PSLV
PSLV stands for Polar Satellite Launch Vehicle. Development of PSLV allow ISRO to launch Indian Remote Sensing (IRS) satellites into sun-synchronous orbits, a service that was, until the advent of the PSLV in 1993, commercially available only from Russia. PSLV used to launch a satellite of up to 1.7 tons in weight into the sun-synchronous polar orbit and to launch the satellite of up to 1.4 tons in weight into the Sub Geosynchronous Transfer Orbit. Various major components are used for the construction of PSLV . Similar components are also used on GSLV. PSLV has gained credence as a small satellite launcher due to its numerous multi-satellite deployment campaigns with auxiliary payloads usually ride sharing along with an Indian primary payload.Four Stages Of PSLV
As the PSLV contains the four stages, so the vehicle is also known as a four-stage vehicle. Let us go through all the stage of PSLV, these are as follows:-First Stage
The first stage of PSLV known as PS-1 also called the core stage. Core stage is to be integrated to PSLV uses the rocket motor in the first stage. The height of this stage is 20 meters or 66 ft long and around 138 tons of propellant is used in this stage. The diameter of the first stage of PSLV is 2.8 meter or 9.2 ft. In order to generate the required lift-off thrust, six large strap-on boosters are used in the XL version of PSLV, which are attached to the core stage. The height of each booster attached to core stage is 2 meters long and around 12 tons of solid propellant is used in these.Four boosters are ground-lit and the remaining two ignite 25 seconds after launch. The stage generates a maximum thrust of 4,846.9 kN (1,089,600 lbs) and has a nominal burn time of 110 seconds. Specific impulse noted of the first stage is 237 s (2.32 km/s) at sea level and 269 s (2.64 km/s) under vacuum. HTPB is used in it as fuel. The solid boosters carry 9 t (20,000 lb) or 12 t (26,000 lb) (for PSLV-XL configuration) propellant and produce 510 kN (110,000 lbs) and 719 kN (162,000 lbf) thrust respectively. Two strap-on boosters are equipped with SITVC for additional attitude control.There is no strap-on booster are used in PSLV-CA.Related Articles:-
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Second Stage
The second stage of PSLV is stacked above the stage that known as core stage. The second stage of PSLV is known as PS-2. The height of this stage is 12.8 meters or 42 ft long and diameter of this stage is 2.8 m (9.2 ft). Around 42 tons of earth storable liquid propellants are used in this stage. The proven liquid engine which is known as High Thrust Vikash Engine ( HTVE ) is used in the second stage ( PS-2 ) of PSLV. The use of Vikas engine increases its thrust and reliability. PS-2 also contains two liquid propellants of about 41.5 t (91,000 lb). The two liquid propellants that used in PS-2 are:- ( i ) unsymmetrical dimethylhydrazine (UDMH) used as fuel and nitrogen tetroxide (N2O4 ) as an oxidizer.The PS-2 stage generates the maximum thrust of 803.7 kN (180,700 lbs) and has a burn time of 133 seconds.Specific impulse noted for the second stage is 293 s (2.87 km/s).The engine is hydraulically gimbaled (±4°) to provide pitch and yaw control, while roll control is provided by two hot gas reaction control motors.Third Stage
The third stage of PSLV is placed over the second stage. The third stage of PSLV is known as the PS-3. The height of this stage is 3.6 meters or 12 ft long and diameter of this stage is 2 meters or 6.6 ft. Around 7.6 tons of solid propellant is used in this stage.The solid rocket motor is used at this stage in order to provide high thrust after crossing atmospheric phase of the launch. The uppermost stage of the vehicle comprises two liquid engines.The PS-3 stage contains Hydroxyl-Terminated Polybutadiene - Based solid propellant ( HTPB ) used as fuel which generates the maximum thrust of 240 kN (54,000 lbs) and has a burn time of 83 seconds. Specific impulse noted for the third stage of PSLV is 295 s (2.89 km/s).This stage has a Kevlar-polyamide fiber case and a submerged nozzle equipped with a flex-bearing-seal gimbaled nozzle (±2°) thrust vector engine for pitch & yaw control. Roll control is provided by the fourth stage reaction control system (RCS).Related Articles:-
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Fourth Stage
The fourth stage of PSLV is known as PS-4. The height of the fourth stage is 3 meters or 9.8 ft long and diameter of this stage is 1.3 m (4.3 ft). Around 2.5 tons of earth-storable liquid propellant is used at this stage. The twin L-2-5 engine is used in the fourth stage.Monomethylhydrazine (MMH) and mixed oxides of nitrogen (MON) are used as fuel. Each engine generates 7.4 kN (1,700 lbf) thrust, hence it generates total 14.8 in thrust and is gimbaled (±3°) to provide pitch, yaw & roll control during powered flight. Coast phase attitude control is provided by RCS. The stage carries 2,500 kg (5,500 lb) of propellant in the PSLV and PSLV-XL and 2,100 kg (4,600 lb) in the PSLV-CA.Burn time for this stage is 425 seconds.Specific impulse is noted for PS-4 is 308 s (3.02 km/s).Payload fairing is attached above the fourth stage. In which the spacecraft is housed.Variants Of PSLV
ISRO has constructed a number of variants of PSLV to for different mission requirements. There are currently three operational versions of the PSLV. The three variants of PSLV are:-PSLV-G
PSLV - G is the standard version of the PSLV. PSLV - G consist four stages. These four stages using solid and liquid propulsion systems alternately and also uses the six strap-on boosters.PSLV - G is able to launch 1,678 kg (3,699 lb) to 622 km (386 mi) into sun-synchronous orbit.Related Articles:- What Is Radar? How Radar Works? Applications Of Radar.
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