SPACE LAUNCH VEHICLES
PSLV - Polar Satellite Launch Vehicle
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The PSLV-C2 on the launch pad (Source: ISRO) High Res - PSLV Model Photo (735kb) |
The Polar Space Launch Vehicle is a versatile heavy launcher developed to permit India to launch its own IRS-class 1600Kg satellites in sun-synchronous orbits, though it could also be used for GTO mission. It also served as the stepping-stone for GSLV heavy lift configuration for mainstream GTO orbit. The basic PSLV configuration is 44.4 meter tall weighing 295 tonne and four stages using solid and liquid propulsion systems alternately. The first stage is amongst the largest solid propellant boosters in the world and carries between 129 to 138 tonnes of Hydroxyl Terminated Poly Butadiene (HTPB) based propellant. It has a diameter of 2.8 m. Its motor case is made of maraging steel. The booster is a five-segment solid rocket motor with HTPB propellant and a composite nozzle. Each segment is 2.8 m in diameter by 3.4 m long. The booster motor fires for 107 seconds and develops a maximum thrust of about 4762 kilo Newton (as against 4,628kN of pre-C4 mission). Pitch and yaw control of the PSLV during the thrust phase of the solid motor is achieved by injection of an aqueous solution of strontium perchlorate in the nozzle to constitute Secondary Injection Thrust Vector Control System (STIVC)[29]. The injection is stored in two cylindrical aluminum tanks strapped to the solid rocket motor and pressurized with nitrogen. SITVC in two strap-on motors is for roll control augmentation Of the six strap-on motors (PSOM), depending on mission requirement first two or four of PSOM are ignited on the ground, to augment the first stage thrust. Each of these solid propellant strap-on motors carries nine tonne of HTPB based propellant, burn for 45 seconds and produces 662 kN thrust. The remaining strap-on motors are ignited 25 seconds (at ~3 Km altitude) after lift off. The second stage employs indigenously built Vikas engine based on the Viking IVA engine of SEP France and carries 41.5 tonne (as against 40 tonne in pre-C5 missions) of liquid propellant - Unsymmetrical Di-Methyl Hydrazine (UDMH) as fuel and Nitrogen tetroxide (N2O4) as oxidizer. It generates a maximum thrust of about 800kN (725kN in pre C5 mission). Pitch & yaw control is obtained by hydraulically gimbaled engine (±4°) and two hot gas reaction control for roll. Future launch will use an uprated version of the Vikas engine that tested in December 2001 that develop a chamber pressure of 58.5 bar against 52.5 bar in the previous version. This new engine uses UH25 (a mixture of Unsymmetrical Di-methyl Hydrazine and hydrazine hydrate) as fuel and nitrogen tetroxide as oxidizer, its new silica-phenolic throat allows extended duration of burning time. It is estimated to increase the stage ISP by about 7 seconds, raising PSLV's SSO payload capability by 70Kg and GTO payload capability by 41Kg[30]. The third stage is a high performance solid motor with 8.4 tonne mass, 7.2 tonne HTPB based propellant (PSLV-C3 had 7.3 tonne and PSLV-C4 had 7.6 tonne) and 2-meter diameter. It has as Kevlar-polyamide fiber case and a submerged nozzle equipped with a flex-bearing-seal gimbaled nozzle (±2°) thrust-vector engine for pitch & yaw control. For roll control it uses the RCS (Reaction Control System) of fourth stage. PSLV-C5 onwards the metallic third stage adapter was replaced by one built using carbon composites. The fourth stage of PSLV has a diameter of 1.3 meter & use twin pressure-fed liquid fuelled engine configuration. The stage has propellant loading of 2 tonne (PSLV-C4 used 2.5 tonne) Mono-Methyl Hydrazine (MMH) as fuel and Mixed Oxides of Nitrogen as oxidizer, each of these engines generates a maximum thrust of 7.4 kN. Engine is gimbaled (±3°) for pitch, yaw & roll control and for control during the coast phase uses on-off RCS. PSLV-C4 used a new lightweight carbon composite payload adopter to enables greater GTO payload capability. HAL made 3.2 m diameter metallic bulbous heat shield of PSLV, of isogrid construction, protects the spacecraft during the PSLV's passage through the dense atmosphere. It is discarded at an altitude of about 110 Km. PSLV's Inertial Navigation System (INS) is situated in its equipment bay, which is located on top of the vehicle's fourth stage. INS guides the vehicle from lift-off to spacecraft injection into orbit. |
PSLV Rocket Configuration:
PSLV has many progressive configurations suitable for different missions. Many of the following performance specification are typical.
First Launch Date: 20 September 1993.
LEO Payload: 3,700 kg to 200 km Orbit at 49.5
degrees inclination; 3,500Kg to 400 Km circular orbit, 43 degrees inclination ;
SSO Orbit: 1200Kg to: 820Km Orbit (limited to 1200Kg due to down range safety);
GTO Payload: 1060 kg (upto 1350Kg [31]) to 18 deg inclination . Liftoff Thrust:
540,000 kgf. Total Mass: 294,000 kg.
Core Diameter: 2.8 m.
Total Length:
44.4
m. Launch Price $: 30.00 million. in 1999 price dollars.
Flyaway Unit Cost $:
17.50 million [32]. in 1985 unit dollars.
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PS0/PSOM (S9) |
PS1 (S125) |
PS2 (L40) |
HPS3 (S7) |
PS4 (L2) |
Payload
Faring |
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Gross_Mass Fuel_Mass Empty_Mass (Stage
Mass-Ratio) |
10,930 Kg 8,920 Kg 2,010 Kg (0.816) |
168,200Kg 138,000Kg 30,200Kg (0.820) |
46,000 Kg 40,600 Kg 5,400 Kg (0.883) |
8,300 Kg 7,600 Kg 1,100 Kg (0.869) |
2,920 Kg 2000 Kg 920 Kg (0.685) |
1,100 Kg |
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Motor
Mass-Ratio |
0.851 |
0.873 |
0.884 |
0.915 |
0.692 |
N.A. |
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Thrust@Vacuum Thrust@Sea_Level (Burn_Time) |
51,251 Kgf 46,390 Kgf (45 sec) |
495,590Kgf Kgf (108 sec) |
73,931 Kgf - (162 sec) |
33,519 Kgf - (109 sec) |
1,428 Kgf - (420 sec) |
N.A. |
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Specific-Impulse Isp@Vacuum
Isp@Sea_Level[33] |
253 sec 229 sec |
269 sec 237 sec |
296 sec 200 sec |
294 sec 190 sec |
308 sec 110 sec |
N.A. |
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Length Diameter |
10.0 m 1.0 m |
20.3 m 2.8 m |
12.5 m 2.8 m |
3.6 m 2.0 m |
2.6 m 2.8 m |
8.3 m [34]
3.2 m |
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Chamber
Pressure[35] Expansion
Ratio |
44.1 bar 6.6:1 |
58.8 bar 8:1 |
52.5 [36] bar 31:1 |
60.4 bar 53:1 |
8.5 bar 60:1 |
N.A. |
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Propellant |
Solid |
Solid |
Liquid |
Solid |
Liquid |
Aluminum Alloy |
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Number
of Engines (Number
of Segments) |
6 motors (3) |
1 motors (5) |
1 (NA) |
1 (1) |
2 (NA) |
N.A. |
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Control
system |
SITVC for
roll control |
Multi-port
SITVC for pitch & yaw |
ECS two
plane gimballing for pitch & yaw control. Hot gas RCS for roll control. |
Gimbaled
thrust vector for pitch & yaw. Roll control-using RCS of 4th
stage. |
Gimbaled thrust
for pitch, yaw and roll. |
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PSLV-C4 Configuration
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Trajectory: Two ballistic phases occurred
during the flight: one after second stage shutdown (around 88 km altitude)
and a longer one after third stage shutdown till it reaches perigee altitude. |
PSLV
Flights:
PSLV-D1
Flight date
& time:20 Sept 1993, 05:12 GMT, Satish Dhawan Space Center, SHAR,
Sriharikota
Payload: IRS 1E (845 Kg)
Flight
sequence, result and discussion: Failure.
Although all strap-ons and main engines performed as expected, an attitude control problem
arose after separation of the second and third stages. The failure of this
flight was primarily due to a software error in the pitch control loop of the
on-board guidance and control processor, and the failure of two small retro
rockets leading to a contact between second and third stages, during the separation
of the second stage. Consequently, the vehicle and its payload failed to reach
Earth orbit.
PSLV D2
Flight date: 15 Oct 1994, 05:05
GMT, Satish Dhawan Space Center, SHAR, Sriharikota
Payload: IRS-P2 (904 Kg)
Flight
sequence, result and discussion:
Successful launch. Orbit: 818 x
820 Km, Inclination: 98.7°(?)
PSLV D3
Flight
date:
21 March 1996, 04:53 GMT, Satish Dhawan Space Center, SHAR, Sriharikota
Payload: IRS-P3 (920 Kg)
Flight
sequence, result and discussion:
Successful launch. Orbit: 818 x
821 Km, Inclination: 98.7°
PSLV C1
Flight
date:
29 Sept 1997, 04:47 GMT, Satish Dhawan Space Center, SHAR, Sriharikota
Payload: IRS-P3 (1200 Kg)
Flight
sequence, result and discussion: Successful launch. Orbit: 301 x 822 Km,
Inclination: (?)°
Several improvements were incorporated in the first operational flight of PSLV (PSLV-C1) to increase its payload capability to 1,200 kg. The major improvements included: increasing the solid propellant in the first core stage from 128 tonne to 138 tonne; increasing the liquid propellant loading in the second stage from 37.5 tonne to 40. 6 tonne by stretching the stage tank; replacing the metallic payload adopter by a CFRP adopter and; effecting weight reduction in the vehicle equipment bay. Besides, in the PSLV-C1 mission, four of the six strap-on motors were ignited on the ground along with the core first stage; in the earlier flights only two were ignited on the ground and the remaining a few seconds after lift-off. This revised sequence gave a substantial payload advantage[37].
A slight underperformance of PSLV forth stage resulted in a velocity shortfall of 130m/sec (of the required 7446 m/sec). It was inserted in an orbit of 822 x 301 km instead of 817 km circular orbit. The orbit was corrected to 737 x 821 km using satellite fuel, and more then 3 years of satellite life was realized.
PSLV C2
Flight
date:
26 May 1999, 06:22 GMT, Satish Dhawan Space Center, SHAR, Sriharikota
Payload:
IRS-P4 (OCEANSAT) (1050 Kg),
DLR-TUBSAT (45 Kg),
KITSAT-3 (103 Kg)
Flight sequence, result and discussion: Successful launch. Orbit: 716 x 738 Km, Inclination: 98.3°
PSLV C3
Flight
date:
22 Oct 2001, 10:23 IST Satish Dhawan Space Center, SHAR, Sriharikota
Payload:
TES (1108 Kg)
BIRD {German} (92 Kg)
PROBA {Belgium} (94 Kg)
Flight sequence, result and discussion: Successful launch.
TES & BIRD: Orbit: 550 x 579 Km, Inclination: 97.8°
PROBA: Orbit: 568 x 638 Km, Inclination: 97.8°
(Source: ISRO)
TES (Technological Experimental Satellite): weighing 1108 kg, is an experimental satellite to demonstrate and validate, in orbit, technologies that could be used in the future satellites of ISRO including attitude and orbit control system, high torque reaction wheels, new reaction control system with optimized thrusters and a single propellant tank, light weight spacecraft structure, solid state recorder, X-band phased array antenna, improved satellite positioning system, miniaturized TTC and power system and, two-mirror-on-axis camera optics. TES also carried panchromatic camera for remote sensing.
BIRD: of the German Space agency, DLR, is a small satellite weighing 92 kg, intended for testing small satellite technologies and a new generation of infrared sensors for the detection of hot spots like forest fires and volcanoes from space. PROBA (PRoject for On-Board Autonomy, 1) was a European Space Agency technology development is a small satellite weighing 94 kg. The payloads in the satellite include high resolution camera with 115 mm diameter aperture and wide angle camera having aperture of 60 mm. It carried a radiation detector, an IR spectrometer, debris impact detectors and an experimental spacecraft processor for spacecraft autonomy experiments. The satellite was built by Verheart in Belgium using the MiniSIL bus developed by SI of England, and was controlled from Belgium.
A few improvements have been carried out in the PSLV-C3 compared to PSLV-C2. They include introduction of lightweight fourth stage (PS4) tank for better vehicle performance, ball-lock separation system for the separation of auxiliary satellite whose interface is also compatible with the European Ariane vehicle.
Flight Profile for High-altitude and Medium-altitude Sun-Synchronous Polar Orbit launch (click on image for Higher Res. image)
Trajectory: Two ballistic phases occurred during the flight: one after second stage shutdown (around 88 km altitude) and a longer one after third stage shutdown till it reaches perigee altitude.
The mission profile for PSLV-C3 has been modified to place the three satellites in their specified orbits. The Indian satellite, TES and the German satellite BIRD were placed in a 568 km Sun-synchronous orbit where as the third satellite, the Belgian PROBA was raised to an elliptical orbit of 568 x 638 km by firing the RCS(Reaction Control System) thrusters of PS4. Two axial thrusters were fired for duration of about 500 seconds in order to impart the necessary increment velocity to put PROBA in the required orbit.
A Data Storage Unit (DSU), which stores the telemetry parameters and transmits in delayed mode was introduced, which takes care of any break in the radio visibility between the vehicle and the ground stations located at Thiruvananthapuram and Mauritius as well as recording of the PROBA separation event. The PROBA separation related parameters are transmitted when the stage passes over the Lucknow ground station of ISRO.
Unlike earlier PSLV missions C3 mission involved firing 4 strap on motors at launch rather then 2, thereby improving the payload capability (reducing the overall ISP loss due to gravity).
Flight
date:
12 Sept 2002, Satish Dhawan Space Center, SHAR, Sriharikota
Payload: METSAT-1 (KALPANA-1)
(1055Kg)
Flight
sequence, result and discussion: Successful launch. Orbit: GTO 216 x 34,641
Km, Inclination: 17.7°
An in-depth article discussing the PSLV-C4 mission can be found here: http://www.bharat-rakshak.com/MONITOR/ISSUE5-3/arun.html
Unlike earlier polar launch mission this PSLV mission was to launch METSAT (Kalpana-1) on Geostationary-Transfer Orbit(GTO) for eventual transition to equatorial Geo-stationary Orbit(GSO).
The satellite was named KALPANA-1 by Prime Minister AB Vajpayee in honor of astronaut Kalpana Chawla who died in the Columbia Space Shuttle disaster on 01-Feb-2003.
Flight
date:
17 Oct 2003, 10:22AM (IST) Satish Dhawan Space Center, SHAR, Sriharikota
Payload: Resourcesat-1 (IRS-P6)
(1,360Kg)
Flight
sequence, result and discussion: Successful launch. Orbit: SSO 821 circular, Inclination:
98.76°
Flyaway Unit Cost:
Rs.80 Crore. (i.e. Rs.800 million; ~US$19million).
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| Resourcesat-1, mounted on top of the PSLV-C5's fourth stage. (Source: Frontline, Vol 20 - Issue 22, Oct 25 - Nov, 07, 2003) | Resourcesat-1 in space (artistic rending). (Source: ISRO) |
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| RESOURCESAT-1 sitting on top of PSLV-C5 fourth stage. Source: www.isro.org | RESOURCESAT-1 undergoing pre-launch tests at ISRO Satellite Centre Source: www.isro.org |
This was first ISRO mission that was launched under inclement northeast monsoon weather, under rain and heavy overcast sky. Heavy rain, which began a few hours before the launch, persisted past the lift-off time. The flight trajectory did not have any deviation. The former ISRO chairmen U R Rao and K Kasturirangan were present in the control room during the launch. The Union Minister of State for Space Satyabrata Mookherjee was also present (Source: The Times Of India. 17 Oct 2003. "PSLV blasts off in inclement weather"). The success was creditable because the mission was carried out by a new project team that included Mission Director N. Narayana Moorthi, Satellite Director K.S.V. Seshadri and Vehicle Director George Koshy.(Source:Frontline). Unlike the earlier launches, the vehicle was not visible to the naked eye during its ascent, thanks to the overcast sky. Further, ISRO wanted the satellite to cross the equator at 10.30 am, and hence the morning launch.
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| The launch vehicle, in the final stages of preparation for the launch (Source: Frontline, Vol 20 - Issue 22, Oct 25 - Nov, 07, 2003) . | PSLV-C5 takeoff in inclement weather. Thick clouds shrouded the vehicle speeding into the horizon, much to the disappointment of lensmen (Source: Frontline, Vol 20 - Issue 22, Oct 25 - Nov, 07, 2003) | |
PSLV-C5 launcher is an improved configuration as compared to the C4 mission. The PS-1 core booster thrust is improved at 4762 kN (vs 4628 kN). The PS-2 liquid stage was loaded with 41.5 tonne fuel (vs 40.6 tonne) and improved thrust 800 kN(vs 725 kN). The second stage has a high-pressure engine to give more power. The metallic third stage adapter is replaced by the one built with carbon composites. This time the engineers have optimised many structures in the launch vehicle. The satellite was injected into orbit at the predicted velocity, 1,082 seconds (18 minutes) after lift-off as against the targeted 1,084 seconds. Dr. B.N. Suresh, the new Director of the VSSC, said: "It was a very precise mission. Every stage performed exactly as predicted. All operations, including the ignition of the stages and their cut-off, took place within one or two seconds of the appointed time." Indeed, the second and fourth stages had some more energy left [Ref: Frontline]
PSLV-C5 was initially slated to also carry a 40Kg HAMSAT micro-satellite as piggyback. But some performance deviations were noted during the thermo-vacuum test. As the corrections could not be made within the time limit, Hamsat has to be left behind this time and will be accommodated on one of the subsequent flights (PSLV-C6).
Since its first flight in 1993, the payload capability of PSLV has been progressively improved by more than 600 kg.
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