The Indian Space Research Organisation's (ISRO)
latest communication satellite, Insat-4B, was successfully
launched early this morning by the European Ariane-5
ECA launch vehicle of Arianespace.
3,025 kg Insat-4B is the second satellite in the INSAT-4
series. An identical satellite, Insat-4A, was launched
by Ariane-5 on December 22, 2005.
12 high power Ku-band transponders and 12 C-band transponders,
Insat-4B will further augment the Insat capacity for
Direct-To-Home (DTH) television services and other communication
and TV services. With the addition of Insat-4B, the
communication capacity will be further increased to
199 transponders from the present 175 transponders.
31st flight in Ariane-5 series, carrying ISRO's satellite
along with the EADS Astrium Skynet-5A, lifted off at
03:33 am Indian Standard Time (IST) from Kourou, French
30 minutes after lift-off, Insat-4B was placed in the
Geosynchronous Transfer Orbit (GTO) in 3-axis stabilised
mode. The satellite is now orbiting the earth with a
perigee (nearest point to earth) of 243 km and an apogee
(farthest point to earth) of 35,876 km and an inclination
of 4.52 deg with respect to the equator. The orbital
period is about 10 hours 34 minutes.
Master Control Facility (MCF) at Hassan in Karnataka
received the first signals from Insat-4B at 4:02 am
IST. The initial checks on the satellite have indicated
satellite's normal health. MCF subsequently issued commands
to the satellite to make the earth viewing face to orient
towards earth. The calibration of the gyros on board
the satellite was also carried out.
satellite is being tracked, monitored and controlled
from MCF. During the initial phase operations, MCF also
utilises INMARSAT Organisation's Telemetry, Tracking
and Command (TTC) ground stations at Beijing (China),
Fucino (Italy) and Lake Cowichan (Canada) besides the
ISRO Telemetry, Tracking and Command (ISTRAC) Network
station at Biak in Indonesia. The satellite's orbit
is being precisely determined by continuous ranging
from the participating ground stations.
the coming days, Insat-4B will be manoeuvred to its
final geostationary orbit, which is about 36,000 km
above the equator, by firing its 440 Newton Liquid Apogee
Motor (LAM). When the satellite reaches near geosynchronous
orbit, deployment of its solar panels and the two antennas
will be carried out and the satellite put in its final
3-axis stabilised mode.
will be followed by trim manoeuvres to take the satellite
to its designated orbital slot at 93.5 degree East longitude
where it will be co-located with Insat-3A. The payloads
will be checked out before the commissioning of the
Measuring 15.4 metre with its solar arrays are fully
deployed in orbit Insat-4B will be 3-axis body stabilised
in orbit using earth sensors, momentum and reaction
wheels, magnetic torquers and eight 10 Newton and eight
22 Newton Reaction Control Thrusters. The satellite
has two solar arrays together generating 5,860 Watt
of electrical power backed up by three 100 Ah Lithium-Ion
satellite has two deployable antennas for various transmit
and receive functions.
ISRO Satellite Centre (ISAC), Bangalore, as the lead
centre, Insat-4B was realised with major contributions
from Space Applications Centre (SAC), Ahmedabad, Liquid
Propulsion Systems Centre (LPSC) at Valiamala and Bangalore,
Vikram Sarabhai Space Centre (VSSC) and ISRO Inertial
Systems Unit (IISU) at Thiruvananthapuram and Laboratory
for Electro Optic Sensors at Bangalore.