Which platform is going to be used on this launch?
ISRO website has the picture of the vehicle (GSLV-F06) on the launch pad"
http://isro.org/gslv-f06/Imagegallery/launchvehicle.aspx#0
GSLV-F06 will fly with russian C15 upper stage. It is a first indo-russian GSLV MkII.
GSLV-F06 will fly with russian C15 upper stage. It is a first indo-russian GSLV MkII.
I was under the impression that what made the GSLV a Mark II was the use of the Indian upper stage.
GSLV MK II, earlier referred to as GSLV D3, will carry an Indian developed cryogenic third stage which will eventually be capable of launching 2,500 kg into Geostationary Transfer Orbit (GTO). The cryogenic engines that have powered the GSLV rocket so far were sold to India by Russia. Of the seven cryogenic engines supplied, five have now been used. Eventually, all future GSLV's will use the Indian Cryogenic Upper Stage (CUS) that develops 9 ton of thrust against 7.5 ton of the Russian CUS and carries 15 ton of propellant against 12.5 ton.KVD-1A has а trust 9.5 tf.
GSLV rocket now taller, heavier
Chennai, December 17, 2010
First Published: 15:02 IST(17/12/2010)
India's geosynchronous satellite launch vehicle (GSLV), scheduled to blast off on Monday with an advanced communication satellite (GSAT-5P), is now taller by two metres and heavier by four tonnes as compared to its standard configuration. The Indian Space Research Organisation's standard configuration for the GSLV rocket is a height of 49 metres and 414 tonnes in weight at lift-off.
The rocket that would lift off Monday stands 51 metres tall and weighs 418 tonnes.
PS Veeraraghavan, director of the Vikram Sarabhai Space Centre, told IANS: "This time the fuel quantity for the cryogenic engine has increased and its thrust power has also gone up. The rocket will be carrying a heavier satellite (GSAT-5P) weighing 2,310 kg."
The Russian made cryogenic engine will be powered with 15.2 tonnes of fuel (liquid hydrogen as fuel and liquid oxygen as oxidizer), an increase of around three tonnes, and the engine's length has also increased.
The rocket has a bigger heat shield - four-metres in diameter and made of fibre reinforced plastic (FRP) - as compared to the standard configuration of 3.4-metre diameter made of aluminium alloy metal.
With the changes in rocket's configuration, necessary calibrations have been carried out in the rocket's navigational systems, control dynamics and aerodynamics so that the flight is smooth and the mission is successful, a source associated with ISRO told IANS.
Over the years, the carrying capacity of the GSLV has also increased -- from 1,530 kg in 2001 for GSAT-1 to 2,220 kg for GSAT-4 in April 2010.
The latest has a payload of 2,310 kg with 36 transponders -- an automatic receiver and transmitter of communication or broadcast signals. Successful launch of the satellite will take the agency's transponder capacity to around 235 from 200 in orbit now.
The launch of the GSLV F06 with GSAT -5prime satellite on board, scheduled to take place on Monday (Dec.20) at 4 pm from Sriharikota has been postponed due to a minor leak in one of the valves of the Russian cryogenic stage. This leak was noticed during the pre-count down checks. The ISRO’s Launch Authorisation Board that met on Sunday at Sriharikota, therefore did not give the permission to go ahead with the 29 hr countdown which was to begin at 11am on Sunday.
The date for the new launch will be announced after ISRO’s rocket technologists find the cause for the leak and take remedial action.
The GSLV-FO6 has major changes incorporated as compared to the previous flights. It includes the loading of 15 tonnes of propellants in its third stage of flight and the uprating of the third stage thrust by 26 per cent, ISRO said.7.5 tf X 1.26 = 9.45 tf
20/12/2010
ISRO may take a call on GSLV mission tomorrow
Bangalore,Dec20 (PTI) Indian Space Research Organisation is expected to take a decision tomorrow on the fresh date for launch of GSAT-5P satellite on board Geo-Synchronous Satellite Launch Vehicle (GSLV-F06) after conducting an experiment to study the leak that led to the mission''s postponement.
As of now, it appears to be a "liveable leak", an ISRO official told PTI here, a day after the space agency put off the launch from the spaceport of Sriharikota due to a "minor leak" in one of the valves of the Russian Cryogenic stage, observed during the pre-countdown checks.
"We are planning to do a small experiment tomorrow to ascertain the cause for the leak. If the leak is the same (as noticed during the pre-countdown checks), then we can go ahead with the launch. If the leak is increasing... beyond certain limits, then we have to stop (the mission)," the official said on condition of anonymity.
If things are okay after verifications, ISRO might schedule the launch for Thursday, sources in the Bangalore-headquartered agency said.
The 29-hour countdown planned to commence at 11 am yesterday had not been authorised by the Launch Authorisation Board that met in the forenoon to review the results of pre-countdown checks.
^Input_2, do you have source for the above rescheduled date?This is a NOTAM created by the responsible Air Traffic Control administration
ISRO to take final decision on GSLV launch tomorrow
United News of India
Chennai, December 21, 2010
A final decision on a new date for the launch of India's advanced and heaviest communication satellite GSAT-5P, by the Geosynchronous Satellite Launch Vehicle (GSLV-F06), using Russian cryogenic stage, is expected to be taken by tomorrow afternoon.
Indian Space Research Organisation (ISRO) sources told UNI here today crucial tests were going at the spaceport of Sriharikota, about 100 km from here, in this regard.
"The tests will continue till tomorrow morning. After the outcome of the tests are known, the scientists will take a final decision on the launch of GSLV Mission", ISRO spokesman S Satish said.
The launch was earlier scheduled for Decemebr 20, but it was postponed after a leak was noticed in one of the valves of the Russian cryogenic engine during pre-countdown tests.
Subsequently, the T-29 hour countdown, scheduled to begin at 1101 hrs on December 19, was stopped.
The spokesman told UNI that an announcement on the date of launch was expected around tomorrow afternoon.
"The tests are continuing and will continue all through the night and tomorrow morning. We can expect some announcement on the date of launch by tomorrow afternoon," he added.
How reliable are Russian Cryos? Is there any fault in manifacturing of cryos itself or our scientists don't have know how about it? This is not for first time ISRO has faced using Russian Cryo in GSLV. I think India should postpone GSLV trials unless its own CRYO gets ready (which should have been done by now.)How reliable are Indian LV? Are You remember leaks on the second stages PSLV-C15 and GSLV Mk III?
ISRO clears GSLV launch after tests news
22 December 2010
Chennai: The Indian Space Research Organisation (ISRO) on Wednesday began preparing for the launch of an advanced communications satellite once again after investigations into a leaking rocket engine valve revealed no danger to flight plans.
The flight of ISRO's heaviest rocket, the Geosynchronous Satellite Launch Vehicle (GSLV-F06), which has a cryogenic final stage, had to be aborted after the fault developed. The cryogenic engine has been supplied by Russia.
The leak in the engine was detected during the pre-countdown tests on Sunday, even as the 51-metre tall rocket was already placed on the launch pad at Sriharikota.
The GSAT-5P satellite is meant to retire the INSAT-2E sent up in 1999 and ensure continuity of telecom, TV and weather services. The flight was originally scheduled for Monday.
According to S Satish, director, ISRO: ''The test results are satisfactory and the rocket's launch date is being finalised.''
The tests were conducted Tuesday to gauge the extent of the valve leak in consultation with Russian scientists. The Russians had supplied seven cryogenic engines through an earlier contract, of which five have already been used in earlier GSLV launches.
GSLV mission to be launched on Dec 25
Bangalore, Dec 22 (PTI) The launch of India''s latest communication satellite GSAT-5P has now been slated for December 25, a week after it was put off following a leak in the Russian cryogenic stage of the launch vehicle.
"The launch is scheduled for December 25 at 4.01 pm (from the spaceport of Sriharikota in Andhra Pradesh). A 29-hour countdown will start on December 24 at 11.01 am," Indian Space Research Organisation (ISRO) spokesperson S Satish told PTI here.
The satellite would be launched by ISRO''s Geo-Synchronous Satellite Launch Vehicle (GSLV-F06), powered by Russian cryogenic stage.
The spacecraft, which would boost India''s communication services including TV and telecommunication, was originally slated for launch on December 20.
But a day earlier, the space agency put off the launch due to a "minor leak" in one of the valves of the Russian Cryogenic stage, observed during the pre-countdown checks.
After the postponement, ISRO said the revised date would be finalised after ascertaining the cause of the leak, remedial actions and due verifications.
Earlier in the day, another ISRO official said on condition of anonymity that the "leak had remained the same and it had not increased which means it is a liveable leak and the mission had been given a go-ahead".
India to launch advanced communications satellite Dec 25
2010-12-22 21:30:00
Chennai, Dec 22 (IANS) With investigations into a leak in a rocket engine's valve providing satisfactory results Wednesday, the Indian Space Research Organisation (ISRO) will celebrate Christmas by launching an advanced communications satellite, an official.
'The test results are satisfactory and the rocket's launch is scheduled Dec 25. The launch countdown will begin 11 a.m. Friday,'
S. Satish, a director at ISRO, told IANS.
The rocket carrying the GSAT-5P satellite is expected to blast off from the second launch pad between 4 p.m.-4.15 p.m. Saturday.
The GSAT-5P is meant to retire the INSAT-2E satellite sent up in 1999 to ensure continuity of telecom, TV and weather services and was originally scheduled for Monday.
However, ISRO Sunday decided to postpone the launch of its geosynchronous satellite launch vehicle (GSLV) after it detected a leak in one of the valves of its Russian-made cryogenic engine.
The leak was detected during the pre-countdown tests, even as the 51-metre tall rocket was on the launch pad at Sriharikota, around 80 km from here.
ISRO officials had said some tests would be conducted Tuesday to gauge the extent of the valve leak. They said the tests and discussions with Russian scientists would go hand-in-hand at Sriharikota.
The Russians had supplied seven cryogenic engines, of which five were used in earlier GSLV launches.
Another ISRO official, speaking on condition of anonymity, told IANS that the tests took around 30 hours and involved filling of liquid oxygen to check the valve. The liquid oxygen had to be later drained. The rocket's ground systems had to be reconfigured for the tests.
The cryogenic engine is fired by liquid hydrogen as fuel and liquid oxygen as oxidizer.
According to the official, the valve leak was in the liquid oxygen system while all other valves were functioning well.
He said the tests started Tuesday at 4 a.m. and concluded at around 8 a.m. Wednesday.
'The activities undertaken were similar to the ones carried out for a regular rocket launch. Around 100 scientists and technologists were involved in tests,' he said.
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1030N 1030N 1200N 1200N
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5. DNG ZONE-5 IS A RECTANGULAR AREA BOUNDED BY
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How reliable are Russian Cryos? Is there any fault in manifacturing of cryos itself or our scientists don't have know how about it? This is not for first time ISRO has faced using Russian Cryo in GSLV. I think India should postpone GSLV trials unless its own CRYO gets ready (which should have been done by now.)How reliable are Indian LV? Are You remember leaks on the second stages PSLV-C15 and GSLV Mk III?
Countdown starts for GSAT-5P launch
The count down has started for the launch of India’s latest communication satellite GSAT-5P on board GSLV-F06 launch vehicle from Sriharikota on Saturday.
ISRO spokesperson S Satish told PTI that the 30-hour count down started at 10.04 hours this morning and was progressing well.
The launch of the satellite, which was originally scheduled for December 20, had been postponed after a leak in the Russian cryogenic engine on board the launch vehicle.
GSAT-5P with 24 C-band transponders and 12 extended C-band transponders is meant for augmenting communication services currently provided by Indian National Satellite System (INSAT). It is meant to boost TV, telemedicine and tele-education, and telephone services.
The satellite, developed by ISRO Satellite Centre, Bangalore, is the fifth in the GSAT series. It has a designed mission life of 12 years.
http://www.thehindu.com/sci-tech/science/article974181.ece (http://www.thehindu.com/sci-tech/science/article974181.ece)So lift-off should occur tomorrow at 1034UTC if all goes well.QuoteCountdown starts for GSAT-5P launch
The count down has started for the launch of India’s latest communication satellite GSAT-5P on board GSLV-F06 launch vehicle from Sriharikota on Saturday.
ISRO spokesperson S Satish told PTI that the 30-hour count down started at 10.04 hours this morning and was progressing well.
Webcasts available?Not exactly webcasts, but satellite broadcast information from this forum:
Usually ISRO starts a channel on Edust/Insat-4CR/insta-4b which shows the whole launch in real time, I remember watching those earlier launches from Edusat, Everything from the "breaking of coconut" ceremony is broadcast live, Cant say which satellite it will come this timeand from a recent post to-day on the same site:
ISRO has started live relay channel on INSAT-4CR, TP 11656 V 3333,
Test going on now, The whole launch can be seen as usual, Now running some launch films from Ariane
ISRO has started live relay channel on INSAT-4CR, TP 11656 V 3333BTW this confirms that INSAT-4CR is active (USSTRATCOM has been apparently tracking the wrong object since end November when it has started reporting it as deorbited :-[ ...)
Anyone got a GMT T-0?If you mean GMT launch time, up to now this is 1034UTC Dec 25
Webcasts available?Not exactly webcasts, but satellite broadcast information from this forum:
http://www.saveondish.com/forum/updated-insat-2e-replacement-launched-on-25th-december-t-32490.htmlQuoteUsually ISRO starts a channel on Edust/Insat-4CR/insta-4b which shows the whole launch in real time, I remember watching those earlier launches from Edusat, Everything from the "breaking of coconut" ceremony is broadcast live, Cant say which satellite it will come this timeand from a recent post to-day on the same site:QuoteISRO has started live relay channel on INSAT-4CR, TP 11656 V 3333,
Test going on now, The whole launch can be seen as usual, Now running some launch films from Ariane
QuoteISRO has started live relay channel on INSAT-4CR, TP 11656 V 3333BTW this confirms that INSAT-4CR is active (USSTRATCOM has been apparently tracking the wrong object since end November when it has started reporting it as deorbited :-[ ...)
There is also another frequency 11589H4000 credits to Javed for telling me about this frequency. Now this frequency shows blank screen and the same picture started coming to 11656 V 3333.Thanks in advance, lnb15k, for reporting live about the launch from what you are watching! :)
The countdown for the launch of GSLV-F06 from Sriharikota this evening is proceeding smoothly. The lift off is scheduled for 4.04 pm.ISRO spokesman Mr Satish told our Chennai correspondent the countdown activities are proceeding without any hitch.
Thanks Seshagirib! NDTV look like they are covering it.
25 Dec, 2010, 12.53PM IST,IANS
Countdown for GSAT satellite launch begins
CHENNAI: Advanced communication satellite GSAT-5P - which will ensure continuity of telecom, television and weather services after an earlier satellite is retired - is set to be launched on Saturday evening at the Sriharikota rocket launch centre in Tamil Nadu .
NDTV says there was a technical failure on the first stage...
I think it was the upperstage propellant tank that exploded.....
I supose that this will not afect PSLV, but for GSLV is not a very good... second failure in a row...
NDTV says there was a technical failure on the first stage...
If true, it would be the first time the S138 had failed on GSLV...All of it's previous failures were to due to upper-stage failures (expect one where L40 nozzle performance caused failure). I would be surprised if it was really the first stage for ISRO has had a wonderful record in solids for many years.
I think it was the upperstage propellant tank that exploded.....
Why do you think it was the third stage?
I think it was the upperstage propellant tank that exploded.....
Why do you think it was the third stage?
The announcement on television said that I stage was working fine.
The announcement on television said that I stage was working fine.
I think it was the upperstage propellant tank that exploded.....
Why do you think it was the third stage?
The announcement on television said that I stage was working fine.
Yes. There was confirmation at around T+15 sec that both 1st stage and LSBs were performing nominally...
Ironic that I had to call an Indian call center to get my connection back up when this happened.Three outright failures and one partial failure.
What's that now, three failures out of their last four?
At what flight time does occur the explosion?I think I heard around T0+80s
A strap-on booster is ejected right after the explosion:
Is it possible to recover the satellite...? considering that the speed was not much at this failure
Is it possible to recover the satellite...? considering that the speed was not much at this failure and failring would not have come out...;-)
Is it possible to recover the satellite...? considering that the speed was not much at this failure and failring would not have come out...;-)Impossible, from 5000 meters droping to sea almost equal droping to cement ground.
This being a problem on the solid propulsion system can mean problems for the PSLV...
This being a problem on the solid propulsion system can mean problems for the PSLV...
This being a problem on the solid propulsion system can mean problems for the PSLV...
IIRC, the S139 stage has never failed before.
Maybe under-performance by one of the LSBs could have caused the vehicle to veer off trajectory resulting in AoA going out of bounds leading to the break-up of the vehicle ??
This being a problem on the solid propulsion system can mean problems for the PSLV...
Is this speculation or official word that the core is to blame?
The vehicle didn't look to have veered off trajectory before the break-up
This being a problem on the solid propulsion system can mean problems for the PSLV...
Is this speculation or official word that the core is to blame?
Maybe under-performance by one of the LSBs could have caused the vehicle to veer off trajectory resulting in AoA going out of bounds leading to the break-up of the vehicle ??
The S139 stage has been working till the end.This being a problem on the solid propulsion system can mean problems for the PSLV...
IIRC, the S139 stage has never failed before.
Maybe under-performance by one of the LSBs could have caused the vehicle to veer off trajectory resulting in AoA going out of bounds leading to the break-up of the vehicle ??
ISRO confirms Altitude Error in Press Conference , Large Altitude error developed.
Control Command Signal from onboard computer failed to reach first stage after 47 second
Self Destruct command issued.
ISRO chairman noted what caused this control command failure needs further analysis.
RAN 2.7kms means what? It is 2.7kms from the launch pad? It was the first stage fell there?
The flight computer lost communication with the actuators in the liquid fueled strap ons, and the vehicle left its planned path, I unterstood.
Sad day for ISRO.
The vehicle developed an error 47 seconds after liftoff and lost command, leading to a higher angle in the flight, said K. Radhakrishnan, chairman of the Indian Space Research Organization.:(
"That caused a higher stress, breaking up the vehicle," Radhakrishnan told reporters.
The rocket carrying an Indian communication satellite launched from (Sriharikota] on Saturday began failing after some 45 seconds, the Indian Space Research Organisation (ISRO) said. “The controllability was lost after 45 seconds after the lift-off. The control commands to the four strap on motors of the first stage did not reach,” ISRO chairman K Radhakrishnan told reporters. He said the first stage performed well till 50 seconds, and after that the rocket started failing.
According to him, the destruct command was issued 63 seconds after the lift off by the Range Safety Officer
So we have the guidance failure at 47 seconds and around 10 km altitude?
RAN 2.7kms means what? It is 2.7kms from the launch pad? It was the first stage fell there?
Probably short for range i.e. downrange distance from the pad.
http://www.hindustantimes.com/Rocket-failed-after-45-seconds-says-ISRO/Article1-642792.aspx (http://www.hindustantimes.com/Rocket-failed-after-45-seconds-says-ISRO/Article1-642792.aspx)QuoteThe rocket carrying an Indian communication satellite launched from (Sriharikota] on Saturday began failing after some 45 seconds, the Indian Space Research Organisation (ISRO) said. “The controllability was lost after 45 seconds after the lift-off. The control commands to the four strap on motors of the first stage did not reach,” ISRO chairman K Radhakrishnan told reporters. He said the first stage performed well till 50 seconds, and after that the rocket started failing.
According to him, the destruct command was issued 63 seconds after the lift off by the Range Safety Officer
So there was a first internal break-up at around T0+50s followed by an explosion triggered by a self destruct command at T0+63s
RAN 2.7kms means what? It is 2.7kms from the launch pad? It was the first stage fell there?
Probably short for range i.e. downrange distance from the pad.
Thanks, that means it finally went to ground around at 2.7kms from the launch pad. But that for which stage :huh: Who knows satellite may be in the sea bottom in full.
After the breakup three dots were blinking. Except one others stopped blinking after sometime and went missing in atmosphere.
So we have the guidance failure at 47 seconds and around 10 km altitude?
Guidance and control are linked systems, but this is not what I'd call a guidance failure. First Ariane V and one Titan IV launch were guidance system failures - erroneous data fed to the control system. The official report here is the guidance performed as expected, but the proper gimbal commands never reached the engines for whatever reason.
RAN 2.7kms means what? It is 2.7kms from the launch pad? It was the first stage fell there?
Probably short for range i.e. downrange distance from the pad.
Thanks, that means it finally went to ground around at 2.7kms from the launch pad. But that for which stage :huh: Who knows satellite may be in the sea bottom in full.
After the breakup three dots were blinking. Except one others stopped blinking after sometime and went missing in atmosphere.
This is exactly the reason I believe that they can recover the satellite...probably I am going too far... ??? :(
No, it means it was 2.7km downrange from the pad at that time. It is *not* the expected impact point, which depends on the velocity at the time thrust was cut off and the aerodynamics.RAN 2.7kms means what? It is 2.7kms from the launch pad? It was the first stage fell there?
Probably short for range i.e. downrange distance from the pad.
Thanks, that means it finally went to ground around at 2.7kms from the launch pad. But that for which stage :huh: Who knows satellite may be in the sea bottom in full.
After the breakup three dots were blinking. Except one others stopped blinking after sometime and went missing in atmosphere.
There was no design fault in the rocket. We suspect the four connectors to the strap-on motors got snapped,' Radhakrishnan said.http://www.sify.com/news/indian-rocket-explodes-seconds-after-launch-intro-night-lead-news-national-kmzvagabccd.html
QuoteThere was no design fault in the rocket. We suspect the four connectors to the strap-on motors got snapped,' Radhakrishnan said.http://www.sify.com/news/indian-rocket-explodes-seconds-after-launch-intro-night-lead-news-national-kmzvagabccd.html
It appears one of the strap ons broke apart spilling propellants during the initial loss of attitude control............
ISRO Chairman K. Radhakrisnan said at a press conference: “The controllability of the vehicle was lost after 47 seconds because we found that the command to control it did not reach the actuator system in the first stage of the vehicle… We suspect that a connector chord, which takes the signal down, has snapped.”http://www.thehindu.com/sci-tech/science/article979052.ece (http://www.thehindu.com/sci-tech/science/article979052.ece)
Director of Vikram Sarabhai Space Centre in Thiruvanthapuram P.S. Veeraraghavan explained that the command to control the vehicle from the Equipment Bay, the electronic brain of the vehicle resident atop the rocket, did not reach the actuators in the vehicle's first stage. “So it was not basically a design problem but a problem of the connector snapping.”
So hypotheses I see talked about here are:Where does your #2 come from?
1) loss of command path between flight computer and TVC
2) loss of structural integrity on a strap-on, leading to asymmetric thrust - initial loss potentially due to turbopump letting go
3) loss of connection between core and strap-ons, structural or command
I'd like to see supporting or refuting evidence for these. And, valid additional hypotheses from established NSF members.
QuoteISRO Chairman K. Radhakrisnan said at a press conference: “The controllability of the vehicle was lost after 47 seconds because we found that the command to control it did not reach the actuator system in the first stage of the vehicle… We suspect that a connector chord, which takes the signal down, has snapped.”http://www.thehindu.com/sci-tech/science/article979052.ece (http://www.thehindu.com/sci-tech/science/article979052.ece)
Director of Vikram Sarabhai Space Centre in Thiruvanthapuram P.S. Veeraraghavan explained that the command to control the vehicle from the Equipment Bay, the electronic brain of the vehicle resident atop the rocket, did not reach the actuators in the vehicle's first stage. “So it was not basically a design problem but a problem of the connector snapping.”
Also seems like the thing started breaking up on its own before an authorized destruct was issued, usually RSO destructs look cleaner than that.Yes, this has been acknowledged by ISRO and is visible on the video
http://www.youtube.com/watch?v=jd8_0UDdpHc (http://www.youtube.com/watch?v=jd8_0UDdpHc)In the video if you look closely at the frames right before the initial explosion, you can see the rocket veering upwards somewhat and then breakup begins. Seem to me to be an obvious guidance failure (probably resulting from that broken cable they mentioned). The failure happened at a high stress point in the flight so when the vehicle went off course (by veering upwards) it simply broke into pieces. Destruct command came later.
agreed sorry for redundant posts. Seems pretty obvious what happened here, ashame that it happened though. They just can't get away from these failures :\Also seems like the thing started breaking up on its own before an authorized destruct was issued, usually RSO destructs look cleaner than that.Yes, this has been acknowledged by ISRO and is visible on the video
So hypotheses I see talked about here are:Where does your #2 come from?
1) loss of command path between flight computer and TVC
2) loss of structural integrity on a strap-on, leading to asymmetric thrust - initial loss potentially due to turbopump letting go
3) loss of connection between core and strap-ons, structural or command
I'd like to see supporting or refuting evidence for these. And, valid additional hypotheses from established NSF members.
Did anyone noticed the moment of lift off ?
It was somewhat different when compared to other GSLV launches i think
It went too fast i believe while clearing the tower and it *might* have damaged launch tower ;
I am not sure about this though.
And the fumes of the rocket was also different
We will now review GSLV programmes: ISROand next PSLV launch delayed from January 20 to early February
You mean Reply #138, but I don't think this view has been backed up.So hypotheses I see talked about here are:Where does your #2 come from?
1) loss of command path between flight computer and TVC
2) loss of structural integrity on a strap-on, leading to asymmetric thrust - initial loss potentially due to turbopump letting go
3) loss of connection between core and strap-ons, structural or command
I'd like to see supporting or refuting evidence for these. And, valid additional hypotheses from established NSF members.
Reply #137. Speculation about turbopump contribution comes from discussions among colleagues this morning.
Isro has lined up four launches next year, including PSLV 17http://timesofindia.indiatimes.com/india/Technical-glitch-after-liftoff-GSLVs-gone-in-63-seconds/articleshow/7164870.cms
The fact that GSLV-Mk2 was lengthened and made a little top-heavier for this flightThis was a Mk.I
This was a Mk.I
Better to go with a design that lends itself towards more reliability. Shorter and fatter seems okay for something that's leaving the atmosphere soon anyway. Longer, thinner and more top-heavy seems inherently more problematic.
I'm curious - the configuration of this LV seems pretty unique (liquid boosters for a solid core) - or is this not so rare?
In fact, it is rare: GSLV Mk.1 and Mk.2 are the only launch vehicles to use a solid core with liquid boosters.
Even more strange, the boosters have a longer burn time than the core. Suboptimal, as the burned out core has to be carried further on and can not be jettisoned before the liquid boosters have burned out too.
"Longer, thinner and more top-heavy" is actually more stable, since its COG is further ahead of its COP. Probably less stiff though.
Hmm, this seems counter-intuitive to me. I would think that the longer a rocket is, the easier it is for torque forces to develop along that length to spin the rocket out of control.
Gee, I wonder if the design could be modified to allow for jettison of the solid core while retaining the liquid boosters. Perhaps if there was a sheath around the solid core which it could slide out from when jettisoned?
Personally, I like the idea of the outer rockets being throttlable while the inner core has the greater main thrust due to solid fuel. That seems more steerable to me.
More mass and more failure modes. That would be a Frankenrocket, really.
Booster steering is not achieved by differential thrust of main engines (this method would be too slow) - instead, engines are gimballed, or small vernier engines are used to steer (Soyuz).
Ares-1 was a solid booster design - how do they gimbal their thrust?
"Longer, thinner and more top-heavy" is actually more stable, since its COG is further ahead of its COP. Probably less stiff though.
Hmm, this seems counter-intuitive to me. I would think that the longer a rocket is, the easier it is for torque forces to develop along that length to spin the rocket out of control.
http://en.wikipedia.org/wiki/Pendulum_rocket_fallacy
I know about the "Pendulum Fallacy" but even if having more mass fartehr forward is better, still I'd think that the larger faring size (surface area) would catch more aerodynamic forces to tip the rocket into a bad orientation.
QuoteBooster steering is not achieved by differential thrust of main engines (this method would be too slow) - instead, engines are gimballed, or small vernier engines are used to steer (Soyuz).
So then you'd benefit from having your engines farther away from the centerline axis to make it easier for them to apply corrective torque, whether it's due to differential thrust, gimbaling, etc. The wider design of the GSLV-Mk3 allows for this.
Ares-1 was a solid booster design - how do they gimbal their thrust?
In both axes :D
Greater torque for correction also implies greater torque for errors to propagate in the first place. If the control to the gimbals was indeed interrupted, that means that all errors were uncorrected and accumulating. Wider separation of the engines only magnifies the effect of imbalances (as in "give me a long enough lever and I shall move the world"). In short, if the brain isn't controlling the feet once out of the starting gate, this kind of race isn't going to end well.
So it is possible to gimbal a solid booster then?
Gee, maybe one day someone will come up with a hybrid liquid-solid design for a launch vehicle. I've heard of colloidal rockets, but I'm not sure what their performance characteristics are. I'd assume more thrust than liquid, but less than that of pure solid.
The fact that GSLV-Mk2 was lengthened and made a little top-heavier for this flight with a larger faring (ie. to accommodate higher payload), makes these things look like they would have all contributed to the added stresses that could have tipped things past the failure point during that period of maximum aerodynamic stress.
I think shorter and fatter is okay for a rocket, since it's punching out of the atmosphere sooner rather than later. If you're making a hypersonic aircraft, let that be long and skinny, for prolonged atmospheric flight path.
I think ISRO should try to regain the initiative and move to directly flight test the GSLV-Mk3, albeit with a dummy payload rather than an expensive telecom satellite.
Experts analysing the voluminous data are of the view that a hardware problem or defect has led to the snapping of the four connectorsfrom: http://economictimes.indiatimes.com/news/politics/nation/hardware-defect-suspected-for-rocket-failure/articleshow/7169237.cms
QuoteExperts analysing the voluminous data are of the view that a hardware problem or defect has led to the snapping of the four connectorsfrom: http://economictimes.indiatimes.com/news/politics/nation/hardware-defect-suspected-for-rocket-failure/articleshow/7169237.cms
Another comment I'd like to make is that I think the Indian govt should seek to have ISRO spin off its already successful proven workhorse PSLV to the private sector, preferably to at least 2 competing service providers.
Okay, well how about spinning off to a single private contractor then?
Okay, well how about spinning off to a single private contractor then?
Arent private contractors already involved?
QuoteExperts analysing the voluminous data are of the view that a hardware problem or defect has led to the snapping of the four connectorsfrom: http://economictimes.indiatimes.com/news/politics/nation/hardware-defect-suspected-for-rocket-failure/articleshow/7169237.cms
Heavier payload caused Indian rocket's failure: Expert
http://www.hindustantimes.com/Heavier-payload-caused-Indian-rocket-s-failure-Expert/Article1-643393.aspxQuoteHeavier payload caused Indian rocket's failure: Expert
Is it pretty standard to use 'connectors' on such critical wires rather than solder them ?
Seems like it would be better to solder them so you dont have to worry about a connector failing ?
Or am I missing something ?
Is it pretty standard to use 'connectors' on such critical wires rather than solder them ?
Seems like it would be better to solder them so you dont have to worry about a connector failing ?
Or am I missing something ?
So these seem to be the sequence of events leading to failure, imho:
1) aerodynamic stresses/vibrations build up as rocket traverses Max-Q
2) stresses/vibrations snap control cables
3) loss of control cable connectivity means engines stop responding to guidance correction commands
4) rocket loses correct orientation and angle of attack
5) rocket suffers structural breakup
Is that a reasonably plausible recap of what's happened, based on the evidence and statements available?
Edit: Wait, that can't quite be right, because I remember reading some statement from ISRO officials that at T+0.2 seconds after liftoff
where did u get this from...Can you please provide any link...because this is new
, they lost signal-connectivity to one of the boosters. So the control cable initially snapped during the stress of liftoff, and not at Max-Q. Fair enough?
How come the rocket run for 45 seconds with cable snapped...the flight seemed perfect till 45 seconds....your first 5 point summary looks the possible explanation...snapping should have taken place at max-Q
In which case, why would stress of liftoff cause such a failure? Would it more likely be due to unaccounted vibration modes, or more likely be due to somebody just carelessly not connecting a cable firmly enough?
So these seem to be the sequence of events leading to failure, imho:
1) aerodynamic stresses/vibrations build up as rocket traverses Max-Q
2) stresses/vibrations snap control cables
3) loss of control cable connectivity means engines stop responding to guidance correction commands
4) rocket loses correct orientation and angle of attack
5) rocket suffers structural breakup
Is that a reasonably plausible recap of what's happened, based on the evidence and statements available?
Edit: Wait, that can't quite be right, because I remember reading some statement from ISRO officials that at T+0.2 seconds after liftoff, they lost signal-connectivity to one of the boosters. So the control cable initially snapped during the stress of liftoff, and not at Max-Q. Fair enough?
In which case, why would stress of liftoff cause such a failure? Would it more likely be due to unaccounted vibration modes, or more likely be due to somebody just carelessly not connecting a cable firmly enough?
ISRO Chairman K. Radhakrisnan said at a press conference: “The controllability of the vehicle was lost after 47 seconds because we found that the command to control it did not reach the actuator system in the first stage of the vehicle… We suspect that a connector chord, which takes the signal down, has snapped.”
http://www.hindustantimes.com/Heavier-payload-caused-Indian-rocket-s-failure-Expert/Article1-643393.aspxQuoteHeavier payload caused Indian rocket's failure: Expert
where did u get this from...Can you please provide any link...because this is new
The FAC to be formed is expected to be similar to the committee set up after the failure of GSLV-D3, primarily for the flight testing of indigenously developed Cryogenic Upper Stage (CUS), on April 15 this year.
The FAC comprising multi-disciplinary experts concluded at the time that the primary cause for the failure was the sudden loss of thrust in one out of the four liquid propellant strap-on stages (S4) immediately after lift-off at 0.2 sec.
Can it be that the rocket was aerodynamically unstable...and that isro is just covering tracks...as suggested in the above article.
How can the connectors be connected in such a delicate fashion that they snap...? Have rockets failed with this connector snapping stuff before ?
How can the connectors be connected in such a delicate fashion that they snap...? Have rockets failed with this connector snapping stuff before ?They can come apart.
How can the connectors be connected in such a delicate fashion that they snap...? Have rockets failed with this connector snapping stuff before ?They can come apart.
US launches have failed when critical cables were either not mated or were mated but the retaining hardware not tightened.
A recent example had a fairing fail to separate...
So these seem to be the sequence of events leading to failure, imho:
1) aerodynamic stresses/vibrations build up as rocket traverses Max-Q
2) stresses/vibrations snap control cables
3) loss of control cable connectivity means engines stop responding to guidance correction commands
4) rocket loses correct orientation and angle of attack
5) rocket suffers structural breakup
Is that a reasonably plausible recap of what's happened, based on the evidence and statements available?
Isn't there a better term than snapping connectors? Are connectors suspended within conduit or attached to frame?
Hmmm .. perhaps the heavier C15 upper stage generated loads at the second stage/third stage interface that were not expected.
Or else, some leaking propellant got onto the connectors.
I think that umbilical connectors are visible in this image of the third stage. This is the general area of the described failure.
http://upload.wikimedia.org/wikipedia/en/a/a2/GSLV_Mk2D3_Cryo_Engine.jpg
Of course workers would have been into this area during the leak investigation.
- Ed Kyle
Isn't there a better term than snapping connectors? Are connectors suspended within conduit or attached to frame?
disconnected, unmated, unplugged,
May be a umbilical chord failed to unmate and somehow pulled at the cable assembly at launch.
This quad failure isn't credible to me, unless it was a progressive failure (1 then another then the other 2) and it was able to fly through 1 of them.
I suggest we wait for the investigation.
Anyway, here's the latest from TIME:
http://www.time.com/time/world/article/0,8599,2040085,00.html
The article seems to mention a liquid core stage with solid strap-on boosters. Isn't it the opposite?
Snapping of 10 connectors led to GSLV failure: ISRO sources
Analysis of the data showed that snapping of connectors had led to the disintegration of the vehicle and it had nothing to do with the increase in the weight of the satellite, which was only marginal
QuoteSnapping of 10 connectors led to GSLV failure: ISRO sourcesQuoteAnalysis of the data showed that snapping of connectors had led to the disintegration of the vehicle and it had nothing to do with the increase in the weight of the satellite, which was only marginal
from
http://netindian.in/news/2010/12/29/0009647/snapping-10-connectors-led-gslv-failure-isro-sources
The disintegration of the payload fairing could have led to this snapping. That could be a theory.I don't think so: The loss of control of the boosters took place at +47s, the payload fairing disintegration took place after +50s
"On the day of the failure it was announced the connectors relaying the command led to the rocket's failure. We have revisited and have confirmed that the connectors located between the cryogenic engine and the lower stage (engine) snapped. We have to find why the snapping happened," Nair said.
"As per the data there are no indications of any control command from the onboard computers to the rocket engines," he said.
He said simulated experiments will have to be carried out to find out why the connectors got disconnected from the rocket.
"Whether vibrations or external forces led to the snapping of connectors has to be found out. We will have to conduct simulation experiments to find that out," Nair said.
To a query as to why the ISRO was taking a long time to come out with a preliminary report, he said: "The preliminary data runs into more than 100 pages even though the flight is of around 50 seconds."
At the time of failure would one expect steering commands or just commands to compensate for perturbations?
^
quote
"
"As per the data there are no indications of any control command from the onboard computers to the rocket engines," he said.
If there were in fact NO commands from the computers to the engines as implied by the statement, the vehicle would/could not have pitched over after launch--correct? No commands would seem to have resulted in a much earlier loss of control... A loss of commands later in the launch would seem more likely, belying the quote above.
"The take-off was smooth and the flight was normal till 47 seconds. But trouble arose in the next three seconds, when 10 connectors located between the second and third stage (cryogenic stage) got separated, leading to the vehicle losing controllability," the sources said.
^
quote
"
"As per the data there are no indications of any control command from the onboard computers to the rocket engines," he said.
If there were in fact NO commands from the computers to the engines as implied by the statement, the vehicle would/could not have pitched over after launch--correct? No commands would seem to have resulted in a much earlier loss of control... A loss of commands later in the launch would seem more likely, belying the quote above.
On a second reading may be we should interpret the statement as:
"....no indications fo any control command from the oboard computers (reaching) to the rocket engines" - (word in italics mine).
So that sounds like something could have happened with the cryogenic upper stage (CUS), that could have caused a major problem to the connectors below it. Could a propellant tank have ruptured/leaked due to aerodynamic stresses, and then disabled those connectors/cables?
It looks like its time to remind everyone that the third stage was experiencing a leak on the launch stand a few days before the launch. That leaking propellant had to go somewhere.
It looks like its time to remind everyone that the third stage was experiencing a leak on the launch stand a few days before the launch. That leaking propellant had to go somewhere.
ISRO has posted the preliminary findings report on the GSLV failure today.
Report: #GSLV Preliminary Failure Report is out - http://isro.gov.in/pressrelease/scripts/pressreleasein.aspx?Dec31_2010 (http://isro.gov.in/pressrelease/scripts/pressreleasein.aspx?Dec31_2010)
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.So apparently no clues yet on the cause(s) of the famous connectors snapping..
ISRO has posted the preliminary findings report on the GSLV failure today.
Report: #GSLV Preliminary Failure Report is out - http://isro.gov.in/pressrelease/scripts/pressreleasein.aspx?Dec31_2010 (http://isro.gov.in/pressrelease/scripts/pressreleasein.aspx?Dec31_2010)Quote from: GSLV Preliminary Failure ReportThe 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.So apparently no clues yet on the cause(s) of the famous connectors snapping..
ISRO has posted the preliminary findings report on the GSLV failure today.
Report: #GSLV Preliminary Failure Report is out - http://isro.gov.in/pressrelease/scripts/pressreleasein.aspx?Dec31_2010 (http://isro.gov.in/pressrelease/scripts/pressreleasein.aspx?Dec31_2010)Quote from: GSLV Preliminary Failure ReportThe 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.So apparently no clues yet on the cause(s) of the famous connectors snapping..
The report says: "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."
So how are these connectors separated at 292 seconds? Is this "snapping" actually a separation process that usually only happens at staging, but that somehow happened prematurely? The phrase "premature snapping" seems to indicate that "snapping" might be a standard procedure when it is not "premature".
- Ed Kyle
Snapping of connectors caused GSLV failure: ISRO
Staff Reporter
Programme Review and Strategy Committee set up to look into the future of the programme
The precise cause of the snapping of conductors is to be analysed further
Failure analysis panel will recommend corrective action on GSLV vehicle
BANGALORE: A Preliminary Failure Analysis Team constituted to study the flight data of GSLV-F06, which crashed seconds after its launch on December 25, said that the primary cause of the failure was “the untimely and inadvertent” snapping of a group of 10 connectors located at the base of the Russian Cryogenic stage.
The fact that all of those connectors are located at the base of the cryogenic stage can't be a coincidence.
These connectors are intended to be separated only on issue of a separation command at 292 seconds after lift-off.Is there a possibility that a modification to the software reproduced inadvertently such a separation command encoding sequence at 47.8s after lift-off ?
Exactly how does stage separation occur? Through explosive bolts?
Premature stage separation is a specific type of structural failure which seems to have more possible causes associated with it than other types.
Whether the connectors failed due to premature stage separation, or whether premature stage separation occurred due to connector failure, there should be some way to discern cause from effect.
1. How is stage separation recorded/registered? Hopefully, there would be something in the telemetry logs which shows whether the stage separated an instant before the control signals were lost, or whether the control signals were lost before the stage separation occurred.
2. What are the main ways through which aerodynamic loads and turbulence are detected - purely through the inertial guidance system?
If so, then the frequency and magnitude of correction commands would be an indicator to the buildup of such forces.
3.But how are sheer forces detected or monitored?
The report says: "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."
So how are these connectors separated at 292 seconds? Is this "snapping" actually a separation process that usually only happens at staging, but that somehow happened prematurely? The phrase "premature snapping" seems to indicate that "snapping" might be a standard procedure when it is not "premature".
- Ed Kyle
Exactly how does stage separation occur? Through explosive bolts?
Looks to me the rocket was not properly balanced.......then the snaps occurred. Since the rocket was stretched, it seems to be nose-heavy,thus breaking apart at maximum dynamic pressures.
Looks to me the rocket was not properly balanced.......then the snaps occurred. Since the rocket was stretched, it seems to be nose-heavy,thus breaking apart at maximum dynamic pressures.
Meanwhile, ISRO to get supercomputer upgrade:
http://www.hpcwire.com/news/New-Half-Petaflop-Super-Will-Boost-Indias-Space-Program-112828474.html
http://www.livemint.com/2011/01/04030242/Wipro-building-India8217s-f.html?atype=tp
http://ibnlive.in.com/news/gslv-failed-as-germanmade-connectors-snapped/139522-11.html
The "snapped" connectors were German-made, for whatever that is worth.
Note that this report says that even the "backup" connectors "snapped".
I'm an electrical engineer, but I am still completely baffled as to what the term "snapped" means when used to describe connectors. :-\
- Ed Kyle
http://ibnlive.in.com/news/gslv-failed-as-germanmade-connectors-snapped/139522-11.html
The "snapped" connectors were German-made, for whatever that is worth.
Note that this report says that even the "backup" connectors "snapped".
I'm an electrical engineer, but I am still completely baffled as to what the term "snapped" means when used to describe connectors. :-\
- Ed Kyle
Yeah, it's more likely the improper use of the term. Perhaps a 'case fracture', or 'premature separation event' (since these would likely be break-away connectors designed to separate at a specific pulling force).
If I were to put money on it, without even knowing the full depth of the issue, I'd say connectors were not properly spec'd (or applied) for the vehicle, given the cryo conditions & vehicle's acceleration environment.
http://ibnlive.in.com/news/gslv-failed-as-germanmade-connectors-snapped/139522-11.html
The "snapped" connectors were German-made, for whatever that is worth.
Note that this report says that even the "backup" connectors "snapped".
I'm an electrical engineer, but I am still completely baffled as to what the term "snapped" means when used to describe connectors. :-\
- Ed Kyle
Yeah, it's more likely the improper use of the term. Perhaps a 'case fracture', or 'premature separation event' (since these would likely be break-away connectors designed to separate at a specific pulling force).
If I were to put money on it, without even knowing the full depth of the issue, I'd say connectors were not properly spec'd (or applied) for the vehicle, given the cryo conditions & vehicle's acceleration environment.
My guess would be premature "separation", although I don't know how anyone could say for certain that the cables separated *at* the connectors (unless there was on-board video). I suppose it might be a good conjecture to make if the symptoms indicated that *all* electrical connections suddenly opened at the same instant.
Aren't "cable cutters" often used for separating electrical connections during staging? Not always though. I've recently read about a failed Atlas booster package electrical separation event where a connector was supposed to be pulled apart by a lanyard as the booster fell away (the lanyard failed on that one, causing a bad separation that must have messed up the booster separation event signal, leading to loss of flight control).
- Ed Kyle
http://ibnlive.in.com/news/gslv-failed-as-germanmade-connectors-snapped/139522-11.html
The "snapped" connectors were German-made, for whatever that is worth.
http://ibnlive.in.com/news/gslv-failed-as-germanmade-connectors-snapped/139522-11.html
The "snapped" connectors were German-made, for whatever that is worth.
Deutsch connectors are used extensively in Delta and Atlas
http://ibnlive.in.com/news/gslv-failed-as-germanmade-connectors-snapped/139522-11.html
The "snapped" connectors were German-made, for whatever that is worth.
Deutsch connectors are used extensively in Delta and Atlas
But Deutsch connectors are not from Germany. Deutsch is a US connector company.
(edit for typo)
I think they mean "disconnect" here when they say snapped. That is generally the way a lay Indian person in Mumbai would describe it when we have electrical complaints. I am not so sure of other places in India. I guess ISRO scientists wanted to use local layman terms while saying this to ensure people here understood.
I also hope they're not trying to blame foreign components here because whatever the source of the component - Indian or foreign - it was their duty to check whether the system worked. Quality check and assurance is the purchaser's responsibility. I think it is more the media waiting for every tid bit of information and bloating the quote out of all context.
It is not clear (to me) if the connectors get separated because of the stage moving away (stage separation ) - that is pulled apart as the stages move away from each other OR there is some other explicit mechanism for de-mating the connector pairs, prior to the stages moving away.
Could anyone in the know clarify?
New information from ISRO on why, potentially, the connectors snapped:QuoteThe 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).from: http://www.sify.com/news/rocket-failure-isro-awaits-data-from-russia-news-national-lb2qugdhiab.html (http://www.sify.com/news/rocket-failure-isro-awaits-data-from-russia-news-national-lb2qugdhiab.html)
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.
http://economictimes.indiatimes.com/news/politics/nation/isro-to-conduct-gslv-test-flight-in-2012-with-russian-cryogenic-stage-engine/articleshow/8044557.cms (http://economictimes.indiatimes.com/news/politics/nation/isro-to-conduct-gslv-test-flight-in-2012-with-russian-cryogenic-stage-engine/articleshow/8044557.cms)
So what about the seventh cryogenic engine from Russia? There were reports that both Isro and Russia disagreed on technical reasons for the failure of the most recent GSLV mission in December.
The last two engines (the sixth and seventh) have greater thrust than previous engines. They was supplied in 2004 and 2005, and stored in specified conditions. So the reason for the failure (in December) was the inadvertent snapping of the connectors, well before time [connectors are critical for controlling the vehicle]. This happened because the shroud gave away (the shroud is a casing that separates the liquid and solid stages of the launch cover). It’s a cover that sits on (the) bottom of the cryogenic stage. Now, why did the shroud go? Was it the 4m heat shield? We then realized that it was the inherent vulnerability of the shroud. The shroud was at the bottom of the cryogenic stage. There were 10 connectors in two stages, and both gave way. Initially, the Russians said it was our 4m shield that was responsible. We put both our analyses, and finally the Russians also came around. We then decided that the seventh engine has to be inspected, too. We did it and found that they weren’t made in the dimensions specified to in the document. There are lots of shortcomings, and the Russians admitted it. Now, the point is that this has to be corrected before it can be used for launch and would require a detailed inspection by them.
Resurrecting an old thread
http://www.indiastrategic.in/topstories986.htm
"The fault was there from the first GSLV that flew with the Russian cryogenic engine in 2001. The weakness in the shroud caught ISRO on December 25 last year,"
"All GSLV's that flew with Russian cryogenic engine have encountered problems carrying a payload of over 2,000 kg"
"In 2007, one of the connecters of the GSLV rocket got snapped and the rocket's performance was considered as below par. The rocket had carried 2,130 kg INSAT-4CR satellite"