Metsat, Indias first meteorological satellite, placed
on the Geosynchronous Transfer Orbit (GTO) on 12 September
2002, was successfully manoeuvred from the Mission Control
Facility (MCF) at Hassan, Karnataka.
The manoeuvre was
done by firing the satellites liquid apogee motor for
31.49 minutes on the morning of 13 September. The satellite
carries 560kg of fuel. With this, Metsat is now orbiting
Earth with a perigee (nearest point to Earth) of 12,100
km and an apogee (farthest point to Earth) of 34,500 km.
of the orbit has been reduced from 17.67 degree at the
time of injection to 5 degree. According to Indian Space
Research Organisation (ISRO), the intended intermediate
orbit has been precisely realised. A few more orbital
manoeuvres will be required before the satellite is finally
placed in geostationary orbit and moved to its designated
slot at 74 degree East longitude in that orbit.
are likely to be completed in the next few days. Flight
to glory 1211 seconds or 20 minutes after the blast off
at 3.53 pm, the 295 t, 44.4 m tall Polar Satellite Launch
Vehicle (PSLV-C4) slung its payload the 1055 kg Metsat
over Indonesia at a GTO of 218 km perigee (nearest point
to Earth) and 34,700 km apogee (farthest point to Earth).
orbit will be inclined at angle of 17.7 degrees to the
equator. There were anxious moments 15 minutes before
the blast off due to some minor snag in the computer systems.
As a result the blast-off time was put back by just one
the successful launch, ISRO chairman K Kasturirangan:
For the first time we have launched an exclusive satellite.
Future meteorological satellites can go with complex and
a higher resolution camera. We will have more transponders
in Insat and extend its life to 15 years.
Metsat is the first
exclusive meteorological satellite built by ISRO and a
precursor to the future INSAT system that will have separate
satellites for meteorology and telecommunication and broadcasting
services. This will enable building of transponders and
their radiated power, into Insat satellites, without the
design constraints imposed by meteorological instruments.
The satellite carries
a very high-resolution radiometer (VHRR), capable of imaging
Earth in the visible, thermal infra-red and water vapour
bands. It also carries a data relay transponder (DRT)
for collecting data from unattended meteorological platforms.
Immediately after injection into GTO, Metsats 550 watts
solar array was automatically deployed.
The onboard 18
Ampere-Hour Nickel-Cadmium battery will supply electrical
energy when the satellite is in the earth's shadow (eclipse).
One of the new elements used in Metsat is the light-weight
planar array antenna which transmits the data from the
VHRR and DRT. Similarly, ISRO has used spacecraft bus
employing lightweight structural elements like carbon
fibre reinforced plastic.
The deployment of the array
as well as the general health of the satellite will be
monitored by a ground station of the ISRO telemetry, tracking
and command network (ISTRAC) located on the Indonesian
island of Biak. While the MCF, Hassan takes control of
Metsat for all its post launch operations ground stations
at Lake Cowichan (Canada), Fucino (Italy) and Beijing
(China) will support MCF in monitoring the health of the
satellite and its orbit raising operations.