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India prepares to return troubled rocket to flight

Posted by Jason Davis

30-07-2013 6:00 CDT

Topics: rockets

India is preparing for the return-to-flight of their Geosynchronous Satellite Launch Vehicle. The GSLV-D5 rocket, featuring an indigenously-developed upper stage engine, will loft a communications satellite into geosynchronous orbit. It is expected to be an important moment for the Indian Space Research Organisation, which has endured back-to-back failures of the GSLV. India's Economic Times reports the launch is scheduled for August 19 at 5:00 p.m. local time (11:30 UTC, 7:30 a.m. EDT). 

GSLV-D3 on the pad


GSLV-D3 on the pad
The ill-fated GSLV-D3 rocket sits on the launch pad prior to its April 15, 2010 launch. The rocket's Indian-built third stage cryogenic engine ignited only briefly, resulting in the loss of the experimental GSAT-4 communication and navigation satellite.

Weighing in at two tons, the GSAT-14 satellite is too heavy for a ride on the workhorse Polar Satellite Launch Vehicle, which, despite its name, can also send payloads to geosynchronous orbit. Since its debut in 2001, the GSLV's third stage was powered by a Russian-built cryogenic engine. According to a 2010 article by Spaceflight Now, India purchased seven off-the-shelf engines to tide them over while they developed their own upper stage. Presumably, India's experience with the CUS will translate to the GSLV Mark III, an all-new rocket capable of lifting heavier payloads.

The new engine debuted April 15, 2010 on GSLV-D3, with the rocket flying under a Mark II moniker. Five minutes into flight, the second stage dropped away as scheduled, and the CUS ignited. It burned for a mere one-and-a-half seconds before the turbopump feeding liquid hydrogen to the engine's thrust chamber failed. Unpowered, the vehicle began to tumble. Its payload—an experimental communications satellite—splashed into the Bay of Bengal. 

The next flight of the rocket took place several months later on December 25. For this mission, GSLV-F06, India went back to the Mark I version, using a slightly-upgraded third stage with a Russian-built engine. 

The mission ended catastrophically, bringing the GSLV's success record to an abysmal four-out-of-seven. According to an ISRO failure report (PDF), the cause was "the untimely and inadvertent snapping of a group of 10 connectors located at the bottom portion of the Russian Cryogenic Stage. The premature snapping of these connectors has led to stoppage of [the] continuous flow of control commands to the First Stage control electronics." In other words, some critical electronic connectors broke, rendering the rocket unable to steer.

ISRO's Cryogenic Upper Stage (CUS)


ISRO's Cryogenic Upper Stage (CUS)
Workers install the Cryogenic Upper Stage for the GSLV-D3 rocket inside the Vehicle Assembly Building at the Satish Dwawan Space Centre. The engine's turbopump failed shortly after ignition.

The GSLV was grounded for three years while engineers regrouped and made changes to the launch vehicle, including the CUS. The turbopump was modified and subjected to extensive testing.

"We have done nearly 35 ground tests since we had the April 2010 failure, on sub-systems, on the engine and on a similar engine in high altitude conditions," ISRO chief Dr. K. Radhakrishnan told the Economic Times. "We have to see [it] through. Stakes are very high, seriousness is very high. [The] entire organisation feels for it. For the last three years, we have been at it."

To a certain extent, the future of India's planetary science program rides on this launch. According to The Times of India, the Chandrayaan-2 moon mission—which features an orbiter, lander and rover—will launch on a GSLV. The Times quoted an unnamed ISRO official as saying, "We are now keeping our fingers crossed that the forthcoming mission should go off without a hitch. We are praying hard for its success."

See other posts from July 2013


Or read more blog entries about: rockets


Bob Ware: 07/31/2013 10:47 CDT

Jason - question... "The turbopump was subjected to ... testing ...." but what about the comm cable & connections? Were those included? That seems to have been the failure point based upon what you wrote? They need to flight test or vaccuum chamber test this full up to see if the apparent cold caused snapping of the comm cables has been solved before risking a reflight.

luke: 08/01/2013 05:38 CDT

Bob based on newspaper reports, they have modified the design for the connectors as well and a problem with the shroud

Bob Ware: 08/03/2013 05:43 CDT

Thanks Luke!

Sridhar Narayanan: 08/09/2013 01:47 CDT

Bob, There were two different failures in two different launches. In April 2010, the GSLV-MK2 was flight tested for the first time with the Indian built cryogenic upper stage (CUS). This launch performed as per plan until the firing the CUS, with the engine igniting as per plan but then a failure of the turbo pump meant that the ignition could not be sustained beyond a second and a half. To fix this problem, there was an extensive redesign of the turbo pump. Also, before the 2010 launch, the stage was not tested under vacuum conditions. Hence ISRO expedited the building of a planned high altitude test facility and tested this redesigned stage under near-vacuum conditions. It has been tested twice successfully before the stage was flight-certified by ISRO's oversight committee. The second failure relates to the shroud design for the upper stage. This happened in December 2010, and this vehicle had a Russian cryogenic upper stage. The vehicle lifted off as per plan, but soon afterwards, there was a catastrophic control failure causing the vehicle to veer off course when it was still in the lower atmosphere. The range safety officer then destroyed the vehicle to protect the launch facility and anybody else in the path of the vehicle. The failure analysis committee determined that the cause of this failure was problems with the design of the shroud for the cryogenic stage, which led to a snapping of the connectors leading to the control unit. This shroud was part of the stage supplied by the Russians and had not failed in previous GSLV flights using the Russian stage. What was different about the December 2011 GSLV vehicle was that the payload fairing was of a larger diameter than previous vehicle. There was disagreement between the Indian and Russian sides about the reason for the failure, but in any case, the shroud has been redesigned and tested so that the problem does not recur even in the case of a larger payload fairing.

Bob Ware: 08/09/2013 05:15 CDT

Sridhar N. - Thank you for the follow up explanation of the launch accidents. I understand them better now. Best wishes to the launch team for a successful launch and the spacecraft team for a healthy spacecraft for the science team to use!

Sridhar Narayanan: 08/16/2013 01:34 CDT

For an even more detailed description of the changes incorporated in GSLV-D5, see page 6 of the launch brochure at the following link

Bob Ware: 08/20/2013 06:42 CDT

Sridhar - Thank you for the great reading material link. The improvements look very beneficial. It looks like you are ready to go fly! Best wishes for a successful flight!

Bob Ware: 08/20/2013 06:44 CDT

Also: as of today I still have not heard or seen anything on the launch. I hope it went well.

Bob Ware: 08/20/2013 06:51 CDT

Ouch. 2nd stage fuel leak. At least it was caught before launch. LV rollback and assessment is underway. Usually means (with cryo stages, replacement of the tanks is the safest best.) By example the Orbiters ET could only be tanked and conditioned 3 times before a launch scrub (cancellation) would have to be called. The leak cause does have to be determined. See:

Bob Ware: 08/20/2013 06:54 CDT

ISRO, keep taking your time and do it right. In the end you all will benefit. There's no point in flying a vehicle that has an issue before launch. Post launch you have no choice but to push to orbit. Utilize your fuel and oxidizer ratios or fuel and fuel if you are using hypergolics.

Sridhar Narayanan: 08/23/2013 08:53 CDT

It is fortunate that the leak was detected during the countdown, but ISRO would do well to also review the broader quality control processes it has. I say that because there have been similar issues earlier as well. The launch of the first GSLV test in 2001 had to be aborted after the ignition of the liquid strap on motors because of a leak in its fuel tank that had gone undetected before that. It was detected just before the solid first stage was ignited and the launch was automatically aborted. Unfortunately, it seems to be the GSLV program that is plagued with such issues. The Polar Satellite Launch Vehicle shares the very same second stage, and has had about 25 consecutive launches that were successful (in fact it has a great record with only one failure - the very first test in 1993).

Bob Ware: 08/24/2013 01:19 CDT

NASA has engineering cameras positioned to watch for leaks as well as sensors at upper and lower limits to watch for fuel levels which data can be used to determine leaks (at pressurization) or boil/bleed off (evaporation) of the fuel before pressurization. Do they do that also?

Bob Ware: 08/24/2013 01:24 CDT

to clarify: if the fuel goes below the sensor, knowing where in the tank the sensor is placed tells them the volume to be replaced. The sensor triggers the threshold alarm. This is also known as the red line parameter. You do not cross this line, regardless of what the event is and its limit is set to.

vyoma: 12/03/2013 02:44 CST

ISRO GSLV-D5 return-to-flight now scheduled in first week of January 2014.

Prasanna: 01/05/2014 06:08 CST

As an update the GSLV D5 successfully launched GSAT 14 the cryogenic stage performed flawlessly

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