Polar Satellite Launch Vehicle (PSLV)

 The Polar Satetllite Launch Vehicle (PSLV) is used to eventually launch polar satellites for India, making India less dependent on foreign rockets for launches. PSLV was developed to place 1000 kg class Indian remote sensing satellites into Polar Sun Synchronous Orbit (SSO).

The PSLV has four stages using solid and liquid propulsion systems alternately. The first stage is one of the largest solid propellant boosters in the world and carries 138 metric tonnes of Hydroxyl Terminated Poly Butadiene (HTPB) propellant with a diameter of 2.8 m. The motor case is made of maraging steel. The booster develops a maximum thrust of about 4,430 kN. Six strap-on motors, four of which are ignited on the ground, augment the first stage thrust. Each of these solid propellant strap-on motors carries nine metric tonne of HTPB propellant and produces 677 kN thrust.

The second stage employs the Vikas engine and carries 40 metric tonne of liquid propellant — Unsymmetrical Di-Methyl Hydrazine (UDMH) as fuel and Nitrogen tetroxide (N2O4) as oxidizer. It generates a maximum thrust of 724 kN.

The third stage uses 7 metric tonne of HTPB-based solid propellant and produces a maximum thrust of 324 kN. Its motor case is made of Kevlar epoxy fiber. The fourth and the terminal stage of PSLV has a twin engine configuration using liquid propellant. With a propellant loading of 2 metric tonne (Mono-Methyl Hydrazine + Mixed Oxides of Nitrogen), each of these engines generates a maximum thrust of 7.4 kN.

The fairing of the PSLV is 3.2 m in diameter and is made of isogrid construction to protect the spacecraft during the atmospheric regime of the flight.

Links : WikiPedia , Official Site