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Sonntag, 4. Oktober 2015 - 19:50 Uhr

Raumfahrt - ISRO modifizierte GSLV Mark III Rakete

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GSLV Mark III's Cryogenic Stage to be Ground Tested in 6 Months
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CHENNAI: ISRO’s next big project under development, the GSLV Mark III, will have one of its most problematic components ground tested within March next year. A senior source at the ISRO Propulsion Complex at Mahendragiri in Tamil Nadu told Express that the various systems for the Mark III cryogenic stage are being integrated and the first test of the entire stage will be completed within six  months.
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The IPRC, which has been entrusted with building the entire cryogenic stage, has made a lot of headway with the Mark III, according to the official who did not want to be named. “We are  progressing steadily. The engine was tested successfully in July. The next stage of the development is the integration of all the systems that make up the whole  cryogenic stage. The fully integrated stage will be ground tested within six  months,” he said.
ISRO Chairman A S Kiran Kumar, who was in Chennai for Hindustan University’s convocation on Saturday, confirmed that tests are going well and that the space agency would test the first GSLV Mk-III by the end of 2016.
But first, IPRC will test the stage as a whole on the ground for up to 25 times the duration for which a mission will require it fired. The next step will see the stage tested at   Sriharikota with complete autonomy of systems. “Once that is done, the project can be taken forward. We actually hope to have the Mark III developed by next year. However, that is only a target, not a prediction,” said the official. The initial version of the GSLV Mk III, however, is likely to have a payload capability of 3,500 kg, with the systems being optimised in a staggered manner.
The GSLV Mark III is planned to be the Indian space agency’s upgraded version of the GSLV launch vehicle. The space agency heaved a big sigh of relief on August 27, when the indigenously built GSLV Mk II had its second successful  launch. But the GSLV Mark II, while a lot more capable at lifting payloads than  ISRO’s established workhorse, the PSLV, is still only capable of delivering payloads of 2.5 tons.
ISRO’s rapidly growing ambitions require vehicles that can deliver much higher  payloads and the GSLV Mark III is the agency’s answer to that. The specifications spell out a payload delivery capability of 5 tons, which will be an absolute requirement for any manned mission that the agency plans to carry out.
ISRO’s problems with the GSLV, even the Mk II, have revolved largely around the cryogenic stage of the rocket. While it took the space agency two failures before its first successful launch, ISRO’s scientists stated that August’s launch had given them enough understanding of the technology to finally be able to brand the vehicle reliable. That was the Mk II, which while indigenously built, was still based  on foreign design. The Mark III is being designed ground up in India.
The ground test of the stage, if successful, will be a significant step forward for the  induction of the Mark III among ISRO’s fleet.
Currently, the cryogenic stage’s systems other than the engine are being built - including the hi-tech fuel tanks and umbilical systems, which have to work at extremely low temperatures. “These systems are coming along quite well and are being integrated. We do not foresee the same problems we did with the Mk II, primarily because we are the ones who  designed it this time and trial and error will no longer be how we learn about it,” he said.
Quelle: The New Indian Express
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Chennai: Based on last year’s GSLV Mark III’s experimental flight, modifications have been done to solid rocket S-200 motors to change dynamic pressure and forces and ground tests have been done, a top Isro official said on Saturday.
“When we flew the launch vehicle last time based on actual test, the solid rocket which was there—S 200 motors—there also certain changes had to be done,” Isro chairman A.S. Kiran Kumar told reporters here. Such changes were needed “to change dynamic pressure and dynamic forces that occur during the atmospheric regime”, he added.
Sharing the developments over GSLV Mark III with reporters on the sidelines of Hindustan University’s convocation here, the top official said “those changes have also been incorporated and ground tests have been conducted on those modified rockets and so, that way we are quite on track for GSLV Mark III (launch)next year”.
Isro successfully tested the atmospheric re-entry of a crew module and studied flight validation and atmospheric flight regime of its heaviest launch vehicle GSLV Mk III on 18 December last year.
Stating that Isro was planning to launch GSLV Mk-III by December next year, he said, “for GSLV Mark III launch the target is December 2016 and a second launch December 2017”. On the Mark III cryogenic engine development, it has been going on “very successfully”, and Isro has done “more than 21 different tests including long duration test”, he said. “Actually in the launch, it is supposed to work for about 635 seconds to put the satellites in orbit, now we have tested the engine for not only that period but also for an extended period for about 800 seconds.”
These tests have been done on one engine and “now we need to repeat it on another hardware and those activities are in progress”, he said. An important aspect about cryogenic engine is that it is totally indigenous development, he said. “The various tests that we have gone through so far is simulated prior to test and tests have validated, giving us great confidence that the entire technology in terms of basics the engineers and scientists have understood the mechanism.”
Quelle: PTI

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