ISRO Successfully Hot-Tests CE20 Cryogenic Engine at 22-Tonne Thrust for LVM3-M7 Mission

The Indian Space Research Organisation (ISRO) has successfully completed the flight-acceptance hot test of a CE20 cryogenic engine that is set to power the upper stage of the upcoming LVM3-M7 mission, marking a significant step in preparations for India's next heavy-lift launch. The test was conducted on July 6, 2026, at the Main Engine and Stage Test facility of the ISRO Propulsion Complex in Mahendragiri, Tamil Nadu. During the test, the CE20 engine initially operated at a thrust level of 19.5 tonnes for 45 seconds before being raised to 22 tonnes for another 25 seconds. ISRO said the engine systems and the Nozzle Protection System performed satisfactorily throughout the test.

The engine will now undergo refurbishment before being integrated into the C32 flight stage being prepared for the LVM3-M7 launch vehicle. The CE20 is an indigenous cryogenic engine developed by ISRO for the upper stage of the LVM3 rocket. The engine is designed to operate in the 19-22 tonne thrust range and has powered multiple LVM3 missions, including Chandrayaan-2, Chandrayaan-3 and commercial launches.

The latest hot test is particularly significant because ISRO is working to establish the CE20's operation at the higher 22-tonne thrust level for future LVM3 missions. Increasing the thrust of the upper-stage engine is expected to contribute to improvements in the launch vehicle's payload capability. ISRO had earlier conducted a major sea-level test of the CE20 at 22-tonne thrust on March 10, 2026. The engine was operated for 165 seconds during that test using a Nozzle Protection System and a multi-element igniter. The test was aimed at demonstrating the engine's performance at the higher thrust level under sea-level conditions.

Testing a large cryogenic engine at sea level presents technical challenges because of the large-area-ratio nozzle used by the CE20. The low pressure at the nozzle exit can lead to flow separation, which may cause excessive vibration and thermal loads. ISRO's Nozzle Protection System was developed to address this challenge and enable extended engine testing under sea-level conditions.

The CE20 has undergone an extensive testing programme as ISRO continues to improve the reliability and performance of the LVM3 propulsion system. Previous testing has demonstrated technologies including multi-element ignition, higher-thrust operation, indigenous turbopump bearings and sensors, as well as bootstrap-mode engine start-up.

The successful flight-acceptance test of the engine assigned to LVM3-M7 brings the mission another step closer to launch. Once refurbishment is completed, the engine will be integrated into the C32 flight stage and subsequently into the LVM3 vehicle. The development of the 22-tonne CE20 configuration is also important for India's wider space programme. Improved upper-stage performance could give the LVM3 greater flexibility for future missions involving heavier spacecraft and more demanding orbital requirements. With the latest test successfully completed, ISRO is continuing its efforts to strengthen the LVM3's capabilities and build greater reliability into India's heavy-lift launch operations.

Disclaimer: This image is taken from The Pioneer.