Ariane 6: solid vs. liquid

[spacediver]

It is now a few weeks that ESA pointed the way to the future of European space transportation during their ministerial conference in Italy. Besides the development of the new Ariane 5 ME upper stage a clear decision towards an Ariane 6 development was made.

In the aftermath of the conference voices of ESA officials could be heard that a decision towards an all solid Ariane 6 (except for the cryogenic upper stage) is already made. If this is true I see a dark future coming for European space transportation.

During the last months I was working on an ESA study for new launch service concepts, including detailed cost estimates for different launcher solutions. For me the most interesting result is that an all cryogenic launcher, using 3 Vulcain 3 engines (optimized for sea level operation) in the first and one Vinci in the second stage and no additional boosters leads to similar cost as all the solid launcher versions that we investigated. The reference mission for all concepts was defined with 6500 kg to a GTO trajectory.

The cost argument is the one mostly heard when the solid vs. liquid discussion is going on, because, as we all know, a solid stage is less costly than a liquid stage. But the truth is that solid launch vehicles always need at least one stage more to reach GTO than the liquid launchers and therefore, on the systems level, lead to about the same systems cost. 

In case of the next European launcher we have to take into account higher development cost for a solid compared to an all cryogenic launcher, much higher development risks for the large (in some concepts segmented) CFRP solid motor casings, the higher dynamic loads for the upper stage and payload and, for me the most important argument, the loss of the large liquid engine technology in Europe!

Once the solid Ariane 6 is in service and the Ariane 5 decommissioned, the ability to build large cryogenic engines in the 100t thrust class will be vanished within a few years. What ever launcher comes after Ariane 6 cannot build on this crucial technology anymore! It is unlikely that anyone in Europe is willing to spend >5 billion Euros to redevelop such an engine again.

To me the case is clear: A solid Ariane 6 is a dead end! The next European launcher should be an all cryogenic, two stage concept without strap-on-boosters.

What do you think?

Spacediver

[IRobot]

Are you sure the Ariane 5 will be decommissioned?? I was under the impression that they complement each other, being Ariane 6 the cheap option with less flexibility.

[Nicolas PILLET]

Are you sure the Ariane 5 will be decommissioned?? I was under the impression that they complement each other, being Ariane 6 the cheap option with less flexibility.

Yes, AR6 is the replacement for AR5.

[woods170]

Are you sure the Ariane 5 will be decommissioned?? I was under the impression that they complement each other, being Ariane 6 the cheap option with less flexibility.

Yes, AR6 is the replacement for AR5.

Much like what happened to Ariane 4 and Ariane 5 it is a fact that AR5 and AR6 will co-exist for a number of years before AR5 is decommissioned.
However, calling AR6 the replacement of AR5 is somewhat besides the thruth. AR6 is the "thing next in line" but with substantially less lift capacity.
AR6 is therefore to be considered as the system to fit a re-defined ESA launcher strategy. Put shortly: AR5 is overpowered and even in dual-launch capacity is not economical. The answer, according to the French, is a smaller, more flexible launcher; AR6.
And for some funny reason the French are now pushing for a solid solution. However, it is NOT a done deal that AR6 will be all solid. The upper stage is very likely going to be cryogenic stage to be developed for Ariane-5 ME.

[rklaehn]

Ariane 6 going all solid means that europe is no longer even trying to compete for the GTO market.

They just want a launcher that is not prohibitively expensive at a low flight rate for institutional and military payloads, and that allows the french to subsidize the solid rocket motor industrial base that they need for ICBMs.

Really a shame given the leading position arianespace has right now for GTO payloads.

[spectre9]

People want to know why solids are hated.

This is why.

Goverments insist on them even though they're crap technology compared to kerolox.

The Russians and SpaceX are the only rocket scientists with brains still operating.

Sorry for the tone of this post but if ESA wants to build a solid Ariane 6 I believe that's absolute stupidity.

People don't build steam trains. Why? There's better.

It's the same with solid rocket fuel.

[woods170]

Ariane 6 going all solid means that europe is no longer even trying to compete for the GTO market.

They just want a launcher that is not prohibitively expensive at a low flight rate for institutional and military payloads, and that allows the french to subsidize the solid rocket motor industrial base that they need for ICBMs.

Really a shame given the leading position arianespace has right now for GTO payloads.

You should remember that Ariane began life as a launcher to assure European independent access to space.
In this case "independent access" was meant for institutional and military payloads.
The fact that Ariane now is the leading launcher in the commercial market is actually a side-effect. Ariane has always been expensive, actually too expensive to justify it's existence for the relatively low number of institutional and military payloads that fly on it.
Therefore, the launcher was offered to launch commercial payloads. That secondary role soon overtook the primary role in absolute number of launches.
But, the consideration for Ariane-6 is no different from that of Ariane-1; to assure European independent access (both institutional and military) to space. The role of that launcher in the commercial market will again be secondary.
The leading role of Arianespace for GTO is nice but not exactly generating a lot of profit. The current models of Ariane-5 are so expensive that ESA needs to pour in millions of Euro's each year, just for Arianespace to break even. Despite Astrium promising otherwise I personally don't think that will change with the arrival of Ariane-5 ME.

[Rugoz]

During the last months I was working on an ESA study for new launch service concepts, including detailed cost estimates for different launcher solutions. For me the most interesting result is that an all cryogenic launcher, using 3 Vulcain 3 engines (optimized for sea level operation) in the first and one Vinci in the second stage and no additional boosters leads to similar cost as all the solid launcher versions that we investigated. The reference mission for all concepts was defined with 6500 kg to a GTO trajectory.

The cost argument is the one mostly heard when the solid vs. liquid discussion is going on, because, as we all know, a solid stage is less costly than a liquid stage. But the truth is that solid launch vehicles always need at least one stage more to reach GTO than the liquid launchers and therefore, on the systems level, lead to about the same systems cost.

In case of the next European launcher we have to take into account higher development cost for a solid compared to an all cryogenic launcher, much higher development risks for the large (in some concepts segmented) CFRP solid motor casings, the higher dynamic loads for the upper stage and payload and, for me the most important argument, the loss of the large liquid engine technology in Europe!

You seem to have more information available than we have. At what launch rate are the solid and liquid designs equal in terms of costs?

Regarding the loss of liquid engine technology. I don't understand this argument. Just because you stop manufacturing vulcain engines doesn't mean all the knowhow will suddenly vanish.

Also if Ariane 6 should be competitive its not helpful to subsidize certain industries just because some people happen to like them.

People want to know why solids are hated.

This is why.

Goverments insist on them even though they're crap technology compared to kerolox.

The Russians and SpaceX are the only rocket scientists with brains still operating.

Sorry for the tone of this post but if ESA wants to build a solid Ariane 6 I believe that's absolute stupidity.

People don't build steam trains. Why? There's better.

It's the same with solid rocket fuel.

Very convincing arguments 

[asmi]

Regarding the loss of liquid engine technology. I don't understand this argument. Just because you stop manufacturing vulcain engines doesn't mean all the knowhow will suddenly vanish.

Really? Have you ever wondered why US is desperately trying to catch up in kerolox engines technology with the Russians, and russian engines are still superior in just about every aspect that matters - more reliable, cheaper, simpler, higher performance. They also once thought that "oh this is impossible to do", and "we'll get back on it later", until they've suddenly discovered that it's actually IS possible, and they are still inferior in that technology. The problem is that technologies in space industry are not static, they evolve rather quickly, and what is considered "good" now will become obsolete much quicker than you think.

As for this ESA's decision - I think it's nonsence from technological point of vew, but this decision has nothing to do with technology, and everything to do with politics.

[woods170]

Regarding the loss of liquid engine technology. I don't understand this argument. Just because you stop manufacturing vulcain engines doesn't mean all the knowhow will suddenly vanish.

Really? Have you ever wondered why US is desperately trying to catch up in kerolox engines technology with the Russians, and russian engines are still superior in just about every aspect that matters - more reliable, cheaper, simpler, higher performance. They also once thought that "oh this is impossible to do", and "we'll get back on it later", until they've suddenly discovered that it's actually IS possible, and they are still inferior in that technology. The problem is that technologies in space industry are not static, they evolve rather quickly, and what is considered "good" now will become obsolete much quicker than you think.

As for this ESA's decision - I think it's nonsence from technological point of vew, but this decision has nothing to do with technology, and everything to do with politics.

Yes. And you should also remember that politics is exactly the reason why the Ariane series of launchers exists in the first place.

[asmi]

Yes. And you should also remember that politics is exactly the reason why the Ariane series of launchers exists in the first place.

True. But as spaceflight enthusiast I don't give a damn about politics. That's why I agree with the post above that this decision is, politely speaking, "not wise".

[baldusi]

I see this in another way. Since ATV is going to be cancelled, and no crew capsule is expected, Ariane 5 payload capacity is not needed. But they are spending a lot of money en Soyuz launches. Which not only means additional budget on top of the Ariane 5 subsidy, but also goes outside of EU members.
Thus, a more expensive LV that actually replaces the Soyuz and allows to launch the heaviest satellites (6.5tonnes to GTO) they might actually spend less money. And surely less foreign currency.
I still think that the critical issue is which generates the lowest cost, since that would reduce the amount of subsidies and maximize the high tech jobs. But on the other hand, French ICBM are the only truly European nuclear technology, since UK uses American rockets and are not that into the EU.
If I had to think like a politician, I would think that this is a way to keep an European ICBM industrial base, for the strange case that an European Defense Forces are formed in the future. If they have German, Italian and Spanish companies subcontracting, then the prospective transition to a full European Nuclear Triad would be easier.
Of course this is sort of far in the future, but good leaders look into the next century. Please remember that the European Coal and Steel Community was made exactly to make the weapon production a crossed ownership system. This might be the first step to make the ICBM production a pan European system.
Regrettably, the rest of nuclear policy of Germany, Italy and Spain makes it impossible to make a pan European nuclear head system.

[spectre9]

Very convincing arguments 

It's not an argument any more.

It's a fact that gets ignored.

Kerolox > solids

The difference is both performance and price now. Casting and transporting solids cost big dollars and the lost payload over time of making your rocket heavier don't make sense.

There's building solid rockets because they're the right option and there's building solid rockets because of refusal to develop better liquid alternatives which Russia/Soviets have had for over 50 years.

[tobi453]

To me the case is clear: A solid Ariane 6 is a dead end! The next European launcher should be an all cryogenic, two stage concept without strap-on-boosters.

What do you think?

Spacediver

Spacediver, I'm from germany and you are absolutely right. I dont know what CNES is thinking, but this is the end of european space transportation.

I am astonished that no public figure of the european spaceflight community has named this concept what it is - rubbish.

This spacenews article makes it pretty clear that the solid concept has been selected:
http://www.spacenews.com/article/cnes-sets-%E2%80%9Ctriple-seven%E2%80%9D-goal-for-ariane-6-rocket

The design of the rocket — two solid-fueled lower stages and a cryogenic upper stage, plus solid-fueled strap-on boosters — was frozen Nov. 21 during a meeting of ESA government ministers.ESA Launcher Director Antonio Fabrizi said this design, and no other, is what ministers approved.

[edkyle99]

In the aftermath of the conference voices of ESA officials could be heard that a decision towards an all solid Ariane 6 (except for the cryogenic upper stage) is already made.

"Liberty" (of a sort) lives. 

 - Ed Kyle

[IRobot]

Regrettably, the rest of nuclear policy of Germany, Italy and Spain makes it impossible to make a pan European nuclear head system.

As Anne Coulter's nuke threat to France is nonsense, the only credible nuclear threat to Europe (that would require a nuclear response) is China.
Russia is making too much money to go to war. And their billionaires love the Med!

France alone has more nukes than China. England has almost as much as France. Germany has 10 US nukes. So Europeans don't see any need to increase nuclear arsenal. And there hasn't  been bloodlust around here in the past 60 years...

[Rugoz]

Really? Have you ever wondered why US is desperately trying to catch up in kerolox engines technology with the Russians, and russian engines are still superior in just about every aspect that matters - more reliable, cheaper, simpler, higher performance.

It's a fact that gets ignored.

Kerolox > solids

The difference is both performance and price now. Casting and transporting solids cost big dollars and the lost payload over time of making your rocket heavier don't make sense.

That is all nice but as far as I can remember kerolox was never seriously considered for ariane 6. In the end it was multiple vulcains vs solids.

This spacenews article makes it pretty clear that the solid concept has been selected:
http://www.spacenews.com/article/cnes-sets-%E2%80%9Ctriple-seven%E2%80%9D-goal-for-ariane-6-rocket

70m euros per launch, 4-5bn development costs. Sound like a bad deal. For that amount of money I would expect something fancy.

[spectre9]

It's a fact that gets ignored.

Kerolox > solids

The difference is both performance and price now. Casting and transporting solids cost big dollars and the lost payload over time of making your rocket heavier don't make sense.

That is all nice but as far as I can remember kerolox was never seriously considered for ariane 6. In the end it was multiple vulcains vs solids.

I thought there was an option to purchase Russian engines?

Just buy RD-180 and build an Atlas V copy.

I think they want to. If they can't make a Falcon 9 or a Soyuz themselves it's a good option.

[asmi]

That is all nice but as far as I can remember kerolox was never seriously considered for ariane 6. In the end it was multiple vulcains vs solids.

I've brought this up as example of what will happen if you "keep technology" without improving it. US is literally paying quite a price for that oversight, and Europe doesn't want to learn from other's mistakes by making their own. But honestly I don't think they've chosen solids because they didn't realize how stupid this decision is - I'm pretty sure that at least their engineers realize full well what's gonna happen - but it's not the engineers who get to make a call on that - it's politicians, and they don't give a damn about anything that doesn't provide them immediate and tangible benefits. The same btw is happening in US Congress now:
Congress: We want NASA to go to the asteroid and build SLS for that.
NASA: But we can't unless we bring asteroid close enough
Congress: Fine, then we want NASA to go to Mars and build SLS for that.
NASA: But we can't do that either since we've got no money for mission module, and astronauts can't live for half a year in a tin can.
Congress: Fine, we don't really care where will you go, but you must build SLS for that.

[sdsds]

For the proposed "PPH" scheme would the stages be stacked at the pad? In an existing integration facility? In a new one? Or is there as yet no proposal regarding that?