Indian Space Program Discussion

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manish.rastogi
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Re: Indian Space Program Discussion

Postby manish.rastogi » 20 Jan 2011 19:43

^^^^thanks....was really helpful for us aam abduls!!!

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Re: Indian Space Program Discussion

Postby ramana » 20 Jan 2011 21:47

Gagan, can you time stamp them? We can then compare to the flight analysis reports from TSS in Hindu.

So the crucial failure occurs when the S/S separates or breaks away from the T/S or cryo stage as the vehicle deviates from flight path.
Maybe this is the snapping of connectors they talk about?


And all other events follow after that.

BTW, Brilliant analysis. Kudos for that.

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Re: Indian Space Program Discussion

Postby SaiK » 20 Jan 2011 22:31

happen to flip time mag while waiting for my turn at clinic. damn.. again a khan blaster on India's program where the $2.8b could have been diverted to save the poor. when will they stop this subliminal harassment ? while chippanda is sending pattapati shivers in every khan's stealth zone.

the agenda to malign is permanent it appears. we will never arrive for them.

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Re: Indian Space Program Discussion

Postby KrishG » 20 Jan 2011 22:42

ramana wrote:So the crucial failure occurs when the S/S separates or breaks away from the T/S or cryo stage as the vehicle deviates from flight path.
Maybe this is the snapping of connectors they talk about?


That's the effect. The fact is that the AoA of the vehicle increased dramatically before the interstage between the 3rd stage and the 2nd stage gave way at around T+54 sec.

According to preliminary analysis the connectors "snapped" leading to the disruption in command signals from the OBC to the L40 boosters. This probably led to the "development of large errors in orientation" of the vehicle which started at ~T+48 sec. Only after this did the interstage between 2nd and 3rd stage give way at ~T+54sec, most probably due to high structural loads.

So, IMHO the signals from the OBC stopped reaching the LSBs long before the upper stage actually broke-off from the rest of the vehicle. 1) What caused the stoppage in command flow ? "snapped" connectors according to ISRO. 2) Is it premature separation or actual breakage in the connectors ? We don't know (ISRO hasn't been very clear about this bit) ! 3) What caused the break or premature separation of connectors and what part did the changes in the vehicle play? Very difficult to point at the causes until the flight data is analyzed. Could even be a software glitch or thousands of possible ways. We will have to wait for the official report by ISRO.

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Re: Indian Space Program Discussion

Postby svinayak » 21 Jan 2011 00:42

SaiK wrote:happen to flip time mag while waiting for my turn at clinic. damn.. again a khan blaster on India's program where the $2.8b could have been diverted to save the poor. when will they stop this subliminal harassment ? while chippanda is sending pattapati shivers in every khan's stealth zone.

the agenda to malign is permanent it appears. we will never arrive for them.

I have seen that there is a large group from various countries which has this agenda of bashing
It has links within India with secular left/maoists front, some Pak, some US see eye yee groups, australian media , British media. The timing is done together to get the maximum one. Earlier failure do not have such coverage.
Some of them seem to be written before the event and then it is published

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Re: Indian Space Program Discussion

Postby ramana » 21 Jan 2011 01:09

KrishG, Considering that the connectors were flight qualified earlier what could have caused the premature 'snapping'? Wasn't the report due by January end?

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Re: Indian Space Program Discussion

Postby KrishG » 21 Jan 2011 01:44

ramana wrote:KrishG, Considering that the connectors were flight qualified earlier what could have caused the premature 'snapping'? Wasn't the report due by January end?


There can be hundreds of reasons.

Image

The red interstage between the 3rd stage and the 2nd stage is where the connectors are housed (the specific connectors in question) and this is where the 'snapping' is said to have occurred.

For more technical details about the connectors, I would refer you to this discussion, which is an interesting one and covers some of the possible scenarios.

http://orbiter-forum.com/showthread.php?p=229625

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Re: Indian Space Program Discussion

Postby ramana » 21 Jan 2011 03:19

Till now I was thinking its near the equipment bay!

If it was the interstage then what was going on?

Maybe the separation bolts initiated earlier and thus snapped?

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Re: Indian Space Program Discussion

Postby Anant » 21 Jan 2011 03:35

I know this isn't strictly related to Indian space per se but a US Delta IV Heavy Launch Rocket successfully launched from California today. What struck me was its apparent simplicity in design. It just looks like parts were replicated and stuck together. What I am round about saying is couldn't we simply the GSLV design to something more cookie cutter like this rocket?

http://www.boeing.com/defense-space/space/delta/delta4/delta4.htm
The launch is here
http://www.cnn.com/2011/US/01/20/rocket.launch/index.html?hpt=T2

Just curious what you experts think. The GSLV to me appears to be far more handsome than this thing but to see this behemot lumber and launch another spy satellite makes me wistful whether we can simply the Indian rockets. Thanks.

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Re: Indian Space Program Discussion

Postby ramana » 21 Jan 2011 04:08

Delta is based on a ICBM which was phased out and made into a launch vehicle. the core is the one at the left (medium). Varoius strap ons are added to give more thrust.

GSLV is also an adaptable design. It has its iterations.

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Resourcesat-2 launch by end of Feb: ISRO

Postby abhishek-nayak » 21 Jan 2011 10:13


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Re: Indian Space Program Discussion

Postby svinayak » 21 Jan 2011 10:54

ramana wrote:Delta is based on a ICBM which was phased out and made into a launch vehicle. the core is the one at the left (medium). Varoius strap ons are added to give more thrust.

GSLV is also an adaptable design. It has its iterations.

ImageImage

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Re: Indian Space Program Discussion

Postby KrishG » 21 Jan 2011 22:26

ramana wrote:Till now I was thinking its near the equipment bay!

If it was the interstage then what was going on?


The initial report clearly mentions where the failure occured:

The finding of the Preliminary Failure Analysis Team is that the primary cause of the failure is the untimely and inadvertent snapping of a group of 10 connectors located at the bottom portion of the Russian Cryogenic Stage. Some of these connectors carry command signals from the onboard computer residing in the Equipment Bay (located near the top of the vehicle) to the control electronics of the four L40 Strap-ons of the First Stage. These connectors are intended to be separated only on issue of a separation command at 292 seconds after lift-off. The premature snapping of these connectors has led to stoppage of continuous flow of control commands to the First Stage control electronics, consequently leading to loss of control and break-up of the vehicle. The exact cause of snapping of the set of connectors, whether due to external forces like vibration, dynamic pressure is to be analysed further and pin-pointed.


The report is conflicting in-the-sense that they mention "snapping" and again "pre-mature snapping".

ramana wrote:Maybe the separation bolts initiated earlier and thus snapped?


Could be. The explosive blots might have gone off prematurely. But, "snapping" is still a word that doesn't seem right or if the connectors literally snapped then what do they mean by "premature snapping". :-? I think that the preliminary report might mean more of a premature separation event than actual unintended breakage. We will have to wait for the final report which I expect to be out by February.

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Re: Indian Space Program Discussion

Postby Varoon Shekhar » 21 Jan 2011 22:41

Posted by Abhishek: http://www.business-standard.com/india/ ... ro/422440/

Article doesn't make sense. In one line, it speaks about 3 launches by February end, including 2 PSLV's. In another sentence, it makes it look like the 3 satellites being launched in one PSLV will be sent up individually in Feb, March and April!

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Re: Indian Space Program Discussion

Postby ramana » 21 Jan 2011 23:32

Varoon, Key is look at the launch vehicle and what it carries. The three sats are on PSLV-C16. We dont know what PSLV-C17 carries.

BTW did you note the tag line of the above news report!
freudian slip?

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Re: Indian Space Program Discussion

Postby Varoon Shekhar » 22 Jan 2011 00:13

Yes, Ramana, the tag article is actually far more accurate and informative than the lead piece! ( if that is what you are referring to). There will be a PSLV/Resourcesat mission, a PSLV mission to GTO with GSAT-12, then a GSAT launch by Ariane, followed by 4 more PSLV missions. Sounds good!

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Re: Indian Space Program Discussion

Postby Craig Alpert » 22 Jan 2011 07:05

Question to all space gurus... Why is it that the Delta Rockets don't leave a trail of smoke once they are up in the air, as oppose to the SDRE rocket? Different "ingredients" for the lack of better word perhaps?

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Re: Indian Space Program Discussion

Postby SaiK » 22 Jan 2011 09:23


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Re: Indian Space Program Discussion

Postby KrishG » 22 Jan 2011 12:54

Craig Alpert wrote:Question to all space gurus... Why is it that the Delta Rockets don't leave a trail of smoke once they are up in the air, as oppose to the SDRE rocket? Different "ingredients" for the lack of better word perhaps?


That would be Delta-IV. All of it's stages are cryogenic (burn LOH/LOX) and doesn't produce thick, dark smoke like solid rockets used as boosters for other launch vehicles. Even the Delta II uses solid boosters.

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Re: Indian Space Program Discussion

Postby juvva » 23 Jan 2011 10:54

PSLV must be using similar connectors and seperation mechanisms(?). Do not see how ISRO can launch anything PSLV or GSLV, before getting into the root cause and fix for the failure.


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Re: Indian Space Program Discussion

Postby NRao » 25 Jan 2011 08:45


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Re: Indian Space Program Discussion

Postby SaiK » 25 Jan 2011 10:07

Once smitten twice shy. Is this too late or there is a possibility of imports?

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Re: Indian Space Program Discussion

Postby Bade » 25 Jan 2011 21:45

Probably there is a possibility of real collaboration now on joint missions etc without a lot of strings attached and clearances required for every exchange. That is progress if true, and other spanners are not thrown in with time. Remains to be seen as usual in such matters.


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Re: Indian Space Program Discussion

Postby sumshyam » 28 Jan 2011 21:20



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Re: Indian Space Program Discussion

Postby D Roy » 30 Jan 2011 19:33

Hey SriSri,

I think in that report of yours you need to change "Our supersonic missile, traveling at Mach 2.8, is nine times faster than other missiles in the world," to "Our supersonic missile, traveling at Mach 2.8, hits the target with nine times more kinetic energy than other missiles in the world,"

Because given that he has been misquoted anyway you can further 'misquote'. :mrgreen:

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Re: Indian Space Program Discussion

Postby SriSri » 30 Jan 2011 19:47

Hi DRoy,

Thanks for reading. :-)

Help me out with the misquote here. What the news agency gave me is mentioned in the report. Want to improve the report and remove the misquote.

Thanks,
Sri

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Re: Indian Space Program Discussion

Postby D Roy » 31 Jan 2011 07:18

yeah just put it in as

"Our supersonic missile, traveling at Mach 2.8, hits the target with nine times more kinetic energy than other missiles in the world,"

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Re: Indian Space Program Discussion

Postby SriSri » 31 Jan 2011 07:44

8) done!

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Re: Indian Space Program Discussion

Postby juvva » 31 Jan 2011 10:12

Some more info on the GSLV failure:
http://www.sify.com/news/rocket-failure ... dhiab.html
"
......
The German made connectors are fixed on a metal plate. The plate, in turn, is fixed to a shroud or cylindrical cover that comes between the cryogenic engine and the lower stage (engine).

According to Nair, the shroud made of composites is part of the Russian cryogenic engine and it got deformed due to the flight load. The committee is yet to conclude why the shroud was not able to bear the load.
........
"

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Re: Indian Space Program Discussion

Postby ramana » 31 Jan 2011 20:49

So these were staging connectors and the failure looks like has been idenitifed on a non ISRO component (shroud). I guess they need to find out why the component failed. The deformation would cause the connectors to separate or snap. Guess due to symmentry of the vehicle and hence aero loads, the redundant paths did not help.

---
Can someone lookup the "German made connectors" on google?
------

In the picture posted by KrishG, the cable or conduit tray runs along the side of the cryo stage. Could be the black stripe? as we simialr scoops on interstage below it.

Usually this has a inverted scoop type transtion (bump) to join the similar one on the interstage. So what they are saying is the transition on the cryo-stage made of composite deformed due to the aero-loads and led to the loss of connection. Shouldn't be for they would design it to take 1:500 loads.

Was the wind situation bad that day? Or it could be wind shear at that altitude which would not be seen normally unless the weather radar saw it?

What was the altitude when the vehicle first experienced the anamoly?

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Re: Indian Space Program Discussion

Postby juvva » 03 Feb 2011 09:11

How did they conclude that the flight loads deformed the shroud?
Could it be wind tunnel testing for that particular component??

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Re: Indian Space Program Discussion

Postby disha » 03 Feb 2011 10:01

^^^will selectively quote the above article later below.

Aerodynamic load is one of the prominent load. The other is the weight load itself. Both of them can only be simulated to a degree, after that it is more of "practicles" and fine tuning your simulation.

Try this in a high rise., carry a 10 kg mass on your shoulders and get into an elevator, and as the elevator goes up (during the accelaration phase) the load you bear will be higher. Now your shoulders may be rated to carry 11 kg mass and you can safely take 10 kg in an elevator accelarating at say y mtrs/sec. Now for the same load, if the elevator is accelarating at x mtrs/sec and where x > y, naturally complications in your shoulder may arise. Or complications may arise if you are taking 11 kg in elevator accelarating at the earlier y mtrs/sec.

It could be that you have factored in the increased load or increased accelaration or both in your calculations. How did you factor it in? Based on calculations which again is based on ratings of certain important structural members. What if the ratings were wrong? Or what happens if an environmental change effects the ratings? Note that the shroud which buckled was attached to the cryogenic stage and is a composite shroud. It could be that the leak from the cryogenic stage caused the material to become brittle thus affecting the load bearing capacity and thus leading to more than expected buckling and causing the connectors to "snap". Or it could be that the buckling was expected and it was within specified limits, but the connectors still snapped since they did not perform to the rated buckling.

An indepth analysis by ISRO will bring out the truth. Also I did indicate in an earlier post that the weight was different and that leads to different set of calculations and those calculations will be confirmed correct or wrong based on the launch being successful or failure.

Coming to the article:

Rocket failure: ISRO awaits data from Russia

'We are expecting some data from the Russians who had supplied the cryogenic engine. The Russians are expected to provide the data by the end of this month,' former ISRO chief G.Madhavan Nair, who heads the committee, told IANS.

According to Nair, the shroud made of composites is part of the Russian cryogenic engine and it got deformed due to the flight load. The committee is yet to conclude why the shroud was not able to bear the load.


So they are indeed looking for material characteristics data.

Experts told IANS that the first 15 kilometres of a rocket's flight is a very crucial time as it is subjected to heavy atmospheric loads. It is more so when the rocket is escaping the earth's gravitational pull at 330 metres per second.


Here the journalist ends up talking about the atmospheric load but there are other "loads" as well.

Compared to the other Russian cryogenic engines that powered the earlier GSLV's, the one that was fixed to the ill-fated Dec 25 rocket was 1.3 metres longer to contain higher fuel.


Change in length and weight.

According to a retired ISRO official, the GSLV broke most likely due to the instability caused by the heavy satellite it carried.


Opinion 1 from a retd. ISRO official -> weight bearing loads causing structural deformities.

Dismissing the contention, another ISRO official said: 'The increase in the satellite GSAT-5P's weight is just 90 kg as compared to the GSLV rocket that carried the GSAT-4, weighing 2,220 kg in April. Such marginal increase in weight will make no difference.'


Opinion 2 from another official -> it is not weight bearing load. Note that the GSAT was increased by 90 kg. At 3 m/s accelaration, the actual weight borne by the structures below it is much higher. And this increase might have been accounted for.

He also discounted the possibility of the rocket becoming unstable because of the two-tonne increase in its overall weight as compared to the April GSLV rocket that weighed 416 tonnes.

'The rocket would have burned around 100 tonnes of first stage fuel by the time the problem started. So a mere addition of two tonnes to the rocket's weight would not make it unstable,' he added.


Here the allusion is towards atmospheric loads, particularly when 100 tonnes (@ 750 kg is shed per sec) is shed, it does create a complex set of interaction between shifting CG and CP. Further the vehicle is crossing different atmospheric regimes and also transitioning from transonic to supersonic. That leads to vibrations, twisting and turning. Does that kind caused the shroud to buckle or the connectors to snap?

=================================

Some posters have argued that we should send in dummy satellites. I am of the position that such an argument is without merit, here are the reasons why:

1. A dummy satellite without means of control is a space junk. It takes a valuable orbit (in this case GTO) which does not decay for several decades and puts future space missions at risk. Further the space junk of 2 tonnes mass has to be tracked and monitored regularly. What happens if its orbit changes due to some circumstances and poses a risk to other nation's missions? Who is liable - itiyaadi itiyaadi.

2. Okay to solve problem 1., we can put in some fuel and thruster and some avionics so that it can be de-orbitted gracefully. The question then arises, what exactly are we saving? 40% of any geo-synch satellite is fuel/thruster and necessary avionics and gyroscopes to make the sat reach its intended orbit and complete its mission by staying there. And this could be 80% of the cost of the satellite. So we are saving only 60% of the payload. Now this 60% is costing only 20% of the overall cost!

3. The launch is successful, we settle on the design and mass produce the components and now ready to send the real sat. How will we know that the real sat will indeed work? If you take the trouble of testing the fuel/thruster and make the sat reach its intended orbit, you would have parked a dummy satellite in a precious space. If you are going to anyway do it, why not as well send the rest of the avionics?

4. Okay we still stick with dummy to the point where we are assured of the success of the mission. Then comes a new mandate, say from dukhdarshan in combination with swan telecom that they want an extra secret k-band transponder for monitoring radiaa tapes (sarcasm here, pointing to user requests for some changes in sat). This increases the weight of the sat by 100 kgs, necessiating addition of some 4 tonnes of fuel. What is the guarantee that this rocket will succeed? Send dummy missions till we qualify the new payload? What happens if we want to use this rocket for sending a mission to moon/mars/venus/asteroid?

There is a reason why ISRO and India's space missions are respected. Even in Khanate. Selene and Chang'e could not achieve what Chandrayaan did. Neither Japan nor China (or even US) operate the largest fleet of earth observation (remote sensing) sats in the world. None of them had multi-payload-single-mission (INSAT!) series to kick start a communication/earth observation revolution in a developing world (give me an example in 2nd world and 3rd world countries!).

None of the above can be achieved by sending dummies in space.

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Re: Indian Space Program Discussion

Postby disha » 03 Feb 2011 10:21

juvva wrote:How did they conclude that the flight loads deformed the shroud?
Could it be wind tunnel testing for that particular component??


That particular component can be encased in a stage and the flight loads might have deformed (twisted, bent) the outer stage affecting the inner components. Also the wind tunnel testing would have given ISRO pressure (torsion itiyadi) parameters which would have been plugged into simulation for material deformities during flight regime and qualified to go for a flight. Except that the truth table for material characteristics might have errors or wrong tolerances.

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Re: Indian Space Program Discussion

Postby juvva » 03 Feb 2011 10:37

^
disha, my question is about the testing/simulation after the failure of the flight to determine the cause of the failure. How did they conclude that the shroud deformed?

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Re: Indian Space Program Discussion

Postby ramana » 03 Feb 2011 10:58

First they would have gone thru the telemetry data of all sensors and compared to expected values derived from trajectory analysis.
They would go through the electrical pulses which will show the timing. From this they know there was early connector separation.
Then go back to sensor data to figure how could the separation occur abnormally? Then do analysis to simulate the postulated failure mechanism. Share with supplier to get better insight. And then tell the press because there are a bunch of persistent folks on a website who want to know!

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Re: Indian Space Program Discussion

Postby vina » 03 Feb 2011 11:15

ramana wrote:First they would have gone thru the telemetry data of all sensors and compared to expected values derived from trajectory analysis.
They would go through the electrical pulses which will show the timing. From this they know there was early connector separation.
Then go back to sensor data to figure how could the separation occur abnormally? Then do analysis to simulate the postulated failure mechanism. Share with supplier to get better insight. And then tell the press because there are a bunch of persistent folks on a website who want to know!


Ramana garu, I would still put it as due to change in propellant loading (this flight had the highest propellant loading for the Russian stage ever) and probably excitation modes in the changed config /some aero elastic nodes excited some parts of the connectors/conduits/structures that support it like a Paki doped up on Jeehard and it went downhill skiing very quickly from there.

Lets see what the final report says

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Re: Indian Space Program Discussion

Postby ramana » 03 Feb 2011 11:30

Could be. Was there any report of wind shear or some such atmospheric anomaly that day?

When is the report due?


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