ISRO conducts successful sea level hot test of CE20 cryogenic engine, paving the way for future missions

The Indian Space Research Organisation (ISRO) has successfully carried out the sea level hot test of its CE20 cryogenic engine.

The space agency said that this critical test featuring restart-enabling systems is a vital step for future missions. Testing the CE20 engine at sea level poses considerable challenges, primarily due to the high area ratio nozzle which has an exit pressure of approximately 50 mbar.

The test was carried out at the ISRO Propulsion Complex in Mahendragiri of Tamil Nadu on November 29.

Main concern

According to ISRO, one of the main concerns during testing at sea level includes flow separation inside the nozzle, which leads to severe vibrations and thermal problems at the flow separation plane leading to possible mechanical damage to the nozzle.

“To mitigate this issue, the flight acceptance tests for CE20 engines are currently being performed at the High-Altitude Test (HAT) facility, thereby adding complexity to the acceptance testing procedure. To reduce the complexity related to the testing at HAT, a sea level test utilizing an innovative Nozzle Protection System was devised that has paved the way for a cost-effective and less complex procedure for acceptance testing of the cryogenic engines,” ISRO said.

It further added that restarting a cryogenic engine is a complex process and the major challenges are vacuum ignition without nozzle closure and use of multi-element igniter.

“ISRO has demonstrated vacuum ignition of the CE20 engine without nozzle closure in earlier ground tests. In this test, the multi-element igniter performance was also evaluated, wherein, only the first element was activated, while the health of the other two elements was monitored,” it added.

Performances normal

During this test, both the engine and facility performance were normal, and the required engine performance parameters were achieved as anticipated. The indigenous CE20 cryogenic engine developed by the Liquid Propulsion Systems Centre of ISRO is powering the upper stage of the Launch Vehicle Mark -3 (LVM3) and has been qualified to operate at a thrust level of 19 tonnes. This engine has successfully powered the upper stage of six LVM3 missions so far.

Recently, the engine was qualified for the Gaganyaan mission with a thrust level of 20 tonnes and also to an uprated thrust level of 22 tonnes for the future C32 stage, towards enhancing the payload capability of the LVM3 launch vehicle.