Rather than fill up the update thread with discussion, this is the place to state your opinion on whether this work or not: extra points for predicting the exact failure mode (if any) or time.I cannot see this making it through 3rd stage operation, but I am rarely right about launches.
I am concerned that ISRO is continually attempting to upgrade the launcher before demonstrating that any one variant has been proven.There are two variants of the Mark I, plus a Mark 2 plus a Mark 3 coming soon.
I am suggesting that the flight history of GSLV has been so short that there may be failure modes that have not been experienced yet.
These include:• Redesign of Lower Shroud which protects the cryogenic engine during atmospheric flight of GSLV-D5• Redesign of the wire tunnel of the cryo stage to withstand larger forces during flight• Revised Aerodynamic characterisation of the entire launch vehicle• Inclusion of Video Imaging System to monitor lower shroud movement during various phases of flight• Improvements in the Cryogenic upper Stage: → Modified design of the Fuel Booster Turbo Pump (FBTP), taking care of the expansion and contraction of the bearings and casing at cryogenic temperatures → Modification of Ignition Sequence to ensure the smooth, successful and sustained ignition for Main Engine (ME), Steering Engine (SE) and Gas Generator (GG)In addition, indigenisation of many critical systems including Liquid Hydrogen Propellant Acquistion System (to prevent the possibility of contamination), Polyimide pipelines and Liquid Oxygen & Liquid Hydrogen Level Sensors has been successfully accomplished.In order to validate the design improvements, the following extensive qualification test have been carried out on the engine at the Main Engine Test (MET) facility and the High Altitude Test (HAT) facility:• Two acceptance tests for flight unit of FBTP • High altitude tests to confirm the ignition sequence in flight under vacuum• Cryogenic Main Engine (200 sec) and Steering Engine (100 sec) acceptance tests
I cannot see this making it through 3rd stage operation, but I am rarely right about launches.
I was reading that ISRO is working on uprating the cryogenic engine from its current 73kN to 90kN thrust:http://isp.justthe80.com/launchers/isro-s-cryogenic-upper-stage-cus#TOC-More-Powerful-Cryogenic-EngineThat still doesn't correct the design flaw of carrying the dead weight of the 1st-stage core post-burnout. But I guess ISRO doesn't mind because of the cheapness of developing GSLV-Mk1/2.Is there any opportunity to correct that flaw somehow? Seems like they'd have to swap out the solid core for a liquid one, and that might even allow them to probably get rid of the strap-ons too.Gee, I didn't realize that the cryogenic upper stage for GSLV-Mk3 was a different technology (gas generator) as compared to GSLV-Mk2 (staged combustion). I'd always thought both rockets were using the same cryogenic engine technology, and that therefore the Mk-3 was just an evolution on the configuration of the Mk-2.If the staged combustion in GSLV-Mk2 is not being replicated in the GSLV-Mk3, then what further platforms will make use of the staged combustion technology? It seems to me that if ISRO has taken the trouble to develop staged combustion technology, that it should want to use it on a launch vehicle that isn't handicapped.To me, that means that either GSLV-Mk2 should be replaced with a better-designed rocket, or else the design flaw in Mk2 should somehow be corrected.
That still doesn't correct the design flaw of carrying the dead weight of the 1st-stage core post-burnout. But I guess ISRO doesn't mind because of the cheapness of developing GSLV-Mk1/2.Is there any opportunity to correct that flaw somehow? Seems like they'd have to swap out the solid core for a liquid one, and that might even allow them to probably get rid of the strap-ons too.
They could decrease the fuel capacity in the boosters to avoid the 1st stage post burn out dead weight problem. Though I am not sure if the weight decrease in L440 chambers will compensate for loss of thrust duration.What is the weight of the 1st stage core shell casing?
The CUS already reached 90 kn in this flight. it started with 75 and reached 90, and then again back to 75. Staged combustion cycle technology development experience will help in the semi-cryo engine under development and probably for future high rated cryo engines for RLV. Once LVM3 is available, ISRO will concentrate on building only >3 ton com sats and so role of GSLV mk2 will be limited to lofting GSO imaging stas and inter-planetary missions.
Or alternatively, they could increase the size of the 1st-stage core, to make it last longer, which would improve capacity rather than lowering it! It would also allow that near-worthless 2nd-stage to be eliminated. Call that the GSLV Mk-2B.Come to think of it - why didn't they just do that from the start?
