ISRO
ISRO will provide the space segment for EDUSAT
System and demonstrate the efficacy of the satellite
system for interactive distance education
EDUSAT is the first exclusive satellite for serving
the educational sector. It is specially configured
for audio-visual medium, employing digital
interactive classroom and multimedia multicentric
system. The satellite will have multiple regional
beams covering different parts of India
Five lower Ku-band transponders for spot beam
coverage with 55 dBW Edge of Coverage-Effective
Isotropic Radiated Power (EOC-EIRP) One lower
Ku-band transponder for national coverage with 50
dBW EOC-EIRP Six upper extended C-band transponders
for national coverage with 37 dBW EOC-EIRP One
Ku-band beacon to help ground users for accurate
antenna pointing and uplink power control
The prime objective of ISRO has been to develop
space technology and its application to various
national tasks. Since 1969, when it was set up, ISRO
has established space systems like the INSAT for
telecommunication, television broadcasting and
meteorological services, and the Indian Remote
Sensing Satellites (IRS) for resources monitoring
and management. ISRO has also developed the
satellite launch vehicles PSLV and GSLV to place
these satellites in the required orbits.
EDUSAT will be launched by the third flight of
ISRO’s Geosynchronous Satellite Launch Vehicle.
Designated as GSLV-F01, this is the first
operational flight of the vehicle. In its two
developmental test flights conducted in April 2001
and May 2003 respectively, GSLV successfully
launched GSAT-1 and GSAT-2 satellites into
Geosynchronous Transfer Orbits (GTOs).
In the first developmental test flight (GSLV-D1),
the vehicle placed 1530 kg GSAT-1 into GTO and in
the second developmental test flight (GSLV-D2), it
placed 1825 kg GSAT-2 into GTO. In its first
operational flight (GSLV-F01), GSLV will launch the
1950 kg EDUSAT.
The 49 metre tall GSLV is a three stage vehicle. The
first stage, GS1, comprises a core motor with 138
tonne of solid propellant and four strap-on motors
each with 40 tonne of hypergolic liquid propellants
(UH25 and N204). The second stage has 39 tonne of
the same hypergolic liquid propellants. The third
stage (GS3) is a cryogenic stage with 12.5 tonne of
Liquid Oxygen and Liquid Hydrogen.
The Aluminum alloy GSLV payload fairing is 3.4 m in
diameter and is 7.8 m long. GSLV employs various
separation systems such as Flexible Linear Shaped
Charge (FLSC) for the first stage, pyro actuated
collet release mechanism for second stage and Merman
band bolt cutter separation mechanism for the third
stage. Spacecraft separation is by spring thrusters
mounted at the separation interface. The three-axis
attitude stabilisation of GSLV is achieved by
autonomous control systems provided in each stage.
Single plane Engine Gimbal Control (EGC) of the four
strap-ons of the first stage are used for pitch, yaw
and roll control. The second stage has Engine Gimbal
Control (EGC) for pitch and yaw and hot gas Reaction
Control System (RCS) for roll control. Two
swivellable vernier engines using LH2 and LOX
provide pitch, yaw and roll control for the third
stage during thrust phase and cold gas system during
coast phase. The Inertial Guidance System (IGS) in
the Equipment Bay (EB) housed above the third stage
guides the vehicle till spacecraft injection. The
closed loop guidance scheme resident in the on-board
computer ensures the required accuracy in the
injection conditions.
For more details, please visit:
www.isro.org
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