Context: Recently, ISRO successfully carried out demonstration of restarting its Vikas liquid engine at a test facility at Propulsion Complex, Mahendragiri.

• It is a step towards developing technologies for recovery of stages, leading to reusability in future launch vehicles which could substantially reduce cost of future space missions.

About Vikas (Vikram Ambalal Sarabhai) Engine

• The Vikas engine, a critical component powering the liquid stages of ISRO's launch vehicles, is instrumental in advancing technologies for stage recovery and future launch vehicle reusability.

• VIKAS (an acronym for Vikram Ambalal Sarabhai) engine is a family of liquid-fuelled rocket engines conceptualized and designed by the Liquid Propulsion Systems Centre of ISRO in the 1970s.

• It has been conceptualized and designed by ISRO’s Liquid Propulsion Systems Centre (LPSC).

• LPSC is centre for design, development and realisation of liquid propulsion stages for ISRO's Launch Vehicles.

• It is workhorse engine that powers liquid stages of ISRO’s launch vehicles. 

• These engines are deployed for ISRO’s Polar Satellite Launch Vehicle (PSLV) and the Geosynchronous Satellite Launch Vehicle (GSLV) series of expendable launch vehicles for space launch use. 

• It improves payload capability of Polar Satellite Launch Vehicle (PSLV), Geosynchronous Launch Vehicle (GSLV) and GSLV Mk-III launch vehicles. 

• The fuel load of the Vikas engine is 40 tonnes for the PSLV, GSLV Mark I and II, and 55 tonnes for the GSLV Mark III.

PSLV (Third generation launch vehicle)

• First Indian launch vehicle to be equipped with liquid stages.

• Four stage vehicle with multiple satellite launch capability and multiple orbit capability. Second and fourth stages are powered by liquid propulsion engines.

• Second stage is powered by a Vikas engine. It uses UDMH (Unsymmetrical Dimethyl Hydrazine) as fuel and Nitrogen tetroxide (N2O4) as oxidiser.

GSLV 

• Three stage vehicle used to launch communication satellites in geo transfer orbit using cryogenic third stage.

• Its second stage is powered by Vikas engines.