initially designed by ISRO to place 1,000 kg class Indian Remote Sensing (IRS)
satellites into 900 km polar Sun-synchronous Orbits. Since the first successful
flight in October 1994, the capability of PSLV has been enhanced from 850 kg to
the present 1,600 kg into 618 km polar Sun Synchronous Orbit. The improvement
in the capability over successive flights has been achieved through several
means. They include increased propellant loading in the stage motors, employing
composite material for the satellite mounting structure and changing the
sequence of firing of the strap-on motors.
In its present configuration, the 44.4 metre tall, 295 tonne PSLV has four
stages using solid and liquid propulsion systems alternately. The first stage,
carrying 138 tonne of propellant, is one of the largest solid propellant
boosters in the world. Six solid propellant strap-on motors, each carrying nine
tonne of solid propellant, are strapped on to the core stage. The second stage
carries 41.5 tonne of liquid propellant. The third stage uses 7.6 tonne of
solid propellant and the fourth has a twin engine configuration with 2.5 tonne
of liquid propellant.
The 3.2 metre diameter metallic bulbous heat shield protects the satellites and
it is discarded after the vehicle has cleared the dense atmosphere. PSLV
employs a large number of auxiliary systems for stage separation, heat-shield
separation and so on. It has sophisticated systems to control the vehicle and
guide it through the predetermined trajectory. The vehicle performance is
monitored through telemetry and tracking.
With seven consecutively successful flights so far, PSLV has proved itself as a
reliable workhorse. It has demonstrated multiple satellite launch capability
having launched four small satellites for international customers besides seven
Indian satellites. PSLV was used to launch ISRO's exclusive meteorological
satellite, KALPANA-1, into a Geo-synchronous Transfer Orbit (GTO) in September
2002. The vehicle will be used to launch a spacecraft for India's first mission
to Moon, Chandrayaan-1.
Vikram Sarabhai Space Centre (VSSC), Thiruvananthapuram, designed and developed
PSLV. The ISRO Inertial Systems Unit (IISU) at Thiruvananthapuram developed the
inertial systems for the vehicle. The Liquid Propulsion Systems Centre (LPSC),
also at Thiruvananthapuram, developed the liquid propulsion stages for the
second and fourth stages of PSLV as well as reaction control systems. SDSC SHAR
processed the solid motors and carried out launch operations. ISRO Telemetry,
Tracking and Command Network (ISTRAC) provides telemetry, tracking and command
Second Launch Pad (SLP)
SLP built at SDSC SHAR at Sriharikota is a state-of-the-art launch complex. SLP
is configured as a universal launch pad capable of accommodating all the
vehicles of ISRO including the advanced launch vehicle to be built in the next
decade and beyond (unlike dedicated pads elsewhere in the world mainly catering
to a particular launch vehicle).
SLP uses integrate-transfer-and-launch concept. The launch vehicle is integrated
inside a permanent building called Vehicle Assembly Building (VAB). After
checkout, it is transported on rails to the launch pad using a Mobile Launch
Pedestal (MLP). The vehicle is then interfaced with the launch pedestal and
fuel-filling and checkout operations carried out. The launch takes place after
the final countdown. SLP helps to increase the launch frequency by reducing the
turn-around time between the integration of the fully assembled vehicles.
SLP was built by involving Indian industry on a turnkey basis including design
and engineering, procurement of systems and sub-systems, fabrication, erection
and commissioning of facilities including civil works.
SLP consists of the following major elements:
Vehicle Assembly Building (VAB):
It is in this building that the vehicle integration is carried out on a Mobile
Launch Pedestal (MLP) and then the vehicle transferred to Umbilical Tower for
launch after carrying out the total checkout of the integrated vehicle. The 82
m tall VAB houses 200 tonne and 30 tonne capacity cranes for lifting vehicle
stages. It has 20 horizontal sliding doors of varying sizes with the largest
being 13 x 20 m. Six 14 x 6 m foldable and vertically repositionable platforms
at different levels help vehicle integration and servicing. VAB is equipped
with an elevator also.
Mobile Launch Pedestal (MLP):
The 19.5 x 19.5 m MLP with bogie system is used to transfer the integrated
vehicle from VAB to the launch pad located at a distance of 1 km. With a height
8.6 m, MLP weighs about 700 tonne and caters for both PSLV and GSLV
requirements. It has a removable bogie system at the bottom, which has a
Umbilical Tower (UT):
The 70 m tall, 10 x 10 m UT weighs about 980 tonne. The fully integrated
vehicle on MLP, on its arrival on rails, is interfaced with the UT with
electrical, pneumatic and fluid filling lines. The final operations like fuel
filling, gas charging and the vehicle checkout are carried out on UT. It has
three platforms, which can be swung and also moved vertically to different
levels. UT has an elevator and a 10 tonne tower crane at the top of the tower.
It has a cryo arm for cryogenic fuel filling operations and monitoring till the
last minute of launch operations.
Jet Deflector: The jet deflector system is used to move the hot gases, ejected
from the launcher during lift-off, away from the launch pad so as to reduce the
thermal and acoustic loads on the vehicle. The design and construction of jet
deflector was one of the major engineering challenges. It has diaphragm wall
construction with piles driven 45 m below ground, constructed for the first
time on the east coast of India.
Lightning Protection Towers:
In order to protect the launch vehicle from severe lightning when the vehicle
is exposed for longer duration, lightning protection towers are erected around
UT. There are four lightening protection towers of 120 m height around UT,
which are interconnected through cables.
Propellant Storage and Servicing Facilities:
Propellant storage and servicing facilities cater to storage of about 1000
tonne of earth storable propellants (UDMH and N2O4), cryogenic propellants
(liquid Oxygen and liquid Hydrogen), water, etc. A large gas storage and supply
system to supply the required quantity of Helium for on-board systems and
Nitrogen system for meeting the purging requirements is part of this facility.
A water tank of 5 lakh litre capacity is also included.
Utilities: These include instrumentation and control systems, compressed air and
fire fighting system, overhead tank, water treatment plant, electrical
substation, air conditioning plant and safety system.
Track for Movement of MLP: MLP with the integrated vehicle moves on a twin
double rail track with a span of 14 m and a length of 1 km.
is the eleventh satellite in the Indian Remote Sensing satellite series. It is
a state-of-the art remote sensing satellite built by ISRO. Weighing 1560 kg at
lift-off, CARTOSAT-1 is intended for cartographic applications. The satellite
will be launched into a 618 km high polar Sun Synchronous Orbit.
carries two state-of-the-art Panchromatic cameras that take black-and-white
stereoscopic pictures in the visible region of the electromagnetic spectrum.
The imageries will have a spatial resolution of 2.5 metre. The cameras cover a
swath of 30 km and they are mounted in such a way that near simultaneous
imaging of the same area from two different angles is possible. This
facilitates in generating three-dimensional maps. The cameras are steerable
across the direction of satellite's movement to facilitate the imaging of an
area more frequently. CARTOSAT-1 also carries a Solid State Recorder with a
capacity of 120 Giga Bits to store the images taken by its cameras. These
images can later be transmitted when the satellite comes within the visibility
of a ground station.
Soon after its injection into orbit, the two solar panels of CARTOSAT-1 are
deployed. The satellite health will be continuously monitored from the
Spacecraft Control Centre at Bangalore with the help of ISTRAC network of
stations at Bangalore, Lucknow, Mauritius, Bearslake in Russia and Biak in