The GSLV-F06 flight was unsuccessful following an explosion at around T+60 seconds.
The S139 does have a very good record flying on both the PSLV and the GSLV, so it would come somewhat as a surprise if it did cause the failure. The strap-on boosters would be another suspect having previously failed on one of the GSLV flights.
It would be too early to debate the exact cause until there some official response from ISRO into what caused the failure.
If it's true that the command lines snapped, then that's a pretty fundamental problem that occurred. It then sounds like the modifications (lengthening and payload enlargement) of the GSLV may have caused new vibrational modes that were unaccounted for, resulting in the basic command systems being compromised.
ReplyDeleteIn hindsight then, perhaps they should have just flown under the standard existing GSLV configuration, rather than attempting to fly yet another design variation.
I also think that PSLV should be fully spun off to a private sector launcher, so that ISRO can fully concentrate on engineering and qualifying new rockets like GSLV, rather than retreating back to resting on the laurels of past proven systems like PSLV.
I read somewhere that telemetry logs show that connectivity with one of the liquid boosters was lost almost right away, at T+0.2seconds after liftoff. So if even just the stress of liftoff could have snapped one of the control cables, doesn't this indicate that there was some possible vibrational mode that had been unaccounted for, in relation to the recent design changes that increased the height and mass of the GSLV?
ReplyDeleteIf so, then it means that ISRO needs to do its homework much more carefully in the future, when making such changes to the standard configuration, lest similar problems repeat themselves again.
"I read somewhere that telemetry logs show that connectivity with one of the liquid boosters was lost almost right away, at T+0.2seconds after liftoff. So if even just the stress of liftoff could have snapped one of the control cables, doesn't this indicate that there was some possible vibrational mode that had been unaccounted for, in relation to the recent design changes that increased the height and mass of the GSLV?"
ReplyDeleteNo. It couldn't be the stress of the liftoff. The vehicle has to do some serious maneuvering after the lift-off. If the connectors snapped that early then the vehicle wouldn't be on the pre-determined trajectory until almost 50 seconds. Yes, the higher stresses due to heavier upper stage and satellite "might" have played a role in the snapping of the connectors but it is very difficult to say that before more information is made available.
I come to know that (from internal sources) there are the FAC report outlines:
ReplyDelete- Satellite weight is slightly higher than planned. This is not a concern at all.
- Increase of size and weight in upper stage (cryogenic stage) played a key role, resulting huge errors in its (vehicle's) orientation leading to build-up of higher angle of attack and higher structural loads.
- Vehicle broke up at 53.8 seconds from lift-off.
- Range Safety Officer issued destruct command at 64 seconds after lift-off.
~ GSLV architecture is ROBUST. ISRO needs to develop a stable design (not architecture, here design means configuration.)
~ Modifying / Increasing 3rd stage engine beyond its capable limit is the primary reason for the mission failure...