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#20
by
Danderman
on 28 Dec, 2013 19:01
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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.
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#21
by
AJA
on 28 Dec, 2013 19:31
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Wow. OK.. care to substantiate your argument?
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#22
by
kanaka
on 29 Dec, 2013 06:03
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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.
Could you please justify your conclusion? Basis of analysis is appreciated.
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#23
by
Danderman
on 30 Dec, 2013 00:21
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First off, this particular launcher in general has a spotty history, plus the LH2 engine has a poor flight record.
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.
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#24
by
antriksh
on 30 Dec, 2013 02:16
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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.
Your concern is unwarranted because ISRO is not doing anything of that sorts. GSLV (Mk1, MK2) and the upcoming GSLV Mk3 or LVM3 are two completely different launch vehicles. Most people have this misconception that LVM3 is an upgraded version of GSLV. LVM3 is a next generation launch vehicle of ISRO which comes under its expansion phase (SLV, ASLV- experimental phase, PSLV, GSLV - operational phase). All stages of LVM3 are of completely new design and share nothing in common with GSLV.
As far as GSLV is concerned, the only challenge left is mastering the cryo engine tech as there is no problem with the aerodynamic structure of the LV and the performance of both the first and second stages have been nominal.
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#25
by
Danderman
on 30 Dec, 2013 03:37
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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.
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#26
by
cave_dweller
on 30 Dec, 2013 22:33
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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.
However, is that enough information for a foregone conclusion?
Technological development is always incremental. Almost all the components of GSLV with the exception of Indigenous Cryogenic Upper Stage (CUS) have been proven.
The Indian CUS was tested once in D3 flight (failure).
http://www.isro.org/gslv-d3/gslv-d3.aspxGiven the background of ISRO, I'd say the odds of success are in favor this time.
So it remains to be seen the outcome of this flight.
Best to you ISRO. Go get it done!!
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#27
by
vyoma
on 31 Dec, 2013 03:11
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GSLV-D5 has many fixes and improvements over GSLV-D3, which was the first flight of indigenous CUS. Quoting from GSLV-D5 brochure
http://www.isro.org/gslv-d5/pdf/brochure.pdf:
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 guess, all eyes will be on turbo pumps and CUS lower shroud.
All the best, ISRO. Let's do it
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#28
by
johnxx9
on 05 Jan, 2014 10:41
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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.
You have an answer now!
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#29
by
isro-watch
on 05 Jan, 2014 10:58
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Yes, the answer !
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#30
by
Mazo
on 05 Jan, 2014 11:20
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After a technology denial regime instituted by the US Government that prevented Russia from transferring the cryogenic staged combustion cycle engine technology to India in 1992 citing MTCR and other meaningless treaties (while NASA was buying Soviet RD-180 technology because it was "better"), today the ISRO has built, tested and demonstrated its own cryogenic engine with a text book launch using an ALL INDIAN vehicle.
25 years later- mission accomplished! Success or Failure - you decide.
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#31
by
xm11
on 05 Jan, 2014 11:25
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GSLV-D5 successfully launches GSAT-14 from SDSC SHAR, Sriharikota
on Jan 05, 2014
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#32
by
xm11
on 05 Jan, 2014 11:28
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#33
by
Danderman
on 05 Jan, 2014 14:31
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I cannot see this making it through 3rd stage operation, but I am rarely right about launches.
I am pleasantly surprised to be wrong on this one.
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#34
by
sanman
on 05 Jan, 2014 16:33
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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.
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#35
by
antriksh
on 06 Jan, 2014 02:18
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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-Engine
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.
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.
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.
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#36
by
cave_dweller
on 06 Jan, 2014 02:46
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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?
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#37
by
sanman
on 06 Jan, 2014 03:13
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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?
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?
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#38
by
sanman
on 06 Jan, 2014 03:26
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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.
Ah, that's right - saw those comments about the variable thrust being cranked up to hit 90.
What about restart capability? I read that this engine has that, but I guess it wasn't tested on this flight.
I'd read that the next big focus for LPSC will be on Semi-cryo engines, and so this development program will result in larger boosters for lower stages. So this seems to be the opposite of everyone else's engine development path. Everybody else did semi-cryo first, because that's easiest and gets you flying sooner - certainly more practical from a business perspective. India seems to have approached development from the opposite side, which seems to be what's taking it so long in getting into the commercial launch market.
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#39
by
cave_dweller
on 06 Jan, 2014 04:25
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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?
I thought about this. I figured it would be much easier to manipulate the fuel content in the strap on boosters rather than modifying the engineering of the solid core.
Solid fuels tend to be heavier and have shorter specific impulse.
ISRO could maintain the same stage design layout.
Decrease fuel capacity in Stage-1 strap on boosters.
Increase fuel capacity in either Stage 2 or Stage 3 and maintain current weight configuration but achieve better performance.
