Author Topic: FAILURE: IRNSS-1H, PSLV C39, SLP, August 31, 2017 (13:30 UTC)  (Read 29521 times)

Offline jcm

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“we have depleted all the propellant through the gap in the heat shield and the fourth stage.” Dr K Sivan Director VSSC
As per reddit above.

Interesting. Looks like there may have been a change in the decay rate around third apogee (2000 UTC Aug 31),
about when the two debris objects seem to have come off.

Jonathan McDowell

Online StevenV

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Could the sat have been configured to auto-passivate on battery failure?

Offline vineethgk

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The Indian space agency is strongly suspecting the failure of pyro elements for the non-separation of the heat shield of its rocket Polar Satellite Launch Vehicle’s (PSLV) XL variant on Aug 31, said a senior official.
According to K. Sivan, Director, Vikram Sarabhai Space Centre (VSSC), all the systems during the rocket’s flight worked well while the only suspect place is the pyro elements.
One fortunate aspect of the failure is that ISRO has all the flight data as the rocket was not lost during its one way journey.
“Tests are going on to find out the reasons for the failure of heat shield separation. Each test takes around 72 hours,” Sivan told IANS.

Offline worldtimedate

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Last month’s failed mission of PSLV appears to have dried up the influx of usual news reports of the forthcoming satellite launch of ISRO appearing in the Indian Newspapers. I have found the following news report though a bit old by 10 to 11 days, yet it brings to light some issue that could have precipitated the failure of the PSLV mission. M.Y.S. Prasad, the former director of SDSC making some interesting points related to the mission failure as well as quality control responsible for the failure of the GSLV-F02 launch in 2006 and component problems in IRNSS-1A.

Source : Non-separation of PSLV heat shield can be due to process quality issue, and not a design failure, say space technology experts

"The PSLV rocket has been successful for the past several years. So the question of design failure does not arise. It could be an issue of a failed component or a process quality issue," M.Y.S. Prasad, a former Director of the Satish Dhawan Space Centre, told IANS.

This is the first time that a satellite launch mission has failed due to this reason, perplexing current and former officials of the Indian Space Research Organization (ISRO). "It is really perplexing that such a thing has happened. Normally, the PSLV rocket has several redundancies built into it," R.V. Perumal, a former ISRO scientist, told IANS.

Noting all the commands are pre-planned and built into the computers, he said that there cannot be any manual command. "The computers have to give the necessary commands. The commands have to be relayed by the electrical circuits. The pyro circuit has to get initiated which, in turn, has to cut the mechanical elements so that the two parts of the heat shield get separated," he said.

Prasad maintained that something could have gone wrong in this four-step sequence or in the sub-systems, as redundancies have only been built into some systems. "The computer programmes may have several redundancies to take care of an eventuality. So they can be tested on ground before and also during preparation for the flight. The electrical circuits and some pyro elements will also have redundancies.

"A rocket has several one-time operation systems. Such systems cannot be pre-tested and cannot have redundancies[/b]. Only sample tests can be made with items manufactured in that batch. And then a system is used in the rocket," he said, terming the one-time operation systems 'the riskiest items; in any rocket.

Ruling out design failure, Prasad said the most probable cause of failure could be the quality of a rocket component or some error in the assembly of systems.

worldtimedate [ ]

Offline K210

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Reason for failure has been found. Report will be released shortly. Launches to resume from november.

Offline Star One

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ISRO to be back with launches in Nov.-Dec.

The Indian Space Research Organisation expects to resume launch of satellites in a couple of months once its failure analysis committee releases its report. The committee is conducting tests on why the PSLV-C39 mission of August 31 failed to release a back-up navigation satellite into space.

ISRO Chairman A.S. Kiran Kumar on Friday said the committee would release its report "very soon". The launches would be resumed in November or December after necessary steps are taken. He was speaking on the sidelines of an event to mark 25 years of the formation of Antrix Corporation, which markets ISRO’s products and services.