Ariane 6: solid vs. liquid

[R7]

French SLBM's are smaller than P135, smaller diameter and they weigh, all three stages total, nearly 1/3rd as much as a single P135 motor.  I suspect that the propellant formulations would be different, they're obviously not using the same tooling, etc.

Same manufacturer. I have difficulties imagining EADS (and ATK too) having two completely separate R&D and production lines for military and civilian products, after creating SLBM they would nab new people blissfully ignorant of any missile tech to Plato's Cave, project pages of Sutton on the wall and then task them to make civilian SRMs from scratch while people experienced with missile motors are twiddling thumbs next door. Nah.

[Lars_J]

Yikes. Not elegant. Has there ever been a LV of this size with two parallel first stages?

If they still insist on using solids, I'm still shocked that they don't go for the Atlas V approach, with a varying amount of smaller solid boosters surrounding a slimmer cryogenic core derived from Ariane 5. But I guess *someone* at ESA really likes those large solids.

To do the Atlas V approach they would also need to develop an RD-180 and CBC equivalent.

No, they already have the CBC equivalent - the current Ariane 5 core - it can be used as a starting point. Now it would never be able to take off without solids, but at least you could replace the Ariane 5 solids with 4-8 smaller solids to fine-tune the performance. Think of it as a hybrid between Ariane 5 and Atlas V.

[Oli]

Same manufacturer. I have difficulties imagining EADS (and ATK too) having two completely separate R&D and production lines for military and civilian products, after creating SLBM they would nab new people blissfully ignorant of any missile tech to Plato's Cave, project pages of Sutton on the wall and then task them to make civilian SRMs from scratch while people experienced with missile motors are twiddling thumbs next door. Nah.

To my knowledge M51 (french SLBM) is being built by Herakles, which also manufactures the nozzle for Vega/EAP and stage seperation for Vega.

The rest of Vega (P80, zefiro 23, zefiro 9) is being built in a factory from Avio in Italy. I guess the P135 casing and thermal protection will come from there.

So there is some "commonality" between M51 and the civlian programs, through herakles' contributions. But remember there are also french players like snecma who won't like giving up Vulcain 2 production.

If they still insist on using solids, I'm still shocked that they don't go for the Atlas V approach, with a varying amount of smaller solid boosters surrounding a slimmer cryogenic core derived from Ariane 5.

You find the answer in this thread.

The three solid first stage has been shown in a more practical side-by-side arrangement in other drawings.

How do you know its more "practical"? 

[R7]

To my knowledge M51 (french SLBM) is being built by Herakles, which also manufactures the nozzle for Vega/EAP and stage seperation for Vega.

Good info, thanks. EADS pages speak of itself as "prime contractor", apparently Safran Herakles is subcontractor. Still, same pattern.

http://www.herakles.com/strategique/m45/?lang=en
http://www.herakles.com/espace/propulsion/?lang=en
http://www.astrium.eads.net/en/programme/m-51.html

[Patchouli]

No, they already have the CBC equivalent - the current Ariane 5 core - it can be used as a starting point. Now it would never be able to take off without solids, but at least you could replace the Ariane 5 solids with 4-8 smaller solids to fine-tune the performance. Think of it as a hybrid between Ariane 5 and Atlas V.

They might need a higher thrust first stage engine then Vulcain.
Could a RS-68 be substituted and the tanks stretched to make them closer to a Delta CBC?

Though as is the H155 might make a good first stage with no SRBs and the RS-68.

[mmeijeri]

They might need a higher thrust first stage engine then Vulcain.

Or more than one Vulcain.

[Patchouli]

They might need a higher thrust first stage engine then Vulcain.

Or more than one Vulcain.

It is a regen engine so there should be no problems with clustering them.

[edkyle99]

They might need a higher thrust first stage engine then Vulcain.

Or more than one Vulcain.

Exactly, and this was one of the Ariane 6 design alternatives (two Vulcain engine core with monolithic solid strap-on boosters), but it lost out to the PPH options.

 - Ed Kyle

[Lars_J]

They might need a higher thrust first stage engine then Vulcain.

Or more than one Vulcain.

It is a regen engine so there should be no problems with clustering them.

How about an Ariane 9 with 9 Vulcain engines in a tic-tac-toe arrangement. Sounds familiar. 

[R7]

How about an Ariane 9 with 9 Vulcain engines in a tic-tac-toe arrangement. Sounds familiar. 

Rumor has it that setup is no longer fashionable

How about 4 Vulcains and 8 big strap-ons, we could call it Le Super-Énergie Vulcain !

[spacediver]

They might need a higher thrust first stage engine then Vulcain.

Or more than one Vulcain.

Exactly, and this was one of the Ariane 6 design alternatives (two Vulcain engine core with monolithic solid strap-on boosters), but it lost out to the PPH options.

 - Ed Kyle

Exactly this was the problem.
They investigated only concepts with strap-on-boosters. But strap-on-boosters are expensive! Really expensive! You can kill every concept by adding boosters.
Adding a third Vulcain to the core and throw out the boosters entirely, as we did last year in the NELS study, would probably have resulted in another Ariane 6 baseline concept.
But concepts without boosters were never taken into account by CNES.

Spacediver

[spacediver]

They might need a higher thrust first stage engine then Vulcain.

Or more than one Vulcain.

It is a regen engine so there should be no problems with clustering them.

How about an Ariane 9 with 9 Vulcain engines in a tic-tac-toe arrangement. Sounds familiar. 

Maybe good for a manned lunar mission...
Total overkill for the required Ariane-6 performance.
Probably more than 50 tons to LEO!
And a core diameter of at least 9m!
Would be a nice little beast but without a market...

Spacediver

[woods170]

They might need a higher thrust first stage engine then Vulcain.

Or more than one Vulcain.

Exactly, and this was one of the Ariane 6 design alternatives (two Vulcain engine core with monolithic solid strap-on boosters), but it lost out to the PPH options.

 - Ed Kyle

Exactly this was the problem.
They investigated only concepts with strap-on-boosters. But strap-on-boosters are expensive! Really expensive! You can kill every concept by adding boosters.
Adding a third Vulcain to the core and throw out the boosters entirely, as we did last year in the NELS study, would probably have resulted in another Ariane 6 baseline concept.
But concepts without boosters were never taken into account by CNES.

Spacediver

Looking into the history of Ariane it appears to me that strap-on boosters were a very important reason (along with the three versions of the H10 third stage) why Ariane-4 was such a versatile and succesfull launch vehicle. It could launch payloads thru a very wide mass-range, thanks - in part - to the strap-on boosters. And them being expensive did not seem to scare the customers away.

[baldusi]

Looking into the history of Ariane it appears to me that strap-on boosters were a very important reason (along with the three versions of the H10 third stage) why Ariane-4 was such a versatile and succesfull launch vehicle. It could launch payloads thru a very wide mass-range, thanks - in part - to the strap-on boosters. And them being expensive did not seem to scare the customers away.

You have to put it in the historical context. What was the competition? What were the trading limitations? What was the competition reliability, availability and price?
But in any case, the big issue is not even the now, but the next decade. Boosters allow for very fine performance steps. Yet, the PPH concept seems to have very coarse performance steps. Specially if they are trying to evolve the Vega to a P135+H, basically merging the rocket families.
The boosters decision is this:
No boosters: Overall cheaper at same performance, but coarser performance points.
Boosters: Overall cheaper at same performance, but finer performance points.
What this means is that if you have just two configurations, let's say P135+P135+H 3tonnes to GTO or 3 x P135+P135+H 7tonnes to GTO (it's an example, not actual numbers). And let's assume that the heavy costs twice as the single. Thus, you might have a lower price at 2 to 3tonnes and 5.5tonnes to 7 tonnes. But a 4tonnes satellite would have to pay twice the cost of a 3tonnes. But if you had a boosted architecture, you might be 15% more expensive in the 2 to 3 and 5.5 to 7, but between 3.1 and 4.5 you'd be significantly cheaper.
That's the real tradeoff of the boosted architecture. As it's now, GTO satellites are made in three groups, less than 3.5, 3.5 to 5 and 5+, with each group having, basically, a 1/3 of the market (in payloads, obviously in revenues is not the same). Since you'd be be pricing yourself out of the middle segment of the market, you'd also be resigning about 30% of your potential revenue. For a company that currently has 50% of the market, that's a lot.
But, you might also argue that in the next decade some new contestants will enter the market and that 50% will be impossible to keep. And if you make use of a boosted architecture you'll end up with a competitive price just on the central 1/3 of the market (because some competitors will not use boosted architectures). Thus, you'll lose even more market share.
That's the sort of economic analysis that is made about this issues (albeit at a much more sophisticated level).

[woods170]

Looking into the history of Ariane it appears to me that strap-on boosters were a very important reason (along with the three versions of the H10 third stage) why Ariane-4 was such a versatile and succesfull launch vehicle. It could launch payloads thru a very wide mass-range, thanks - in part - to the strap-on boosters. And them being expensive did not seem to scare the customers away.

You have to put it in the historical context. What was the competition? What were the trading limitations? What was the competition reliability, availability and price?
But in any case, the big issue is not even the now, but the next decade. Boosters allow for very fine performance steps. Yet, the PPH concept seems to have very coarse performance steps. Specially if they are trying to evolve the Vega to a P135+H, basically merging the rocket families.
The boosters decision is this:
No boosters: Overall cheaper at same performance, but coarser performance points.
Boosters: Overall cheaper at same performance, but finer performance points.
What this means is that if you have just two configurations, let's say P135+P135+H 3tonnes to GTO or 3 x P135+P135+H 7tonnes to GTO (it's an example, not actual numbers). And let's assume that the heavy costs twice as the single. Thus, you might have a lower price at 2 to 3tonnes and 5.5tonnes to 7 tonnes. But a 4tonnes satellite would have to pay twice the cost of a 3tonnes. But if you had a boosted architecture, you might be 15% more expensive in the 2 to 3 and 5.5 to 7, but between 3.1 and 4.5 you'd be significantly cheaper.
That's the real tradeoff of the boosted architecture. As it's now, GTO satellites are made in three groups, less than 3.5, 3.5 to 5 and 5+, with each group having, basically, a 1/3 of the market (in payloads, obviously in revenues is not the same). Since you'd be be pricing yourself out of the middle segment of the market, you'd also be resigning about 30% of your potential revenue. For a company that currently has 50% of the market, that's a lot.
But, you might also argue that in the next decade some new contestants will enter the market and that 50% will be impossible to keep. And if you make use of a boosted architecture you'll end up with a competitive price just on the central 1/3 of the market (because some competitors will not use boosted architectures). Thus, you'll lose even more market share.
That's the sort of economic analysis that is made about this issues (albeit at a much more sophisticated level).

Note that your entire argument rests on assumptions with regards to the final configurations and performances of the Ariane 6 vehicle.

As long as this vehicle is still being developed, and hard (as in: set in concrete) config and performance figures don't appear, the entire discussion about Arianespace losing or gaining market-share is moot.
Also, this vehicle does not start flying until 2022. Who knows how GTO satellites are categorized by then. They just might have switched to ion drives by then mostly, drastically reducing their weight. Heck, with that possibility in mind I would even see Ariane 6 performing dual launches.. 
But, let's not get into that discussion...

[Notaris]

By the way when we talk about solids, maybe it would make sense to make them reusable. After all they're stable enough such that you only have to attach a parachute to it and let them drop in the ocean.

Always had the idea, that reusable solids are same expensive as new solids...

Sorry for digging out old comments of this thread. If I remember right the following two points are true:

a) The dimensioning load case for the shuttle boosters were reentry, thus reusability had a performance impact beyond the mass penalty of the recovery system

b) Main reason for choosing reusable shuttle boosters was that the forecasted production capacity could not keep up with the forecasted STS flight rate (which obviously was never reached by far!)

[spacediver]

Looking into the history of Ariane it appears to me that strap-on boosters were a very important reason (along with the three versions of the H10 third stage) why Ariane-4 was such a versatile and succesfull launch vehicle. It could launch payloads thru a very wide mass-range, thanks - in part - to the strap-on boosters. And them being expensive did not seem to scare the customers away.

When the Ariane-program started in the early 70's, satellites were in the class of 1-1,5 tons to GTO, and a commercial satellite market not even existed. When the marked evolved, the US had the launcher gap after Challenger and satellite masses increased, it was a logical step to add booster to the existing launcher to increase payload mass without the need of a total new launch vehicle design.

Now the situation is completely different. We have competition on the commercial market and cost are the most important issue.

To add boosters to a "clean sheet" launcher concept can only be justified by allowing adaptation to different payload mass requirements.
This is where payload manifests and forecasts come into play.

For the NELS study we had two GTO payload requirements: 3,5t and 6,5t.
We investigated different payload forecasts from different organizations (ESA, CNES, DLR etc..) and came to the conclusion that we have about 80% of all launches for the large payload segment (3,5t - 6,5t) and only 20% for payloads below 3,5t.
In this case it is logical to optimize the launcher for the heavy payload class and accept some cost penalty for the small payload missions. We therefore proposed a HH-concept with three sea level optimized Vulcain engines in the first stage for the 6,5t missions. Upper stage with one Vinci.
For the small payloads we would have used exactly the same launcher but installed only two engines to the first stage. For launch, the first stage would only be filled up to 65% of its fuel capacity. This would save only the cost of one Vulcain but for one or two launches a year it would not justify another production line for a smaller first stage.
If we would optimize the launcher for the small payloads and add boosters for the large ones, we would have a tremendous cost penalty for each of the 80% of large payload launches.   

If the payload manifest would be the other way around (20% large and 80% small) then the booster version would probably be the more attractive one.

Now comes the problem with CNES: they are an institutional customer for Ariane, and institutional payloads are normally the smaller ones! So CNES is interrested in an optimized launcher for their own payloads and does not care about the competitiveness of the new launcher in the commercial GTO market.

That is why CNES never took launcher concepts into account that are not using strap-on-boosters, except for the Multi-P.

Spacediver

[Oli]

@spacediver

You once said 70m/launch is not realistic. You have any idea why the keep emphasizing that price point so much?

[Notaris]

@spacediver

You once said 70m/launch is not realistic. You have any idea why the keep emphasizing that price point so much?

Because, depending on market price for launches (i.e. income for performing commercial launches), Ariane 6 would risk to require more governmental support than Ariane 5 - killing the underlying argument for Ariane 6!

[pippin]

Looking into the history of Ariane it appears to me that strap-on boosters were a very important reason (along with the three versions of the H10 third stage) why Ariane-4 was such a versatile and succesfull launch vehicle. It could launch payloads thru a very wide mass-range, thanks - in part - to the strap-on boosters. And them being expensive did not seem to scare the customers away.

But did that really make a lot of sense? You carry all the cost for the different variants in your program while, at least later in the program, the were mostly flying the L variants. I would not be surprised if the overall program costs could have been reduced by doing away with, for example, the solid boosters (after all the liquid ones also shared the engines with the main stage).
And ballast steel isn't really that expensive so there is rarely ever a reason to _exactly_ match a payload mass with a capability.

Ariane always had a lot of aspects to the program that were in the "for the fun of it", "to develop some capability" or "to keep some partner happy" department.
And you know what I think about the whole Ariane 6 program in that respect....