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#140 by input~2 on 30 Nov, 2013 06:31
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Please post GSLV MkIII related posts in the dedicated thread for GSLV MkIII
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#141 by ss1_3 on 03 Dec, 2013 06:00
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Launch pushed to January first week
http://economictimes.indiatimes.com/news/politics-and-nation/isros-gslv-d5-launch-likely-early-next-month/articleshow/26780715.cms -
#142 by input~2 on 03 Dec, 2013 19:43
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#143 by input~2 on 13 Dec, 2013 20:37
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Thailand has been warned of potential debris falling close to its territory from GSLV D5 launch "between December 15 to January 14"
(source) -
#144 by kanaka on 15 Dec, 2013 12:57
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Thailand has been warned of potential debris falling close to its territory from GSLV D5 launch "between December 15 to January 14"
(source)
Thailand has been warned!!!! Does this mean that our scientists are not confident of successful launch
?
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#145 by AJA on 15 Dec, 2013 13:59
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Thailand has been warned!!!! Does this mean that our scientists are not confident of successful launch
?
Yup. Sujata Singh is due to make an announcement in the next week... if the Thai government doesn't invite the protesters for talks, then we're going to drop the GSLV D-5 near their islands and scare them into it.
</sarcasm>
This does beg the question though... If we're going to go ahead with launches even when, as in this case, there's a chance of spent stages falling near/on populated areas... if we're going to deem pre-launch warnings as sufficient mitigating steps to avoid damage - then why did/do they even factor launch groundtracks into a selection of the launch site/azimuth?
In other words, why aren't we considering the very tip of India, or a straight south (or even North) trajectory for the PSLV etc.? We can just warn Sri Lanka (or parts of India) like we've warned Thailand prior to a launch.
The subjective nature, and arbitrariness of the line dividing acceptable and not acceptable is always confounding. -
#146 by William Graham on 15 Dec, 2013 19:50
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In other words, why aren't we considering the very tip of India, or a straight south (or even North) trajectory for the PSLV etc.? We can just warn Sri Lanka (or parts of India) like we've warned Thailand prior to a launch.
It is possible that this could have something to do with reliability - or in the GSLV's case, lack thereof. To date, more GSLVs have ended up in the Indian Ocean than the correct orbit, its success rate is less than 30%, and it hasn't had a successful launch in the last four attempts. The PSLV by contrast has had 21 consecutive successful launches with around a 90% success rate overall. So maybe they just realise this one is more likely to fail. -
#147 by input~2 on 15 Dec, 2013 20:39
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Thailand has been warned of potential debris falling close to its territory from GSLV D5 launch "between December 15 to January 14"
(source)
Thailand has been warned!!!! Does this mean that our scientists are not confident of successful launch ?
Thailand has just been warned that the 2nd stage debris from GSLV D5 "will fall about 260 kilometres off Phang Nga's coast ". This will be published later in a NOTAM and is normal practice. No relation to a lack of confidence of ISRO!
Here are the NOTAMed zones for GSLV F6 for the failed December 25, 2010 launch , the closest to Thailand was about 260 km from the coast
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#148 by AJA on 16 Dec, 2013 06:53
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Firstly, 260 km off the coast is international waters, so I think all our discussion below's moot. I think ISRO's just being nice. Mea culpa.. I should have clicked through and read the link posted by input~2.
Having said that though..It is possible that this could have something to do with reliability - or in the GSLV's case, lack thereof. To date, more GSLVs have ended up in the Indian Ocean than the correct orbit, its success rate is less than 30%, and it hasn't had a successful launch in the last four attempts. The PSLV by contrast has had 21 consecutive successful launches with around a 90% success rate overall. So maybe they just realise this one is more likely to fail.
I thought the launch azimuth was decided and corresponding NOTAMs detailing ZOEs were issued regardless of predicted launch vehicle success or failure... and even assuming an FTS malfunction[2], preventing destruction..
i.e. if you're outside the boxes, you're always safe[1] - whether the rocket breaks up or not... (the cross range dimensions of the box are calculated based on the maximum deviation that the rocket can make - pitch and yaw without aero-structural loads ripping it to shreds, as well as the total burn time of the propellant).
And in any case, that doesn't answer the PSLV question. It's proven its reliability, so we shouldn't hesitate from sending it over Sri Lanka. That's more mass to polar orbit, almost for free! No design changes.. nothing..
Of course, this might still not be desirable if the spent stage would fall on to the Sri Lankan land mass (or even their offshore - useful EEA) in the course of a nominal launch. If it would require us to clean up the surrounding area, it would probably nullify the cost advantage (but we still keep the greater mass to orbit advantage).
Now it's a question of numbers. How much does the launch angle and the subsequent yaw manoeuvre cost us in terms of mass penalty? Would it open up a new market segment?
[1] To the same extent that people around the launch pad itself are safe...
[2] On its own, and assuming the guidance input is all fine, this is probably ok to analyse. But if you couple a software error - like mixing up East and West... it gets ridiculous real fast.. lol -
#149 by vyoma on 16 Dec, 2013 07:38
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Now it's a question of numbers. How much does the launch angle and the subsequent yaw manoeuvre cost us in terms of mass penalty? Would it open up a new market segment?
I remember reading sometime ago about performance penalty on PSLV due to dogleg maneuver, to avoid flying over Sri Lanka:Seems like this might be one of the more dramatic examples of course shaping among world-wide launch sites? I suppose that imposes some performance penalty, as would trying to shoot for the poles from anywhere this close to the equator?
Performance penalty is close to 500 Kgs of payload loss. ISRO is considering second spaceport that will not require such course shaping.ISRO is working on third launch pad in SHAR and considering a new launch site that will improve the payload capacity of current launch vehicles by 500 kgs. Currently, a launch blocks the launch pad for 60 days. With the third launch pad, ISRO is hoping to reduce the gap to 30 days. We need more frequent PSLV launches that will boost commercial activities.
I guess proposed Kulasekarapattinam space port should eliminate this performance penalty:
http://www.deccanchronicle.com/131113/news-current-affairs/article/kulasekarapattinam%E2%80%99s-ideal-launch-pad -
#150 by vyoma on 16 Dec, 2013 09:13
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This just in! Exact launch date will be decided/announced on Dec 27th.Quote
"The GSLV launch will be in January. The exact date will be decided Dec 27 at a meeting," M.Y.S.Prasad, director, Satish Dhawan Space Centre (SDSC), told IANS over phone from Sriharikota in Andhra Pradesh.
http://www.business-standard.com/article/news-ians/isro-to-decide-dec-27-on-gsat-14-launch-date-113121600343_1.html -
#151 by input~2 on 16 Dec, 2013 09:26
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Thanks for the referenceQuote from: IANS
ISRO officials told IANS that the rocket would be moved to the launch pad Dec 28 or 29 and after that around 10 days would be needed to ready the rocket for its flight.
So launch not earlier than January 7
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#152 by chota on 19 Dec, 2013 10:52
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Quote
GSLV-D5 is all set to soar the skies off Sriharikota space-port. The launch is targeted on 1618 hrs of January 5, 2014
https://www.facebook.com/isroofficial
https://twitter.com/isroofficial -
#153 by Galactic Penguin SST on 19 Dec, 2013 11:53
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Quote
GSLV-D5 is all set to soar the skies off Sriharikota space-port. The launch is targeted on 1618 hrs of January 5, 2014
https://www.facebook.com/isroofficial
https://twitter.com/isroofficial
= 10:48 UTC -
#154 by chota on 23 Dec, 2013 00:13
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Details on the restoration flight.
http://www.thehindu.com/news/national/gslvd5-to-lift-off-on-january-5/article5487536.ece -
#155 by chota on 23 Dec, 2013 12:10
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Out now, the lauch vechicle integration photos and old brochure
http://www.isro.org/gslv-d5/pdf/brochure.pdf
http://www.isro.org/gslv-d5/Imagegallery/launchvehicle.aspx -
#156 by AJA on 23 Dec, 2013 20:00
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http://www.thehindu.com/news/national/gslvd5-to-lift-off-on-january-5/article5487536.ece
QuoteThe leak was blamed on the fuel tank made of aluminium alloy called Afnor 7020 which tended to develop cracks over a period of time. The GSLV-D5 was dismantled and the “restoration process” done under the guidance of K. Narayana, former Director, Satish Dhawan Space Centre, Sriharikota. The GSAT-14 communication satellite, which was encapsulated in the heat shield, was preserved and tested periodically.
Since the liquid fuel leaked from the second stage tank made of aluminium alloy Afnor 7020, the Liquid Propulsion Systems Centre (LPSC), ISRO, Mahendragiri, Tamil Nadu, came up with a new second stage with its propellant tank made of aluminium alloy 2219. The four strap-on booster motors were refurbished. The rocket’s first stage, which uses solid propellants, has been replaced with a new one. The restored vehicle has new electronic components because the components in the four strap-on motors in the earlier vehicle had become wet from the fuel leak.
....
The GSLV-D5’s cryogenic stage had been stored for the past three months-and-a-half. Mr. Dathan added: “The cryogenic stage’s critical components and valves have been tested, and found in good condition. There are three levels of checks on the vehicle. Phase III, level I checks have been done. This means all the fluid lines and electrical circuits have been checked. Everything is giving results as expected. We are ready to go ahead with the launch.”
Given that they've gone for new "dry" units of all the liquid stages...
Any word on whether they will/have changed out the prop tanks on GSAT-14? Or if not, if they've atleast drained it of all its propellant, and will be filling it again? I would think that it'd offer a benefit from the the corrosion resistance perspective? Or does it not matter/make it worse if you drain once the tanks have been "wetted"?
Also, is this corrosion resistance greater or lesser in orbit? Thinking about solute diffusion, and relative densities... -
#157 by input~2 on 26 Dec, 2013 20:38
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#158 by vyoma on 27 Dec, 2013 13:15
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ISRO’s Launch Authorisation Board approves GSLV-D5 Jan 5 launch. 29-hour countdown to begin on Jan 4th.
http://www.thehindubusinessline.com/news/science/lab-clears-gslv-d5-launch-countdown-from-jan-4/article5508570.ece
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#159 by AJA on 28 Dec, 2013 18:38
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On the launch pad.
(Attached large version of the same pic)
In the VAB prior to MLP rollout ...
Nice shot of the payload air-conditioning duct. I assume all these white wire-ties(?) are to hold this duct in place, during tanking, and cryo-filling etc?
Transporting the cryo stage into the VAB (horizontally) for stacking and integration..
I'm asking again... but could somebody explain why the coldest stage is painted black? Sure, it may not be paint, and it may just be the colour of the insulation material, but what good insulators are coloured black?
?
