March 12, 2026
ISRO successfully conducted a sea level hot test of its Cryogenic engine (CE20) at 22 tonne thrust using nozzle protection system and multi-element igniter, on March 10, 2026 at ISRO Propulsion Complex, Mahendragiri. Earlier, the sea level tests utilizing nozzle protection system was being carried out at 19 tonne thrust level.
The CE20 cryogenic engine powers the upper cryogenic stage of LVM3 launch vehicle. In order to enhance the payload capability of the LVM3 vehicle, future missions of LVM3 are planned to be operated with an uprated C32 stage with 22 tonne thrust for the CE20 engine. In view of this, the flight acceptance test of the CE20 engine also needs to be conducted at 22 tonne thrust level. Therefore, the present test qualified the sea level testing of the engine with a test duration of 165 seconds at 22t thrust level using the Nozzle Protection System (NPS). The performance of the engine as well as the test facility was as expected during the entire test duration.
Testing the CE20 engine at sea-level possess considerable challenges primarily due to high area ratio nozzle, which has an exit pressure of ~50 mbar. Main concern during testing at sea-level include flow separation inside the nozzle, which leads to severe vibrations & thermal problems at the flow separation plane leading to possible mechanical damage of the nozzle.
The Cryogenic engine utilized for this test has undergone a record maximum number of hot tests (20 No.s) successfully, that has enabled the demonstration of several key technologies using a single engine such as engine ignition using multi element igniter, ignition margin demonstration for Gaganyaan over a wide range of propellants tank pressure and pre-ignition chamber pressure, engine qualification for Gaganyaan at 20 tonne thrust level, demonstration & qualification of 22tonne thrust level operation, boot-strap mode starting of CE20 engine without start-up system for enabling re-start in flight, indigenous turbopumps bearings qualification, indigenous sensor qualification and Nozzle Protection System qualification for high area ratio nozzle hot test at sea level.