New Delhi [India], Indian Space Research Organization (ISRO) has achieved a major achievement by successfully hot testing a liquid rocket engine manufactured using Additive Manufacturing (AM) technology at ISRO Propulsion Complex, Mahendragiri. This achievement marks a remarkable advance in propulsion. Technology for Space Missions "ISRO achieved a major milestone with the successful hot test of the Liqui rocket engine manufactured through Additive Manufacturing (AM) technology for a duration of 665 seconds on May 9, 2024. The engine used The PSL is the PS4 engine of the upper stage, the agency said, adding, “The PS4 engine, fabricated in the conventional machining and welding route, is in use for the fourth stage of PSLV, which has a thrust of 7.33 kN in vacuum state. The same engine is also used in the Reaction Control System (RCS) o First Stage (PS1) of PSLV." It further said that the engine uses nitrogen tetroxide as oxidizer and mono methyl as fuel in pressure-fed mode. Uses an Earth-storable bipropellant combination of hydrazine and was developed by the Liquid Propulsion Systems Center (LPSC).) By employing ISRO's laser powder bed fusion technology, the number of parts was reduced from 14 to a single-piece, eliminating 19 weld joints. This streamlined manufacturing process resulted in substantial savings in raw material usage and a 60 percent reduction in total production time. Detailed flow and thermal modelling, structural simulation and cold flow characterization were conducted to ensure the performance parameters of the engine before the test, ISRO conducted four successful developmental tasks. Hot tests of the integrated engine were followed by a full qualification period of 665 seconds, during which all performance parameters were found to be as expected. ISRO plans to integrate this AM PS4 engine into its regular PSLV programme, which represents a significant leap in space propulsion technology.