ISRO Semi Cryogenic engine & stage development

ISRO Semi Cryogenic engine & stage development

In 2008, ISRO initiated a program to develop semi cryogenic engine technology to allow low cost access to space. The program aims to complete the engine design, fabrication and testing within 6 years. The goal is to develop an extremely efficient, high-pressure staged combustion cycle engine with a vacuum thrust of 2000 kN. The semi cryogenic engine uses a combination of liquid Oxygen and Kerosene (ISRO uses ISROSENE) as propellants which are eco-friendly and cost effective. Using this engine, a semi cryogenic stage will be developed that will constitute the core stage of ISRO’s future launch vehicles (unified launch vehicle (ULV) and re-usable launch vehicles (RLV)).

ISRO has been using solid, hypergolic liquid and cryogenic propellants based stages in its satellite launch vehicles (SLV). ISROs workhorse polar satellite launch vehicle (PSLV) uses alternative solid and liquid propellant based stages where a total of four stages are used. ISRO has also developed cryogenic engine and based on it a cryogenic upper stage (CUS) for its geosynchronous satellite launch vehicle (GSLV MK2).  

Figure 1. Isro's semi cryogenic engine (from presentation of Dr. B.N. Suresh, (VSSC) ).

To bring down the cost of access to space, ISRO now plans to use semi cryogenic propellants based core stage in its future launch vehicles. Semi cryogenic engine has efficiency and cost advantages over engines that use solid and hypergolic liquid propellants. The specific impulse of semi cryogenic engine is higher than its solid and hypergolic counterparts, which means that it can lift a higher payload for the same propellant mass.  In addition, the propellants for semi-cryogenic engine are safer to handle & store, and are more eco friendly. When compared to cryogenic engine, semi cryogenic engine is less efficient, but its advantage lies in comparatively reduced engine design complexity and fuel handling cost.

ISRO has plans for a Semi Cryogenic Stage (SC160) with 160 ton propellant loading powered by the 2000 kN semi cryogenic engine to be used in place of L110 stage of GSLV Mk III. This will enhance the GTO payload capability from 4 T to 6 T. In the 12th FYP this stage development will be initiated.

Updates:
Annual report 2011-2012: Engine design, generation of fabrication drawing of sub systems and integration drawings have been completed. Preliminary Design Review of Engine Gimbal Control system have been completed and technical specification document of both Hydraulic Actuation System and Hydraulic Power System generated. Hypergolic igniter trials have been successfully demonstrated. Single element of pre burner and thrust chamber are realised. 3 tests have been completed for single element Semi cryo pre-burner injector.