ISRO crossed a major milestone yesterday (November 30, 2001) when it
successfully tested an up-rated version of the liquid propellant Vikas
engine at ISRO’s Liquid Propulsion Test Facilities at Mahendragiri in
Tamilnadu. The Vikas engines are employed in the second stage of India’s
Polar Satellite Launch Vehicle (PSLV) as well as the second and the four
strap-on stages of Geo-synchronous Satellite Launch Vehicle (GSLV).

The up-rated version of the Vikas engine tested yesterday developed a
chamber pressure of 58.5 bar against 52.5 bar in the current version. This
new engine uses UH25 (a mixture of Unsymmetrical Di-methyl Hydrazine and
hydrazine hydrate) as fuel and nitrogen tetroxide as oxidiser. A number of
short duration tests of the up-rated version had been conducted in the past
few months to check the inter-play of various parameters to ensure a stable
combustion before conducting the test yesterday. In addition to the
verification of performance of the engine for full duration, the test has
also validated the Silica-phenolic throat for the extended duration of
burning time. The quick look data has indicated normal performance of the

After completion of qualification, the new up-rated Vikas engine is planned
to be introduced in the second developmental test flight of GSLV, which is
scheduled during 2002. The new engine has the potential to increase the
payload capability of GSLV by about 150 kg in the Geo-synchronous Transfer
Orbit (GTO).