| Satellites: : Aryabhata | APPLE | INSAT-1
| INSAT-2
| INSAT-3
| Bhaskara
| IRS | Rohini Launcher
: : SLV
| PSLV | ASLV | GSLV
INSAT-1A | INSAT-1B | INSAT-1C | INSAT-1D
Between 1982 and 1990 four U.S.-built INSAT 1
satellites were launched to support Indian
domestic communications and Earth observation
requirements as a joint venture among the Indian
Department of Space, the Department of
Telecommunications, the Meteorological
Department, All-India Radio, and All India
Doorarshan Television. The Ford Aerospace
spacecraft had a mass of 650 kg on station and
carried twelve 6/4 GHz transponders with an
output power of 4.5 W and three (two active plus
one backup) 6/2.5 GHz transponders. Both INSAT 1A
(April, 1982) and INSAT1C (July, 1988) were lost
due to malfunctions within 18 months of launch.
INSAT 1B (August, 1983) was no longer in
operational service during 1993-1994, instead
being used for special experiments. INSAT 1 D
(June, 1990) was operational at 83 degrees E.
INSAT-2A | INSAT-2B | INSAT-2C | INSAT-2D | INSAT-2E
The INSAT 2 program was underway in 1983 to
develop an indigenous multi-purpose GEO
spacecraft that relied heavily on the previous
Ford Aerospace design. In 1985 the basic
spacecraft configuration was adopted, calling for
an on-station dry mass of 860 kg which later rose
to 910 kg (1,160 kg at beginning of life). The
communications payload was increased with six
additional 7/5 GHz transponders for a total of
18, plus two S-band transponders. The spacecraft
bus is rectangular with side dimensions of 1.6 m
by 1.7 m by 1.9 m. The asymmetric, accordion type
solar panel produces 1.4 kW at beginning of life
and is offset on the other side of the bus by an
extendible solar sail.
INSAT 2A was finally launched on 9 July 1992
by an Ariane booster, about three years behind
schedule. The spacecraft was positioned at the
primary INSAT location of 74 degrees E, which was
vacated by INSAT 1B in April, 1992. INSAT 2B was
launched 22 July 1993 by an Ariane rocket and
positioned at 93.5 degrees E.
In March, 1994, India selected Arianespace to
launch INSATs 2C and 2D in 1995 and 1996,
respectively. The design lifetime is nine
years.The spacecraft are similar to the earlier
INSATs but are 200 kg heavier at launch (2,100
kg) and will carry larger solar arrays for 1.6 kW
of electrical power. The communications payload
consists of 12 C-band, 6 extended C-band, 3
Ku-band, and 2 S-band transponders plus a new
low-power C-band transponder for a mobile
communicatins feeder. INSAT-2C and INSAT-2D, in
addition to carrying communication transponders
in INSAT-2A and 2B, incorporate Ku-band
transponders for business communication, extended
coverage C-band transponders to enable TV
programme outreach beyond Indian boundaries
catering to the population from South East Asia
to the Middle East and transponders for mobile
service. They do not have the meteorological
payload. INSAT-2C and INSAT-2B are co-located in
the geostationary orbit thus enabling efficient
use of allocated orbital slots.
While INSAT-2A and INSAT-2B are almost
identical twins INSAT-2C and INSAT-2D are
different; they do not carry the meteorological
payload. But INSAT-2E, which was successfully
launched on 03 April 1999 by the European Ariane
Rocket at Kourou in French Guyana, carries an
improved version of the VHRR as the
meteorological payload. INSAT 2E also features a
special INTELSAT compatibility. DOS will lease to
INTELSAT organization eleven 36 MHz equivalent
units of C-band capacity on board INSAT-2E. The
capacity for use by INTELSAT is being built into
INSAT-2E.
Each INSAT satellite is the product of the
well-orchestrated effort of the four major
centres of ISRO. The main frame of the satellite
which carries the controls, telemetry and
tele-command, deployment and power systems is
manufactured by the ISRO Satellite Center at
Bangalore, which also does the mission planning
and analysis and manages the whole project. The
gyro units, reaction wheels and momentum wheels,
to keep the satellite stable in orbit, are
fabricated at the Vikram Sarabhai Space Center,
Thiruvanthapuram, which is also responsible for
the antenna reflectors and scanning mechanism for
the Very High Resolution Radiometer(VHRR), that
forms the main meteorological payload of INSAT.
The VHRR itself is a contribution of the Space
Applications Center, Ahmedabad, which also
provides for communications transponders. Another
vital component, the apogee boost motor (that
takes the satellite from its transfer orbit to
the geostationary orbit) and the thrusters
(required for maintaining the satellite in its
assigned slot in orbit) are manufactured at the
Liquid Propulsion Systems Center at
Thiruvanthapuram.
INSAT has enabled a vast expansion in the
television service with over 800 TV transmitters
linked through INSAT. The television network
provides access to over 80 per cent of
India’s population. INSAT-2C and INSAT-2D
enable Indian television outreach beyond Indian
boundaries catering to the population from South
East Asia to Middle East. Educational television
service through INSAT has been introduced both at
university level in the national network and at
primary school level in several states including
Andhra Pradesh, Orissa, Maharashtra, Gujarat and
Uttar Pradesh. A channel on the INSAT has been
dedicated for development of education and
training. A two-year pilot project for
demonstration of satellite-based developmental
communication and training has been taken up in
Jhabua district of Madhya Pradesh.
INSAT is unique in its design combining
telecommunication, television and radio
broadcasting and meteorological services on a
single platform. The involvement of various users
like Department of Telecommunication, Ministry of
Information and Broadcasting. India
Meteorological Department enabled proper tuning
of INSAT system towards identified national
developmental needs. Work on INSAT-3 series of
satellites has already begun. Five satellites in
the INSAT-3 series have been planned and the
first two satellites, INSAT-3A and INSAT-3B were
initially planned for launch in 1999 and 2000.
Sources and
Resources
- Other source : www.bharatrakshak.com
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