ISRO's Cryogenic Engine

The CE-20 is a cryogenic rocket engine developed by the Liquid Propulsion Systems Centre, a subsidiary of Indian Space Research Organisation (ISRO). It has been developed to power the upper stage of the LVM-3. It is the first Indian cryogenic engine to feature a gas-generator cycle. The high thrust cryogenic engine is the most powerful upper stage cryogenic engine in operational service in the world today.

ISRO's Semi-Cryogenic Engine

The SCE-200 (also referred as Semi-Cryogenic Engine-200) is a 2 MN thrust class liquid rocket engine, being developed to power India's future heavy and super heavy-lift launch vehicles. It is being developed by Liquid Propulsion Systems Centre of ISRO and is expected to have its first flight in a couple of years.

Burning liquid oxygen (LOX) and RP-1 kerosene in an oxidizer-rich staged combustion cycle, the engine will boost payload capacity of India's existing LVM-3 replacing current L110 stage powered by 2 Vikas engines. It is also expected to power ISRO's upcoming New Generation Launch Vehicle (NGLV) rockets (previously planned as ULV) as well as ISRO's future reusable rockets based on RLV technology demonstrator.

What Is Semi-Cryogenic Engine

Cryogenics is the study of the production and behaviour of materials at very low or extremely low temperatures.

The Cryogenic Engine uses liquid hydrogen and liquid oxygen as propellants.
There are some disadvantages posed by cryogenic engines: the use of liquid hydrogen at extremely low temperatures is very difficult to store, being the lightest element.
The cost of manufacturing and using liquid hydrogen is very expensive

A semi-cryogenic engine uses refined kerosene instead of liquid hydrogen. 
It uses liquid oxygen as an oxidiser.
Compressed Natural Gas (CNG) can also be used as fuel.
Apart from regular 'application' missions, the Semi-Cryogenic engine will also be used in the Gaganyaan Human Spaceflight project. 
India’s strategic partner Russia is offering its semi-cryogenic technology along with critical components for this mission.

Advantages of Semi Cryogenic Engine

 

Kerosene is much lighter than liquid fuel and can be stored at a normal temperature.
The Kerosene combined with liquid oxygen provides more thrust to the rocket.
It also occupies less space which makes it possible to have more propellant in the fuel compartment or tank.
The semi-cryogenic engine is more environment-friendly, cost-effective and more powerful compared to a cryogenic engine.
It can carry a huge weight to a higher altitude. 
The payload can be increased since the weight of the fuel will come down by 500kg.

On 10 May 2023, the first integrated test on an intermediate configuration of the 2000 kN Semi cryogenic-Engine was conducted at Semi Cryogenic Integrated Engine & Stage Test facility in IPRC, Mahendragiri. During the test lasting 15 hours, complex chill-down operations were performed to meet necessary conditions for engine start.