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Insat-3B lofted successfully
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Arianespace
and the Indian Space Research Organisation successfuly
lifted the first in the third generation of Insat satellites
on 22 March at 04:58 Indian time. The Arianespace-505
launcher had an additional payload in the Asiastar satellite
which was launched for digital radio service, WorldSpace.
Asia Star was first injected into orbit 28 minutes after
lift-off, |
and seven minutes
later, INSAT-3B was injected (in a three-axis stabilised
mode into a Geo-synchronous Transfer Orbit - GTO) with a
perigee of 560 km and an apogee of 35,770 km and an inclination
of 7 degree with respect to the equator.
The satellite is at present orbiting around the earth with
a period of 10.64 hours. The Insat Master Control Control
Facility (MCF) at Hassan in Karnataka acquired the telemetry
signal from Insat-3B at 5.30 (IST) three minutes prior to
its separation from the launcher.
On separation of
the satellite from the composite adopter, satellite health
checks were conducted and a series of commands issued from
the MCF so as to orient its earth-viewing face towards earth.
The outermost panel of the stowed solar array on the south
side was also oriented towards the sun to start generating
the electrical power required by the satellite during its
transfer orbit phase.
The calibration of the gyros on board the satellite has
also been carried out. The operations were completed in
about (100 minutes). Insat-3B is being tracked, apart from
MCF, Hassan, by INTELSAT Organisation's ground stations
at Perth (Australia), Fucino (Italy) and Lake Cowichan (Canada).
The satellite will go out of the visibility of MCF, Hassan
at about 03:36 pm (IST) this afternoon and will come within
the radio visibility of MCF, Hassan at 02:36 am tomorrow.
The satellite's orbit is being precisely determined by continuous
ranging from the participating TTC stations. The orbit raising
operations on INSAT-3B will be carried out by firing the
440 Newton liquid apogee motor on board in stages till the
satellite attains its final geostationary orbit, about 36,000
km above the equator.
The first Apogee Motor Firing (AMF-1) is planned during
the third transfer orbit tomorrow (March 23, 2000) at about
07:30 am IST. The satellite has about 1,100 kg of propellant
(Mono-Methyl Hydrazine - MMH and Mixed Oxides of Nitrogen
- MON-3) for orbit raising operations as well as for station
keeping and in-orbit attitude control for the duration of
its designed life of 10 years.
When the satellite reaches near geo-stationary orbit, deployment
of two solar panels and the two antennas will be carried
out and the satellite put in its final three-axis stabilised
mode. The payloads will be checked out before commissioning
the satellite. The deployment of the solar array and the
two antennas will be carried out after the satellite attains
near geo-synchronous orbit.
Insat-3B will
be collocated with INSAT-2E at 83 deg East longitude. It
may be noted that Insat satellites now occupy four slots
-- Insat-2B and Insat-2C are collocated at 93.5 deg (E)
longitude, INSAT-1D and INSAT-2A are collocated at 74º E
longitude and Insat-2DT is located at 55º E longitude besides
Insat-2E at 83 deg East longitude.
Insat-3B is primarily
intended for business communication, developmental communication
and mobile communication. The communication payload provides
12 extended C-band channels, each having a bandwidth of
36 MHz. The Ku-band payload provides three channels, having
a bandwidth of 77/72 MHz. The Mobile Satellite Service transponders
operate in C/S band frequencies. Compared to INSAT-2C/2D,
the power of extended C-band transponders on board INSAT-3B
has been increased from 10 W to 15 W and that of Ku-band
from 20 W to 55 W.
Once commissioned, INSAT-3B is expected to further boost
the Very Small Aperture Terminal (VSAT) services. The major
VSAT users include banking and financial institutions, stock
markets, white goods sector, fast moving consumer goods
sector and medium to heavy engineering companies. Several
public and private sector units have established dedicated
closed-user group networks for their in-house applications.
At present seven transponders from INSAT-2B and INSAT-2C
are being used for these applications and INSAT-3B will
almost double the transponder capacity for these services.
For the first-time Ku-band frequencies will also be used
for VSAT services, which enables use of smaller ground terminals.
INSAT-3B will provide the first set of transponders for
Swaran Jayanti Vidya Vikas Antariksh Upagraha Yojana (Vidya
Vahini) which had been announced by the Prime Minister on
15 August 15 1998. These transponders will be used exclusively
for interactive training and developmental communication
and will be a further extension of the present Training
and Developmental Communication Channel of Insat that is
being used by several agencies.
Tele-medicine is also expected to be introduced that will
help in remote iagnostics and extension of super special
hospital treatment to the rural population. INSAT-3B Mobile
Satellite Service (MSS) has forward link channel in C X
S band and return link in S X C band. MSS can support portable
terminals and carry voice, fax or data. It also supports
messaging service using reporting terminals.
Pix courtesy Arianespace.
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