Arianespace and the Indian Space Research Organisation (ISRO) are expanding their relationship after the successful launch of ISRO’s INSAT-3A communications satellite aboard the French Ariane 5 rocket last week.

Arianespace will be carrying two more satellite payloads for ISRO – the INSAT 4A and 4B. These will be the 12th and 13th ISRO satellites to be booked with the French company. Since the launch of ISRO’s Apple experimental satellite in 1981, Arianespace has orbited 10 Indian satellites. Designed, built and integrated by ISRO, the INSAT 4A and INSAT 4B satellites will each weigh about 3,200 kilograms (7,054 pounds) at liftoff. INSAT 4A and INSAT 4B are dedicated to telecommunications, with 12 Ku-band and 12 C-band transponders each. Their coverage zone will be the Indian subcontinent. Arianespace CEO Jean-Yves Le Gall said: “Winning these two contracts in today’s slow market is a mark of renewed confidence in our launch system.”

The INSAT-3A is the third satellite in the INSAT-3 series. INSAT-3B and INSAT-3C were launched by Ariane-5 and Ariane-4 rockets on March 22, 2000 and Jan. 24, 2002, respectively. INSAT 3E is slated to be boosted into orbit by Arianespace later this year. An Ariane 5 rocket placed the 2,950 kilogram (6,503 pound) INSAT-3A, as well as PanAmSat’s [Nasdaq: SPOT] Galaxy XII satellite, into geostationary orbit on April 9. The INSAT-3A satellite completed its first orbit-raising maneuver on April 11 when its 440 Newton liquid apogee motor was fired for 73 minutes, 42 seconds by commands issued from ISRO’s master control facility (MCF) in Hassan. With the motor’s firing, the INSAT-3A perigee has been raised from 860 kilometers (534 miles) to 11,500 kilometers (7,146 miles). The apogee remains at 36,000 kilometers (22,370 miles) and the inclination of the orbit with respect to the equatorial plane has been reduced from 2 degrees at the time of launch to 0.9 degrees. ISRO said that all systems on board the satellite are functioning normally.

During the initial phase of INSAT-3A operations, MCF is using Inmarsat’s earth stations in Beijing, China, Fucino, Italy, and Lake Cowichan, Canada.

When the satellite reaches near-geostationary orbit, deployment of its solar panels and the two antennas and the solar sail will be carried out and the satellite will be put in its final 3-axis stabilized mode. Trim maneuvers will then take the satellite to its designated orbital slot at 93.5 degrees East. The payload will be checked out before the commissioning of the satellite.

Other INSAT satellites are located in the following orbital slots: INSAT-2DT at 55 degrees East, INSAT-2E and INSAT-3B at 83 degrees East, INSAT-3C and KALPANA-1 at 74 degrees East.

The INSAT-3A is a multipurpose satellite for providing telecommunications, television broadcasting, meteorological and search & rescue services. It carries 24 transponders – 12 operating in the normal C-band frequency, six in the extended C-band and six in the Ku-band. Nine of the 12 normal C-band transponders provide expanded coverage and the remaining three have India coverage beams, as do the extended C-band and Ku-band transponders.For meteorological observation, INSAT-3A carries a three channel very high resolution radiometer with 2 kilometer resolution in the visible band and 8 kilometer resolution in thermal infrared and water vapor bands. In addition, INSAT-3A has a camera that operates in the visible and short wave infrared bands, providing a spatial resolution of 1 kilometer. A data relay transponder operating in UHF band is incorporated for meteorological data collection from unattended platforms located on land and river basins. The data is then relayed in extended C-band to a central location.

INSAT-3A also has a transponder for satellite-aided search and rescue as part of India’s contribution to the international search and rescue program.

–Fred Donovan