Indian Space Programme Discussion

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Bade
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Re: Indian Space Programme Discussion

Postby Bade » 05 Jan 2014 06:45

SriKumar wrote:
Varoon Shekhar wrote:GSLV Mk.2 4 × L-40H / Vikas GS-1 / S-139 GS-2 (L-37.5H) / Vikas GS3 (CUS-12) / CS -
GSLV Mk.2A 4 × L-40H / Vikas GS-1 / S-139 GS-2 (L-37.5H) / Vikas GS3 (CUS-15) / CS -
GSLV Mk.2C 4 × L-40H / Vikas GS-1 / S-139 GS-2 (L-40H) / Vikas GS3 (CUS-15) / CS PAM-G

"It is the CE 7.5 Engine which is part of the CUS15 cryogenic stage."

So was there some uprating of the stage, from the first failed launch of the Indian Cryo-engine. From CUS-12 to CUS-15. What were the modifications?
If I recall right, the failure of the desi cryo stage was due to the cryo turbo-pump(s) failing. The ISRO brochure posted by PratikDas on previous page says something about turbopump modification.

http://timesofindia.indiatimes.com/indi ... 417612.cms
From the April 2010 failure, when the cryogenic engine failed 800 milliseconds after ignition, Isro learned that dissimilar contractions of different materials led to problems in three bearings in the fuel booster turbo pump. "Here we made some changes to the design of one of the casings and tested the new pump under normal operating temperatures. Its working perfect now," Radhakrishnan said. In the case of the December 2010 misfire, scientists found some Russian connectors had snapped. This was corrected by changing the mounting design, which was later tested on ground using the wind tunnel blow down method.

"We have thoroughly studied the past experiences and made changes. We are all upbeat," said Radhakrishnan while travelling from the Isro headquarters in Bangalore to Sriharikota on Saturday.

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Re: Indian Space Programme Discussion

Postby member_28108 » 05 Jan 2014 06:50

Preparations for Propellant filling operation of GSLV-D5 Cryo Stage is under progress

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Re: Indian Space Programme Discussion

Postby SriKumar » 05 Jan 2014 07:00

Bade wrote: http://timesofindia.indiatimes.com/indi ... 417612.cms
From the April 2010 failure, when the cryogenic engine failed 800 milliseconds after ignition, Isro learned that dissimilar contractions of different materials led to problems in three bearings in the fuel booster turbo pump. "Here we made some changes to the design of one of the casings and tested the new pump under normal operating temperatures. Its working perfect now," Radhakrishnan said. In the case of the December 2010 misfire, scientists found some Russian connectors had snapped. This was corrected by changing the mounting design, which was later tested on ground using the wind tunnel blow down method.

"We have thoroughly studied the past experiences and made changes. We are all upbeat," said Radhakrishnan while travelling from the Isro headquarters in Bangalore to Sriharikota on Saturday.
Hey ......thanks for the link. This is the first time I am seeing a number associated with the time of failure. If you recall the launch video, they announced 'cryogenic stage ignition' and there was applause among the viewers. After that the blip on the screen started to to depart from the expected trajectory and then it was clear for all to see. Regarding the recent failure of the GSLV with russian cryo stage, indeed the connectors had snapped. I thought they traced that to a failure of the shroud as the primary cause. If I recall right, the payload fairing was larger than before, or something like that, and that caused some (aerodynamic?) issues around the shroud....per some press reports or the ISRO failure report. The current GSLV brochure mentions this as one of the improvements 're-characterization of the vehicle aerodynamics' plus re-design of the shroud.

Added later: The above article is in 2010 at which point the primary cause was not determined. Article in 2014, but more detail below. This link has more on the cause of connectors snapping (air pressure around the shroud). http://indianspaceweb.blogspot.com/2011 ... ilure.html
Last edited by SriKumar on 05 Jan 2014 07:24, edited 2 times in total.

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Re: Indian Space Programme Discussion

Postby member_28108 » 05 Jan 2014 07:15

putnanja wrote:From the GSLV-D5 documenton ISRO site


ok, noobie question, so please don't laugh :) The first stage which is solid provides altitude gain of almost 70kms, and that is while trying to escape the earth's gravity. However, the CUS provides altitude gain of around 73kms in outer space where the earth's pull will be less. How exactly is the cryogenic stage providing better capability? does it have to do with the size/propellants required for cryogenic stage as compared to the solid stage?


A cryogenic engine is needed after a certain amount of time (rather payload weight and insertion needs) because we need to move a certain amount of fuel and oxidizer at a sufficiently fast rate to impart a sufficient increase in velocity(deltaV). To do that - solid and liquid traditional fuel cannot do that rapidly enough as the rate of pumping versus fuel efficiency is not possible to be achieved with current traditional solid and liquid noncryogenic fuels.(solids are not pumped but burn as is where is and the rate is determined by altering the surface area of the burning solid fuel to put it simply) For oxygen and hydrogen in gaseous form the problem is the holding tanks for these in gaseous form would be just too large offsetting fuel transmission needs (good) to tank weight (bad).So we need to hold the fuel in as efficient form in smaller tanks . Verner Von Braun found out that this could be overcome by holding the gaseous fuel as cryogenic liquids (LOX - liquid oxygen) and Liquid hydrogen (LH2) and this allows compact storage in weight saving smaller tanks and the gas can now be "vaporized" at the time of injection into the ignition chamber but be held cryogenically till then during pumping so we can now throw a huge amount of efficient fuel rapidly allowing a bigger "bang for buck" though the bang is a controlled one :)
The problems we face are one of handling that cryogenic fuel - holding pumping and efficiently igniting in a controlled manner this fuel. Not so easy as metals etc behave differently at such low temperatures so the holding containers, pumps etc must work properly both at cryogenic temperatures as well as in the vacuum of space.
Just to indicate how complex this is the rocket cone gets heated so much that it should melt so part of the cryogenic fuel actually circulates around the engine nozzle (the inverted aluminium bucket :) ) to cool it and simultaneously gets converted to gaseous form to enter the ignition chamber.

If I am right there is some photo showing the external temperature of the cryogenic rocket engine nozzle which is technically cool enough to put a hand on it but for the fact we cannot stand near the rocket when it is firing !! I cannot seem to get hold of that picture.

Hoe this helps

If you want to read some more see
http://www.slideshare.net/pandu_sravs/c ... nes-report

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Re: Indian Space Programme Discussion

Postby Gagan » 05 Jan 2014 07:30


Jan 05, 2014
Preparations for Propellant filling operation of GSLV-D5 Cryo Stage is under progress

They've tested the cryo stage so many times now, and in all sorts of conditions, even high altitude test chamber, in vaccum.

God speed to the GSLV flight !!!
All the best ISRO team !!!

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Re: Indian Space Programme Discussion

Postby member_28108 » 05 Jan 2014 07:58

Image

From ISRO's FB page.

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Re: Indian Space Programme Discussion

Postby Raja Bose » 05 Jan 2014 08:05

^^^Thats one beauitiful rocket, aint it?! 8)

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Re: Indian Space Programme Discussion

Postby ravar » 05 Jan 2014 08:20

Quote-
"Just to indicate how complex this is the rocket cone gets heated so much that it should melt so part of the cryogenic fuel actually circulates around the engine nozzle (the inverted aluminium bucket :) ) to cool it and simultaneously gets converted to gaseous form to enter the ignition chamber." Unquote

Vikas engine uses the same tech for cooling itself but for ISRO the challenge has been with materials to withstand the cryo and extreme hot temperature within a few inches apart, which is the holy grail in such engines

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Re: Indian Space Programme Discussion

Postby disha » 05 Jan 2014 08:31

SriKumar wrote:... This link has more on the cause of connectors snapping (air pressure around the shroud). http://indianspaceweb.blogspot.com/2011 ... ilure.html


SriKumar, you are confusing and conflating two GSLV failures.

The failure due to snapping of connectors happened with the one of the last of Russian CUS. The Russians were not forthcoming with the shroud design data (maybe they just did not want to be held liable or show up as buffoons). This was a design failure. The recommendation was doing away with shroud all together.

Look at the latest photos carefully, between the H2 tank and O2 tank, there is only trusses (covered in thermal blankets) but no shroud.

The last GSLV failure in the Indian CUS was due to bearings getting jammed. The CUS did achieve ignition and burnt for 800 msec., and then jammed up. It was a material failure and not a design failure.
Last edited by disha on 05 Jan 2014 09:31, edited 1 time in total.

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Re: Indian Space Programme Discussion

Postby SriKumar » 05 Jan 2014 08:37

Actually, I do not believe I conflated the two. Please check my post on the previous page where I mention the desi cryo stage specifically. In the post above, I refer to both, and the quoted Hindu article also refers to both (and maybe hence the confusion) but my comment with regard to the russian cryo stage is about snapping of connectors and shroud.
Last edited by SriKumar on 05 Jan 2014 08:50, edited 4 times in total.

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Re: Indian Space Programme Discussion

Postby member_28108 » 05 Jan 2014 08:39

ravar wrote:Quote-
"Just to indicate how complex this is the rocket cone gets heated so much that it should melt so part of the cryogenic fuel actually circulates around the engine nozzle (the inverted aluminium bucket :) ) to cool it and simultaneously gets converted to gaseous form to enter the ignition chamber." Unquote

Vikas engine uses the same tech for cooling itself but for ISRO the challenge has been with materials to withstand the cryo and extreme hot temperature within a few inches apart, which is the holy grail in such engines


I was just mentioning it (regenerative cooling and rocket nozzle temperature mitigation) to indicate how complex the design of a rocket engine is !

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Re: Indian Space Programme Discussion

Postby member_23694 » 05 Jan 2014 10:04

All eyes on today’s launch of refurbished GSLV-D5
http://www.thehindu.com/sci-tech/scienc ... 538111.ece

the most heartening part
M.C. Dathan, Director, Liquid Propulsion Systems Centre (LPSC), ISRO, said: “We have done everything humanly possible” to ensure the success of the mission. “We have drawn on all the expertise available,” he said.


Best of LUCK . Hard work does pays off :D

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Re: Indian Space Programme Discussion

Postby Austin » 05 Jan 2014 10:09

Good Luck to ISRO and Team GSLV , Wishing them a successful launch

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Re: Indian Space Programme Discussion

Postby SwamyG » 05 Jan 2014 10:12

Good luck onlee.

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Re: Indian Space Programme Discussion

Postby kvraghavaiah » 05 Jan 2014 10:18

ISRO,

We are optimistic that today's launch will be a full success. You have done everything you can for that.

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Re: Indian Space Programme Discussion

Postby disha » 05 Jan 2014 10:58

All, I have created a thread to discuss GSLV-D5 Launch - any launch specific discussion, status tracking etc will be available there.

Also links for any webcasts/news links/updates will be available in the GSLV-D5 launch and post launch discussions thread.

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Re: Indian Space Programme Discussion

Postby Comer » 05 Jan 2014 11:15

prasannasimha wrote:*snip*
Hoe this helps

If you want to read some more see
http://www.slideshare.net/pandu_sravs/c ... nes-report

Thanks a lot for very lucid and clear explanation.

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Re: Indian Space Programme Discussion

Postby Gagan » 05 Jan 2014 13:13

Propellant filling operation of GSLV-D5 Cryo Stage has commenced at 11:42 hrs (IST).
Last edited by SSridhar on 05 Jan 2014 13:32, edited 1 time in total.
Reason: Post it in the GSLV-D5 thread

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Re: Indian Space Programme Discussion

Postby Kakarat » 05 Jan 2014 15:01


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Re: Indian Space Programme Discussion

Postby Comer » 05 Jan 2014 15:37

PratikDas wrote:The video is good and the narration crisp but I couldn't listen to more than a few minutes of it. The accent is like the one on board Air India informing passengers how to wear their seat belts or escape the plane in case of an emergency. Not a *single* Indian I know speaks in an operatic manner like that - even the ones with an excellent grasp of the English language, both written and verbal. Who are they trying to impress? In contrast, many of ISRO's leaders who spoke after Mangalyaan's launch seemed more authoritative, earnest and down right inspirational.

OT: If I am correct, the same person/voice is used in the planetarium shows. It is very grating after a few minutes.

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Re: Indian Space Programme Discussion

Postby vdutta » 05 Jan 2014 15:47

So far so good. Congrats

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Indian Space Programme Discussion

Postby Peregrine » 05 Jan 2014 16:32



Cheers Image

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Re: Indian Space Programme Discussion

Postby Singha » 05 Jan 2014 17:11

not sure who owns this site but has good laymen language description of all our projects and technical goals in launchers
http://isp.justthe80.com/launchers

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Re: Indian Space Programme Discussion

Postby A_Gupta » 05 Jan 2014 17:12

Congrats to Team ISRO!

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Re: Indian Space Programme Discussion

Postby member_22539 » 05 Jan 2014 17:16

Congrats to ISRO and to India. May we march steadily ahead on the path of technological progress.

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Re: Indian Space Programme Discussion

Postby Kakarat » 05 Jan 2014 17:25

ISRO GSLV-D5 launch Video

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Re: Indian Space Programme Discussion

Postby member_26535 » 05 Jan 2014 17:29

Congratulations team ISRO.. this looks to be a fantastic copybook launch.. As a nation we have successfully overcome another technology denial regime . I hear that it will take atleast 2 more successful launches for this to be considered a reliable workhorse like PSLV. Hope we achieve that in the next couple of years.

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Re: Indian Space Programme Discussion

Postby pankajs » 05 Jan 2014 17:34

GSLV rocket's success will mean immense savings: ISRO chief
"We will be launching satellites GSAT-6, 7A, 9 using GSLV. We will also be using this rocket for our second Chandrayaan mission and for the launch of GISAT," he said.

According to him, another communication satellite GSAT-15 will be launched using the Ariane rocket.

Other than the flight testing of cryogenic engine, 2014 will be an important year for ISRO.

Radhakrishnan noted that in September, the Mars Orbiter will be injected into the Mars orbit while the test flight of GSLV-Mark III version will also include a crew module for characterisation of re-entry from the space.

"The GSLV-Mark III experimental mission will be in April this year. The rocket will have a passive cryogenic stage/engine. The main purpose of the mission is to study the aerodynamics and stability of the rocket," he said.

He said the cryogenic engine for the next GSLV version will take around three years for being flight ready.


According to him, the next fiscal (April 2014-March 2015) would see ISRO launching three IRNSS (Indian Regional Navigational Satellite System) satellites taking the total to four and be ready for usage.

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Re: Indian Space Programme Discussion

Postby member_25400 » 05 Jan 2014 18:29

putnanja wrote:From the GSLV-D5 documenton ISRO site
ok, noobie question, so please don't laugh :) The first stage which is solid provides altitude gain of almost 70kms, and that is while trying to escape the earth's gravity. However, the CUS provides altitude gain of around 73kms in outer space where the earth's pull will be less. How exactly is the cryogenic stage providing better capability? does it have to do with the size/propellants required for cryogenic stage as compared to the solid stage?


Solid fuel based engines can provide great thrust, but have a tendency to have poorer specific impulse. Think of this as the trade-off between power (thrust) and fuel efficiency. (since rockets have to carry both fuel and oxidizer, so specific impulse is actually a measure of an engine's propellant efficiency). There are some other trade-offs. (briefly described below)

Solid fuels can be stored easily for long periods of time, making them suitable for military applications like missiles. Cryogenic engines being liquid fueled, can be designed to be re-started or throttled back (though not always done so). The rocket equation (actually payload mass fraction of ~0.9) tells us that for every 1 kg of payload that we get to orbit, we tend to use ~9 kg of propellant (ignoring structure/tank weight). By reducing the amount of propellant & tanking to be lifted off & accelerated for an upper stage, we can reduce the size/thrust required for the rocket as a whole by a similar multiplication factor.
Cryogenic engines also help by increasing the density of fuel/oxidizer (reduces tank size and weight). But they require difficult handling, careful insulation, complicated design and material science.

Easy ref: http://www.esa.int/Education/Solid_and_ ... l_rockets3
Last edited by member_25400 on 05 Jan 2014 19:22, edited 1 time in total.

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Re: Indian Space Programme Discussion

Postby Varoon Shekhar » 05 Jan 2014 18:47

"He said the cryogenic engine for the next GSLV version will take around three years for being flight ready."

He of course means the engine for the Mark 3 vehicle, right? For the Mark 2, any reference to the next launch? This year, early next year?

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Re: Indian Space Programme Discussion

Postby A Nandy » 05 Jan 2014 19:05

I have a question. Why is the spent first stage not separated immediately but carried on as dead weight for some time ?

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Re: Indian Space Programme Discussion

Postby SSridhar » 05 Jan 2014 19:06

putnanja wrote:How exactly is the cryogenic stage providing better capability? does it have to do with the size/propellants required for cryogenic stage as compared to the solid stage?

Two things matter, the specific impulse, thrust per unit mass of propellant(s) and re-startability of engine.

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Re: Indian Space Programme Discussion

Postby SSridhar » 05 Jan 2014 19:07

A Nandy wrote:I have a question. Why is the spent first stage not separated immediately but carried on as dead weight for some time ?

Because, the attached strap-ons are still firing.

Added later: From the GSLV-D05 ISRO Brochure, you can see that the core stage shuts off in 100 secs whereas the liquid strap-ons end in 148 secs.

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Re: Indian Space Programme Discussion

Postby A Nandy » 05 Jan 2014 19:12

Ok, I am no expert, but the strap-ons are lifting dead weight after that time. Maybe the first stage firing time can be increased to coincide with the end of the the strap-ons firing.

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Re: Indian Space Programme Discussion

Postby Varoon Shekhar » 05 Jan 2014 19:14

[quote="PratikDas"]The video is good and the narration crisp but I couldn't listen to more than a few minutes of it. The accent is like the one on board Air India informing passengers how to wear their seat belts or escape the plane in case of an emergency. Not a *single* Indian I know speaks in an operatic manner like that - "

It's wonderful to see this diversity of English language style in India. Why should everyone speak in the same way.There are those who might even prefer the manner of the presenter in the ISRO video, to the conventional Indian style, without denigrating that style.

You can hear more or less the same accent/speech style in official Air India, ICICI and CNN-IBN announcers.It would even be nice to hear a few Indians in India speak with an American or Canadian accent. Let many styles blossom! Those aren't going to be the majority, anyway.

Congratulations to ISRO for this excellent, and very difficult, achievement. It was a long time coming, but well worth the wait. Yes, as someone remarked, we can eagerly await the day when such launches become routine!

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Re: Indian Space Programme Discussion

Postby member_28348 » 05 Jan 2014 19:44

i mean no disrespect but why does ISRO allow prof. yashpal talk in every post launch speeches?

i bet he's not a part of any technical team for those launches. today, he couldn't even describe the cryogenic engine's maiden achievement well.
every time he thanks ISRO for even allowing his speech and says "its good to be alive" in the end.

is it because ISRO considers him as the same NASA did for carl sagan- a cosmic inspirational guide?

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Re: Indian Space Programme Discussion

Postby Victor » 05 Jan 2014 19:51

Congratulations to India and ISRO. A major milestone crossed.

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Re: Indian Space Programme Discussion

Postby member_28108 » 05 Jan 2014 19:52

He has been on many failure analysis committees especially of the cryogenic engine.
Also may be there as a lucky charm :D
Last edited by member_28108 on 05 Jan 2014 19:56, edited 1 time in total.

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Re: Indian Space Programme Discussion

Postby member_28108 » 05 Jan 2014 19:54

The strapons do not eject earlier because they fire for a longer time.This was a trade off because the GSLV was designed by minimizing the modifications of systems we already had and the Ist stage is directly a copy of the PSLV stage so this was used but the strap ons needed to fire for a longer time so indeed they are carrying for some time a dead weight.

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Re: Indian Space Programme Discussion

Postby Varoon Shekhar » 05 Jan 2014 19:54

He is very natural, non-bureaucratic and pleasant to listen to. He is very sincere in his praise of ISRO, and is obviously deeply moved by its successes like the Mars mission and the GSLV.


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