Towards return of Europe to dominance of the launch market, Page 2: ESA needs an independent oversight agency.

 Copyright 2023 Robert Clark

 Recent news reports are the Ariane 6 will not be able to compete with the SpaceX Falcon 9, requiring an increase in subsidies to ArianeSpace resulting in a total of €350 million($380 million) per year:

Oops—It looks like the Ariane 6 rocket may not offer Europe any launch savings
Europe is subsidizing the launch of Internet satellites for Jeff Bezos.
ERIC BERGER - 10/12/2023, 11:26 AM
https://arstechnica.com/space/2023/10/oops-it-looks-like-the-ariane-6-rocket-may-not-offer-europe-any-launch-savings/

 At a launch cadence of 6 launches per year this is a subsidy of nearly €60 million per launch. This means European tax payers will be paying over a billion euros for the contracted 18 launches on the Ariane 6 of the commercial venture the Kuiper satellite system of Jeff Bezos. In effect, European tax payers will be paying a billion euro subsidy to Jeff Bezos, the 2nd richest man in the world.

European Space Agency mulls extra Ariane 6 cash.

BY CALEB LARSON

OCTOBER 20, 2023 7:00 AM CET

Strategic autonomy? Ariane 6 is in danger of turning into a fiasco for the ESA and France’s aerospace industry. Since being commissioned a decade ago, Ariane 6 has been surpassed by Elon Musk's SpaceX which has slashed the cost of launches with its partially reusable rocket technology. Because its predecessor Ariane 5, a super reliable commercial launcher, has already been retired, the European Commission is even having to look to SpaceX to get its satellites into orbit. That's exactly the kind of outsourcing Paris wants to avoid in its focus on building strategic autonomy.

https://www.politico.eu/article/european-space-agency-mulls-extra-ariane-6-rocket-cash-ask/

 The fiasco has come to pass as Europe was forced to ask SpaceX to launch its vaunted Galileo GPS system on the Falcon 9, when it was intended to be launched on the Ariane 6:

Europe Reluctantly Chooses SpaceX to Launch Its GPS Satellites.
Elon Musk's SpaceX is set to undertake its first launch of European satellites equipped with classified technology, specifically for the Galileo system.
https://www.politico.eu/article/european-space-agency-mulls-extra-ariane-6-rocket-cash-ask/

 Reports are the Vega-C is in a similar bad position with respect to the SpaceX Falcon 9 using rideshare for small payloads:

The Accidental Monopoly
How SpaceX became (just about) the only game in town
Jeff Foust
October 13, 2023
SpaceX came with these Transporter missions, which have been really disrupting,” said Marino Fragnito, senior vice president of the Vega business unit at Arianespace. They have been a boon for smallsat developers, he acknowledged, offering low-cost access to space. “But at the same time, they have created a big problem in terms of the business case for all of the other players.”
He accused SpaceX of, in effect, predatory pricing, willing to lose money on Transporter missions to drive out competition. He noted that past Vega smallsat rideshare missions sold payloads at $25,000 per kilogram, whereas SpaceX has sold Transporter launches for one-fifth that price. “It’s crazy.”
https://spacenews.com/the-accidental-monopoly/

 This has been warned about for several years now:

Europe is starting to freak out about the launch dominance of SpaceX
The Falcon 9 has come to dominate commercial satellite launches.
ERIC BERGER - 3/22/2021, 11:24 AM
However, there now appears to be increasing concern in Europe that the Ariane 6 and Vega-C rockets will not be competitive in the launch market of the near future. This is important, because while member states of the European Space Agency pay for development of the rockets, after reaching operational status, these launch programs are expected to become self-sufficient by attracting commercial satellite launches to help pay the bills.
Economic ministers in France and Italy have now concluded that the launch market has changed dramatically since 2014, when the Ariane 6 and Vega-C rockets were first designed. According to a report in Le Figaro newspaper, the ministers believe the ability of these new European rockets to compete for commercial launch contracts has significantly deteriorated since then.
https://arstechnica.com/science/2021/03/european-leaders-say-an-immediate-response-needed-to-the-rise-of-spacex/

 European tax payers have the right to ask where the great expense of the Ariane 6 launcher is deriving from.

 No one in European space community is willing to ask or answer the question, “How much just to add a second Vulcain to the Ariane 5/6 core?”

 Then can someone, anyone in the European space community at least ask the question, “Does a single P120 solid rocket used for the Ariane 6 SRB’s and the Vega-C first stage really cost €20 million?”
 “So that the two SRB’s on the Ariane 62 cost €40 million, and the four on the Ariane 64 cost €80 million?”

“So that out of the €115 recommended cost of the Ariane 64, €80 is just for the 4 solid side boosters?”

 It is important to recognize that the high price of the Ariane 6 and the Vega-C is coming solely from the large solid rockets they use.

 

 It is common to think of solid side boosters as only adding a small amount to the price of a launcher, like with the small solids used on the Delta IV or Atlas V. But it is quite important to realize these are for small side boosters that might be only ca. 1/10th the mass of the core. But for the Ariane 6 the large side boosters are the size of the core in mass, and for the Vega the large solid booster is the core.

 Then the concept of the low cost solid booster is no longer valid; indeed these solid rockets boosters are the cause of the high cost of these launchers. To give an illustrative example, imagine the size of the side boosters on the Delta IV and Atlas V were 10 times larger than they are. I think you can see that would mean their cost would be radically higher than they are now.

 So how bad is the pricing of the P120 solids used for the Ariane 6 solids and the Vega-C first stage? Three separate and independent arguments suggest the P120 solid booster costs ca. €20 million each.

 ArianeSpace suggested a price of €75 million for the Ariane 62 with two SRB's and €115 million for the Ariane 64 with four SRB's. The €40 million increase in price for the two additional SRB's on the Ariane 64 suggests that is the price for two, or €20 million each.

 A second argument for the high cost of the P120 solid rocket comes from comparing it to the cost of the GEM 63 SRB used on American launchers. The GEM 63 is estimated to cost in the range of $5 million to $7 million each. But the P120 is three times the size of the GEM 63. So based on that we expect the price to be in the range $15 million to $21 million each.

 A third argument comes from looking at the price of the Vega-C. It's in the range of €35 million. Elon Musk has estimated the first stage of the Falcon 9 is 60% of the price of the rocket, with the upper stage, fairing, and range costs making up the rest of the cost. 

 The Vega-C is a 4-stager instead of the 2-stage Falcon 9, but the salient point still remains: the much larger size of the first stage than the other stages means it makes up the largest proportion of the cost. 

 Using the 60% Elon Musk estimate for the cost of the first stage would give a €21 million cost for the P120 first stage of the Vega-C.

 So there is abundant evidence the large side boosters used on the ArianeSpace rockets are quite expensive. But is there an alternative? Yes! The price of a single Vulcain is only €10 million. So eliminate the Ariane 6 SRB's entirely and use two to three Vulcains on the core instead. Not using the SRB's results in a greatly reduced price.

 For a two Vulcain Ariane 6 sans SRB's, use a smaller upper stage of ca. 10 ton size so it would be loftable by the two Vulcains. Then it could get ca. 12 tons to LEO.

 For a three Vulcain version without SRB's, it could get ca. 20 tons to LEO if you use a larger 40 ton to 50 ton upper stage made possible by the higher take-off thrust of the three Vulcains

 And for the replacement of the Vega-C? Use an approx. half-size Ariane 6 core and again a small ca. 10 ton upper stage so as to be loftable on a single Vulcain. This could get ca. 5 tons to LEO. This compared to the 2 tons LEO payload of the Vega-C. And it would be much cheaper than the Vega-C in not using the large SRB's.

 These LEO payload numbers can be easily confirmed by a rocket equation calculation.

 See discussion here:

Towards return of Europe to dominance of the launch market.

https://exoscientist.blogspot.com/2023/10/towards-return-of-europe-to-dominance.html

 In looking at how it is determined the path ESA will take in selecting it’s future launchers, what missing is an independent review authority tasked with reviewing the finances and architectures chosen.

 This is what is done with NASA. NASA has an Office of Inspector General independent of the NASA leadership tasked with reviewing the finances and architectures for the space programs NASA selects. It serves as an independent oversight agency:

NASA should consider commercial alternatives to SLS, inspector general says
"NASA’s aspirational goal to achieve a cost savings of 50 percent is highly unrealistic."
ERIC BERGER -  10/13/2023, 3:07 PM

https://arstechnica.com/space/2023/10/inspector-general-on-nasas-plans-to-reduce-sls-costs-highly-unrealistic/

 Note the report breaks down the costs of the different components of the Artemis program. This is a necessity for analysing the cost effectiveness of the different parts of the program.

 But such is lacking at ESA. For instance in that article “European Space Agency mulls extra Ariane 6 cash”, it is ESA that is effectively providing oversight of itself.

 With this arrangement ESA won’t question whether the architectures it chooses to begin with are the right ones or cost effective ones. Thus THE major question that must be asked remains unasked: is use of large solid side boosters cost effective? Would a cheaper architecture be obtained by using all-liquid propulsion?

 

  Robert Clark

Towards a revolutionary advance in spaceflight: an all-liquid Ariane 6.

 Copyright 2023 Robert Clark

Imagined Ariane 6 sans SRB's with twin Vulcains.

 Abstract.

 Most orbital rockets have payload fractions in the range of 3% to 4%. The Ariane 6 using 2 and 4 SRB’s, because of the large size of the SRB’s and because solids are so inefficient on both mass ratio and ISP, the two key components of the rocket equation, it will count among the worst rockets in history at a payload fraction of only 2%.

 In contrast a two Vulcain Ariane 6 could have a payload fraction of 7% and a three Vulcain Ariane 6 could have a payload fraction of 7.5%. This is well-above what any other rocket has ever achieved in the history of space flight.

 So how is an all-liquid Ariane 6 able to accomplish this? First, this version is based on the Ariane 5 core. The mass ratio for the Ariane 5 it turns out is quite extraordinary for a hydrogen+liquid oxygen(called “hydrolox”) stage at 16.3 to 1. This is in the range commonly seen by dense propellants. To use a colorful analogy, it’s like the ArianeSpace engineers in designing the Ariane 5 core found a way to make liquid hydrogen as dense as kerosene!

 Obviously, this is not what happened. But they must have found a way to achieve extreme lightweighting of a hydrolox stage. To put this in perspective, the mass ratio of the famous Centaur hydrolox upper stage is at 10 to 1, achieved back in the 1960’s. And the Delta IV hydrolox core is at a quite ordinary 8.7 to 1 mass ratio. So the Ariane 5 core is about twice as good as the Delta IV core on this key mass ratio scale.

 Because the Ariane 5 core has the high Isp of a hydrolox stage while achieving (somehow!) the high mass ratio of a dense propellant stage, it calculates out to have the highest delta-v of any rocket stage in the history of spaceflight.

 Since delta-v is the single most important parameter for orbital rockets, you can legitimately argue the Ariane 5 core is the greatest rocket stage ever produced in the history of spaceflight.

 The high 7.5% payload fraction of the all-liquid Ariane 6 would mean SpaceX would have to be chasing ArianeSpace rather than the other way around.

 To put this advance in perspective, it would be like SpaceX using the very same Merlin engines and the very same propellant tanks, and the very same size Falcon 9, suddenly being able to change the Falcon 9 payload from 22 tons to 40 tons.

 It will represent a paradigm shift in terms of the payloads that rockets will be expected to deliver to orbit.

 Usually, when we think of a radical shift in rocket capability we imagine some great advance in engines such as nuclear, or some great advance in materials to greatly reduce tank weight.

 Quite extraordinary is the the fact this radical increase in rocket capability can come from using currently existing engines and tanks.

Introduction.

 Mitchell Burnside Clapp is an engineer and former Air Force officer who had been prominent in programs back-in-the-day to find low cost space access, such as the DC-X. Here, he was calculating some existent or previous space stages that just on the ideal delta-v parameter would have SSTO capability:

==================================================

Propellant density, scale, and lightweight structure

.

Mitchell Burnside Clapp

Jul 19, 1995, 3:00:00 AM

There has been some speculation about Atlas being one of the
lightest aerospace structures ever built. The thing that keeps
it from being a single stage to orbit machine is its relatively
heavy and low performance engines.

I decided to examine the historical record on this issue and
developed the table you see below. All the weights are in
thousands of pounds; the Ideal DV colum is in kft/sec. Prop wt
refers to the weight of propellants. The Isp numbers are
referenced as far as possible to vacuum Isp. The engine data are
from CPIA Revised Liquid Propellant Engine Manual (1972), and
Rocketdyne, SEP, Aerojet, and Pratt and Whitney product
information sheets. The vehicle weight data are from Isakowitz’
Space Launch Systems, 1st Ed. Ideal DV is calculated from the
rocket equation [DV = Isp * g * ln (gross/(gross-prop))]. The
column labeled PMSMF refers to the Propulsion-Free Structural
Mass Fraction, which refers to the weight of the stage after the
engine is removed, divided by the gross weight. This residual
weight includes the electronics, tankage, and so forth.

Here are the data:

Stage Prop Wt Gross Wt Engine Wt Isp PFSMF Ideal DV
Titan II Stg 1 260.0 269.0 3.258 287 2.13% 31.372
Black Arrow Stg 1 28.7 31.1 1.426 250 2.99% 20.755
Saturn V Stg 1 4584.0 4872.0 93.080 265 4.00% 24.114
Titan III Stg 1 294.0 310.0 3.343 283 4.08% 26.959
Titan IV Stg 1 340.0 359.0 3.343 283 4.36% 26.731
Delta 6925 Stg 1 211.3 223.8 2.528 295 4.46% 27.383
Atlas E 248.8 266.7 4.371 312 5.07% 27.073
Saturn V Stg 2 993.0 1071.0 17.400 425 5.66% 35.821
Zenit Stg 1 703.0 778.0 26.575 337 6.22% 25.364
Titan III Stg 2 77.2 83.6 1.144 312 6.29% 25.796
Saturn IB Stg 2 233.0 255.0 3.480 425 7.26% 33.504
Titan II Stg 2 59.0 65.0 1.102 308 7.54% 23.611
Saturn IB Stg 1 889.0 980.0 16.072 263 7.65% 20.111
Ariane 5 Stg 1 342.0 375.0 3.630 430 7.83% 33.624
Saturn 5 Stg 3 238.0 263.0 3.480 425 8.18% 32.179
Energia Core 1810.0 1995.0 21.000 452 8.22% 34.583
Zenit Stg 2 178.0 198.0 2.480 350 8.85% 25.816
Black Arrow Stg 2 6.5 7.8 .531 265 9.52% 15.450
Titan IV Stg 2 77.2 87.0 1.144 312 9.95% 21.919
Delta 6925 Stg 2 13.4 15.4 .207 267 11.82% 17.416

...

7. There are several stages that have SSTO-class delta-V figures
(anything over 30000 fps). The Titan II first stage can itself
deliver 1400 pounds to low earth orbit as it sits, with no
modifications to engine or structure. That’s pretty impressive,
even if a load of propellant for it costs $2.5 miilion.

==================================================

https://groups.google.com/g/sci.space.policy/c/PZgWB9WWhNw/m/gWAavQL8AAAJ

 However, since the SSTO was dismissed as not worth-while an important implication of such high delta-v stages was missed: when the first stage gets such high delta-v, the upper stage can be much smaller to get the same payload to orbit.

 Or said another way, a high delta-v first stage gets high payload to orbit with just a small size upper stage. 

 Of those high delta-v stages Burnside Clapp listed as of 1995, the Ariane 5 is the only one yet existent. And in actuality its even much better than listed in the table.

 You see, the Ariane 5 core had a forward skirt called the JAVE("Jupe AVant Equipée") that transmitted the thrust of the two side boosters to the core. Without the side boosters, this would be removed in our version. The JAVE weighed 1,700 kg. So lets calculate again the ideal delta-v without the JAVE. Note I'm using the lighter Ariane 5 "G" stage here, rather than the later "E" version, at a 158 ton propellant load and 12 ton dry mass. Removing the JAVE brings down the dry mass to 10.3 tons. I'll use the slightly better 434s vacuum Isp for the Vulcain now rather than the 430s Mitchell Burnside Clapp used in his 1995 calculation. Then the ideal delta-v is:

434*9.81Ln(1 + 158/10.3) = 11,900 m/s, or 39,000 ft/sec. 

 This is by far the best ideal delta-v ever produced by any single rocket stage in the entire history of spaceflight, exceeding also the delta-v's for the separate rocket stages on the Falcon 9.

 How were the Europeans able to produce such an extraordinary rocket stage? Firstly, they used hydrogen/oxygen(hydrolox) propellant on the core; this is known to produce the highest efficiency on the ISP scale of any chemical propellant. But this is well known and you see several stages among the highest listed used hydrolox. What's really extraordinary is the mass ratio, i.e., propellant fraction of the stage.

The mass ratio is gross mass divided by dry mass and it is important for a rocket stage for it is used in the rocket equation to determine what is the delta-v it could achieve:

 

The total mass of the stage would be 158 + 10.3 = 168.3 tons. Then the mass ratio would 168.3/10.3 = 16.3. As a point of comparison the famous Centaur upper stage was able to get a 10 to 1 mass ratio and this was considered a remarkable engineering achievement for a hydrolox rocket stage. 

 Hydrolox stages are able to get high ISP, but because hydrogen is such low density, the mass ratio is usually comparatively low. Dense propellant combinations such kerosene/oxygen(kerolox) are usually higher. For instance the mass ratio for the Atlas 5 kerolox first stage is about 16 to 1, and the Falcon 9 first stage is somewhat higher at about 20 to 1. But kerolox is about 3 times denser than hydrolox. So conceivably a kerolox stage such as the Atlas 5 or Falcon 9 using the same lightweighting methods as the Ariane 5 could get a mass ratio of 50 to 1!

 The mass ratio of the Ariane 5 core for a hydrogen stage is so remarkable that it should be used as a model for any stage hydrolox or kerolox.

Cost of the side SRB's is the source of the high Ariane 6 pricing.

 That parameter of ideal delta-v that the Ariane 5 core has superiority on over any other rocket ever built suggests that that should be built upon and not disregarded. Instead what has been used on the Ariane 5 and Ariane 6 are solid stages that are among the worst on this key parameter. Because solids are pressure-fed meaning the entire propellant tank has to operate as the combustion chamber requiring thick tank walls, they usually have poor mass ratio, despite the solids propellants higher density. Worse, the other key parameter in the rocket equation ISP is also among the worst with solids. 

 If it were only small solid side boosters used with the Ariane 5 and Ariane 6 then this would not have the severe reducing effect on the rocket efficiency that they did have. But instead the side rockets used on the Ariane 5 and 6 were huge in comparison to other side boosters used for example with the Atlas 5 and Delta IV, which were commonly only ~1/10th the size of the booster core stage.

 My speculation here, but I think the Space Shuttle design is what influenced ArianeSpace to use such large solid side boosters. Perhaps it was not known at the time when the Ariane 5 was first being designed but the Space Shuttle was a financial disaster. Such large side boosters are also used on the SLS which is also a financial disaster. The huge solid boosters used in both contributed to that.

 The newly designed solids on the Ariane 6 make the situation worse. Their size is about the size of the entire core stage of the Ariane 6, and the fact they use carbon-fiber make them more expensive. To understand how expensive is that use of carbon-fiber for the solids note the reason SpaceX decided to move away from carbon-fiber to steel for the StarShip:

Why SpaceX Abandoned Carbon Fiber.
…
The other concern was cost. SpaceX determined that it would spend upwards of $130,000 per ton to use carbon fiber as the primary rocket body material. On the other hand, it would spend just $2,500 per ton for stainless steel. It doesn’t take a mathematician to figure out that spending 50 times as much on carbon fiber would put considerable strain on the Starship project.
https://markets.rockwestcomposites.com/we-now-know-why-spacex-abandoned-carbon-fiber

 To provide an estimate of how bad is the cost issue against the Ariane 6 solids in comparison to just using an additional Vulcain, note the €75 million cost of the two SRB version of the Ariane 6 compared to the €115 million of the four SRB version. Then, as a first order estimate, we can take the cost of two SRB’s as €40 million. But the cost of a single Vulcan is only €10 million! So the two SRB’s planned for the base version costs 4 times as much as just adding a second Vulcain!

Therefore, again as a first order estimate, we can take the cost of a Ariane 6 with no SRB’s by subtracting off the estimated €40 million for the two SRB’s to get a no SRB price of only €35 million.Then the price of the two SRB's is more than the price of the entire rest of the rocket. So adding on a Vulcain at €10 million would give a price of €45 million, about $50 million. Note this compares quite favorably with the current $67 million cost of the Falcon 9 new.

 Further indication of how expensive are the Ariane 6 SRB's is found by comparing to other carbon-fiber, also called graphite-fiber, SRB's. The GEM 63 are carbon-fiber solid side boosters have about a 50 ton propellant load and cost estimated in the range $5 to $7 million.Then we can estimate the Ariane 6 SRB's to cost three times more to bring them to $15 to $21 million each, in the price range of the estimate you get from comparing the Ariane 6 two SRB and Ariane 6 four SRB pricing.

 There needs to be a discussion among the European space community about the use of these large expensive boosters when the same can be accomplished much more cheaply  by just using additional Vulcain engines on the core.

Payload Calculation for a Two Vulcain Ariane 6. 

 In the blog post, "Multi-Vulcain Ariane 6", I estimated about 11 tons to LEO using a two Vulcain, no SRB version for the Ariane 6. Note though I was originally trying to find a lower cost approach to the Ariane 6, so I actually used the Ariane 5 core. BUT because of my thrust constraints I chose to use the original, somewhat smaller version the Ariane 5 "G" core, rather than the later "E" version, at 12 ton dry mass and 158 propellant mass.

 For the upper stage, again because of limited take off thrust constraints I did not use the current ESC-A cryogenic upper stage of the Ariane 5 at ~19 ton gross mass, nor the ~30 ton cryogenic upper stage of the Ariane 6. I also did not like that the ESC-A had such a poor mass ratio at only 5 to 1. I used instead the Ariane 4's H10 cryogenic upper stage:

ARIANE 4 STAGE 3
Specifications are given in H10/H10+/H10-3 order.
Designation: H10/H10+/H10-3
Engine: single cryogenic open cycle SEP HM-7B
Length: 10.73 m/11.05 m/11.05 m
Diameter: 2.60 m
Dry mass: 1,200 kg/1,240 kg/1,240 kg, excluding interstage 2/3
Oxidizer: liquid oxygen
Fuel: liquid hydrogen
Propellant mass: 10,800 kg/11,140 kg/11,860 kg
Thrust: 63 kN vac/63.2 kN vac/64.8 kN vac
http://www.braeunig.us/space/specs/ariane.htm

 Note that in addition to being lighter this has a much better mass ratio at over 10 to 1, rivaling the famous Centaur upper stage. I also assumed the Vulcain thrust could be ramped up ca. 9% as was shown possible with the SSME's and the RS-68 engine on the Delta IV rocket. Then I asserted for the Vulcain likely the same would hold, as they are all hydrolox engines. 

 But a commenter to my blog cited a report giving estimated Ariane 6 values that estimated a 104 tons sea level thrust, so 208 tons for two, already held for the latest version:  

Launcher analysis and cost benefits

No 638719. Launcher analysis and cost benefits. Max Calabro (TIA). Emmanuella Gizzi (AVIO). Ref. Ares(2018)1042920 - 23/02/2018 

 If that is the case then I don't have to assume the Vulcain 2.1 thrust ramped up.

 But even without a higher thrust level Vulcain, we could take a smaller propellant load of ca. 140 tons for the Ariane 6 core so it could still have sufficient thrust for takeoff. Since this is only about a 10% reduced propellant load for the first stage it would be a relatively small reduction in payload.

 While I used the smaller, earlier Ariane 4 H10 upper stage because of my reduced thrust, we can now use the higher efficiency and thrust Vinci engine rather than the original HM-7B on this upper stage. The Vinci has a 180 kiloNewton vacuum thrust and 457s vacuum Isp. But using a slightly longer nozzle we can give it the 465.5 vacuum Isp of the RL10-B2. Remarkably with a sufficiently long nozzle we can give an upper stage hydrolox engine a vacuum Isp in the 480+s range. However, we'll use in our calculations the Isp number proven possible with currently in use engines of a 465.5s vacuum Isp.

As for the dry mass of the core with a second Vulcain, we removed the JAVE subtracting off 1,700 kg from the dry mass. Adding on a second Vulcain adds on 1,800 kg, bringing the dry mass back to about the original 12 tons.

However, another consideration is the doubled thrust might require thickened tank walls. I estimated in an earlier blog post that the increased thrust might require an additional 1,000 kg for the thicker tank walls. However, it should be noted the supported weight that needs to be carried above the core with a smaller upper stage and smaller payload mass is half as big as that of the Ariane 5. So advanced structural analysis programs need to be applied to find the needed degree of tank strengthening and added weight to the dry mass.

Still at most 1,000 kg needs to be added to the dry mass according to my prior estimate and this results in a proportionally small reduction in the payload mass. Then for this first order estimate we'll take simply 12,000 kg as the dry mass.

Now use the payload estimator at SilverbirdAstronautics.com giving the results:

 The payload to LEO calculated is 14,000 kg, exceeding the ~10 ton LEO payload of the Ariane 6 version with two SRB's by 40%.

 For the payload to geosynchronous transfer orbit, change the apogee to 35,700 km. The result is:

 

  The calculated payload to GTO of 6,652 kg is nearly 50% higher than the 4,500 kg GTO payload of the Ariane 6 version with two SRB's.

 

Payload Calculation for a Three Vulcain Ariane 6. 

 A three Vulcain format for an all-liquid Ariane 6 is actually preferred. The reason is you don't have such a thrust limitation as the two Vulcain case.This allows you to choose a larger upper stage resulting in a higher payload. 

 I have presented the two Vulcain case here and in some previous postings because of the low development cost, less than $200 million. Indeed, it most likely could be done for less than $100 million. 

 However, adding two additional Vulcains will require a higher development cost. It still likely will be in the few hundred million dollars range, well less than the multi-billion dollar development cost of the current version of the Ariane 6. 

 Again a key consideration is added tank wall thickness needed for the tripled thrust. In a prior blog post, I discussed a rocket that had been proposed by Northrup Grumman, the  Liberty rocket that would use a shuttle derived SRB as a first stage, a la the Ares I rocket, and an Ariane 5 core as an upper stage. 

 As described in this video, the SRB to be used would have had a thrust 12 times that of the Vulcain yet the increased thickness of the tanks on the Ariane 5 core would only need to be 50%:

 As the tank mass of the Ariane 5 core is in the range of 4 tons, this would mean the increased tank mass would have needed to be in the range of 2 tons. Since the three Vulcain format would mean far less less thrust than that of the Liberty rocket, the increased tank mass would be less than this. So we'll take the additional core mass as a max of 2,000 beyond that of the additional 3,600 kg for the added two Vulcains. 

 Since we have higher thrust we'll use the larger Ariane 5 "E" core at 170 propellant load and 14 dry mass. Subtracting off again the 1,700 kg for the JAVE, while adding on 3,600 for the two added Vulcains and 2,000 kg for the thickened tank walls brings the dry mass to about 18,000 kg. But because we have much more liftoff thrust with three Vulcains we can use much larger upper stages, such as the currently planned 30 ton hydrolox upper stage of the Ariane 6, or even larger 40 ton or 50 ton hydrolox stages.

 We'll take our upper stage as 50 tons propellant load with a Centaur-like 10 to 1 mass ratio, so a 5 ton dry mass, a la the ULA Centaur V. We'll use three Vinci engines on the upper stage to give a thrust of 540 kN and assume a RL10-like 465.5s Isp. Then the input page on the SilverbirdAstonautics.com payload estimator appears as:

The payload to LEO is estimated as:

And the GTO payload is:

 This is slightly less than the LEO payload of the Falcon 9, but about the same payload of the Falcon 9 for the lucrative GTO market.

 It is likely cheaper also than the Falcon 9 new. The reason is the Ariane 6 core and upper stage without SRB's is about €35 million, and the bulk of this price would be the core since the upper stage is such small relative size. For instance the price of the Falcon 9 is 3/4ths due to the first stage compared to the second stage. 

 Then using a 50% larger upper stage for the Ariane 6 might add another €5 million to the price, bringing it to €40 million. Then the two additional Vulcains would bring the price to €60 million, a bit less than the $67 million price of the Falcon 9 new.

The All-Liquid Ariane 6 as a Revolutionary Advance in Spaceflight.

 A key parameter for rocket efficiency that rocket engineers always use is payload fraction. For almost all rockets this is in the range of 3% to 4%. But because of those huge SRB’s the Ariane 6 uses, its payload fraction counts as among the worst in history at only in the range of 2%. But the two Vulcain no SRB version of the Ariane 6 would be in the range of 7%! And the three Vulcain no SBR version would be in the range of 7.5%.

On this key parameter rocket engineers use to rate orbital rockets the all-liquid Arianes would literally be the best rockets in the history of space flight with no other rocket even coming close.

They would literally be a paradigm shift in rocket efficiency. Other launch companies would have to strive to reach their level of efficiency. And most simply could not.

 To put this advance in perspective, it would be like SpaceX using the very same Merlin engine and the very same propellant tanks, and the very same size Falcon 9, suddenly being able to change the Falcon 9 payload from 22 tons to 40 tons. 

Plus, while being nearly twice as good as the Falcon 9 on this key parameter the all-liquid Ariane 6 would also be cheaper!

 Robert Clark

 

Who in European space will ask the impertinent question: How much would it cost to add a second Vulcain to the Ariane 5/6?

 Copyright 2023 Robert Clark

 

ArianeSpace Needs to Transition to Reusability to Survive.

 European space advocates have been lamenting that there seems to be no near term route to keeping up with SpaceX, getting reusable launchers, and towards achieving manned space flight. However, in point of fact ESA already has the components to form a launcher comparable to the Falcon 9 and at lower price, while keeping pace with SpaceX in reusability, and in manned spaceflight.

 All it would require is someone, anyone in the Europeans space community to ask the impertinent question, "How much would it cost to add a 2nd Vulcain to the Ariane 5/6?"

  For once that question is asked, and ArianeSpace forced to answer honestly, they would have to admit it could be done for only a development cost in the range of only ~$200 million. But then it would become obvious how to proceed.

 First, note that the Ariane 6 that was planned to compete with the SpaceX Falcon 9 has been pushed back to 2024, when its original launch date was in 2020, extending the time where SpaceX is cornering the market. Note also the Ariane 6 will not be reusable. In fact ArianeSpace has admitted they won't be fielding a reusable launcher until the 2030's. 

 ULA was driven to the brink of bankruptcy by denying the importance of reusability. There is little doubt the same will happen to ArianeSpace if they wait a decade to field a reusable vehicle. Independent European space observers have also made this point about the choice of the non-reusable Ariane 6:

Europe’s lack of rocket ‘audacity’ leaves it scrambling in the space race
European policymakers want to stop SpaceX from dominating the launch market.
BY JOSHUA POSANER
JANUARY 15, 2021 12:28 PM CET 6 MINUTES READ
That 2014 decision haunts French Economy Minister Bruno Le Maire, who keeps a warning of that moment on his desk.
“The European space adventure is magnificent, but in 2014 there was a fork in the road, and we didn’t take the right path,” Le Maire told a conference last September. “We should have made the choice of the reusable launcher. We should have had this audacity.”
https://www.politico.eu/article/europe-arianespace-rocket-space-race/

 The Fast Route to Reusability.

 The problem with reusability for the Ariane 5 and 6 is they use solids for a large portion of their takeoff thrust. These large side boosters also make up a large portion of the cost. In fact, the situation has actually gotten worse with the Ariane 6. But the Space Shuttle program demonstrated you don't save on reuse with solid side boosters. By the time you fish the SRB's out of the ocean, tow them to port, transport them from port back to the manufacturing facility, clean them out from all the burnt on combustion products, and then finally refill them with propellant, the cost is no better than just using new ones to begin with. A little thought makes it easy to see why. Solid side boosters are just a filled in metal pipe. The cost of that metal pipe is small compared to all the processing involved in making the SRB. Keeping the same metal pipe but increasing all the needed steps for processing does not reduce the cost of the SRB.

 So to get the low cost reusable rocket you have to dispense with the SRB's. Necessarily that means you have to use additional liquid-fueled core engines. Then is adding an additional core engine a multi-billion dollar, or euro, development? 

 No! I was quite startled to find JAXA was able to add an additional hydrolox engine to the H-II first stage for only an approx. $200 million development cost.

 See the highlighted passage in this article where the cost to add another engine to the H-II was only 27 billion Yen, about $200 million: 

 

 But that means instead of the multi-billion current development cost of the Ariane 6, the same could have been accomplished for just a few hundred million and would also have been reusable! I made this point here:

Multi-Vulcain Ariane 6.

https://exoscientist.blogspot.com/2018/02/multi-vulcain-ariane-6.html

 Thus the importance of asking that impertinent question of ArianeSpace, "How much to add an additional Vulcain to the Ariane 5/6?"

WHY Are the Far More Expensive SRB's Used Rather then the Cheaper Liquid-fueled Engines? 

 Knowledgeable ESA observers have been aware for awhile now that the ESA policies for distributing funds and costs to the differing member states do not result in the most cost effective vehicles. It’s a policy called geographical-return that requires member states costs to be apportioned by some set proportion of the billion dollar development costs. So if some member states have been contributing some large proportion of the costs through solid side boosters, that cost continues to be part of the development for new rockets or upgrades.

 The governments of the member states regard this as a good thing because it helps to keep active, and paid, the space industries and space industry employees in their countries. But another key reason why some member states like the funds for the ESA to go to develop solid rocket side boosters is because those funds help also to develop solid rockets for their defense programs. So rather than those countries having to pay the entire cost of the solid rocket missiles in their defense programs on their own, some portion of that is actually paid for by the ESA in developing solid rocket side boosters for space launchers.

 You can see why there is a great incentive for those member states, which have great influence on the direction and funding choices for the ESA, to continue to want to use solid rocket boosters in all launchers produced by the ESA.

 But the stunning fact is how much more expensive the solids are for the Ariane 6 than just adding another Vulcain engine! The latest cost figures for the Ariane 6 are the €75M for the two SRB version and €115M for the four SRB version. 

 This suggests, as a first order estimate, that we can take the cost of two SRB’s as €40M. But the cost of a single Vulcan is only €10 million! So the two SRB’s on the Ariane 6 base version costs 4 times more than an additional Vulcain! Therefore, again as a first order estimate, we can take the cost of a two Vulcain Ariane 6 with no SRB’s as only €45 million, ~$50 million. This compares quite favorably to current $67 million cost of the Falcon 9.

 The reason why this isn’t done can not be attributed to some supposed multi-billion development cost to add an additional Vulcain to the Ariane core. Actually, it’s the current plan for the Ariane 6 with the newly developed solids, new upper stage, and new Vinci engine whose development cost is in the $4+ billion range. It’s really quite stunning to realize the same could have been accomplished at only a ~$200 development cost simply by adding another Vulcain to the Ariane 5 core, using the same original cryogenic upper stage. Nearly a factor of 20 times cheaper!

 But nobody knows this because nobody asks that one simple question, “How much would it cost to add a second Vulcain to the Ariane 5/6?”

 Now, once you have the all-liquid Ariane 6 that costs even cheaper than the Falcon 9, you can also keep up with SpaceX in reducing price by reusability by also reusing the core stage via powered landing a la the F9 booster. Again, the solids in the current Ariane 6 version would not save on reusing them as the Space Shuttle program abundantly showed. So that huge €40 million cost just for the SRB’s on the Ariane 6(more than the cost of the entire rest of the rocket!) out of the total  €75 million would be fixed no matter how many times you wanted to reuse the core.

 It might be argued that even a fully throttled down single Vulcain would have too much thrust for a hovering landing. Actually, this is the case also with the Falcon 9. It uses what SpaceX calls "hover-slam" for landing. The thrust is precisely timed so the booster just reaches 0 velocity as it touches down. Actually, I'm not a fan of "hover-slam". Much better for the Ariane case would be to use two Vinci engines for the landing only. It is designed to be air-startable and restartable. It weighs without the nozzle extension for vacuum use only 160 kg. So two would weigh only 320kg on the first stage. It's use would allow true hovering landing for the first stage.

Three Vulcains on the Ariane 5/6 Match the Falcon 9 in Payload at a Lower Price.

 The two Vulcain Ariane 5/6 would have lower payload than the Falcon 9. But it would be quite competitive for the lucrative geosynchronous transfer orbit(GTO) used by many communications satellites, at ~6,000 kg to GTO at lower price than the F9. The F9 is at about 8,000 kg to GTO. But most satellites don't need this full capacity anyway.

 However, if we used three Vulcains we could then match the Falcon 9 in payload and still be at lower price. This comes from again using the first order estimate of €40 million for the two SRB's. So the Ariane 6 with no SRB's would be €35 million, as a first order estimate. So adding on two Vulcains would be €55 million, as a first order estimate. But this is still less than the $67 million price for the Falcon 9.

 In an upcoming blog post I'll discuss further the three Vulcain case showing it can match the Falcon 9 in payload. Intriguingly, by using multiple copies of such 3 Vulcain cores, I estimate 4 to 6, you can also get a 'superheavy' lift vehicle capable of 100-tons to LEO, a 'moon rocket'. Using multiple copies  of already existing cores allows you to get the 'superheavy' lift at far less development cost than the $20 billion of the SLS, or the $10 billion of the ill-conceived Superheavy/Starship.

 Manned Launchers.

 Finally, in regards to manned launchers, just use the all-liquid Ariane 6 since you no longer have the safety issues of using SRB’s on manned launchers.

 

  Robert Clark