Vikas engine has been the workhorse engine for the launch vehicles of ISRO. The engine with a nominal thrust of 80t is powering the second stages of PSLV & GSLV, liquid strapons of GSLV and the core liquid stage of LVM-3.

Liquid engines that support throttling of the engine thrust facilitate booster stage recovery in launch vehicles. In order to enable booster stage recovery in future launch vehicle configurations, the first Throttling demonstration hot test of the Vikas engine was successfully accomplished on January 30, 2023 for a targeted 67% thrust level throttling for a duration of 43s.

Throttling of the engine was achieved by a closed loop thrust regulation system and the engine had been successfully throttled from the chamber pressure of 58.5 bar in steps of 50 bar, 45 bar & 40 bar, with dwelling at each pressure level for 7s. In addition, the Vikas engine was also throttled down to 45% for the last 3 s before the engine shut down.

The results of the first hot test of Throttleable Vikas Engine indicate stable combustion and subsystem performed in accordance with the prediction. The overall performance of engine sub-systems, control systems & test facility systems were as expected.