Indian Space Research Organisation's (ISRO) latest communication
satellite Insat-3E was placed near geostationary orbit
(GSO) on 1 October 2003.
the third and final stage of orbit raising operation the
440 Newton liquid apogee motor was fired from 3 minutes
and 6 seconds. The satellite has achieved an orbital period
of 23 hours and 46 minutes and is continuously visible
to the master control facility at Hassan.
is expected to reach its geostationary orbital slot of
55 degree East Longitude in next 10 days with the planned
drift of 2.3 degree per day. Currently, the spacecraft
is at 38 degree East longitude.
to ISRO the liquid apogee motor has performed well, taking
the satellite from its geosynchronous transfer orbit (GTO)
of 649 km perigee and 36,000 km apogee with an orbital
inclination of 7 degree with respect to the equatorial
plane to its present near GSO orbit with zero degree inclination.
A total velocity of 1460 m/sec was added by the motor
at the Apogee point of the orbit to take the satellite
from GTO to GSO.
apogee motor was fired for a total duration of 121 minutes
in three phases on 29 September, 30 September and 1 October.
had 1,592-kg propellant at the time of its injection into
GTO by Ariane-5 launch vehicle on 28 September. After
the firing the apogee motor for three times the satellite
has 510 kg of fuel. According to ISRO this is sufficient
to arrest the drift and park the satellite at its orbital
slot as well as maintain the satellite in its orbit and
controlling its orientation during its design life of
more than 12 years.
solar arrays and antennae of Insat-3E were deployed by
commanding from master control facility, Hassan. First
the solar array on the satellite's south side was deployed.
It was followed by the deployment of antenna reflector
on the west side and the north side solar array.
solar array has a total area of 29.6 sq m and it is designed
to generate 2.9 kW (BoL) of power in orbit. The satellite
has two deployable antennas and one fixed antenna to carry
out various transmit-and-receive functions.
three-axis stabilisation of Insat-3E was also carried
out successfully. In this configuration spacecraft will
be locked to earth continuously through the optical sensors
and will maintain the correct attitude to look at the
earth in a stable manner. Insat-3E's Momentum Wheels was
also switched on and stabilised to nominal speed of 4,500
revolutions per minute to provide gyroscopic stiffness
and provide three-axis stabilisation.
communication payloads will be switched on after reaching
the orbital slot, and in-orbit testing of the payloads
will be carried out for a duration of three weeks. Insat-3E
is expected to be ready for service by the first week
of November 2003.