It carries twenty four transponders
_ twelve operating in the normal C-band frequency, six in Extended
C-band and six in Ku-band. Nine of the twelve normal C-band transponders
provide expanded coverage and the remaining three have India coverage
beam. All the extended C-band as well as the Ku-band transponders
have India coverage beams. INSAT-3A also carries a Ku-band beacon.
For meteorological observation, INSAT-3A
carries a three channel Very High Resolution Radiometer (VHRR) with
2 km resolution in the visible band and 8 km resolution in thermal
infrared and water vapour bands. In addition, INSAT-3A carries a
Charge Coupled Device (CCD) camera which operates in the visible
and short wave infrared bands providing a spatial resolution of
1 km. A Data Relay Transponder (DRT) operating in UHF band is incorporated
for realtime hydrometeorological data collection from unattended
platforms located on land and river basins. The data is then relayed
in extended C-band to a central location.
INSAT-3A also carries another
transponder for Satellite Aided Search and Rescue (SAS & R)
as part of India's contribution to the international Satellite Aided
Search and Rescue programme.
INSAT-3A is launched by European
Ariane-5 Launch Vehicle into a Geosynchronous Transfer Orbit (GTO)
with a perigee of 200 km and an apogee of 35,980 km. The satellite
is manoeuvered to its final orbit by firing the satellite's apogee
motor. Subsequently, the deployment of solar array, antennae and
the solar sail is carried out and the satellite is commissioned
after in-orbit checkout.
INSAT-3A is the third satellite
in the INSAT-3 series. INSAT-3B and INSAT-3C were launched in March
2000 and January 2002 respectively by the Ariane launch vehicle
and both the satellites are now providing regular service. INSAT-3A
is to be located at 93.5 deg east longitude in the geostationary
orbit.
INSAT is a multipurpose satellite
system for telecommunications, broadcasting, meteorology and search
& rescue services. Commissioned in 1983, INSAT is the largest
domestic communication system in the Asia-Pacific Region. It now
comprises of five satellites _ INSAT-2DT, INSAT-2E, INSAT-3B, INSAT-3C
and METSAT _ with a total capacity of over hundred transponders
in C, Extended C and Ku-bands besides meteorological instruments.
