Chennai: Preparatory work for the launch of the geosynchronous launch vehicle (GSLV) slated for the evening of 1 September, 2007, is going briskly at the Satish Dhawan Space Centre, Sriharikota, Andhra Pradesh.

The rocket carrying communication satellite Insat 4CR weighing 2,130 kg will blast off from the second launch pad.

The success of the forthcoming launch is crucial for the country as it is ISRO''s second attempt to launch an Insat satellite from Indian soil using an Indian rocket.

The launch vehicle''s configuration is identical to that of GSLV F02 that failed in July 2006 owing to manufacturing error. (See: Inadvertent manufacturing error cost nation Rs256 crore and ISRO forced to destroy GSLV in mid air). The rocket carried Insat 4C weighing 2,168 kg - the heaviest satellite carried by the GSLV.

Interestingly ISRO has reduced the weight of the Insat 4CR by 38 kg now.

Closely following this will be the launch of polar satellite launch vehicle (PSLV) sometime during the middle of September to put an Israeli satellite Polaris weighing around 300 kg into orbit. The vehicle is configured as ''core alone'' that is without PSLV''s standard six strap on motors.

The 44-metre high PSLV weighs 295 tonnes. The core-alone version sheds about 65 tonnes, and weighs 230 tonnes. The version is also lighter on ISRO''s purse as it costs around Rs70 crore to build, cheaper by around Rs15 crore vis-à-vis the fully loaded PSLV.

ISRO had earlier flown a `core alone'' PSLV this April with Agile a 352 kg Italian satellite.

The year-end will see another PSLV flight carrying a remote sensing satellite- Oceansat or Cartosat. The launch vehicle will also carry a cluster of six micro-satellites from Canada piggyback on the same launch. Together, these six micro-satellites will weigh only 26 kg.