ISRO Successfully Tests CE20 Cryogenic Engine with Advanced Nozzle Design
The Indian Space Research Organisation (ISRO) has achieved a significant milestone with the successful sea-level hot test of its CE20 cryogenic engine. Conducted on November 29, 2024, at the ISRO Propulsion Complex in Mahendragiri, Tamil Nadu, the test showcased the engine’s cutting-edge nozzle design and restart capabilities.
Overcoming Sea-Level Testing Challenges
Testing cryogenic engines at sea level presents unique challenges, particularly for high area ratio nozzles like the CE20, which features a nozzle area ratio of 100. The engine’s nozzle has an exit pressure of approximately 50 mbar, making it prone to flow separation. This can lead to vibrations, thermal stress, and potential mechanical damage.
To address these issues, ISRO has traditionally relied on its High-Altitude Test (HAT) facility for flight acceptance tests. However, this approach increases complexity and cost. In a major breakthrough, ISRO implemented an innovative Nozzle Protection System, enabling safe and effective sea-level testing. This development simplifies the acceptance testing procedure while reducing costs.
Demonstrating Engine Restart Capabilities
A key aspect of the test was evaluating the performance of the engine’s multi-element igniter, which is crucial for restart capability in space. Restarting a cryogenic engine is a highly complex process, particularly in a vacuum. ISRO previously demonstrated vacuum ignition without a nozzle closure in earlier ground tests.
In this test, only the first igniter element was activated, while the health of the other two elements was closely monitored. The results confirmed that both the engine and the test facility performed optimally, achieving the desired performance parameters.
CE20: Powering India’s Space Ambitions
The CE20 cryogenic engine, developed indigenously by ISRO’s Liquid Propulsion Systems Centre, powers the upper stage of the LVM3 launch vehicle. It has already demonstrated its reliability by successfully supporting six LVM3 missions.
Recently, the engine was qualified for the Gaganyaan mission at a thrust level of 20 tonnes. It has also been upgraded to achieve a thrust level of 22 tonnes for the future C32 stage, enhancing the payload capacity of the LVM3 launch vehicle.
This successful test underscores ISRO’s commitment to advancing its cryogenic engine technology, which plays a pivotal role in India’s space exploration goals.