus of cryogenic engines is to lift and place heavier objects in space. In terms of efficiency, a cryogenic engine provides more force per kilogram of cryogenic propellant than other types of rocket engines that use solid and liquid propellants. It does this by employing Liquid Oxygen (LOX) and Liquid Hydrogen (LH2) as propellants, which liquefy at -183 deg C and -253 deg C respectively.
Semi Cryogenic Engines and Their Benefits
What sets a Semi Cryogenic engine apart from a standard Cryogenic engine is its use of Refined kerosene instead of liquid hydrogen, with liquid oxygen serving as an Oxidizer. This change brings certain advantages to the table. Primarily, Semi Cryogenic engines require Refined Kerosene which is lighter than liquid fuel and can be stored at normal temperature. Moreover, when Refined Kerosene is combined with liquid oxygen, it provides a higher thrust to rockets.
Another advantage of using Refined Kerosene is that it occupies less space. This allows more propellant to be carried in a Semi Cryogenic engine’s fuel compartment. Compared to standard Cryogenic engines, Semi Cryogenic engines are more powerful, environmentally friendly, and cost-effective. These benefits underscore their growing recognition and utilization within the field of aerospace propulsion technologies.
