Tim Furniss/LONDON

India's first Geostationary Satellite Launch Vehicle (GSLV), which was launched from Sriharikota on 18 April, fell 4,040km (2,510 miles) short of its initial geostationary transfer orbit (GTO) apogee target, leading some space insurance monitors, including Airclaims, to classify it as a partial failure.

Instead of the planned 181km perigee of the orbit, the actual orbit was 169km, according to US Spacecom data, while the apogee was 31,961km, compared with the planned 36,000km.

The 100lb-thrust (0.44kN) engine on the 1,540kg (3,400lb) G-SAT 1 experimental rural communications satellite, which the GSLV was carrying, had to use the additional propellant planned for station-keeping in operational orbit to help raise the apogee during its standard circularisation burn from GTO to geostationary orbit (GEO).

The final circular GEO orbit it achieved was about 1,000km lower than planned, says the Indian Space Research Organisation (ISRO). It adds that this will not significantly affect the three-year life of the satellite.

The shortfall has been blamed on a premature cut-off of the GSLV's Russian 12KRB cryogenic upper stage KVD-1 liquid oxygen-kerosene engine at 698s into the planned 710s burn.

The first attempt to launch the GSLV-D1 on 28 March ended in a launch pad abort when a liquid propellant strap-on booster lost thrust.

Despite the orbit shortfall, ISRO considers the 18 April launch a success. It now plans to launch the GSLV-D2 in late 2002, which will carry a 1,800kg G-SAT satellite. A third GSLV will attempt to orbit the 2,000kg Insat 3A satellite into GTO in 2003, enabling India to enter the commercial launch business by offering flights for about $40 million.

The number of GEO satellites in the 2,000kg range are likely to be very small, however, with standard communications satellites today typically weighing around 5,000kg.

The 12-year GSLV programme has cost over $300 million. The first GSLV flight was originally to have taken place in 1995.

Problems with the development of an indigenous C-12 liquid oxygen-liquid hydrogen cryogenic upper stage engine and US criticism of a planned technology transfer deal with Russia led to India purchasing seven KVRB engines in 1994, although the C-12 engine could be ready before all of these engines are used.

Source: Flight International