INSAT-3C launch delayed further

By R.K. Radhakrishnan

CHENNAI, AUG. 8. The Indian Space Research Organisation's (ISRO) INSAT-3C satellite launch will suffer a delay of at least two months, as Arianespace today announced that its earliest Ariane-5 launch would be only in late-November.

INSAT-3C, which was initially expected to be placed in orbit around July, was later slated for a mid-September launch. The Indian satellite will be the first to go up in the modified Ariane-5, when it lifts off in November. The delay will enable the space agency to carry out the corrective measures suggested by an enquiry board, which went into the underperformance of the last Ariane-5 flight.

It was following the underperformance of Ariane flight 142 (Ariane 5), which ejected two satellites - Bsat and Artemis - on July 12 that Ariane suspended Ariane-5 flights. The inquiry board appointed to investigate the malfunction of Ariane 5's EPS upper stage during Flight 142 submitted its report to Arianespace on August 1.

``Arianespace is now targeting the next Ariane 5 launch for late November, a delay of approximately two months compared to the initial schedule for this mission,'' a communication from Arianespace said.

The seven-member enquiry board identified a combustion instability during the Aestus engine's ignition. The resulting degraded engine combustion conditions led to a lower than normal thrust output.

The inquiry board recommended that the hydraulic conditions that occur during Aestus engine ignition should be dynamically modelled mathematically, the upper stage's ignition phase needed to be improved to make it steadier and smoother, the qualification criteria should be adapted to the modified ignition phase, the test benches be adapted to more closely duplicate flight conditions, the in-flight operating margins be demonstrated by an engine test program and that the next flight engines should be qualified according to these new criteria.

After analysing the board's recommendations, Arianespace - in conjunction with the European Space Agency and the French CNES space agency, and supported by the Ariane program industrial partners - has defined an action plan to carry out the recommendations.

The ISRO has also been examining the Ariane enquiry report and is said to be satisfied with it. It is pointed out that the enquiry report on the underperformance of the GSLV is still not in the public domain.

Meanwhile, Arianespace is continuing its launch activities at the Guyana Space Center, with the next mission, Flight 143, to use an Ariane 4 to orbit the Intelsat 902 communications satellite. Arianespace Flight 143 is now scheduled for the end of August.

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