SriKumar wrote:If I recall right, the failure of the desi cryo stage was due to the cryo turbo-pump(s) failing. The ISRO brochure posted by PratikDas on previous page says something about turbopump modification.Varoon Shekhar wrote:GSLV Mk.2 4 × L-40H / Vikas GS-1 / S-139 GS-2 (L-37.5H) / Vikas GS3 (CUS-12) / CS -
GSLV Mk.2A 4 × L-40H / Vikas GS-1 / S-139 GS-2 (L-37.5H) / Vikas GS3 (CUS-15) / CS -
GSLV Mk.2C 4 × L-40H / Vikas GS-1 / S-139 GS-2 (L-40H) / Vikas GS3 (CUS-15) / CS PAM-G
"It is the CE 7.5 Engine which is part of the CUS15 cryogenic stage."
So was there some uprating of the stage, from the first failed launch of the Indian Cryo-engine. From CUS-12 to CUS-15. What were the modifications?
http://timesofindia.indiatimes.com/indi ... 417612.cms
From the April 2010 failure, when the cryogenic engine failed 800 milliseconds after ignition, Isro learned that dissimilar contractions of different materials led to problems in three bearings in the fuel booster turbo pump. "Here we made some changes to the design of one of the casings and tested the new pump under normal operating temperatures. Its working perfect now," Radhakrishnan said. In the case of the December 2010 misfire, scientists found some Russian connectors had snapped. This was corrected by changing the mounting design, which was later tested on ground using the wind tunnel blow down method.
"We have thoroughly studied the past experiences and made changes. We are all upbeat," said Radhakrishnan while travelling from the Isro headquarters in Bangalore to Sriharikota on Saturday.