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#120 by chota on 29 Aug, 2013 16:54
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"The leak is suspected to be in the lower portion of the propellant tank or the fluid lines between the tank and fuel filling system of the Second stage"
"A new Liquid Second Stage (GS-2) is being assembled to replace the leaked-stage"
"All the four Liquid Strap-on Stages are being replaced with new ones"
"Cryogenic Stage will be preserved"
"GSLV Vehicle assembly and checkout is expected to be completed by first week of Dec'13 and launch in same month"
http://www.isro.org/pressrelease/scripts/pressreleasein.aspx?Aug29_2013
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#121 by AJA on 30 Aug, 2013 20:17
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So what happens to these 'wetted' strapons - especially the engines, and the plumbing that was isolated from direct contact by closed valves? And the second stage engine? Discarded as toxic waste? Are they even going to bother inspecting them for salvage potential?
It'd be nice if we had 4 sub-orbital/sounding rocket payloads and some "world-famous-in-India" JugaaD mounting mechanism
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#122 by chota on 31 Aug, 2013 15:44
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#123 by chota on 04 Sep, 2013 11:15
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The second stage has a single tank to store both UDMH and N204 both of which are seperated by a common bulkhead
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#124 by sanman on 14 Sep, 2013 03:35
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ISRO to assemble new stage for GSLV flight:
http://www.deccanherald.com/content/356989/isro-make-stage-gslv.html -
#125 by Stan Black on 15 Sep, 2013 07:39
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ISRO to assemble new stage for GSLV flight:
http://www.deccanherald.com/content/356989/isro-make-stage-gslv.html
So the designation D5 is more a mission identifier than the actual rocket serial number. And where are they sourcing all these spare rocket stages; from F03 and F05, or from D4 (or was that F06)? -
#126 by sanman on 27 Sep, 2013 20:01
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ISRO Chairman: GSLV D5 ready for launch on December 15
http://www.indianexpress.com/news/gslv-d5-ready-for-launch-on-december-15-isro-chairman/1175296/
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#127 by input~2 on 05 Nov, 2013 11:08
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#128 by Star One on 05 Nov, 2013 11:53
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Preparations in full swing for December 15 GSLV mission
Thanks for that article. It mentions its performance to a variety of orbits, is it known what it can launch to the Moon or Mars as I know it will also be fulfilling India's further ambitions in interplanetary missions? -
#129 by sanman on 05 Nov, 2013 14:37
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Thanks for that article. It mentions its performance to a variety of orbits, is it known what it can launch to the Moon or Mars as I know it will also be fulfilling India's further ambitions in interplanetary missions?
They wanted to use it for this Mars mission, but it wasn't ready in time with an adequate reliability track record.
They'll be using it on the next Chandrayaan-2 mission to the Moon, which will land an Indian rover on the surface.
Probably it could get used for further missions to Mars too, since it will be able to send significantly more payload. -
#130 by baldusi on 05 Nov, 2013 18:44
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PSLV is a four stages rocket. GSLV is a three stage with an H2 third but a very inefficient first (the boosters actually carry the empty weight of the first stage for almost a minute!). For GTO, the GSLV Mk.II should do about twice than the PSLV. I wonder, if they would use the extra performance for direct injection.
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#131 by chota on 06 Nov, 2013 12:14
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Quote
PSLV is a four stages rocket. GSLV is a three stage with an H2 third but a very inefficient first (the boosters actually carry the empty weight of the first stage for almost a minute!).
The 4 boosters burn longer than the Core Stage and remain attached to the middle core.
Though PSLV and GSLV share the same solid first stage, PSLV uses SITVC whereas GSLV uses EGC on each of the 4 L40 strapons for stabilization. SITVC on S139 solid motor is a backup. L40 also has fins for stability and can be started and stopped. -
#132 by AJA on 06 Nov, 2013 17:03
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Yeah, but what baldusi said still holds. The rocket's carrying an empty stage. Having said that, the empty core isn't dead-weight - given that it acts as the thrust transfer structure from the strap-ons to the rest of the stack. It'd be interesting to read about why they didn't reverse the solid/liquid config. i.e. solid strap-on boosters, and liquid core, with the same burn times for both types.
Would that not offer an additional abort-to-LEO mode? i.e. if something was wrong with the solid boosters, you could cut them loose prematurely, and they'd rocket off (provided they don't crash into the rest of the stack. The pyro motors used to jettison could possibly give them enough of a kick and a 'point-away'?). If something was wrong with the liquid stage, then you'd shut it down, and do only a solid burn for the first stage.
There'd be an IMMENSE performance hit, but if you could still make orbit with it, then the payload could possibly still reach its intended orbit, albeit by spending its own fuel, and shortening its own lifetime. Even if it couldn't, something could be done with it in a rudimentary orbit - as opposed to writing it off?
Did/do any launch vehicles offer this? The flight control software would have to be amazingly nimble, to say nothing of the rest of the stack being strong enough to not break up under aero-acoustic & aero-structural loads of a drastic change in flight direction, and being exposed to booster exhaust/buffeting. -
#133 by sanman on 06 Nov, 2013 20:00
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But what you've all said applies to GSLV-Mk2 only, and that vehicle seems like it was really meant as just a stepping stone to validate the technologies for GSLV-Mk3 (Yes, I see a bunch of Mk2 missions on the roadmap, but I'd always assumed that's because Mk2's hardware is cheaper to use for those missions than the Mk3)
Once the Mk3 gets rolling, I'd thought that the roadmap might be significantly revised, especially if ISRO takes on more paying customers. -
#134 by akula2 on 07 Nov, 2013 11:13
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Wow, months.
My initial reaction was: oh no! how much money will be lost (high taxpayers, ISRO & to Govt/businesses who can't lease/buy) because of this leak disaster and the impending delay
But as with all rockets, that's good news when they find the issue on the ground and not half way uphill!
I've made plans to build my own Satellites by 2020 (three). -
#135 by chota on 18 Nov, 2013 05:55
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Tomorrow 19-Nov, the exact GSLV launch date will be confirmed. It might get delayed to end of December.
http://newindianexpress.com/states/kerala/Meet-on-GSLV-mission-launch-set-for-19th-November/2013/11/18/article1897001.ece
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#136 by vyoma on 20 Nov, 2013 04:23
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GSLV D5 (MkII) launch December end; no dates yet.
http://www.deccanchronicle.com/131120/news-current-affairs/article/gslv-launch-december-endQuoteSpeaking to reporters at the city airport, Dr K. Radhakrishnan, chairman of the Indian Space Research Organisation (ISRO) said that scientists identified problem in the cryogenic stage of the GSLV and had rectified the issue. “The launch vehicle is ready for launch and we plan to launch it in December,” he said.
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#137 by vyoma on 20 Nov, 2013 13:27
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This interview has some info about GSLV rebuilding and launch preparation (last question):
http://thehindu.com/opinion/interview/mars-orbiter-tests-have-shown-our-ability-to-predict-isro-chairman/article5372129.ece
Mission Readiness Review on Dec 3rd. -
#138 by ss1_3 on 27 Nov, 2013 12:29
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This article places the launch in third week of December:
http://bit.ly/18nN6DDQuoteThe indigenous cryogenic third stage engine is ready. The mission readiness meet will be held on December 3 and the GSLV-D5 will be launched by December third week from Sriharikota
Article also contains updates on upcoming MkIII launches. -
#139 by AJA on 28 Nov, 2013 03:13
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This article places the launch in third week of December:
http://bit.ly/18nN6DDI. have. no. words. No words.Yes, it's ToI, but this is a new low - even for them.Quote" ... The GSLV Mark III variant, initial launch planned by April next year is a sub-orbital flight test having the first and second stage active solid and liquid propellants, its cryogenic stage will be passive," said Vikram Sarabhai Space Centre (VSSC) director S Ramakrishnan.
(Emphasis mine)
What. in. the. HELL. does that mean? Testing a rocket with an upper stage mass simulator is simply not the same as saying 'Yeah, we'll launch the rocket in the final operational flight configuration - with a fully fuelled, and fully operational upper (and most expensive) stage; but we won't start it' - which is what that quote seems to imply. Unbelievably, that seems to be a direct quote from the VSSC director. If I were him, I'd call back and clarify - but I doubt ToI'll run errata.
But wait.. that's not it.Quote"An advanced heavy cryogenic engine C-25 is being designed with 25 ton propellant loading with 20 tonnes of engine thrust for the GSLV Mk-3 D-1 mission in early 2017," he said. "The huge cryogenic engine is slated for completion and testing by 2015."
(Emphasis mine)
WHAT? 25 ton propellant loading, with 20 tonnes of thrust (yes, I noticed the inconsistency in spelling of 'tonne' in the same sentence) is not an engine... on the contrary, it's a very heavy piece of equipment that's going to fall out of the sky! Again, these figures might be accurate, if the stage has 25 tonnes of prop, and has 2 x 20 tonne thrust engines. (But that's quite an acceleration for the upper stage and payload, unless the engines are capable of deep throttling).
It might even be possible to have a 25 tonne upper stage (and this is prop weight only, and not engine weight) that is already orbital prior to its ignition. But I seriously doubt that - especially since the same 'article' has said that the GSLV-Mk III's first developmental flight is going to be sub-orbital.
Finally,QuoteOxygen remains a liquid only at temperatures below minus 1830 Celsius and Hydrogen at minus 2530 Celsius, developing a cryogenic engine from such propellants is a crucial test.
<Shaking head>
I swear all it takes to get the degree symbol into any commonly used text editor is googling "degree symbol" and copy pasting it. Like so. °
Don't tell me the typesetting software for thenewspaper doesn't support it. They were extremely quick to chest-thump and use the rupee symbol (which still doesn't have a unicode character assigned to it) as soon as it was adopted (EDIT: before unicode support) - but they can't use "°" ? ESPECIALLY when, you know, being the country that's credited with the invention of 'zero' (atleast in the same chest thumping vein of popular culture), we should really understand place value. Screw that, you should really understand place value if you're literate. Forget country of origin.
Yeah, there's a vanishingly small chance that the 'reporter' was aware of research in , but that still doesn't change the boiling points of LOX and LH2.
Oh, and yes... I also noticed the use of a comma instead of a semicolon, and the telling lack of a conjunction.
</rant>
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