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Source-This post on PS4 engine is based on “ISRO’s engine design saves raw material, time” published in “The Indian Express” on 12th May 2024.
Why in the News?
ISRO successfully tested the PS4 engine of the PSLV stage for an extended duration.
About PS4 engine

1. About: The PS4 engine is a vital component of the Polar Satellite Launch Vehicle (PSLV), utilized by the Indian Space Research Organisation (ISRO) for satellite launches.
2. Purpose and Functionality: It serves as the uppermost stage of the PSLV. It comprises of two Earth-storable liquid engines. These engines are crucial for propelling the rocket’s upper stage during its mission.
3. Propellant Combination: It employs a bipropellant combination, utilizing nitrogen tetroxide as the oxidizer and monomethyl hydrazine as the fuel. This combination ensures efficient and reliable performance.
4. Thrust and Operation: Each PS4 engine is capable of producing a thrust of 7.3 kiloNewtons (kN) in vacuum conditions. It facilitates propulsion and manoeuvring of the upper stage.
5. Transition to 3D Printing: Traditionally manufactured using machining and welding methods, the PS4 engine has now shifted to 3D printing. This transition allows for intricate designs and optimal material utilization.
6. Utilization in Reaction Control System (RCS): It also serves in the Reaction Control System (RCS) of the initial stage (PS1) of the PSLV rocket. The RCS ensures precise control during ascent, trajectory adjustments, payload deployment, and docking manoeuvres.
UPSC Syllabus: Science and technology ( Defence)



