(23 April 2007 10:00 pm)

MUMBAI: In its eleventh flight, conducted from Satish Dhawan Space Centre (SDSC) SHAR, Sriharikota, this afternoon (April 23, 2007), ISRO's Polar Satellite Launch Vehicle, PSLV-C8, successfully launched the 352 kg Italian astronomical satellite, AGILE, into a 550 km circular orbit, inclined at an angle of 2.5 deg to the equator.

PSLV-C8 mission was unique in many respects. In this mission, PSLV was flown, for the first time, without the six strap-on motors of the first stage. Also, for the first time, PSLV launched a satellite into an equatorial circular orbit of 550 km. PSLV-C8 was the first major commercial launch the contract for which was won against stiff international competition.

Along with the Italian satellite, AGILE, an Advanced Avionics Module (AAM), weighing 185 kg, to test advanced launch vehicle avionics systems like mission computers, navigation and telemetry systems, was also flown on PSLV-C8. All the operational flights of PSLV so far have been successful and thus PSLV has emerged as the workhorse launch vehicle of ISRO.

After the final count down, PSLV-C8 lifted off from the Second Launch Pad (SLP) at SDSC SHAR at 3:30 pm with the ignition of the core first stage. The important flight events included the separation of the first stage, ignition of the second stage, separation of the payload fairing at about 116 km altitude after the vehicle had cleared the dense atmosphere, second stage separation, third stage ignition and third stage separation, fourth stage ignition and fourth stage cut-off. AGILE was placed in orbit 1370.7 sec after lift off.

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

PSLV has emerged as the workhorse launch vehicle of ISRO with ten consecutively successful flights so far. Since its first successful launch in 1994, PSLV has 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 has launched India's exclusive meteorological satellite, Kalpana-1, into Geosynchronous Transfer Orbit (GTO). PSLV will also be used to launch India's first spacecraft mission to moon, Chandrayaan-1, during 2008.

In its standard configuration, the 44 m tall PSLV has a lift-off mass of 295 tonne. It is a four-stage launch vehicle with the first and the third stages as well as the six strap-ons surrounding the first stage using HTPB based solid propellant. PSLV's first stage is one of the largest solid propellant boosters in the world. Its second and fourth stages use liquid propellants. PSLV's bulbous payload fairing has a diameter of 3.2 metre. 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.

AGILE is an X-ray and Gamma ray astronomical satellite of the Italian Space Agency (ASI), Rome. The design, development and fabrication activities of the satellite were led by Carlo Gavazzi Space, Milan, Italy. The launch was arranged by Cosmos International through Antrix Corporation. The satellite carries scientific instruments capable of studying distant celestial objects in X-ray and Gamma ray regions of the electromagnetic spectrum.