 "Chandrayaan-3: Here is the story behind India's cryogenic engine")
Today marks the launch of Chandrayaan-3, an important mission by the Indian Space Research Organisation (Isro). Using their powerful Geosynchronous Satellite Launch Vehicle (GSLV) Mk-III rocket, ISRO has sent a lander and rover towards the moon from the Satish Dhawan Space Centre (SDSC) in Sriharikota.
While the rocket’s first stage is powered by solid fuel, the second stage is by liquid fuel, and the third and final stage consists of a cryogenic engine powered by liquid hydrogen and liquid oxygen.
Here is everything you need to know about the engine that will bring Chandrayaan-3 through the final stages of its launch mission.
What is a cryogenic engine?
Cryogenic engines are highly efficient propulsion systems used in the upper stages of rockets. They offer a higher specific impulse, which measures the efficiency or thrust of an engine, resulting in an increased payload capacity.
The tanks have a capacity of over 27,000 kg of fuel and can fire for at least 720 seconds.
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The main components of a cryogenic rocket engine include an igniter, combustion chamber (thrust chamber), fuel cryo pumps, fuel injector, oxidiser cryo pumps, gas turbine, cryo valves, regulators, fuel tanks, and a rocket engine nozzle.
Typically, these engines use a combination of liquid oxygen (LOX) as the oxidizer and liquid hydrogen (LH2) as the fuel. The use of cryogenic fuels allows for high performance and efficiency in rocket engines.
Difference between cryogenic engine and stage
A cryogenic engine is a specific type of rocket engine that uses cryogenic fuels, while a stage is a distinct section or component of a rocket that performs a specific function and is typically discarded during flight.
Cryogenic engines are commonly used in the upper stages of rockets to achieve higher performance and efficiency. This is crucial to reach and deliver payloads to space.
How was it developed?
The development of the CE-20 cryogenic engine is a result of a collaborative effort among the Liquid Propulsion Systems Center, Vikram Sarabhai Space Centre, Isro Propulsion Complex, and Satish Dhawan Space Centre.
India’s cryogenic technology
According to a report by Swarajya magazine, based on the book ‘India’s Rise As A Space Power’ by UR Rao, in the late 1980s, India sought to acquire cryogenic engines for its Geosynchronous Satellite Launch Vehicle (GSLV) rocket. The United States (US) and France offered their engines at high prices, but a deal was eventually struck with Glavkosmos, the commercial arm of the Soviet Union's space agency Roscosmos. However, the US objected, citing concerns about violating the Missile Technology Control Regime (MTCR), which restricts the spread of missile technology. The US's real motive may have been to protect its commercial interests. Sanctions were imposed on both the Isro and Glavkosmos in 1992.
The then prime minister P V Narasimha Rao decided that India would create its own cryogenic engines, despite the ban on the sale of space components to Isro.
This led to the start of the cryogenic technology programme in April 1994 with a Rs 300 crore budget.
CE-20 cryogenic engine
For the Chandrayaan-3 mission, the CE-20 cryogenic engine was used. The CE-20 was India’s first cryogenic engine with a gas-generator cycle and the largest cryogenic engine to be made by ISRO. It took its first flight in June 2017.
CE-20 will power the upper stage of the GSLV Mk-III rocket, the country's heaviest launch vehicle.
On February 24, 2023, the flight acceptance hot test of the CE-20 cryogenic engine, designed to power the Cryogenic Upper Stage of the LVM3 launch vehicle for the Chandrayaan-3 Mission, was successfully conducted.
The test took place at the ISRO Propulsion Complex in Mahendragiri, Tamil Nadu, specifically at the High Altitude Test Facility. It lasted for a planned duration of 25 seconds.
“All the propulsion parameters during the test were found satisfactory and closely matched with predictions,” said ISRO
This paved the way for the integration of the CE-20 engine with propellant tanks, stage structures, and related fluid lines, ultimately creating a fully functional and integrated flight cryogenic stage.
Future of cryogenic manufacturing in India
The President of India, Droupadi Murmu, officially opened the integrated cryogenic engine manufacturing facility (ICMF) at HAL, Bengaluru on September 27, 2022.
The ICMF, established by HAL in Bengaluru, aims to produce cryogenic and semi-cryogenic engines needed for the Indian space programme.
The project cost for setting up this facility amounts to Rs. 208 crores.
The ICMF brings together the manufacturing and assembly processes for these engines in one place. It is equipped with various indigenous fabrication equipment, machinery, and utilities for surface treatment.