All set for ISRO's first commercial launch on Apr 23

Chennai, Apr 22: The stage is set for tomorrow's first full-fledged commercial launch of the Polar Satellite Launch Vehicle (PSLV-C8) from India's space port of Sriharikota.

In its 11th flight, the PSLV-C8 will deploy an Italian space Agency satellite, Agile, in circular orbit and also carry ISRO's Advanced Avionics Module (AAM) as another payload.

The PSLV-C8 will lift off from the second launch pad at the Satish Dhawan Space Centre at 1530 hrs tomorrow.

ISRO sources told UNI today that the 48-hour countdown which began at 1530 hrs last evening, was progressing smoothly and the stage is all set for the launch tomorrow.

''The launch preparations are going on satisfactorily'', the sources added.

The final countdown would begin at 1530 hrs today.

PSLV-C8, the workhorse launch vehicle of the ISRO will place the 352 kg Italian astronomical satellite ''AGILE, into a 550 km circular orbit, inclined at an angle of 2.5 degree to the equator.

ISRO's Advanced Avionics Module (AAM), weighing 185 kg, to test advanced launch vehicle avionics systems like mission computers, navigation and telemetry systems, would be the second payload of PSLV-C8.

The unique feature of this launch was that for the first time, the PSLV-C8 would lift off without its six strap-on booster motors, as the total weight of Agile and AMM put together was only 540 Kg.

This would be the first full-fledged commercial launch for ISRO as it had charged a handsome amount for launching Agile. Earlier, in its four earlier flights, PSLV had launched satellites from abroad, but the ISRO had charged only a nominal fee. The launching of Agile would be part of ISRO's mission to get at least ten per cent share of the US two billion dollar global market.

''Ours is a very cost-effective launch. The market is worth US two billion dollars and it would be good even if we manage to get a ten per cent share of it'', according to ISRO Chief G Madhavan Nair, who exuded confidence of a successful launch on the morrow.

With a much lighter payload and the low inclination of the orbit in which AGILE is to be placed, PSLV-C8 is configured without the six solid propellant strap-on motors of the first stage. Also, the propellant in the fourth stage is reduced by about 400 kg compared to previous PSLV flight. The core-alone PSLV-C8 will have a lift-off mass of 230 tonne.

A PSLV with the normal configuration, which includes the strap-on motors, could put a satellite weighing 1,600 kg in orbit.

The PSLV, a four-stage vehicle, is 44 m tall and weighs 295 tonne. The PSLV-C8, minus the strap-on motors, will weigh around 240 tonne.

The Agile satellite would have payloads to investigate gamma ray bursts, pulsars and supernova remnants.

The Agile mission was supported by the Italian Space Agency, the Italian Institute of Astrophysics and the Italian Institute of Nuclear Physics.

The AMM would monitor the performance of the vehicle. It would carry an advanced computer, a next generation telemetry system and an advanced inertial navigation system.

With nine consecutive successful flights, PSLV has emerged as the workhorse launch vehicle of the ISRO.

This 'Mr Dependable' launch vehicle would also be used to launch India's first spacecraft mission to moon, Chandrayaan-1 next year.

Since its first successful launch in 1994, PSLV had launched eight Indian remote sensing satellites, an amateur radio satellite, HAMSAT, a recoverable space capsule SRE-1 and six small satellites for foreign customers into 550-800 km high polar Sun Synchronous Orbits (SSO). Besides, it had also launched India's exclusive meteorological satellite, Kalpana-1, into Geosynchronous Transfer Orbit (GTO).

The vehicle has S-band telemetry and C-band transponder systems for monitoring its health and flight status respectively. It also has sophisticated auxiliary systems like stage and payload fairing separation systems.

PSLV was originally designed to place 1,000 kg class of India's remote sensing satellites into a 900 km polar SSO. Its payload capability had been successively enhanced and in its ninth flight, PSLV-C6, in May 2005, launched two payloads - 1,560 kg CARTOSAT-1 and 42 kg HAMSAT - into a 620 km SSO.

In its previous flight on January ten this year, PSLV-C7 launched four payloads - 680 kg CARTOSAT-1, 550 kg Space capsule Recovery Experiment (SRE-1), 56 kg LAPAN-TUBSAT of Indonesia and the six kg PEHUENSAT-1 of Argentina - into a 635 km high polar SSO.

UNI