INDIAN SPACE AGENCY TO LAUNCH THREE SATELLITES IN APRIL

Indian space agency to

 Launch three satellites in April

           The Indian Space Research Organisation (ISRO) proposes to launch the latest remote sensing satellite and two others in the second week of April, seeking to replace a crucial component in its fully-assembled launch vehicle by dismantling one section. ISRO will take apart its polar satellite launch vehicle (PSLV) at the Sriharikota launch facility some 80 km from here to substitute the existing gas motor with an upgraded one, ISRO sources said. 'We know that our four-stage rocket is fully assembled. However, since the gas motor is in an inaccessible location in the second stage it has to be opened up for us to remove the previous one and fit a newer one,' an ISRO official told IANS.

         The official also said after the agency's last two missions involving its heavy rocket -- geo-synchronous satellite launch vehicle (GSLV) -- ended in failures, resulting in a total loss of some Rs.600 crore, top officials wanted to be all the more cautious. The launch of the three satellites -- Indian 1,200-kg Resourcesat-2, Indo-Russian 93-kg-Youthsat and Singapore's 103-kg X-Sat -- was earlier slated for February. They will send pictures and other data for various uses. India is a major global player in this area. The official explained that the gas motor tested a temperature-tolerance level of some 390 degree Celsius but in order to be sure that the gas motor tolerates a higher temperature, some more calibrations had to be done.

        The gas motor powers and helps manoeuvre the rocket's second-stage operations, which in turn, enable the rocket to maintain a steady course on its way up. This motor is powered by the hot gases tapped from the rocket, the official explained.  The 44-metre-tall PSLV rocket has a four-stage rocket powered by solid propellants in the first and third stage and liquid propellants in the other two.  India has the largest constellation of remote-sensing satellites providing imageries in a variety of spatial resolutions. The operational remote sensing satellites include the Cartosat-2B, Oceansat-2, RISAT-2, Cartosat-2A, IMS-1, Cartosat-2, Resourcesat-1 and TES.
Officials said for some time, Resourcesat-2 and Resourcesat-1 would work together before the latter goes into oblivion. Launched in 2003, Resourcesat-1 has outlived its original mission life of five years. The other remote-sensing satellites which the space agency plans to launch are RISAT, Megha-Tropiques, INSAT-3D, and the Astrosat -- a satellite for astronomy to observe celestial bodies.

Prof. John Kurakar