The Indian Space Research Organization (ISRO) has successfully test-fired its CE-20 Cryogenic engine, as part of the preparation for the next launch of its heaviest rocket. This latest test comes a week after the Indian Space agency placed 36 satellites of the UK-based 'OneWeb', into Low Earth Orbit, using its heaviest rocket LVM3. The next launch to be carried out using the LVM3 will be performed sometime around January or February 2023, Chairman, ISRO, Dr. S. Somanath told WION. 

According to ISRO, "The flight acceptance hot test of a CE-20 engine is successfully carried out for a duration of 25 s in the High-Altitude Test facility of ISRO Propulsion Complex at Mahendragiri". It is noticeable that the CE-20 engine has flown on all five flights of the LVM3 rocket and has delivered success in every single launch. Now, the question arises why is a further engine test required? 

The LVM3 rocket is a three-stage heavy-lift launch vehicle developed by ISRO. The vehicle has two solid strap-on boosters (burns solid fuel), a core-stage liquid booster (burns a combination of liquid fuels) and a cryogenic upper stage (burns liquid hydrogen with liquid oxygen). LVM3 is designed to carry a 4-ton class of satellites into Geosynchronous Transfer Orbit (GTO) or about 10 tons to Low Earth Orbit (LEO), which is about twice the capability of its predecessor, the GSLV Mk II or GSLV rocket. 

The LVM3 is powered by three stages - solid, liquid and cryogenic. Solid-fuel boosters are the most reliable and the technology that ISRO has been using for the longest time. Hence, the need for testing is not as high, when compared to liquid-fuel and cryogenic engines which are far more complicated machines than solid-fuel ones. Also, the CE-20 Cryogenic engine being less than a decade old, means there are more reasons for ISRO to test-fire it. 

This also brings forth another fact - Solid-fuel rockets are only meant to be fired once and after a complete burn, they have to be discarded (comparable to a candle). So, the engine being tested is discarded after the test and a new one will have to be flown on the actual rocket. While some parts can be recovered, refurbished and re-used, it isn't commercially viable in most cases, so, a new solid booster is built. However, in the case of liquid-fuel or cryogenic engines, it is possible to refurbish and reuse the engine multiple times. This means, the same engine, which is tested on earth at a test facility, can be checked, re-fueled and flown. It is the same principle that is being used to execute missions by re-usable rockets, where the rocket engines fly to space, land back on earth and are refurbished and re-used for further launches. 

ISRO said, "The major objectives of the flight acceptance test were to confirm the integrity of the hardware, assessment of subsystems' performance and tune the engine for meeting the mission requirements parameters for engine tuning for flight operation. Analysis of test data confirmed the satisfactory performance of the engine systems. This engine will be assembled to the C25 flight stage being integrated for the LVM3 M3 vehicle". 

Given the successful test, ISRO can now work on performing further refurbishment on the engine and integrating it into the Cryogenic stage, which can eventually be assembled onto the rocket. It must also be noted that this test is crucial.

Source: WION

Image: ISRO has successfully test-fired its CE-20 Cryogenic engine, as part of the preparation for the next launch of its heaviest rocket. Credit: WION