The Indian space agency, ISRO, has announced the successful test firing of the ‘CE-20’ cryogenic engine that will be used for the Chandrayaan-3 mission.
The ‘CE-20’ is an indigenous cryogenic engine developed by ISRO’s Liquid Propulsion Systems Centre. It powers the top-most and third stage of India’s heaviest rocket LVM3.
Liquid-fuelled engines that are meant for the flight are test fired on the ground and then cleaned and assembled onto a rocket, unlike solid-fuelled engines where only a single and complete burn is possible.
A cryogenic engine is powered by super-cooled gases, which are in liquid form. The engine’s combustion chamber burns liquid hydrogen (maintained at minus 253 degrees Celsius) and liquid oxygen (maintained at minus 183degrees Celsius) and this is a very efficient combination of fuels as it provides more thrust per kilogram of fuel it uses, when compared with other fuels. The hydrogen (fuel) and oxygen (oxidiser) combination is also an environment-friendly option, as opposed to gasoline fuels.
In the initial portion of the flight, the first-stage ‘S200’ and second-stage ‘L110’ of the LVM3 rocket will take the Chandryaan-3 spacecraft off the ground and into space. Thereafter, the CE-20 will be responsible for further accelerating the Chandryaan-3 module in space and ejecting it into an ‘Earth parking orbit’, where the spacecraft rotates around the earth with extreme variations in its distance to earth.
Roughly, the spacecraft would be more than 45,000km away from Earth at its farthest point in the orbit (apogee) and 180km away from Earth in its closest point in orbit(perigee). From there on, the Chandrayaan-3 module would use its on-board propulsion to perform orbit raising manoeuvres to progressively move further away from earth and be captured by Lunar gravity and finally attempt a Lunar landing.
Regarding the latest test, ISRO said that it was carried out at the ISRO Propulsion Complex, Mahendragiri, in Tamil Nadu.
“The hot test was carried out for a planned duration of 25 seconds at the High-Altitude Test Facility. All the propulsion parameters during the test were found satisfactory and closely matched with predictions” it added.
Further, the cryogenic engine will be integrated with propellant tanks, stage structures, and associated fluid lines to prepare the fully integrated flight cryogenic stage.
ISRO refers to the Chandrayaan-3 launch mission as LVM3-M4, indicating the fact that it is the fourth operational launch of the LVM3, which is India’s heaviest and largest rocket.
The maiden operational launch of LVM3 was Chandrayaan-2 in 2019 after the rocket flew on its second operational and maiden commercial mission in October 2022, ferrying 36 satellites for UK-based firm OneWeb.
LVM3-M3, the third operational launch of LVM3, will be carried out for OneWeb in March 2023, following which the Chandryaan-3 will be carried out in the second half of this year or by early 2024. The Chandrayaan-3 flight will be the seventh launch mission of LVM3.
As per ISRO’s nomenclature, a brand-new rocket undergoes a handful of developmental flights (denoted by a ‘D’ prefix along with a launch number) and based on the successful outcome of those, the vehicle is declared operational and then performs routine missions (denoted by the ‘M’ prefix along with a launch number).
The three-stage LVM3 rocket weighs close to 650 tons at lift-off and the vehicle is powered by solid, liquid and cryogenic fuels, in the same order.