INSAT-4B Launched Successfully & Placed in Intermediate Orbit (Forwarded)

Indian Space Research Organisation
Bangalore, India

March 12, 2007

INSAT-4B Launched Successfully

ISRO's latest satellite, INSAT-4B
http://www.isro.org/insat-4b/insat4b-poster.htm, was successfully launched
early this morning (March 12, 2007) by the European Ariane-5 ECA launch
vehicle of Arianespace. The 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.

With 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.

The 31st flight in Ariane-5 series, carrying ISRO's INSAT-4B and its
co-passenger, Skynet-5A of EADS Astrium, lifted off at 03:33 am Indian
Standard Time (IST) [2203 UTC, March 11] from Kourou, French Guyana. About
30 minutes after lift-off, INSAT-4B was placed in the Geosynchronous
Transfer Orbit (GTO) in 3-axis stabilised mode. INSAT-4B 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.

The Master Control Facility (MCF) at Hassan in Karnataka acquired the first
signals from INSAT-4B at 4:02 am IST [2232 UTC, March 11]. The initial
checks on the satellite have indicated normal health of the satellite. 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.

INSAT-4B 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.

In 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. This 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
satellite.

INSAT-4B carries the following payloads:

* 12 Ku- band 36 MHz and 27 MHz usable bandwidth Transponders (9 and 3
numbers respectively) employing 140 W TWTAs to provide an EIRP of 52 dBW
over the footprint covering Indian main land.

* 12 C-band 36 MHz bandwidth transponders employing 63 W TWTA to provide an
EIRP 39 dBW with expanded coverage encompassing Indian geographical
boundary, area beyond India in southeast and northwest regions.

INSAT-4B measures 15.4 metre with its solar arrays are fully deployed in
orbit. The satellite 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 Batteries.

The satellite has two deployable antennas for various transmit and receive
functions.

With 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. Besides, several industries in both public and private sectors
have contributed to the realisation of INSAT-4B. MCF is responsible for
initial phase and in-orbit operation of all geostationary satellites of
ISRO.

Established in 1983, the Indian National Satellite (INSAT) is the largest
domestic communication satellite systems in the Asia Pacific Region with
nine satellites in operation. It provides services in telecommunication,
television broadcasting, meteorology including disaster warning,
tele-education and telemedicine. The system has 175 transponders at present
for communication services besides meteorological instruments (Very High
Resolution Radiometer and Charged Coupled Device (CCD) cameras) for
providing meteorological data. With the addition of INSAT-4B, the
communication capacity will be further increased to 199 transponders.

*****

Indian Space Research Organisation
Bangalore, India

March 13, 2007

INSAT-4B Placed in Intermediate Orbit

The first critical orbit-raising manoeuvre on INSAT-4B was successfully
conducted at 5:35 am [0005 UTC] this morning (March 13, 2007) with the
firing of the 440 Newton Liquid Apogee Motor (LAM) on board for 93 minutes
by commanding the satellite from Master Control Facility (MCF) at Hassan in
Karnataka. With this LAM operation, INSAT-4B perigee has been raised to
14,244 km. The apogee is at 35,752 km and the inclination of the orbit with
respect to the equatorial plane has been reduced from 4.5 deg at the time of
entering into orbit to 1.15 deg now. The present orbital period is 15 hours
21 minutes.

It may be recalled that INSAT-4B was successfully launched by Ariane 5
launch vehicle yesterday (March 12, 2007) from Kourou, French Guyana. The
launch vehicle placed INSAT-4B in the intended Gesynchronous Transfer Orbit
(GTO) with a perigee (closest point to the earth) of 250 km and apogee
(farthest point to earth) of 35,886 km. MCF acquired the first signals at
4:02 am IST on March 12, 2007 [2232 UTC, March 11] and conducted initial
phase operations on INSAT-4B. The satellite which had gone out of radio
visibility of MCF at 2:04 pm [0834 UTC] yesterday, came within its radio
visibility again at 1:00 am [1930 UTC, March 12] this morning. The satellite
was oriented suitably before the start of LAM operations.

All systems on board the satellite are functioning normally. The satellite
went out of MCF radio visibility at 12:02 pm [0632 UTC] this afternoon. It
will again come within MCF's radio visibility at 6:11 am [0041 UTC]
tomorrow. Further orbit raising maneuvers are planned in the next few days.