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            ISRO tests rocket motor, delays 
            satellite launch 
            
              After 16 successful launches of its workhorse rocket Polar 
              Satellite Launch Vehicle (PSLV) in the last 17 years, the Indian 
              space agency is now testing a key component to re-qualify its 
              on-flight  
            
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              Chennai: 
              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. 
              
               
               
              (Venkatachari 
              Jagannathan can be reached at v.jagannathan@ians.in) 
              
                
              
                
              
                
              
                
              
                
              
                
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