Author Topic: Ariane 6 Discussion Thread: Place Your Ariane 6 Discussions Here.  (Read 560380 times)

Offline Star One

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^

You realize Ariane ME development was estimated to cost around 1.5-2bn, this Ariane 6 will be between 2.5 and 3.5bn. Given the design that is more than credible.

IMO there is no reason to continue with A5 ME, I would try to introduce A6 earlier.

Or drop A6 and wait, but certainly not both.

Why don't they just keep evolving the A5 & as well as looking to increase performance but also find a way to decrease costs? To me the A6 looks like a step back in a lot of ways over the A5.

Offline mmeijeri

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Why don't they just keep evolving the A5 & as well as looking to increase performance but also find a way to decrease costs?

They are doing that.
We will be vic-toooooo-ri-ous!!!

Offline Remes

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It's a bad day for Europe!

This bullsh.. thing is the beginning of the end of European access to space!
For sure it is not a rocket to impress anyone or anything. But maybe that is a decision which will be a first step to a more economical approach in space. Trying to find the super alloy, the ultimate production technology, the perfect computer equipment, ..., that was always somehow linked to the space sector and all this super technology was in series production and everything was so expensive.

Now ESA seems to be saying:"No, we are not looking for the perfect wonder for endless money. We are looking for a solid concept, for proven (up to simple technologies) and we try to make it more economically efficient".

This comments about improving efficiency, carrying more payload and becoming cheaper: c'mon, Where is that going to happen? Price of technology rises much faster then the price you get for the additional amount of payload.

In regards of the ESC-B: Well, a little bit newer technology might easily reduce the dry weight without too much risk or cost.

I like the idea of 40+ P135 produced per year. A space vehicle in series production.

« Last Edit: 07/09/2013 09:39 PM by Remes »

Online woods170

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The driver was that the stage structure was restricted to certain absolute defined maximum dimensions, as dictated by the available 'working space' on top of the Ariane 5 EPC.
Similar restrictions led to the kludge that is now known as ESC-A. For the time being, those restrictions remain in place, as the plan is to complete development of the Vinci upper stage (and associated structures) in such a way that the stage has as much commonality as possible between Ariane 5 ME and Ariane 6.

Err... C'mon. You know that's not true.
Believe it or not, it IS true, the available space between Fairing and EPC is VERY limited and it is required to make A5ME US fit into this 'working space'.

And you can trust spacejulien on his word. He is intimately involved in the development of A5ME / A6.

Offline pippin

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Believe it or not, it IS true, the available space between Fairing and EPC is VERY limited and it is required to make A5ME US fit into this 'working space'.

And you can trust spacejulien on his word. He is intimately involved in the development of A5ME / A6.

Might be that the space is limited, but the horrible ESC-A design actually wastes a lot of space by using the undersized LOX tank. A more structurally efficient design would have been both shorter AND lighter.
And the same is probably true for ESC-B, too: make it lighter and you can go with a smaller stage (less fuel) so it can be shorter as well....

Offline pippin

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Now ESA seems to be saying:"No, we are not looking for the perfect wonder for endless money. We are looking for a solid concept, for proven (up to simple technologies) and we try to make it more economically efficient".
But that's not what they are doing. They talk about it but in reality they are spending billions to develop a launcher that even by their own predictions as of now will not be cheaper per sat launched than the current Ariane 5!

They plan to SPEND BILLIONS to KEEP the cost level they are at today!!!! And that's only the plan!

Quote
In regards of the ESC-B: Well, a little bit newer technology might easily reduce the dry weight without too much risk or cost.
Bingo. Well, it's probably not just "a bit" but for half the money they plan to spend on A6 you could easily tweak quite a bit out of the overall A5 design over the years and be perfectly fine for the next 15-20 years.

But we had all that in this thread before, didn't we?

Offline Oli

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Quote from: woods170
And you can trust spacejulien on his word. He is intimately involved in the development of A5ME / A6.

So what does our insider spacejulien think of the A6 in its current configuration? ;D

Offline spacejulien

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Believe it or not, it IS true, the available space between Fairing and EPC is VERY limited and it is required to make A5ME US fit into this 'working space'.

And you can trust spacejulien on his word. He is intimately involved in the development of A5ME / A6.

Might be that the space is limited, but the horrible ESC-A design actually wastes a lot of space by using the undersized LOX tank. A more structurally efficient design would have been both shorter AND lighter.
And the same is probably true for ESC-B, too: make it lighter and you can go with a smaller stage (less fuel) so it can be shorter as well....

ESC-A was an interim step towards ESC-B which is today A5ME US, so design choices for ESC-A were made in view of ESC-B with a foreseen loading of 28 t and corresponding thrust of the engine of 180 kN. A stage with a lower-thrust engine would have a corresponding lower optimum loading. With 5.4 m diameter interfaces to EPC and Fairing and less than 7 m stage height (on the outer cylinder) between EPC and Fairing the wide, short tank design with common bulkhead at reduced (4m) diameter was the best compromise. And we have run trade studies for almost a decade on the ESC-B design. The result is an ugly, non-elegant, heavyweight (wrt its dry mass) but the best compromise attainable under the imposed requirements.
« Last Edit: 07/09/2013 10:54 PM by spacejulien »
Posts I contribute here reflect my personal view only; they do not necessarily reflect any official position or opinion of my employer.

Offline Oli

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Quote from: pippin
They plan to SPEND BILLIONS to KEEP the cost level they are at today!!!! And that's only the plan!

You forget that A6 will also serve the institutional market well. You know, galileo, earth observation, space science stuff that nowadays mostly ends up on soyuz or proton. Money for the russians. A5 is an efficient GTO launcher, but basically Europe's present to the comsat industry.

Offline pippin

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I didn't dispute that both stages are optimum designs given their requirements.

But I'd assume ESC-A would not have been designed as it is if it had been known that it would be used for so long.
And A5ME US _could_ be further optimized, if that was needed, right?

Now I agree that on A5 it will probably not be needed so if the A6 upperstage is indeed different then there's no reason to add expensive optimizations.
I was under the impression, the upperstage would be reused from ME, it's been widely reported in the press here but then that's probably just a confusion due to the similar engine.

Offline pippin

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You forget that A6 will also serve the institutional market well. You know, galileo, earth observation, space science stuff that nowadays mostly ends up on soyuz or proton.

No it's not because it's much more expensive than Soyuz.

Offline spacejulien

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Quote from: woods170
And you can trust spacejulien on his word. He is intimately involved in the development of A5ME / A6.

So what does our insider spacejulien think of the A6 in its current configuration? ;D

I have heard all the arguments mentioned in this thread (and before in other threads) also in my professional context over and over again. There are strong arguments for each development, A5ME and A6. There are also good arguments against each of them. No one could make an absolute ranking of all those pros and cons, the result depends on how each one weighs these arguments.
Fortunately for me, my job is not the decision-making on on political level  but to implement what has been decided. So my opinion doesn't really matter, in fact I shall not favor one over the other. But, between A5ME and A6, I am more convinced of the A5ME concept, technically as well as economically.
Posts I contribute here reflect my personal view only; they do not necessarily reflect any official position or opinion of my employer.

Offline Oli

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Quote from: pippin
No it's not because it's much more expensive than Soyuz.

I heard Arianespace offers Soyuz for 70m. It doesn't have to be equally cheap, just not 2-3 times as much as A5.

Fact is a Soyuz replacement is wanted. So you can build a launcher which replaces A5 and Soyuz, or only a Soyuz replacement. The former, IMO, is overall economically more attractive and does not warrant an absurdly high market share like today.

Quote from: spacejulien
But, between A5ME and A6, I am more convinced of the A5ME concept, technically as well as economically.

A6 questions :):

Did they consider composite tanks for the liquid concepts? You know similar to the ones Boeing develops for SLS.

Which design do you think would have to lowest recurrent cost if development costs are not considered (up to a certain limit, say 5bn)? The HHSC maybe? (of all the solid/hydrogen/methane SC or GG concepts).


By the way, I found this very interesting 4xVinci - Vinci Design in a Herakles document. See below. That would have been a funny launcher (this and the quadri-vulcain didn't make the final round).


« Last Edit: 07/10/2013 11:25 PM by Oli »

Offline newpylong

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I am by no means an expert on the Ariane line but this seems like it certainly is a step backwards. Spend a lot of money to develop a launcher with less capability in hopes of it being cheaper? Wouldn't it make more sense to keep developing the A5 with the same goals?

Online woods170

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I am by no means an expert on the Ariane line but this seems like it certainly is a step backwards. Spend a lot of money to develop a launcher with less capability in hopes of it being cheaper? Wouldn't it make more sense to keep developing the A5 with the same goals?

Ariane 1 thru 4 all constituted more-or-less linear increases in mass performance to orbit. With Ariane 4 this increase was initially so large that 'dual' launch was fairly much the default option for the Ariane 4 'heavy' versions. But as time progressed, even the heaviest version of Ariane 4 became increasingly incapable of dual launch. Reason: satellites kept growing in weight.
Initially, Ariane 5 was to be just another enlargement of the Ariane 1-4 lineage. But then enter Hermes in the picture. This proposed mini-shuttle was so heavy that a simple enlargement of Ariane 4 would not do.
Hence one of the drivers to do a completely new design for Ariane 5.
' 5' was very substantially more powerful then ' 4', not in the least because of those massive EAP's. When Hermes went off the stage, the baseline design for Ariane 5 had been set firmly, meaning that this launcher was suddenly way too capable for "single" launch. Thus, dual launch became (again) standard practice for the newest addition to the Ariane lineage. But not so much by design, but by accident (so to speak).

Dual launch however has it's drawbacks. A major one is that there is constant jugling of payloads to match the launcher performance to a certain orbit type. It is this jugling that ESA and CNES want to do away with. Hence it being one of the drivers behind Ariane 6 being a less capable (mass to orbit) launcher than Ariane 5.
But make no mistake: proposed performance of Ariane 6, for a standard GEO transfer orbit, is still 1,600 kg more than that of the most powerful version of Ariane 4.
As such, Ariane 5 can be considered to be "the stranger in our midst":
The growth in mass performance to orbit is more-or-less linear from Ariane 1 to 6, with Ariane 5 being the major exception. But, as explained earlier, there was a reason why Ariane 5 is such an exceptionally large launcher.
« Last Edit: 07/10/2013 02:51 PM by woods170 »

Offline Star One

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Why don't they just keep evolving the A5 & as well as looking to increase performance but also find a way to decrease costs?

They are doing that.

Therefore what's the point of the A6?

Would they A6 even be capable of dealing with some of the less run of the mill payloads like JWST, JUICE or ATV?

Online woods170

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Why don't they just keep evolving the A5 & as well as looking to increase performance but also find a way to decrease costs?

They are doing that.

Therefore what's the point of the A6?

Would they A6 even be capable of dealing with some of the less run of the mill payloads like JWST, JUICE or ATV?

None of those payloads is scheduled to be lifted by Ariane 6. That makes your theoretical exercise superfluous.

Offline Star One

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Why don't they just keep evolving the A5 & as well as looking to increase performance but also find a way to decrease costs?

They are doing that.

Therefore what's the point of the A6?

Would they A6 even be capable of dealing with some of the less run of the mill payloads like JWST, JUICE or ATV?

None of those payloads is scheduled to be lifted by Ariane 6. That makes your theoretical exercise superfluous.

I am aware of that, that is why I said like them, or do you think ESA are not going to develop any one off or out of the ordinary payloads in the future.

Offline pippin

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Well, so far ESA didn't really develop a lot of these payloads, didn't they?
ATV was developed with the size it has simply because that's what the size of a payload on A5 was. It's going away and should ESA ever want something similar in the future, it would simply be sized smaller. Progress, Dragon and Cygnus are all smaller and work just fine.

And other than that, ESA to my knowledge has never ever built a payload that required a full A5 launch. JWST was a barter agreement and NASA's problem (that they could probably have solved by throwing a lot of money at DIVH.

No, the size is not the problem with A6, the problem is the fact that it eats a lot of development s without really bringing any advantage.

Offline edkyle99

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Now that the design is final (see updates thread), discuss.
It's a bad day for Europe!
As an American, I'm admiring this Ariane 6 design.  I see it as a bold engineering step toward simplicity and cost efficiency.  It is a design that is already showing signs of becoming the "new normal" (see "Pegasus 2" for one example). 

I can imagine seeing Ariane 6 rockets stacked and flown in metronome fashion while Mr. Musk struggles to get his complex, leaky, many-engined liquid rockets off of their multiple, costly launch pads and while others battle to get access to the Russian rocket engine monopoly.   

 - Ed Kyle
« Last Edit: 07/10/2013 11:17 PM by edkyle99 »

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