The first operational launch vehicle of India is the Polar Satellite Launch Vehicle (PSLV). Developed by the Indian Space Research Organisation (ISRO), the PSLV has been the backbone of India's launch vehicle fleet and has played a pivotal role in numerous satellite missions since its first successful launch in 1994.
The PSLV was conceptualized and designed to meet the specific requirements of launching satellites into polar orbits, which are crucial for Earth observation, remote sensing, and scientific missions. It is a versatile and reliable launch vehicle that has garnered a reputation for its consistent performance and mission success.
The development of the PSLV began in the late 1980s, and its maiden flight took place on September 20, 1993. However, this initial launch was not successful. It was not until the second launch attempt on October 15, 1994, that the PSLV achieved its first successful mission, placing the IRS-1E satellite into orbit.
The PSLV stands approximately 44 meters tall and has a lift-off weight of about 320 tons. It is a four-stage launch vehicle, with each stage utilizing different propulsion technologies. The first stage employs solid rocket boosters (S139) to provide the initial thrust during the launch phase. These boosters burn a combination of hydroxyl-terminated polybutadiene (HTPB) and ammonium perchlorate as a propellant.
Once the solid rocket boosters burn out, the PSLV's second stage, known as the PS2, takes over. The PS2 uses liquid propellants, consisting of a mix of unsymmetrical dimethylhydrazine (UDMH) and nitrogen tetroxide (N2O4), to continue propelling the vehicle. The PS2 is powered by Vikas engines, which are highly reliable and have been extensively used in ISRO's launch vehicles.
After the PS2 completes its burn, the third stage, called the PS3, comes into operation. The PS3 is a solid rocket stage and uses a high-energy composite propellant, composed of ammonium perchlorate and powdered aluminum, to propel the vehicle further. This stage provides the necessary thrust to place the satellite into its intended orbit.
The final stage of the PSLV, known as the PS4, is a liquid propellant stage that uses a combination of liquid propellants, such as UDMH and nitrogen tetroxide. The PS4 is responsible for injecting the satellite into its precise orbit and conducting any necessary orbital maneuvers before satellite separation.