Author Topic: ISRO Unified Launch Vehicle (ULV)  (Read 41337 times)

Offline vineethgk

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Re: ISRO Unified Launch Vehicle (ULV)
« Reply #20 on: 10/06/2014 09:16 AM »
Antriksh, a question just came to my mind on looking at the ULV configurations in OP. Will a configuration without any strapons (i.e only the SC-160 and C-25) have sufficient thrust to deploy a smaller payload to orbit? The reason I ask is because current configurations depicted seem to cover a payload range from PSLV-XL to a bit above GSLV-III, but there is no equivalent for a sub-1000 kg-to-SSO payload that PSLV-CA currently fulfils.

Offline johnxx9

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Re: ISRO Unified Launch Vehicle (ULV)
« Reply #21 on: 10/06/2014 10:53 AM »
Antriksh, a question just came to my mind on looking at the ULV configurations in OP. Will a configuration without any strapons (i.e only the SC-160 and C-25) have sufficient thrust to deploy a smaller payload to orbit? The reason I ask is because current configurations depicted seem to cover a payload range from PSLV-XL to a bit above GSLV-III, but there is no equivalent for a sub-1000 kg-to-SSO payload that PSLV-CA currently fulfils.

If the figures Antariskh is giving for CLC is true(160 tonnes of propellant) than launching without boosters would not be possible. The vehicle mass in this case without any boosters will be close to 200 tonnes. The engine would generate only around 1.7-1.9 tonnes of thrust at sea level. So thrust-to-weight ratio will be lesser than 1.

For any vehicle to go up vertically, thrust to weight ratio has to be greater than 1. I don't think it will the case in this scenario. So boosters would be needed.

Offline vineethgk

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Re: ISRO Unified Launch Vehicle (ULV)
« Reply #22 on: 10/06/2014 12:59 PM »
If the figures Antariskh is giving for CLC is true(160 tonnes of propellant) than launching without boosters would not be possible. The vehicle mass in this case without any boosters will be close to 200 tonnes. The engine would generate only around 1.7-1.9 tonnes of thrust at sea level. So thrust-to-weight ratio will be lesser than 1.

For any vehicle to go up vertically, thrust to weight ratio has to be greater than 1. I don't think it will the case in this scenario. So boosters would be needed.

Hmmm.. Okay. What if they reduced the propellant in the first stage (and maybe shortened the first stage correspondingly). Would it have carried a payload into orbit without any changes in the upper stage? I was just trying to compare it to Angara 1.2 which has a first stage engine of similar thrust, but a more powerful Lox/Kerosene second stage (300kN vs 200 kN, but less Isp). Just a hypothetical question, maybe even non-sensical.  :)
« Last Edit: 10/06/2014 01:00 PM by vineethgk »

Offline johnxx9

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Re: ISRO Unified Launch Vehicle (ULV)
« Reply #23 on: 10/06/2014 06:36 PM »
Hmmm.. Okay. What if they reduced the propellant in the first stage (and maybe shortened the first stage correspondingly). Would it have carried a payload into orbit without any changes in the upper stage? I was just trying to compare it to Angara 1.2 which has a first stage engine of similar thrust, but a more powerful Lox/Kerosene second stage (300kN vs 200 kN, but less Isp). Just a hypothetical question, maybe even non-sensical.  :)

Angara has around 130 tonnes of propellant in the core IIRC. And the Angara 1.2PP flight used the upperstage that will go on Angara A5. I do not think there are any plans to use this same upperstage fro Angara 1.2 in the future. If you see the 1.2PP launch video you can notice that it didn't exactly blast off from the pad. 

Frankly we are still not certain about the ULV. That's why asked Antriksh whether he can confirm the 160 tonne propellant loading of the core. Whether ULV will have a core alone version will depend on this. 

Offline baldusi

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Re: ISRO Unified Launch Vehicle (ULV)
« Reply #24 on: 10/06/2014 07:31 PM »
As an economist, there's not much to do but do a trade. Does having a single core, even if you need to add two cheap solids, is cheaper than having to support two cores? Simple as that. Having extra performance if cheap enough is not bad. Little used designs, even when theoretically cheaper, might not be economically better. In particular, they have quite a payload range to cover with ULV.
On the top side, let's assume a Heavy version. Their launch site is just 13deg N, so if they can get a bit better LEO than Angara-3 (let's say 15tonnes), then their GTO performance should be around 6tonnes, which would cover almost all the top of the market. At the lowest performance, it should be able to do 3.5 tonnes to LEO, or 1.5tonnes to SSO. If they can cover that range with a single core, they are done. Indian labor is cheap.
Please remember that a shortened core would need a custom upper stage and GSE. The fairing attachment, the platforms, everything would change. You'd basically lose most advantages of a universal core. BTW, I still believe that they'll go with a single solid model. Just to put some perspective, Atlas V SRB are about 50tonnes and Delta IV's GEM-60 about 30toones. Thus, developing an S25/30 should give them all the needed flexibility they might require in 2,4,6,8 configuration (plus heavy, if necessary).
« Last Edit: 10/06/2014 07:33 PM by baldusi »

Offline johnxx9

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Re: ISRO Unified Launch Vehicle (ULV)
« Reply #25 on: 10/07/2014 07:40 AM »
As an economist, there's not much to do but do a trade. Does having a single core, even if you need to add two cheap solids, is cheaper than having to support two cores? Simple as that. Having extra performance if cheap enough is not bad. Little used designs, even when theoretically cheaper, might not be economically better. In particular, they have quite a payload range to cover with ULV.
On the top side, let's assume a Heavy version. Their launch site is just 13deg N, so if they can get a bit better LEO than Angara-3 (let's say 15tonnes), then their GTO performance should be around 6tonnes, which would cover almost all the top of the market. At the lowest performance, it should be able to do 3.5 tonnes to LEO, or 1.5tonnes to SSO. If they can cover that range with a single core, they are done. Indian labor is cheap.
Please remember that a shortened core would need a custom upper stage and GSE. The fairing attachment, the platforms, everything would change. You'd basically lose most advantages of a universal core. BTW, I still believe that they'll go with a single solid model. Just to put some perspective, Atlas V SRB are about 50tonnes and Delta IV's GEM-60 about 30toones. Thus, developing an S25/30 should give them all the needed flexibility they might require in 2,4,6,8 configuration (plus heavy, if necessary).

I think the idea of ISRO for having different solid boosters is continuity. All the SRBs that are supposed to go on ULV are already there. S12 for PSLV, S60 also on PSLV, S138 on PSLV,GSLV, and S200 on Mk III. Maybe they want to continue with them although it wouldn't be the most economical approach.

Offline johnxx9

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Re: ISRO Unified Launch Vehicle (ULV)
« Reply #26 on: 10/07/2014 07:47 AM »
Also, another interesting configuration to make up the lower end of spectrum for ULV would be CLC + CUS (upperstage of GSLV). This could put small payloads of around a tonne to SSO.

Offline vineethgk

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Re: ISRO Unified Launch Vehicle (ULV)
« Reply #27 on: 10/07/2014 10:23 AM »
I think the idea of ISRO for having different solid boosters is continuity. All the SRBs that are supposed to go on ULV are already there. S12 for PSLV, S60 also on PSLV, S138 on PSLV,GSLV, and S200 on Mk III. Maybe they want to continue with them although it wouldn't be the most economical approach.
Is there an S60 stage being used currently in PSLV? I was under the impression that it is a new stage that needs to be developed for ULV. Other than the core (S139) and strapons (S12), isn't the 3rd stage (~7 tonnes propellant) the only other solid stage in the rocket?

Also, another interesting configuration to make up the lower end of spectrum for ULV would be CLC + CUS (upperstage of GSLV). This could put small payloads of around a tonne to SSO.
Hmmm... But it would still require the core stage to be downsized a bit, am I right? Also since CUS uses a Staged-Combustion cycle engine, how would its manufacturing effort and cost compare to C-25?

Maybe as @baldusi mentioned, its all down to economics. Creating additional core configurations could create an overhead for development and maintenance, and using the base version can turn out to be more economical for sub-1000kg payloads even in cases where there is no scope of bundling additional satellites (though it would still be a bit over-powered for the job). Maybe the very same reasons convinced ISRO to abandon a 3-stage variant of PSLV that they thought of initially.

Offline johnxx9

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Re: ISRO Unified Launch Vehicle (ULV)
« Reply #28 on: 10/07/2014 12:23 PM »
Is there an S60 stage being used currently in PSLV? I was under the impression that it is a new stage that needs to be developed for ULV. Other than the core (S139) and strapons (S12), isn't the 3rd stage (~7 tonnes propellant) the only other solid stage in the rocket?
/quote]

Sorry! My bad! There's no S60 as of now. The other thing is in the interview with ISRO chairman about ULV he mentions only S9, S138 and S200 as the boosters. There is no mention of S60.

Hmmm... But it would still require the core stage to be downsized a bit, am I right? Also since CUS uses a Staged-Combustion cycle engine, how would its manufacturing effort and cost compare to C-25?

Depends on the core. Even if it has a propellant loading of 150 tonnes ISRO could put a CUS on top and launch small payloads. Not sure how practical it could be. But the idea is to just have a configuration which does what the PSLV does now.

Offline antriksh

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Re: ISRO Unified Launch Vehicle (ULV)
« Reply #29 on: 10/07/2014 01:50 PM »
Antriksh, a question just came to my mind on looking at the ULV configurations in OP. Will a configuration without any strapons (i.e only the SC-160 and C-25) have sufficient thrust to deploy a smaller payload to orbit? The reason I ask is because current configurations depicted seem to cover a payload range from PSLV-XL to a bit above GSLV-III, but there is no equivalent for a sub-1000 kg-to-SSO payload that PSLV-CA currently fulfils.

No, no such configuration is economical in my understanding. Perhaps by reducing loading may work out economical. 
Nasadiya Sukta:
Srishti se pehle sat nahin thaa, asat bhi nahin | Antariksh bhi nahin, aakaash bhi nahin thaa | chhipaa thaa kyaa, kahaan, kisne dhakaa thaa | us pal to agam, atal jal bhi kahaan thaa ||

From: 1st verse of 129th Hymn of the 10th Book of Rig Veda

Offline baldusi

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Re: ISRO Unified Launch Vehicle (ULV)
« Reply #30 on: 10/07/2014 03:14 PM »
Solids are not Legotm. When you have an inline solid, the thrust transfer is different to a booster, that has to have attachments on the side. And then you have what is called a thrust law, solids have variable thrust, for things like reducing MaxQ pressure, limiting burn out acceleration, etc. But to do that you have to actually design the solid grain geometry. This means a new development and pouring tooling, like mandrel. So you can adapt that easily. The S200 that act as boosters of the GSLV mkIII can be used as is, but it might be a tiny bit inefficient.
And adapting stages is a problem. You need new adapters, the stresses of payload weight and vibration are different. But the big cost are the manufacturing line and ground support equipment. You have to keep a whole new set of drawings, engineers, analysis, tooling, factory floor, etc. dedicated. And then you have to have all the support equipment and structures at the launch facilities. All to "save" a bit of marginal cost on a few small launches. It simply doesn't work economically. ULV concept is to reduce this. That they can have a single pad design, with a single access and platform, with a single design of processing facilities, etc. That's how you save money. Look at EELV, SpaceX, ILS Proton, Sea Launch, Ariane 5, Angara, etc. Everybody tries to move to a single launch configuration. At most, simply use some optional solis or multiple cores.

Offline simonbp

Re: ISRO Unified Launch Vehicle (ULV)
« Reply #31 on: 10/07/2014 10:16 PM »
Antriksh, a question just came to my mind on looking at the ULV configurations in OP. Will a configuration without any strapons (i.e only the SC-160 and C-25) have sufficient thrust to deploy a smaller payload to orbit? The reason I ask is because current configurations depicted seem to cover a payload range from PSLV-XL to a bit above GSLV-III, but there is no equivalent for a sub-1000 kg-to-SSO payload that PSLV-CA currently fulfils.

No, no such configuration is economical in my understanding. Perhaps by reducing loading may work out economical. 

Which is basically the same conclusion that Boeing came to regarding the Delta IV Small (Delta IV first stage, Delta II second stage). The big expensive core stage drives the cost of the entire vehicle, so it's not much cheaper than the full-size rocket.

The real solution for smaller payloads is to dual-manifest, especially to GTO.

Offline vineethgk

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Re: ISRO Unified Launch Vehicle (ULV)
« Reply #32 on: 10/11/2014 09:03 AM »
Okay. Trying to leap again before learning to walk, so to say..  ;) But here's yet another hypothetical question I'd love to see answered by more knowledgable folks here..

If (and that's a pretty big 'if') ISRO were to have requirement for an LV with GTO capability of 8-10 tonnes or more, what could be the options for its first stage (from a ULV heritage)?

1. Bundling two additional SC-160 Kerolox stages. ( and would the central core burning at a lower thrust initially and scaling to its max after other two burns out provide some advantage here?)
2. Build a larger (5m?) Kerolox core stage with two SCE-200 in cluster, with large solids providing added thrust. I guess building a core with large diameter would be a critical problem here. Chinese seems to have had a pretty tough time with manufacturing their large CZ-5 core.

Do either of these options look workable, and appears to meet the payload requirements? In case both of them fits the bill more or less, which design would make better sense in the long term? I'm assuming both these configurations would require a more powerful Hydrolox upper stage to do the job, maybe something that uses two CE-20s in cluster or a yet to be developed CE-60.
« Last Edit: 10/11/2014 09:06 AM by vineethgk »

Offline johnxx9

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Re: ISRO Unified Launch Vehicle (ULV)
« Reply #33 on: 10/12/2014 07:59 AM »
Okay. Trying to leap again before learning to walk, so to say..  ;) But here's yet another hypothetical question I'd love to see answered by more knowledgable folks here..

If (and that's a pretty big 'if') ISRO were to have requirement for an LV with GTO capability of 8-10 tonnes or more, what could be the options for its first stage (from a ULV heritage)?

1. Bundling two additional SC-160 Kerolox stages. ( and would the central core burning at a lower thrust initially and scaling to its max after other two burns out provide some advantage here?)
2. Build a larger (5m?) Kerolox core stage with two SCE-200 in cluster, with large solids providing added thrust. I guess building a core with large diameter would be a critical problem here. Chinese seems to have had a pretty tough time with manufacturing their large CZ-5 core.

Do either of these options look workable, and appears to meet the payload requirements? In case both of them fits the bill more or less, which design would make better sense in the long term? I'm assuming both these configurations would require a more powerful Hydrolox upper stage to do the job, maybe something that uses two CE-20s in cluster or a yet to be developed CE-60.

The first solution would be the more plausible one as it's comparatively easier than the second one. Again, it's just comparatively easier but it still some work.

Offline johnxx9

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Re: ISRO Unified Launch Vehicle (ULV)
« Reply #34 on: 11/11/2014 11:29 AM »
[ur=http://economictimes.indiatimes.com/news/politics-and-nation/experimental-flight-of-gslv-mark-3-in-december-isro-chief/articleshow/45110347.cmsl]Experimental flight of GSLV Mark 3 in December: ISRO chief[/url]

Quote
Pointing out that the cryogenic engine used in the launch vehicle, developed  totally indigenously, make India one of the few countries with the technology,  Radhakrishnan said India still lagged behind several other countries in the  capacity of its launch vehicles.

 "China has launch vehicles with 5.5  tonnes capacity, Europe has 11 tonnes capacity launch vehicle, US has 13 tonnes capacity launch vehicles and Russia has nearly 10 tonnes capacity vehicles," he said.

The ISRO chief said the long term target is to make a launch vehicle with 12 tonnes capacity.

Offline antriksh

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Re: ISRO Unified Launch Vehicle (ULV)
« Reply #35 on: 11/11/2014 01:58 PM »
[ur=http://economictimes.indiatimes.com/news/politics-and-nation/experimental-flight-of-gslv-mark-3-in-december-isro-chief/articleshow/45110347.cmsl]Experimental flight of GSLV Mark 3 in December: ISRO chief[/url]

Quote
Pointing out that the cryogenic engine used in the launch vehicle, developed  totally indigenously, make India one of the few countries with the technology,  Radhakrishnan said India still lagged behind several other countries in the  capacity of its launch vehicles.

 "China has launch vehicles with 5.5  tonnes capacity, Europe has 11 tonnes capacity launch vehicle, US has 13 tonnes capacity launch vehicles and Russia has nearly 10 tonnes capacity vehicles," he said.

The ISRO chief said the long term target is to make a launch vehicle with 12 tonnes capacity.

I hope hes talking about TSTO RLV.

Nasadiya Sukta:
Srishti se pehle sat nahin thaa, asat bhi nahin | Antariksh bhi nahin, aakaash bhi nahin thaa | chhipaa thaa kyaa, kahaan, kisne dhakaa thaa | us pal to agam, atal jal bhi kahaan thaa ||

From: 1st verse of 129th Hymn of the 10th Book of Rig Veda

Offline johnxx9

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Re: ISRO Unified Launch Vehicle (ULV)
« Reply #36 on: 11/11/2014 03:39 PM »
[ur=http://economictimes.indiatimes.com/news/politics-and-nation/experimental-flight-of-gslv-mark-3-in-december-isro-chief/articleshow/45110347.cmsl]Experimental flight of GSLV Mark 3 in December: ISRO chief[/url]

Quote
Pointing out that the cryogenic engine used in the launch vehicle, developed  totally indigenously, make India one of the few countries with the technology,  Radhakrishnan said India still lagged behind several other countries in the  capacity of its launch vehicles.

 "China has launch vehicles with 5.5  tonnes capacity, Europe has 11 tonnes capacity launch vehicle, US has 13 tonnes capacity launch vehicles and Russia has nearly 10 tonnes capacity vehicles," he said.

The ISRO chief said the long term target is to make a launch vehicle with 12 tonnes capacity.

I hope hes talking about TSTO RLV.

RLV is ofcourse on the cards. But we should not forget that ISRO wouldn't want to delay in developing a heavy launcher in search of reusability. RLV will the best choice in the long term. Depending on the realistic timeline of RLV, there might be a good possibility that ISRO might develop an expendable version of it. And they would have the technology required using ULV CLCs as the boosters+core.

Offline johnxx9

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Re: ISRO Unified Launch Vehicle (ULV)
« Reply #37 on: 12/03/2014 06:50 PM »
The future PSLV replacement and the smallest rocket in the ULV family.

Offline sanman

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Re: ISRO Unified Launch Vehicle (ULV)
« Reply #38 on: 12/03/2014 08:16 PM »
RLV is ofcourse on the cards. But we should not forget that ISRO wouldn't want to delay in developing a heavy launcher in search of reusability. RLV will the best choice in the long term. Depending on the realistic timeline of RLV, there might be a good possibility that ISRO might develop an expendable version of it. And they would have the technology required using ULV CLCs as the boosters+core.

But how much need is there for such a heavy launcher?

Reusability always makes a good case, because it saves money (when it's done right).
As long as the reusable vehicle is kept relatively simple, and isn't turned into a white elephant like the US Space Shuttle program was, then the cost savings from not having to replace the vehicle for each new flight should add up relatively quickly.

I think the TSTO would be a better choice to develop first, before the ULV family, because it would be heavily used even while the subsequent ULV family was under development.

Even if you argue that ULV would enable ISRO to service international customers at a profit, the demand for such heavy payloads is comparatively less, and meanwhile an RLV would be able to keep itself very busy servicing domestic and international customers. Furthermore, such an RLV could be iteratively refined - as SpaceX is doing - and spun off to a private sector launch operator.

And why couldn't a TSTO be scaled up later on to become a heavier launcher?
When the bottom line is cost, then it seems to me that RLV should logically be prioritized.
ISRO always likes to boast of its cost-saving mentality, so that in itself should make the case for RLV before ULV.






Offline johnxx9

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Re: ISRO Unified Launch Vehicle (ULV)
« Reply #39 on: 12/05/2014 06:49 PM »
The whole family. Excluding the variant with S60 SRBs.
 

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