• The Indian Space Research Organisation’s quest for having the most powerful and world-class launch vehicle to take heavier satellites weighing about 4 tonnes to predetermined geosynchronous orbit crossed the final hurdle on Friday evening when the Propulsion Research Complex at Mahendragiri, situated about 60 km from here, successfully ground-tested indigenously developed GSLV MK III’s cryogenic upper stage C-25.
• “The 640-second-long test of C-25 of the country’s most powerful launch vehicle that can carry heavier satellites weighing 4,000 kg was successful as it met all pre-determined parameters such as chamber pressure, propellant flow, injection pressure, temperature and other critical parameters,” 

Details on cryogenic upper stage of the GSLV:

• The cryogenic upper stage of the GSLV is the large C-25, which is the most difficult component of the launch vehicle to be developed. It will be powered by the indigenously developed CE-20 engine.
• The 13.50 meter-long C-25 with 4-meter diameter would contain propellant – liquid hydrogen and liquid oxygen – weighing about 25 tonnes.
• Through the successful ‘hot test’ conducted at IPRC, Mahendragiri, for 640 seconds in February last, the CE-20 engine crossed a major milestone earlier and the CE-25 was tested for a short duration of 50 seconds on last January 25.
• “The long duration cryogenic C-25 Developmental State propellant system test is a great milestone in the country’s space history as it is capable of producing a thrust of 20 tonnes.
• This is the endurance test of the propulsion stage to prove its capability to withstand the rigours of extreme environments in terms of vibration, shock and low temperature to qualify it for actual flight duration.
• With this test, the ISRO has demonstrated that India has got the capability of designing, fabricating and evaluating indigenously developed GSLV through a range of test facilities.
• For the upper stage alone, more than 200 multiple engine tests were conducted to validate the efficiency of C-25.