ISRO achieved a major milestone on May 9, 2024 by successfully conducting the high-temperature test of a liquid rocket engine manufactured using Additive Manufacturing (AM) technology. This engine is used in the PS4 engine on the PSLV upper stage and has been tested for 665 seconds. The PS4 engine with a vacuum thrust of 7.33 kN is used in the PSLV fourth stage reaction control system and the PSLV first stage reaction control system (PS1).
The engine was redeveloped by LPSC to comply with the Design for Additive Manufacturing (DfAM) concept. This approach brought significant benefits to the engine. The laser powder bed fusion technology used reduced the number of parts from 14 to one and eliminated 19 welds.
This results in significant savings in raw material consumption per engine, reducing 565kg of forging and plate material to just 13.7kg of metal powder per engine. In addition, the overall production time was reduced by 60%. The engine is manufactured by M/s WIPRO 3D Industries of India and tested at the ISRO Propulsion Center in Mahendragiri.
The engine uses a dual ground storable propellant in pressurized mode, combining nitrogen tetroxide as the oxidizer and monomethyl hydrazine as the fuel. It was developed by ISRO’s Liquid Propulsion Systems Center (LPSC).
As part of the development program, an injection head for the engine was developed and successfully tested under high temperature conditions. Before hot testing, detailed flow and thermal modeling, structural simulations and cold flow characteristics of the primary parts were carried out to ensure the reliability of engine performance.
As a result, four integrated engine development hot tests were successfully conducted for a total duration of 74 seconds to verify the engine’s performance parameters. In addition, the engine was successfully tested for a period of 665 seconds and all performance parameters were found to be as expected. This AM PS4 engine will be integrated into the regular PSLV program.