Page 14 - April 2021
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     COVER STORY
 India’s APPLE (Ariane Passenger Payload Experiment) satellite being transported
chronous orbit. This was realised by the design of the Polar Satellite Launch Vehicle (PSLV). The PSLV has been the most successful launch vehicle developed by ISRO. The first development flight of the PSLV was a failure in 1993 but after having understood the causes of the fail- ure, the first successful flight took place in October 1994. So far, 53 launches of the PSLV have taken place with only two failures. The PSLV has been utilised for launching satellites in sun synchronous orbit, geosynchronous orbit, Lunar orbit and the Mars orbit. It was used for the launching of the meteorological satellite ‘Kalpana’ in geostationary orbit. During one of the notable launches, 104 small satellites were launched.
Even before the successful launch of the PSLV, the configuration definition of the Geosynchronous Satellite Launch Vehicle (GSLV) was taken up. Initially, it was planned to get the technology of cryogenic engines from the USSR. This did not happen due to the embargo on technology transfer. Thus, while we pur- chased certain cryogenic stages from the
USSR, the required cryogenic technol- ogy was indigenously developed and the same is now being used in GSLV Mark II and GSLV Mark III vehicles. The GSLV Mark III is the largest launch vehicle developed by ISRO so far. The GSLV Mark III vehicle is now slated to be the vehicle for launching of the ‘Gaganyaan’ carrying three In- dian astronauts. The PSLV was used for
the successful Space Recovery Experi- ment. ISRO has already carried out the technology demonstration for reusable launch vehicle RLV TD and experimen- tal flight of the scramjet airbreathing vehicle has taken place. ISRO has now established a dedicated Human Space Flight Centre after the Gaganyaan pro- gram was approved by the Government.
In the realisation of the launch ve- hicles, a large number of industries are involved. Now efforts are underway to see if the entire launch vehicle can be delivered by the industry with ISRO taking the responsibility of quality as- surance and launch operations. If this materialises, ISRO can concentrate on the development of newer technologies.
is needed to be able to launch our own satellites when we need to do so. When needed, we can get our national civil- ian communication satellites launched using launch services provided by other countries but it is clear that we cannot get our advanced remote sensing satel- lites launched in the same way. This was realised very early and accordingly the development of the technology required was undertaken by ISRO.
DEVELOPMENT OF INDIGENOUS LAUNCH VEHICLES
The most important technologies neces- sary for the realisation of the solid and liquid propellants have been developed indigenously. The first rocket launch from TERLS — NASA rocket Nike Apache — took place on November 21, 1963. The development of our own sounding rockets was started in 1966. The studies for defining our own satellite launch vehicles were started in 1968. The development of the control and guidance systems for the launch vehicles was un- dertaken simultaneously. This resulted in
The GSLV Mark III, slated
to be the vehicle for launching the Gaganyaan, is the largest launch vehicle developed by ISRO so far.
the development of the Satellite Launch Vehicle SLV 3 under the leadership of Dr A P J Abdul Kalam. This was a small vehicle but it was the most important first step. While the work was going on, Dr Sarabhai had defined the goal of re- alising a launch vehicle for launching operational communication satellites. SLV 3 was followed by the Augment- ed Satellite Launch Vehicle (ASLV). The first two flights of ASLV were fail- ures but the third and the fourth were successful.
It was clear that we would need a vehicle to launch a small communica- tion satellite in geosynchronous transfer orbit and also be capable of launching a remote sensing satellite in sun syn-
  14 SCIENCE INDIA APRIL, 2021
           



















































































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