Indian Space Programme Discussion

Singha · Post by **Singha** » 01 Sep 2015 21:39

we need colour 4K autotracking camera feeds for TV and seamlessly worked into youtube uploads.
ISRO does publish some gorgeous still images from such cameras, but video will help too.

Singha · Post by **Singha** » 01 Sep 2015 21:41

right now i am trying to see videos on isro.org....over a 50mbps link it is still choppy and halting.
better they leverage youtube and ride on back of global infra of the google cloud.

srin · Post by **srin** » 01 Sep 2015 22:21

Singha wrote:right now i am trying to see videos on isro.org....over a 50mbps link it is still choppy and halting.
better they leverage youtube and ride on back of global infra of the google cloud.

They already use Youtube - I watched the launch live there.

disha · Post by **disha** » 02 Sep 2015 03:04

SSSalvi wrote:
2. Due to protocol ( not for security but for safety ) no one is allowed near pad .. the cameras covering rocket from near are permanently mounted for technical monitoring rather than for news. ( you can notice the change in camera for thermal monitoring just a few seconds before liftoff ).

Subsequent flight is monitored with thermal/optical autotracking camera ( notice the flame is is always in the center of field and camera moving in steps .. not by human hand ).

I doubt if the newsmen are even observing from open ground so they covering launch video is impossible.

I think ISRO can do us all a favour., it can put the safety protocol disclaimers deep in legalize and bury it deep in the contract which every journo needs to read and sign. And then allow the DDM to go near the launch pad - particularly during GSLV Mk III launch. Darwin's law will be applied and the DDM will halal themselves.

The reason DDM did not show up was simple - there was no free accomodation, food and wine <- particularly the last one. No free lamb kebabs with johny walker whiskey or old monk rum.

The only other english channel that must have covered it live must be "The Hindu".

member_28108 · Post by **member_28108** » 02 Sep 2015 06:59

SSSalvi wrote:
prasannasimha wrote:Are they really "frangible tiles" I could not find that out on Google. I thought that they were condensate on the CUS stage that fell off as icy shards when it was launching. You see the same on Apollo launch videos.
Prasannasimhaji, Checked earlier posts but I could not find what your comment refers to.

Even in GSLV D6 launch video I could not see any fragments falling off.

One of the earlier PSLV flight was stopped/postponed for a day at the last moment when they detected 2nd stage was getting affected by atmospheric temperature and so a very simple jugaad was played - they just covered second stage with a thermocole like material and tied it over with rope ( literally ).

This was to isolate the stage from direct atmosphere contact.

As soon as the rocket lifted off the covering was seen tearing off and breaking into flying pieces.

A similar thing was observed in a few other pslv launches also.

I don't know if a similar thing was done in GSLV also ( anyway it has a liquid second stage ).

These things

and also seen here

http://www.isro.gov.in/sites/default/fi ... b10703.jpg

SSSridhar referred to these shards falling as "frangible tiles"

This was part of the conversation

prasannasimha wrote:
Are they really "frangible tiles" I could not find that out on Google. I thought that they were condensate on the CUS stage that fell off as icy shards when it was launching. You see the same on Apollo launch videos.
SSridhar wrote
Normally that is true. But, I think when thermal shrouds are used, as in this case (I have not seen them used before by ISRO), the shrouds conceal some kind of tiles inside and the shroud falls off at the time of launch dispersing these tiles.

member_28108 · Post by **member_28108** » 02 Sep 2015 07:24

^ you can actually see the "tiles" or shards (3 pieces) separating from the launcher at the section with the PSLV C28 Logo on the (viewers) left hand side) just below a wire seen across the photo.

sudhan · Post by **sudhan** » 02 Sep 2015 12:35

I believe those are frozen condensates as prasannasimha says, shaken off by the vibrations generated by the rocket motors' ignition..

I believe the UDMH and the Cryo fuel tanks accumulate the condensates..

One can witness a mother load of these condensate tiles on apollo launches..

member_28108 · Post by **member_28108** » 02 Sep 2015 14:26

http://space.stackexchange.com/question ... ound-stage
[urlhttp://space.stackexchange.com/questions/2532/ariane-4-shroud-around-stage/url]

hnair · Post by **hnair** » 02 Sep 2015 16:13

IIRC, a few years ago, Vidyarthi-sir has mentioned the debris as "frangible insulation falling off" (as SSridhar pointed out). Could not find that post.

Probably the interstages have flight control components that needs cooling or maybe the non-Indian payloads need them. Or possibly some parts need liquid nitrogen pumped in to reduce humidity, static issues, flushings et al. Or all of the above and more. There are a lot of harnesses detaching off nowadays at liftoff, from the earlier spartan PSLV days.

Vidyarthi-sir, if you are reading, please do post here once a while

Neela · Post by **Neela** » 02 Sep 2015 17:33

Onboard camera footage from GSLV D6

0:31-0:37 - Looks like the strap-ons and S139 separate as a single unit after possibly an explosion-initiated drop-off

SSridhar · Post by **SSridhar** » 02 Sep 2015 17:51

Fabulous. Getting the L110 & S139 together is a better option indeed.

Rahul M · Post by **Rahul M** » 02 Sep 2015 18:08

finally !! we have been waiting for on-board camera footage for ISRO launches since eons !
jingo khush hua !

sudhan · Post by **sudhan** » 02 Sep 2015 18:17

Thanks for the video link, Neela ji! Finally a camera on board!!

I never knew the strapons separated with the solid motor together!

Now to have air borne, 'over the clouds' video feed as part of the live coverage! The sight of a GSLV breaking through the clouds and charge into space will be a sight to behold!! (Throw in a vapor cone or two, a night launch... )

I will stop fantasicing here

Singha · Post by **Singha** » 02 Sep 2015 18:59

Is that stage3 falling away in the end?

A Nandy · Post by **A Nandy** » 02 Sep 2015 19:03

Wow, onboard footage finally!! Next step, cameras to be on the outer side of the launcher

The later portion of the video shows the magnificent ignition of the indigenous cryogenic stage.

Magnificent it is

sudhan · Post by **sudhan** » 02 Sep 2015 19:04

@Singha ji:

The last part of the video shows the stage 2 falling off and Stage 3 (CUS) igniting..

The description below the video says the second camera was installed on Stage 2, facing up and the first camera on Stage 2 facing down.

SSridhar · Post by **SSridhar** » 02 Sep 2015 19:08

Singha wrote:Is that stage3 falling away in the end?

Singha, that is Stage 3 (CUS) igniting brilliantly and going away . . .

sanjaykumar · Post by **sanjaykumar** » 02 Sep 2015 19:45

Thank yooooo ISRO.

Mort Walker · Post by **Mort Walker** » 02 Sep 2015 20:18

Absolutely cool footage!

Varoon Shekhar · Post by **Varoon Shekhar** » 02 Sep 2015 20:27

[quote="dhiraj"]http://www.thehindu.com/news/isro-to-bo ... 594838.ece

[

Between D5 and D6 :
Strapons moves from 680 to 760 KN
First stage from 4800 to 4815
Second stage from 720 to 799
Further if i heard correctly CUS weight reduced by around 70 Kg."

Dhiraj, it's great news, but where did you get this information? The Hindu article is talking about future launches.

For these improvements in GSLV-D6, was it mainly a question of increasing the propellant load? Or were there increases in the thrust chambers of the respective stages? ( not for the first stage, where it would be increased fuel)

Varoon Shekhar · Post by **Varoon Shekhar** » 02 Sep 2015 20:28

Yah, that footage of the cryogenic stage moving upwards after separating, is beguiling!

member_28348 · Post by **member_28348** » 02 Sep 2015 20:48

JUICE OF THE ISRO'S FIRST PUBLIC ON-BOARD ROCKET CAMERA FOOTAGE-

https://lh3.googleusercontent.com/VD81c ... 59-h643-no
https://lh3.googleusercontent.com/h68EP ... 62-h643-no
https://photos.google.com/album/AF1QipN ... J5sYkOshd1

JUST SIT BACK AND ENJOY THIS VIEW

member_28348 · Post by **member_28348** » 02 Sep 2015 20:50

OOPS...

member_28108 · Post by **member_28108** » 02 Sep 2015 21:28

If you go through the GSLV D6 launch video you can actually see the first portion of the video(prior to seperation) on the video screen of two computer monitors ! I had brought attention to it and someone said it was a "boring video" of the shroud separation (even that would be great) whereas it was indeed a video recording to record separation events.

Incidentally this odd combo of solid core with 4 liquid strap-ons was done to avoid a booster separation event as that had not been simulated at the time for the GSLV Mk1 and 2(whereas it was done for GSLV Mk3)

nirav · Post by **nirav** » 03 Sep 2015 00:28

Rahul M wrote:finally !! we have been waiting for on-board camera footage for ISRO launches since eons !
jingo khush hua !

sudhan wrote:Thanks for the video link, Neela ji! Finally a camera on board!!

I never knew the strapons separated with the solid motor together!

Now to have air borne, 'over the clouds' video feed as part of the live coverage! The sight of a GSLV breaking through the clouds and charge into space will be a sight to behold!! (Throw in a vapor cone or two, a night launch... )

I will stop fantasicing here

Something like this will be madness.

Awesome Shuttle launch.Big Pic.

nachiket · Post by **nachiket** » 03 Sep 2015 02:30

prasannasimha wrote:Incidentally this odd combo of solid core with 4 liquid strap-ons was done to avoid a booster separation event as that had not been simulated at the time for the GSLV Mk1 and 2(whereas it was done for GSLV Mk3)

I'm trying to understand the difference between how the Mk2 and Mk3 first stages behave respectively, and why it is so.

In Mk2, the S139 and four L40 strap-ons ignite together on the launch pad and burn for 109 and 149 seconds respectively before the whole stage falls off as one unit.

In Mk3, only the 2 S200 boosters provide thrust at launch. There is no counterpart to the S139 first stage (unless you consider the S200s as the counterpart since they are solid fueled boosters unlike the L40s).

The "second" stage (which is the first if you don't count the boosters) is the twin-Vikas L110 which ignites 113 seconds after launch and operates simultaneously with the S200s only for a short time before the S200s run out of fuel and fall off.

As a layman, the Mk2's method seems more efficient, in that the boosters operate along with the first stage for most of their burn time instead of just carrying it weight. Alternatively, the Mk3 seems to lack a real "first" stage - a true counterpart to the S139 which will ignite along with the S200s and fall off with them before the L110 takes over. If such a stage (S139 can be used as is) is added "below" the L110, will it make a significant difference to the payload capability?

I'm pretty sure I'm missing something over here. Pliss to help figure out what.

TIA

Singha · Post by **Singha** » 03 Sep 2015 06:34

seems to me what we need is fatter, shorter stages .... perhaps 6m diameter.....will permit a massive 8m diameter payload stage also. being liquid fueled, motor diameter should not matter for burn time or thrust as its just fuel tanks mostly inside. this might permit getting rid of the strap ons...remove additional failure points and parts.

another direction things went is the Falcon9. it is only 2 stage and features no strap ones.
1st stage has 9 engines, 2nd stage has 1 engine.
5 tons to GTO
but 70m long vs around 45m for our GSLV mk3 vs 58 m for Ariane4

http://www.spacex.com/falcon9

it is also 100tons lighter than our mk3 gslv. its certainly a fresh approach to the problem, our gslv is following the tried and tested ariane type design...given our long history of working with the french and the ESA.

member_28108 · Post by **member_28108** » 03 Sep 2015 06:42

Actually thr Mk 2 is less efficient than "what it could be" as it is lugging the burnt out solid core with the 4 strap on boosters firing. The whole point of staging is to discard "dead weight" At the time of design they were not confident of strap on booster separation dynamics and GSLV Mk 2 was a patchwork with whatever proven existing technologies they had except for the CUS stage which they thought could be bought from another country. Complex geopolitical reality did not allow that so India was forced to develop its own cryogenic stage.This upped the ante to also develop a proper configuration rocket so the GSLV Mk 3 and ULMV were designed as serial replacements/improvements to the GSLV Mk2 once we figured out Cryogenic technology.
The Initial advantage of using a solid rocket booster is the greater thrust and fuel density and actually lowers the mass(which is why even the space shuttle used them) Once they get the semicryoengine working I presume that will fire along with the solid rockets to improve the final configuration.
Wiki explains the use of tripropellants

Tripropellant rockets designs often try to use an optimum mix of propellants for launch vehicles. These use mainly dense fuel while at low altitude and switch across to hydrogen at higher altitude. Studies by Robert Salkeld in the 1960s proposed SSTO using this technique.[4] The Space Shuttle approximated this by using dense solid rocket boosters for the majority of the thrust for the first 120 seconds, the main engines, burning a fuel-rich hydrogen and oxygen mixture operate continuously throughout the launch but only provide the majority of thrust at higher altitudes after SRB burnout.

disha · Post by **disha** » 03 Sep 2015 06:46

Nachiket'ji in a rush., but will explain later why that is so and no Mk2 sequence is not more efficient than Mk3. It is needed that way. And no., mk II is not either less efficient just because it seems to be "lugging" the stage. It is not.

shiv · Post by **shiv** » 03 Sep 2015 07:06

sudhan wrote:I believe those are frozen condensates as prasannasimha says, shaken off by the vibrations generated by the rocket motors' ignition..

I believe the UDMH and the Cryo fuel tanks accumulate the condensates..

Some of those condensates look remarkably like perfect geometric rectangles
http://www.isro.gov.in/sites/default/fi ... SLV-D5.jpg

hnair · Post by **hnair** » 03 Sep 2015 08:00

The GSLV Mk1 and Mk2 were designed when even the very first PSLV was not launched and hence takes a low risk path

1) Why lug the burned out solid tube? Because after burnout, the central solid stage acts as a structural truss for the four strapons in GLSV design. A multi-function design of a booster wall, (very vaguely) similar to the structural strength provided balloon tanks of Karel Bossart's original Atlas ICBM/launcher
2) The ideal design would have been a first stage with a cluster of four Vikas and two/more smallish SRB strapons. But certifying clustering et al were considered too risky and delay prone, what with PSLV launcher itself being at its infancy. Plus developing a new series of SRBs would also introduce new delays. So two risks (clustered liquid engines + new diameter SRBs) were considered too much and they went ahead with a PSLV first-stage + 4 separate liquid boosters.
3) Would have added tremendous delays, in addition to the CUSP issues
4) The first Vikas clustering is done for the MK3 and was certified sometime in 2008 or so. Pretty late for the then struggling Mk2 program

IIRC, disha has explained that once in the past - the four liquids are in essence the first stage, with a single, mature SRB (PSLV first stage). But SRB cant be separated after burnout and hence used as a structural element. Switching of solid and liquids is a jugad to get over the risks.

member_28108 · Post by **member_28108** » 03 Sep 2015 08:01

^ If you see the boosters and liquid stages there does seem to be some "paneling " so what looks white and "metallic " may be foam cladding but if yousee the L40 Booster it is in two stretches between corrugated areas. Not sure of its implications.

member_28108 · Post by **member_28108** » 03 Sep 2015 08:02

^ If you see the boosters and liquid stages there does seem to be some "paneling " so what looks white and "metallic " may be foam cladding but if yousee the L40 Booster it is in two stretches between corrugated areas. Not sure of its implications.

Mort Walker · Post by **Mort Walker** » 03 Sep 2015 08:32

In the video of the CUS separation as it is viewed from GS2 looking up to the cryo stage nozzle, the points of light in the background appear to be stars. Is that correct?

vina · Post by **vina** » 03 Sep 2015 08:55

Singha wrote:
http://www.spacex.com/falcon9

it is also 100tons lighter than our mk3 gslv. its certainly a fresh approach to the problem, our gslv is following the tried and tested ariane type design...given our long history of working with the french and the ESA.

Nah. Falcon 9 is basically 9 WeakAss (Vikas) thrust class Kerosene+Lox engines firing. Now the specific impulse of kerosene + Lox is far higher than solids and the UDMH+N204 Weakass . So what this means that that mass fraction to orbit of Falcon 9 >> GSLV Mk3, even putting a LH2+LOX stage on top doesn't allow the GSLV MK5 to pull it back over the Falcon.

hnair wrote:The ideal design would have been a first stage with a cluster of four Vikas and two/more smallish SRB strapons.

That config of 4 WeakAss engines clustered as core stage with two smallish SRB is the Ariane 4 ! But the GSLV Mk2 is rather inefficient compared to Ariane 4 because of the configuration chose by ISRO. The Viking engine of the Ariane and the Vikas are exactly the same, developed by a joint team!.

disha · Post by **disha** » 03 Sep 2015 10:38

Vina - you are making several false statements.

1. Solid boosters are *never* going to go away.
2. Newer classes of chemical composites AND better material casings are giving solid motor rockets ISPs approaching that of the liquid (UDMH/N2O4)
3. Chinese are *way* behind on solid motor rocket fabrications.

Check out latest chemical compositons.

symontk · Post by **symontk** » 03 Sep 2015 13:24

nachiket wrote:
prasannasimha wrote:Incidentally this odd combo of solid core with 4 liquid strap-ons was done to avoid a booster separation event as that had not been simulated at the time for the GSLV Mk1 and 2(whereas it was done for GSLV Mk3)
I'm trying to understand the difference between how the Mk2 and Mk3 first stages behave respectively, and why it is so.

In Mk2, the S139 and four L40 strap-ons ignite together on the launch pad and burn for 109 and 149 seconds respectively before the whole stage falls off as one unit.

In Mk3, only the 2 S200 boosters provide thrust at launch. There is no counterpart to the S139 first stage (unless you consider the S200s as the counterpart since they are solid fueled boosters unlike the L40s).

The "second" stage (which is the first if you don't count the boosters) is the twin-Vikas L110 which ignites 113 seconds after launch and operates simultaneously with the S200s only for a short time before the S200s run out of fuel and fall off.

As a layman, the Mk2's method seems more efficient, in that the boosters operate along with the first stage for most of their burn time instead of just carrying it weight. Alternatively, the Mk3 seems to lack a real "first" stage - a true counterpart to the S139 which will ignite along with the S200s and fall off with them before the L110 takes over. If such a stage (S139 can be used as is) is added "below" the L110, will it make a significant difference to the payload capability?

I'm pretty sure I'm missing something over here. Pliss to help figure out what.

TIA

There are 2 problems for a rocket lift off and both of them work against each other

1. You need get the rocket off the atmosphere ASAP as both air gives the friction and as you climb you have less gravity
2. Your rocket cannot go into a high acceleration while in atmosphere since it will affect the overall aero design

For the first one, a solid stage is better as it gives the instant impulse to quickly move off the atmosphere. For the second one, you need to limit the first stage impulse so that velocity is in the safer side. So when more solid stages are added to LVMK3 you need to look for overall velocity increase

Creating a rocket design with stages on top of each like PSLV is actually inefficient. Design like LVMK3 is better as the L110 can be independently fired without waiting for strap on burn out. Whereas in PSLV, only after 1st stage separation the L42 can be fired. L110 also helps in adjusting to peak / minimum output from S200's. By doing this it can always push the envelope to achieve optimal velocity for a given top stages and payloads

symontk · Post by **symontk** » 03 Sep 2015 13:26

hnair wrote:The GSLV Mk1 and Mk2 were designed when even the very first PSLV was not launched and hence takes a low risk path

2) The ideal design would have been a first stage with a cluster of four Vikas and two/more smallish SRB strapons. But certifying clustering et al were considered too risky and delay prone, what with PSLV launcher itself being at its infancy. Plus developing a new series of SRBs would also introduce new delays. So two risks (clustered liquid engines + new diameter SRBs) were considered too much and they went ahead with a PSLV first-stage + 4 separate liquid boosters.

Yes this is better, but remember each of the L40 strapons have fins and so the new design has to accommodate that (4 of them)

symontk · Post by **symontk** » 03 Sep 2015 13:29

disha wrote:Vina - you are making several false statements.

1. Solid boosters are *never* going to go away.
2. Newer classes of chemical composites AND better material casings are giving solid motor rockets ISPs approaching that of the liquid (UDMH/N2O4)
3. Chinese are *way* behind on solid motor rocket fabrications.

Check out latest chemical compositons.

True, solids will stay, it gives the instant boost, you will see the difference in the payload weight for a small replacement of LVM3 S200's with S139's. its because by using S139, the L110 have the fire at a lower altitude to maintain the optimal velocity which overall reduces the payload weight

But of course using solids in higher stages may not be a good design option

Singha · Post by **Singha** » 03 Sep 2015 14:27

So is the falcon9 config most efficient and tfta or the ariane4 the proven industry workhorse?