ISRO Conducts Sea-Level Test of CE20 Cryogenic Engine at 22-Tonne Thrust
ISRO conducts sea level test of cryogenic engine at 22 tonne thrust level with full area nozzle
Hot test at Mahendragiri marks key step toward enhancing payload capacity of LVM3 launch vehicle.
Nellore, March 13:
The Indian Space Research Organisation (ISRO) successfully conducted a sea-level hot test of its CE20 cryogenic engine at a thrust level of 22 tonnes on March 10 at the ISRO Propulsion Complex in Mahendragiri.
The test was carried out using a Nozzle Protection System (NPS) and a multi-element igniter. Earlier sea-level tests using the nozzle protection system had been conducted at a thrust level of 19 tonnes.
The CE20 cryogenic engine powers the upper cryogenic stage of the LVM3 launch vehicle. To enhance the payload capability of LVM3, future missions are planned to operate with an upgraded C32 stage capable of producing 22 tonnes of thrust.
In line with this objective, the latest test was conducted for a duration of 165 seconds at the enhanced thrust level. ISRO said the engine and the test facility performed as expected throughout the test.
Testing the CE20 engine at sea level poses significant technical challenges due to its high area ratio nozzle, which has an exit pressure of around 50 millibars. One of the major concerns during such tests is flow separation inside the nozzle, which can cause severe vibrations and thermal stress that may damage the nozzle.
The engine used in the test has successfully undergone a record 20 hot tests, enabling the demonstration of several critical technologies using a single engine platform.
These include ignition using a multi-element igniter, ignition margin demonstration for the Gaganyaan mission under varying propellant tank pressures, qualification of the engine at 20-tonne thrust for Gaganyaan, demonstration of 22-tonne thrust operation, and bootstrap mode starting of the CE20 engine without a start-up system to enable in-flight restart capability.
The tests also validated indigenous turbopump bearings, sensors, and the nozzle protection system designed for high area ratio nozzle testing at sea level.
Nellore: 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.
