Author Topic: LIVE: GSLV Mk-3 1st test launch (X1) December 18, 2014 (0400UTC)  (Read 417196 times)

Offline sanman

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Re: GSLV Mk-3 first test launch (X1) April 2014
« Reply #120 on: 01/06/2014 03:40 am »
The dimensions of CUS12 and CUS25 are different, so its not feasible to switch the stages.

Are you sure that swapping in the engine really amounts to swapping the entire stage? It seems to me that it's more feasible to swap in the smaller CE7.5 engine into the larger CUS of the Mark-3. Then do vibrational testing, etc. Anyway, just a thought. It really seems to be a shame that they're doing the initial Mark-3 flight without testing the full launch stack, because it's not a true test of the vehicle. Instead, it looks like this aerodynamic test is being done to save face, in spite of the CE20 not being ready. Oh well, I guess it's more baby steps - Gradatim Ferociter and so on.

Offline johnxx9

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Re: GSLV Mk-3 first test launch (X1) April 2014
« Reply #121 on: 01/06/2014 09:37 am »
The dimensions of CUS12 and CUS25 are different, so its not feasible to switch the stages.

Are you sure that swapping in the engine really amounts to swapping the entire stage? It seems to me that it's more feasible to swap in the smaller CE7.5 engine into the larger CUS of the Mark-3. Then do vibrational testing, etc. Anyway, just a thought. It really seems to be a shame that they're doing the initial Mark-3 flight without testing the full launch stack, because it's not a true test of the vehicle. Instead, it looks like this aerodynamic test is being done to save face, in spite of the CE20 not being ready. Oh well, I guess it's more baby steps - Gradatim Ferociter and so on.

That is way too complex for a single flight. The stage and the whole LV is built around the laid out specs. So, if I were to change the engine (or a stage) a lot of other stuff need to be changed and changes/effects needs to studied. ISRO has already invested significantly into the upperstage although they are still some distance from completion. 

Offline AJA

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Re: GSLV Mk-3 first test launch (X1) April 2014
« Reply #122 on: 01/06/2014 11:15 am »
Both GG & SC cycles have gas generator.

I'm aware of that. I used the term gas-generator in the conventional sense, and wasn't referring either to the gas generated by LH2 boiling, through regenerative heat exchange between fuel-exhaust in the nozzle cooling jacket (for the expander cycle) or to the gas generated in the fuel-rich, lower temperature pre-burner combustion (the staged-combustion cycle).

The quote you mention is from this paper titled "Turbomachines for Cryogenic Engines", presented by N K Gupta of LPSC at the Proceedings of the 37th National & 4th International Conference on Fluid Mechanics and Fluid Power, held at IIT-Madras between Dec 16-18, 2010; and not from the GSLV-D5 brochure (which doesn't specify the cycle used).

I did find an ISRO Press release about a hot-fire acceptance test of a cryogenic engine from 2008 that talks about a 42,000 rpm integrated turbopump driven 73 kN (Vacuum) engine (with an Isp of 454 seconds, 2 x 2kN steering engines, and a 13% uprated thrust mode) -- that I assume is the CE-7.5 (not explicitly stated in the release)-- and says that this uses the staged combustion cycle.

Anyway, back to the paper you took the quote from. In the very next paragraph after the quoted text, the paper says that ISRO's planning to build an engine with a gas generator cycle
Quote
ISRO has embarked on a plan for realizing a gas generator cycle based cryogenic engine in the 12 to 20 tonne thrust range.

The graphs, diagrams and the data are for the CE-20 and the C25.
Interestingly, the gas-generator does burn LOX/LH2...

Quote
Hot gas at 853 K received from LOX/LH2 gas generator runs the turbine

But they then dump the exhaust instead of sending it into the main combustion chamber to realise staged combustion!!

And this is in 2010... TWO YEARS AFTER the acceptance test of the staged combustion engine. I don't understand why they went with staged combustion for the smaller engine, but are proceeding without it for a subsequent, larger engine. Surely the Isp and performance gains are more pronounced here? I know scaling introduces complexities... but it's still surprising.

Offline pippin

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Re: GSLV Mk-3 first test launch (X1) April 2014
« Reply #123 on: 01/06/2014 11:27 am »
Probably a booster engine where cost and T/W are more important than ISP?
« Last Edit: 01/06/2014 11:28 am by pippin »

Offline antriksh

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Re: GSLV Mk-3 first test launch (X1) April 2014
« Reply #124 on: 01/06/2014 11:28 am »
The dimensions of CUS12 and CUS25 are different, so its not feasible to switch the stages.

Are you sure that swapping in the engine really amounts to swapping the entire stage? It seems to me that it's more feasible to swap in the smaller CE7.5 engine into the larger CUS of the Mark-3. Then do vibrational testing, etc. Anyway, just a thought. It really seems to be a shame that they're doing the initial Mark-3 flight without testing the full launch stack, because it's not a true test of the vehicle. Instead, it looks like this aerodynamic test is being done to save face, in spite of the CE20 not being ready. Oh well, I guess it's more baby steps - Gradatim Ferociter and so on.

In launch vehicle design certification, the most challenging part is LV's journey through the atmosphere where its subjected to maximum pressure, load and stress. Now, ISRO can wait for 3 more years and then conduct the same launch with an operational cryo stage just to find out that something is wrong in the LVM3 design or it can do that testing now and certify the design. They have the first two stages ready, so its better to sort out any aerodynamic challenges now rather than discovering them after 3 yrs.
Nasadiya Sukta:
Srishti se pehle sat nahin thaa, asat bhi nahin | Antariksh bhi nahin, aakaash bhi nahin thaa | chhipaa thaa kyaa, kahaan, kisne dhakaa thaa | us pal to agam, atal jal bhi kahaan thaa ||

From: 1st verse of 129th Hymn of the 10th Book of Rig Veda

Offline antriksh

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Re: GSLV Mk-3 first test launch (X1) April 2014
« Reply #125 on: 01/06/2014 02:26 pm »

And this is in 2010... TWO YEARS AFTER the acceptance test of the staged combustion engine. I don't understand why they went with staged combustion for the smaller engine, but are proceeding without it for a subsequent, larger engine. Surely the Isp and performance gains are more pronounced here? I know scaling introduces complexities... but it's still surprising.

ISRO started with russian cryo engine as a reference design, which was staged combustion. During the development process, they realised the complexities involved in testing the subsystems (in sc engine, subsystem level tests are not possible). It seems after mastering the SC tech,  for the CE20 engine, they chose cost and development complexity over efficiency or payload gain (200 kg).
Nasadiya Sukta:
Srishti se pehle sat nahin thaa, asat bhi nahin | Antariksh bhi nahin, aakaash bhi nahin thaa | chhipaa thaa kyaa, kahaan, kisne dhakaa thaa | us pal to agam, atal jal bhi kahaan thaa ||

From: 1st verse of 129th Hymn of the 10th Book of Rig Veda

Offline sanman

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Re: GSLV Mk-3 first test launch (X1) April 2014
« Reply #126 on: 01/10/2014 03:22 am »
Just another article reiterating that the planned April 2014 flight of the GSLV-Mk3 will carry the crew module on a suborbital flight:

http://timesofindia.indiatimes.com/india/Isro-inches-closer-to-manned-mission/articleshow/28609291.cms

Offline vyoma

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Re: GSLV Mk-3 first test launch (X1) April 2014
« Reply #127 on: 01/10/2014 03:31 am »
Just another article reiterating that the planned April 2014 flight of the GSLV-Mk3 will carry the crew module on a suborbital flight:

http://timesofindia.indiatimes.com/india/Isro-inches-closer-to-manned-mission/articleshow/28609291.cms

This is cool :) I'm eagerly waiting for crew module tests. By the way, what's the difference between the module used in SRE and this crew module - in terms of technology used?

Offline sanman

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Re: GSLV Mk-3 first test launch (X1) April 2014
« Reply #128 on: 01/10/2014 03:42 am »
I've no idea, but I'm imagining that testing the full crew module would sort of make SRE-2 redundant. SRE-2 is supposed to test communication blackout handling, as well as aerothermal structures and materials, and also carry some simple biological payload, I think.

http://en.wikipedia.org/wiki/Space_Capsule_Recovery_Experiment_II

If the crew module is being launched on Mk3, then I don't see why they couldn't do all the same tests on that flight. Anyway, just speculation.

Heh, I kind of like this rejiggering of the schedule along the way - it kind of keeps you on the edge of your seat, since nothing is totally set in stone.

Offline antriksh

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Re: GSLV Mk-3 first test launch (X1) April 2014
« Reply #129 on: 01/10/2014 02:13 pm »
Just another article reiterating that the planned April 2014 flight of the GSLV-Mk3 will carry the crew module on a suborbital flight:

http://timesofindia.indiatimes.com/india/Isro-inches-closer-to-manned-mission/articleshow/28609291.cms


Isro, as an additional feature, has also built in a separate escape module within the crew capsule. Sources said this module will in itself be a miniature space vehicle that can safely bring home its passengers.


 ::) :-\
Nasadiya Sukta:
Srishti se pehle sat nahin thaa, asat bhi nahin | Antariksh bhi nahin, aakaash bhi nahin thaa | chhipaa thaa kyaa, kahaan, kisne dhakaa thaa | us pal to agam, atal jal bhi kahaan thaa ||

From: 1st verse of 129th Hymn of the 10th Book of Rig Veda

Offline vyoma

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Re: GSLV Mk-3 first test launch (X1) April 2014
« Reply #130 on: 01/10/2014 02:32 pm »
Just another article reiterating that the planned April 2014 flight of the GSLV-Mk3 will carry the crew module on a suborbital flight:

http://timesofindia.indiatimes.com/india/Isro-inches-closer-to-manned-mission/articleshow/28609291.cms


Isro, as an additional feature, has also built in a separate escape module within the crew capsule. Sources said this module will in itself be a miniature space vehicle that can safely bring home its passengers.


 ::) :-\

Well, that's confusing!! It sounds like a crew module within a crew module ;D  May be they're referring to "Launch Escape System" or even ejection seats, which separates the crew module from rocket in case of emergency during launch or first/second stage separation.

Offline sanman

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Re: GSLV Mk-3 first test launch (X1) April 2014
« Reply #131 on: 01/10/2014 03:53 pm »
ISRO's going for a traditional Launch Escape System, so I think the reporter's just muddled up on their understanding.

Offline vyoma

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Re: GSLV Mk-3 first test launch (X1) April 2014
« Reply #132 on: 01/11/2014 02:39 am »
ISRO aims to fly GSLV Mk3 X1 up to 120km altitude, at which point crew module will also be tested:
Quote
A manned space flight to a low-earth orbit (upwards of 160 km to a few hundred km) is on Isro's radar. Except the US' Apollo missions to the moon, all other human space flights took place in these zones.
Quote
The experimental flight, however, will not carry a functional cryogenic engine. The heavy-duty rocket will fly up to an altitude of 120 km, after which it will take a parabolic path and dive in the Bay of Bengal.

http://www.deccanherald.com/content/379799/big-leap-indias-efforts-manned.html


Quote
When GSLV Mk-III will be tested in three months' time, the heavy-d­uty rocket will fly the module to an altitude of about 120 km to see if it is safe for human flight. “GSLV Mk-III will carry the cr­ew module to study re-entry and thermal behaviour,” said Isro chairman K Radhakrishn­an here on Friday.

http://www.deccanherald.com/content/379831/india-test-human-crew-space.html

Offline antriksh

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Re: GSLV Mk-3 first test launch (X1) April 2014
« Reply #133 on: 01/11/2014 04:43 am »
C25 stage & L110 Vikas engines!!!



Nasadiya Sukta:
Srishti se pehle sat nahin thaa, asat bhi nahin | Antariksh bhi nahin, aakaash bhi nahin thaa | chhipaa thaa kyaa, kahaan, kisne dhakaa thaa | us pal to agam, atal jal bhi kahaan thaa ||

From: 1st verse of 129th Hymn of the 10th Book of Rig Veda

Offline antriksh

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Re: GSLV Mk-3 first test launch (X1) April 2014
« Reply #134 on: 01/11/2014 04:46 am »
 ;D Looking forward to LVM3-x!!


Nasadiya Sukta:
Srishti se pehle sat nahin thaa, asat bhi nahin | Antariksh bhi nahin, aakaash bhi nahin thaa | chhipaa thaa kyaa, kahaan, kisne dhakaa thaa | us pal to agam, atal jal bhi kahaan thaa ||

From: 1st verse of 129th Hymn of the 10th Book of Rig Veda

Offline antriksh

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« Last Edit: 01/11/2014 09:30 am by antriksh »
Nasadiya Sukta:
Srishti se pehle sat nahin thaa, asat bhi nahin | Antariksh bhi nahin, aakaash bhi nahin thaa | chhipaa thaa kyaa, kahaan, kisne dhakaa thaa | us pal to agam, atal jal bhi kahaan thaa ||

From: 1st verse of 129th Hymn of the 10th Book of Rig Veda

Offline vyoma

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Re: GSLV Mk-3 first test launch (X1) April 2014
« Reply #136 on: 01/11/2014 09:06 am »
Thanks for posting pics and video, antriksh. I had seen that video earlier. That opening song, which is from movie "Border", gives me goosebumps every time I hear it   :)

Offline antriksh

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Re: GSLV Mk-3 first test launch (X1) April 2014
« Reply #137 on: 01/11/2014 09:54 am »
Thanks for posting pics and video, antriksh. I had seen that video earlier. That opening song, which is from movie "Border", gives me goosebumps every time I hear it   :)

 ;D
Nasadiya Sukta:
Srishti se pehle sat nahin thaa, asat bhi nahin | Antariksh bhi nahin, aakaash bhi nahin thaa | chhipaa thaa kyaa, kahaan, kisne dhakaa thaa | us pal to agam, atal jal bhi kahaan thaa ||

From: 1st verse of 129th Hymn of the 10th Book of Rig Veda

Offline spaceash2

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Re: GSLV Mk-3 first test launch (X1) April 2014
« Reply #138 on: 01/11/2014 11:28 am »
It looks like Reentry module will be tested with GSLV III
Is this same as SRE?

http://www.deccanherald.com/content/379799/big-leap-indias-efforts-manned.html

Offline vyoma

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Re: GSLV Mk-3 first test launch (X1) April 2014
« Reply #139 on: 01/11/2014 11:57 am »
It looks like Reentry module will be tested with GSLV III
Is this same as SRE?

http://www.deccanherald.com/content/379799/big-leap-indias-efforts-manned.html

No. Crew module and SRE are different, although they may share some common bits of technology (just speculating here).

GSLV Mk3 will carry this 3 people capacity crew module: http://en.wikipedia.org/wiki/ISRO_Orbital_Vehicle

SRE-2, which is a smaller sized capsule compared to crew module, will be carried by a PSLV in near future: http://en.wikipedia.org/wiki/Space_Capsule_Recovery_Experiment_II


Check these earlier posts as well:
By the way, what's the difference between the module used in SRE and this crew module - in terms of technology used?

I've no idea, but I'm imagining that testing the full crew module would sort of make SRE-2 redundant. SRE-2 is supposed to test communication blackout handling, as well as aerothermal structures and materials, and also carry some simple biological payload, I think.

http://en.wikipedia.org/wiki/Space_Capsule_Recovery_Experiment_II

If the crew module is being launched on Mk3, then I don't see why they couldn't do all the same tests on that flight. Anyway, just speculation.
« Last Edit: 01/11/2014 11:58 am by vyoma »

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