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#60
by
K210
on 22 Aug, 2015 16:00
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Im surprised nobody has realised that the strapons for this launch have been upgraded. Prior to this mission they used to produce 680kn now they produce 760kn, the second stage has also been increased from 720kn to 800kn.
Those are the figures for D1. They had already been increased for later launches.
No they are the figures for D5 as can be seen in the screenshot below. The D6 specs are attached for comparison.
GSLV D-5
http://i.imgur.com/Ggk8bWz.pngGSLV D-6
http://i.imgur.com/4Hp3Ae8.png
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#61
by
K210
on 22 Aug, 2015 16:42
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It's the same as what i posted.The d-5 specs on ISRO's site show 680kn for strapons and 720kn for second stage.
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#62
by
vineethgk
on 22 Aug, 2015 18:45
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I guess this is expected? They might have configured the engines for a lower thrust for the previous test flight, and might be ramping up gradually to its full capability in subsequent ones. Also, it is carrying a heavier payload this time.
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#63
by
Stan Black
on 22 Aug, 2015 20:20
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That will teach me. I have some notes stored in an Apple Numbers document, that my current Macintosh cannot read because the software is a later a version. Thanks Apple! And added to that ISRO have changed there website and none of the links I have noted down work. Thanks ISRO!
For some reason GSLV-D5 was the same specification as the GSLV-D1. PSLV-C5 saw an increase of PS2 stage engine to 800, and some have been 799 or 804 kN. Same for most GSLV. GSLV strap-ons too have had increased thrust compared to GSLV-D1.
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#64
by
kanaka
on 23 Aug, 2015 01:10
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Thrust in 3rd stage is decrease. Is this the cryo stage??
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#65
by
northenarc
on 23 Aug, 2015 01:26
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So GSLV is a solid first stage surrounded by four hypergolic boosters, but how are they steering? I've read the Vikas engine can gimbal, do they on GSLV? I noticed a tube running down the boosters and wondered if it might be to shoot extra hydrazine into the stream in a steering scheme similar to PSLV and it's solids. Or maybe it just gimbals and I'm reading too much into it.
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#66
by
edkyle99
on 23 Aug, 2015 04:50
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So GSLV is a solid first stage surrounded by four hypergolic boosters, but how are they steering? I've read the Vikas engine can gimbal, do they on GSLV? I noticed a tube running down the boosters and wondered if it might be to shoot extra hydrazine into the stream in a steering scheme similar to PSLV and it's solids. Or maybe it just gimbals and I'm reading too much into it.
Steering is provided by gimballing the Vikas engines on the strap-on boosters during the solid motor burn. The core solid motor burns out about 42-ish seconds before the strap-ons shut down, so obviously they steer the launch vehicle during that phase as well.
- Ed Kyle
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#67
by
vyoma
on 23 Aug, 2015 05:37
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GSLV D1 had following steering mechanism:
GS1 (first stage):
a) Gimbal on L40 liquid strapon motors
b) SITVC on S125 solid core
GS2 (second stage):
a) Gimbal for pitch & yaw control. Hot gas RCS for roll control.
GS3 (third stage):
a) 2 vernier engines for thrust phase steering; and cold gas RCS for coast phase steering.
However, SITVC on GS1 solid core was removed
GSLV D3 onwards. So, the current GSLV D6 doesn't have any steering mechanism on S139 solid core in first stage.
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#68
by
northenarc
on 23 Aug, 2015 17:28
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Thank you both, interesting that the SITVC was removed during development, I suppose they thought it would be needed for the S125 solid but it was ultimately redundant.
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#69
by
abhishek
on 24 Aug, 2015 00:35
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#70
by
seshagirib
on 24 Aug, 2015 14:35
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Thank you both, interesting that the SITVC was removed during development, I suppose they thought it would be needed for the S125 solid but it was ultimately redundant.
For the GSLV "composite" first stage, the liquid strapons fire for a longer duration then the core solid stage making SITVC redundant for the solid stage.
I suspect the SITVC was built in , just in case the design evolved to a "more normal" configuration, with an enhanced core solid stage firing longer then the strapons.
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#71
by
vyoma
on 25 Aug, 2015 03:30
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#72
by
Ohsin
on 26 Aug, 2015 06:25
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#73
by
seshagirib
on 26 Aug, 2015 07:04
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^Yes.Count down has commenced.
isro.org:
Aug 26, 2015 : GSLV-D6 / GSAT-6 Update: The 29 hr countdown activity of GSLV-D6/GSAT-6 Mission has commenced today, Wednesday, Aug 26, 2015 at 11:52 hr IST Launch is scheduled at 16:52 hr IST on Aug 27, 2015
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#74
by
seshagirib
on 26 Aug, 2015 07:07
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29 hrs Countdown should have started. Webcast is streaming with wait screen too.
http://24framesdigital.com/isro/webcast/270815/video.html
^ I am being prompted for a plug in ( firefox browser). Can someone please tell me what plug in is required? ( don't want to be stranded on launch day )
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#75
by
Steven Pietrobon
on 26 Aug, 2015 07:26
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You need to have Windows Media Player Plug-In installed and activated. Select Tools -> Add-ons to see if you have the Plug-In. It might be already installed, but not activated.
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#76
by
Ohsin
on 26 Aug, 2015 07:32
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#77
by
Galactic Penguin SST
on 26 Aug, 2015 09:10
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Moved for live coverage!
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#78
by
seshagirib
on 27 Aug, 2015 04:22
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^^Thanks!! ohsin and pietrobon,I got the windows media player plug in and I am GO! for todays launch.
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#79
by
seshagirib
on 27 Aug, 2015 04:28
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Aug 27, 2015
GSLV-D6 / GSAT-6 Update: Preparations for propellant filling of cryo stage are under progress