Technology
×

Liquid propellant strap-on failure primary cause for Insat 4C crash













BANGALORE:The Failure Analysis Committee (FAC), constituted for investigating the failure of ISRO‘s Geosynchronous Satellite Launch Vehicle, GSLV-F02 mission from Satish Dhawan Space Centre (SDSC SHAR) Sriharikota, on 10 July, 2006 has submitted its report.


The 49 metre tall and 414 tonne GSLV comprises three stages. The first stage consists of a solid propellant motor and four liquid propellant strap-ons. The second stage is also a liquid propellant stage and the third is a cryogenic stage.



GSLV-F02 launch was the fourth in the series. All the three earlier missions (GSLV-D1, D2 and F01) were completely successful. The mission objective of GSLV-F02 was to place Insat-4C, an operational satellite into Geo-synchronous Transfer Orbit (GTO). About 55 sec into the flight, GSLV-F02 started deviating significantly from its nominal flight path resulting in the vehicle breaking up at 62 sec after lift-off. The debris fell into Bay of Bengal.


The 15 member FAC chaired by K Narayana, former Director of SDSC SHAR, with the participation of experts from academic and research institutions besides ISRO, has reviewed the performance of GSLV-F02 from lift-off to the end of flight. FAC had detailed deliberations for over 100 hours in several sittings and was assisted by eight specialist sub-committees examining the flight data of vehicle subsystems, manufacturing documents, inspection, calibration and test results, etc. Especially, the details related to the realisation of liquid propulsion stage of GSLV were closely scrutinized. Several tests simulating possible failure modes were also conducted to identify the exact cause.


FAC has concluded that the performance of all vehicle subsystems, except one strap-on stage was normal until 56.4 sec. 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. With only three strap-on stages working, there was significant reduction in the control capability. However the vehicle attitude could be controlled till about 50 sec. At the same time the vehicle reached the transonic regime of flight and the vehicle attitude errors built up to large values, resulting in aerodynamic loads exceeding the design limits thus leading to break up of the vehicle.


The thrust of the liquid engines used in the strap-on stages is precisely controlled by a set of regulators. Detailed analyses have indicated that in S4 engine the thrust control was not effective. Instead of stabilizing at 5.85 MPa (Mega Pascal) chamber pressure, it reached 7.11 MPa at 2.8 sec. This was much beyond the design limits and the engine failed at 0.2 sec after lift-off, that is 5 sec after its ignition.


Simulations and analyses of flight data and verification through calibration tests have led to the conclusion that the propellant regulator in the failed engine had much higher discharge coefficient in its closed condition. The reason for this could be an inadvertent error in manufacturing, which escaped the subsequent inspection, and acceptance test procedures. This regulator has functioned satisfactorily in all the previous 50 engines manufactured and tested so far, states an official release.


The larger flow of propellant led to higher operating pressure in the gas generator (4.7 MPa against design specification of 3.6 MPa). Due to this higher operating pressure of the gas generator, the water flow rate into it got reduced. The combined effect of larger flow of propellants and reduced flow of water led to a very high gas temperature of 1823 K against design specification of 900 K and pressure of 4.7 MPa against the design specification of 3.6 MPa. The very high operating pressure and temperature resulted in the structural failure of the gas generator. The consequent abrupt stopping of the turbo pumps that feed propellants at very high pressures to the engines led to loss of thrust of S4 engine. The water calibration tests conducted simulating the malfunction of the propellant regulator hardware could closely reproduce the flight phenomenon thereby confirming the larger flow area.


FAC has concluded that the design of GSLV is robust and recommended implementation of strict control on fabrication, inspection and acceptance procedures. Among others, FAC has recommended fabrication processes to be critically reviewed and updated. It has recommended for independent inspection of all critical dimensions of components and subassemblies by in-house agencies. Further, long duration hot test on one out of every 20 engines fabricated has been recommended to ensure that production process is under control. In addition, FAC has recommended strengthening the process of clearance of launch during Automatic Launch Sequence (ALS) phase.


FAC conclusions and recommendations have been accepted and necessary action has been initiated to implement all of them, the release adds.

Latest Reads

http://www.indiantelevision.com/sites/drupal7.indiantelevision.co.in/files/styles/340x340/public/images/tv-images/2018/01/04/sanjeev.jpg?itok=jSKv0oLN
Pune Times joins hands with the Pune Police to launch the 'City Safe' app, as part of #MakeMyCitySafe initiative

Pune Times, city supplement of leading media house, The Times of India, has joined hands with Pune Police to support an initiative for women’s safety in the city. Pune Times has launched its campaign #MakeMyCitySafe as a big shout out to the youth of Pune to come together to make the city safer...

Technology Software Applications
http://www.indiantelevision.com/sites/drupal7.indiantelevision.co.in/files/styles/340x340/public/images/tv-images/2017/12/06/Navanit-Samaiyar_0.jpg?itok=fQLjKjss
HAL Robotics ropes in Navanit Samaiyar as board member and advisor

MUMBAI: HAL Robotics has roped in Navanit Samaiyar as its board member and advisor. Samaiyar has a record of setting up, scaling and transforming businesses across a very wide cross section of industries spanning from IT/ ITeS to steel, telecom, engineering goods, earthmoving machinery, logistics...

Technology Hardware Components
http://www.indiantelevision.com/sites/drupal7.indiantelevision.co.in/files/styles/340x340/public/images/tv-images/2017/11/07/Arnab-Goswami.jpg?itok=VUCIzU8A
Republic TV launches Android app

MUMBAI: Republic TV is on a roll. From rocking the ratings chart in launch week itself to going international, the channel has added one more accomplishment to its kitty. The Republic TV Android app is now live.

Technology Software Applications
http://www.indiantelevision.com/sites/drupal7.indiantelevision.co.in/files/styles/340x340/public/images/tv-images/2017/10/11/STB.jpg?itok=WsiaUBr8
STB cos in India, China enhancing features, providing customised solutions, Technavio enlists top vendors

MUMBAI: The global STB market is characterised by intense competition as the market is saturated in developed countries. The market share of these players is declining because of the entry of new players. The STB companies are enhancing the features of STBs and providing customised solutions to...

Technology Hardware Set-top Boxes
http://www.indiantelevision.com/sites/drupal7.indiantelevision.co.in/files/styles/340x340/public/images/tv-images/2017/10/09/PFT.jpg?itok=VJugic3c
India's PFT Clear Media ERP suite to help US' PBS content delivery

MUMBAI: Prime Focus Technologies (PFT), the technology arm of Prime Focus, announced that its CLEAR™ Media ERP Suite has been selected by Public Broadcasting Service (PBS) to enhance their Network Operations Center (NOC) ecosystem efficiencies and sustainability, with the objective of reducing...

Technology Software Applications
http://www.indiantelevision.com/sites/drupal7.indiantelevision.co.in/files/styles/340x340/public/images/tv-images/2017/10/09/JosephSiino.jpg?itok=doyka7Tg
Broadcasters, OTTs to gain as Via adds xHE-AAC at special rate

MUMBAI: Via Licensing Corporation, a intellectual property solutions provider, has announced the upcoming availability of Extended High Efficiency AAC (xHE-AAC) as part of the Advanced Audio Coding (AAC) patent pool. The expanded patent pool licence will be available at no additional cost to...

Technology Software Applications
http://www.indiantelevision.com/sites/drupal7.indiantelevision.co.in/files/styles/340x340/public/images/tv-images/2017/10/06/Brian_Morris-Colin_Smith.jpg?itok=xVBB0KbV
Tata Comm to deliver Motorsport videos on global devices

MUMBAI: Tata Communications will now deliver video content for Motorsport.tv viewers' all devices over its global network. The two have partnered to power the growth of the network’s internet television platforms.

Technology Software Applications
http://www.indiantelevision.com/sites/drupal7.indiantelevision.co.in/files/styles/340x340/public/images/tv-images/2017/10/06/ChyronHego_0.jpg?itok=qWRkJ4jh
How to create live video content sans pros, convert radio broadcast into visual show

MUMBAI: ChyronHego will be showcasing its live production, automation solutions at Broadcast India show in Mumbai in mid-October.

Technology Software Applications
http://www.indiantelevision.com/sites/drupal7.indiantelevision.co.in/files/styles/340x340/public/images/tv-images/2017/10/03/Arvin%20patel%20tivo.jpg?itok=Ieo7eXfw
Sony renews IP licence deal with TiVo

MUMBAI: TiVo Corporation, a leader in entertainment technology and audience insights, has announced that Sony Corporation, a leader in consumer electronics, has renewed its multi-year intellectual property (IP) licence agreement. The license to TiVo’s patent portfolios covers all of Sony’s...

Technology Software Applications

Latest News

Load More

Sign up for our Newsletter

subscribe for latest stories