Arianespace launch thread

[tater]

So a 2 Vulcain, single stick vehicle works for the 10t payload, but not 20t. Looks like with 3 engines it's upper limit is more like 12t.

To get it to 20t payload with the same stick (and not changing tanks), we'd need side boosters, adding engines doesn't get it past ~12t by much.

An Ariane 6 Heavy  works, actually. >22t to LEO. 3 current core stages stuck together like DIVH.

If they changed the core to 2 Vulcains for a single stick option, then a A6 Heavy (all 3 cores the same, w/2 Vulcain) would do 25t to LEO (assuming they only want to make one kind of core),

Of course they would likely need an entirely new integration facility.

Edited May 18, 2023 by tater

[Exoscientist]

2 hours ago, tater said:

So a 2 Vulcain, single stick vehicle works for the 10t payload, but not 20t. Looks like with 3 engines it's upper limit is more like 12t.

To get it to 20t payload with the same stick (and not changing tanks), we'd need side boosters, adding engines doesn't get it past ~12t by much.

An Ariane 6 Heavy  works, actually. >22t to LEO. 3 current core stages stuck together like DIVH.

If they changed the core to 2 Vulcains for a single stick option, then a A6 Heavy (all 2 cores the same, w/2 Vulcain) would do 25t to LEO (assuming they only want to make one kind of core),

Of course they would likely need an entirely new integration facility.

 Three Vulcains means it could loft higher mass so you could use a larger upper stage. Try it with a 40 ton propellant load hydrolox upper stage.

  Bob Clark

[tater]

14 minutes ago, Exoscientist said:

 Three Vulcains means it could loft higher mass so you could use a larger upper stage. Try it with a 40 ton propellant load hydrolox upper stage.

Still says 12.7t, even without increasing the S2 dry mass at all, just the prop load. Doesn't even get to 20t if you leave the current S2 dry mass and bump the props to the same as the core. Doesn't work.

A6 Heavy gets you less than current F9 (expended) performance while trashing 3 F9 sized boosters. If you are right on Vulcain cost, then it does so with more in just engine cost than F9 costs SpaceX.

They need a clean sheet to be competitive.

Silverbird was the site I used, BTW.

Also, reuse with 1-2 engines possible, I suppose (easier with 1 in some ways), but the thrust is almost certainly too high even for a F9 hoverslam (F9 thrust is ~2X dry mass of returning stage, A6 1 engine thrust is more like 10X dry mass). It would still need restart, etc, so a long pole. There's a reason their work on landed stages is with smaller methalox engines.

Edited May 18, 2023 by tater

[Exoscientist]

 I get in the range of 20 tons to LEO by the rocket equation. I used the 158 ton propellant load of the original Ariane 5 “G” version. I bumped its dry mass to 14 tons for the 3rd Vulcain. I used a Centaur-like upper stage with an approx. 90% propellant fraction at 40 ton propellant mass at only 4 tons dry mass. I also assumed it had a high efficiency hydrolox vacuum engine matching the RL-10, as the Ariane 6 Vinci engines does, at 465 s vacuum Isp. Then the rocket equation gives a delta-v of:

434*9.81Ln(1 + 158/(14 + 44 +20)) + 465*9.81Ln(1 + 40/(4 + 20)) = 9,190 m/s, probably sufficient to orbit with a 20 ton payload. The rocket equation does not take into account takeoff TWR though so you need a more accurate payload estimator to say for sure.

   Bob Clark

[tater]

48 minutes ago, Exoscientist said:

 I get in the range of 20 tons to LEO by the rocket equation. I used the 158 ton propellant load of the original Ariane 5 “G” version. I bumped its dry mass to 14 tons for the 3rd Vulcain. I used a Centaur-like upper stage with an approx. 90% propellant fraction at 40 ton propellant mass at only 4 tons dry mass. I also assumed it had a high efficiency hydrolox vacuum engine matching the RL-10, as the Ariane 6 Vinci engines does, at 465 s vacuum Isp. Then the rocket equation gives a delta-v of:

434*9.81Ln(1 + 158/(14 + 44 +20)) + 465*9.81Ln(1 + 40/(4 + 20)) = 9,190 m/s, probably sufficient to orbit with a 20 ton payload. The rocket equation does not take into account takeoff TWR though so you need a more accurate payload estimator to say for sure.

The core stage dry mass is ~15t, Stage 2 is ~3.5t.

Prop load for S1 is 140t, for S2 is is 31t.

Isp of Vulcain is 318 at SL (431 (vac)), and for Vinci it's 457.

Ariane 5 has a fairing mass of ~2400 kg, so I used that.

If you add extra Vulcains, they are 1300 kg each.

I actually used the vac thrust for my calcs, and Isp/thrust are lower at SL than vac, so my numbers are too high.

If I change to average thrust/Isp for S1, I get just 9t to LEO for the 3 engine version.

Oops. If I drop the thrust and Isp to the same average versions (literally the SL value averaged with the higher vac value), the 1 stick payload drops to 8585kg.

So yeah, not competitive.

The 2 Vulcain A6 Heavy gets 18t to LEO.

Oddly enough, the 1 Vulcain per core A6H gets nearly as much, 16t to LEO.

 

Still not even close to competitive.

[Exoscientist]

39 minutes ago, tater said:

The core stage dry mass is ~15t, Stage 2 is ~3.5t.

Prop load for S1 is 140t, for S2 is is 31t.

Isp of Vulcain is 318 at SL (431 (vac)), and for Vinci it's 457.

Ariane 5 has a fairing mass of ~2400 kg, so I used that.

If you add extra Vulcains, they are 1300 kg each.

I actually used the vac thrust for my calcs, and Isp/thrust are lower at SL than vac, so my numbers are too high.

If I change to average thrust/Isp for S1, I get just 9t to LEO for the 3 engine version.

Oops. If I drop the thrust and Isp to the same average versions (literally the SL value averaged with the higher vac value), the 1 stick payload drops to 8585kg.

So yeah, not competitive.

The 2 Vulcain A6 Heavy gets 18t to LEO.

Oddly enough, the 1 Vulcain per core A6H gets nearly as much, 16t to LEO.

 

Still not even close to competitive.

 For the higher thrust of three Vulcains you should use the higher propellant load of the Ariane 5. Even the later Ariane 5 “E” version at a larger 170 ton propellant load would work. To get a better estimate that takes into account lift off TWR use the Silverbird Astronautics payload estimator at https://www.silverbirdastronautics.com/LVperform.html

  Bob Clark

 

Edited May 18, 2023 by Exoscientist

[tater]

19 minutes ago, Exoscientist said:

 For the higher thrust of three Vulcains you should use the higher propellant load of the Ariane 5. Even the later Ariane 5 “E” version at a larger 170 ton propellant load would work. To get a better estimate that takes into account lift off TWR use the Silverbird Astronautics payload estimator at https://www.silverbirdastronautics.com/LVperform.html

I already said I was using silverbird. As for prop load, no, I would not use the value for the 5.4m dia Ariane 5, because the Ariane 6 is only 5m. Making a new tank is not the same as swapping engines, or changing the side boosters—it's starting over. Ariane 6 was designed in 2014, so if you start changing it more than a little, any changed version is now gonna be in the 2030s anyway—so why bother making lemonade out of this lemon? It still only gets ~10t, not even 2/3 of what F9 delivers with booster recovery, and the 3 engines cost more than the entire F9 launch costs SpaceX.

Making a 3 engine variant might well be possible with an entirely new rocket, or stretching the core, etc—but the end result is still not competitive with existing vehicles (F9), OR with vehicles that will fly possibly before current Ariane 6, certainly before any novel variant might (in a decade the way they work). Rejiggering existing or nearly existing rockets is a waste of time.

 

[StrandedonEarth]

F9 has shown that if you want to land propulsively, you need to throttle so deeply just to not overstress the airframe that it makes the most sense to have several engines with the center engine used for landing. Trying to land a two or three engine booster propulsively  makes it way more challenging than it needs to be. 

Hydrolox is really a poor choice for a booster anyway; not nearly dense enough. 

[Exoscientist]

1 hour ago, StrandedonEarth said:

F9 has shown that if you want to land propulsively, you need to throttle so deeply just to not overstress the airframe that it makes the most sense to have several engines with the center engine used for landing. Trying to land a two or three engine booster propulsively  makes it way more challenging than it needs to be. 

Hydrolox is really a poor choice for a booster anyway; not nearly dense enough. 

 F9 still has higher thrust than dry mass of booster even using only one engine. So F9 uses what SpaceX calls “hover-slam” where the thrust is precisely timed so that vehicle reaches 0 velocity just as it touches down. The same could work with the Vulcain throttled down on only one engine. Actually I don’t like “hover-slam”. Better: use two Vinci engines. They are only 160 kg each and would allow hovering landing.

  Bob Clark 

 

[tater]

1 hour ago, Exoscientist said:

 F9 still has higher thrust than dry mass of booster even using only one engine. So F9 uses what SpaceX calls “hover-slam” where the thrust is precisely timed so that vehicle reaches 0 velocity just as it touches down. The same could work with the Vulcain throttled down on only one engine. Actually I don’t like “hover-slam”. Better: use two Vinci engines. They are only 160 kg each and would allow hovering landing.

160 kg minus the 1.84m dia nozzle.

Arianespace, for all their issues employs engineers, just as SpaceX does. You'll note they don't use either engine for the vehicle they are working on that will land. New engines, different fuel.

 

https://en.wikipedia.org/wiki/Prometheus_(rocket_engine)

 

Edited May 19, 2023 by tater

[StrandedonEarth]

54 minutes ago, Exoscientist said:

 F9 still has higher thrust than dry mass of booster even using only one engine. So F9 uses what SpaceX calls “hover-slam” where the thrust is precisely timed so that vehicle reaches 0 velocity just as it touches down. The same could work with the Vulcain throttled down on only one engine. Actually I don’t like “hover-slam”. Better: use two Vinci engines. They are only 160 kg each and would allow hovering landing.

  Bob Clark 

 

Sure, they could do a Vulcain hoverslam, if the airframe can handle the gees. You’ll notice I never implied TWR < 1, just low enough for the airframe. I’d WAG that a Vulcain landing would pull10-20g, which means a lot of extra structure. 

[tater]

27 minutes ago, StrandedonEarth said:

Sure, they could do a Vulcain hoverslam, if the airframe can handle the gees. You’ll notice I never implied TWR < 1, just low enough for the airframe. I’d WAG that a Vulcain landing would pull10-20g, which means a lot of extra structure. 

They’d also need the culture to try it, and iterate. Don’t think that’s in their blood.

[Kermann Nolandung]

I guess adapting an expensive engine that was not designed to be reused and is moreover HydroLOx is just a dead-end.

About the cost of SRBs, in a parliamentary report I found references  that say prices 130 M€ for Ariane 64 and 80 M€ for Ariane 62 but it target costs 91 M€ for Ariane 64 and 74 M€ for Ariane 62. It don't know if there are up to date, but it reduces the cost of two boosters to 17 M€.
I'm not very surprised, as optimizing booster production compare to A5 was a key argument to justify the Ariane 6 architecture.

[Exoscientist]

16 hours ago, tater said:

I already said I was using silverbird. As for prop load, no, I would not use the value for the 5.4m dia Ariane 5, because the Ariane 6 is only 5m. Making a new tank is not the same as swapping engines, or changing the side boosters—it's starting over. Ariane 6 was designed in 2014, so if you start changing it more than a little, any changed version is now gonna be in the 2030s anyway—so why bother making lemonade out of this lemon? It still only gets ~10t, not even 2/3 of what F9 delivers with booster recovery, and the 3 engines cost more than the entire F9 launch costs SpaceX.

Making a 3 engine variant might well be possible with an entirely new rocket, or stretching the core, etc—but the end result is still not competitive with existing vehicles (F9), OR with vehicles that will fly possibly before current Ariane 6, certainly before any novel variant might (in a decade the way they work). Rejiggering existing or nearly existing rockets is a waste of time.

 

 Good you are using the Silverbird Astronautics estimator but it does have some quirks. First, it always takes the vacuum values for both thrust and Isp even for first stage engines because it already takes into account the diminution at sea level. Another key point is that you should set the inclination to match the latitude of the launch site to maximize payload. This is actually a fact of orbital mechanics. So after selecting the launch site as Kourou, French Guyana for the Ariane, set the launch inclination as 5.2 degrees to match that sites latitude. Also, you should probably set the “restartable upper stage” option as No, since this sometimes reduces payload when selected Yes, perhaps because it will keep some propellant on reserve for restart. Here we are finding the max expendable payload, so we’re not using a restart option.

 About using the larger Ariane 5 propellant tank for the 3 Vulcain version, once it is observed that this way you can match the Falcon 9 payload and at lower cost, it will become apparent that is the way to go.

  Bob Clark 

[tater]

6 minutes ago, Exoscientist said:

 About using the larger Ariane 5 propellant tank for the 3 Vulcain version, once it is observed that this way you can match the Falcon 9 payload and at lower cost, it will become apparent that is the way to go.

There's no way it's at lower cost, and it's also literally a "start over" on the project, so what, 10 years?

It;s not lower cost since we have heard a SpaceX engineer at a conference say their internal cost on a F9 was maybe $25M (not sure if that included fairing reuse, or just booster reuse). Vulcain is €10M or so, so 3 of those, not counting any of the other costs already exceeds F9 cost. Ariane can't compete, they need a ~20t to LEO rocket that costs them <$25M to build and launch to compete.

[Exoscientist]

On 5/19/2023 at 9:15 AM, tater said:

There's no way it's at lower cost, and it's also literally a "start over" on the project, so what, 10 years?

It;s not lower cost since we have heard a SpaceX engineer at a conference say their internal cost on a F9 was maybe $25M (not sure if that included fairing reuse, or just booster reuse). Vulcain is €10M or so, so 3 of those, not counting any of the other costs already exceeds F9 cost. Ariane can't compete, they need a ~20t to LEO rocket that costs them <$25M to build and launch to compete.

 I was using “cost” and “price” interchangeably, which I shouldn’t have done. What I meant was price to the customer. Currently, that’s $67 million for the F9. So still going by the €40 million first order estimate for the price of two SRBS, resulting in an estimate of a €35 million price for the Ariane 6 without SRB’s, suggests a price for a 3 Vulcain Ariane 6 as €55 million, still less than the $67 million price for the F9.

 I’m betting that the production of the Ariane 5 cores can be restarted much more quickly and less costly, than if it were an entire new development from scratch. Again, that is one of those impertinent questions that someone, anyone  in the European space community should ask.

 “Nolandung”, do you have a source for the 91 M€ for Ariane 64 and 74 M€ for the Ariane 62 price numbers? The higher price numbers I cited come from 2021.

  Robert Clark

Edited May 20, 2023 by Exoscientist

[tater]

9 minutes ago, Exoscientist said:

 I was using “cost” and “price” interchangeably, which I shouldn’t have done. What I meant was price to the customer. Currently, that’s $67 million for the F9. So still going by the €40 million first order estimate for the price of two SRBS, resulting in an estimate of a €35 million price for the Ariane 6 without SRB’s, suggests a price for a 3 Vulcain Ariane 6 as €55 million, still less than the $67 million price for the F9.

Then SpaceX drops their price below that.

The current price of a F9 launch is slightly below any competitor. They pocket the difference between that sale price and their actual cost. Since no one is actually competing, their price is still higher than it could be. Arianespace needs an internal cost as low as SpaceX, or they cannot compete on price. Ever (unless they are subsidized to sell launched below their internal cost).

[Kermann Nolandung]

11 hours ago, Exoscientist said:

 “Nolandung”, do you have a source for the 91 M€ for Ariane 64 and 74 M€ for the Ariane 62 price numbers? The higher price numbers I cited come from 2021.

  Robert Clark

There in 2019, there is some mix between euros and dollars :  Space launchers: restoring Europe's space ambition - Senate (www-senat-fr.translate.goog)

On the one hand, the price per kilo put into orbit has fallen since 2014 . Although no official communication on marketing prices has been made by Arianespace, the press has reported the following orders of magnitude: 130 million dollars for Ariane 64 and 80 million dollars for Ariane 62 versus, as we have seen , a Falcon 9 priced at less than $50 million in the commercial market 67( * ) . Worse, this price difference would be justified by a difference in production cost: according to the same source, the cost targets were 90.6 million euros for an Ariane 64 and 73.6 million euros for an Ariane 62 68( * ) against, as already mentioned, a cost of 44 million dollars for a consumable Falcon 9 launch .

[Exoscientist]

13 hours ago, Kermann Nolandung said:

There in 2019, there is some mix between euros and dollars :  Space launchers: restoring Europe's space ambition - Senate (www-senat-fr.translate.goog)

On the one hand, the price per kilo put into orbit has fallen since 2014 . Although no official communication on marketing prices has been made by Arianespace, the press has reported the following orders of magnitude: 130 million dollars for Ariane 64 and 80 million dollars for Ariane 62 versus, as we have seen , a Falcon 9 priced at less than $50 million in the commercial market 67( * ) . Worse, this price difference would be justified by a difference in production cost: according to the same source, the cost targets were 90.6 million euros for an Ariane 64 and 73.6 million euros for an Ariane 62 68( * ) against, as already mentioned, a cost of 44 million dollars for a consumable Falcon 9 launch .

 Thanks for that.

 

  Bob Clark

[Exoscientist]

 

Towards every European countries own manned spaceflight.

In my blog post, https://exoscientist.blogspot.com/2023/05/who-in-european-space-will-ask.html, I noted the only reason why ArianeSpace is using the more expensive solid rocket boosters rather than just adding another Vulcain is political. The majority of the development funds and revenues from launch go to those ESA member states producing the solids. If those solids were no longer used that majority of funds would drop down to nearly nothing.

 So that‘s a severe political problem for the other member states who might want to go to an all-liquid propulsion form for the Ariane 6. But there may be a way to get to there anyway. If a member state wanted to spend their own money to build a prototype Ariane 6 core using two Vulcains how could other member states prevent it? It’s their own money. They can spend it anyway they want. As discussed in the blog the Ariane 5/6 core stage price is less than the Falcon 9.  Then remember quite key to why the all-liquid approach is preferable is because how low cost the development costs would be. The example of JAXA adding a second hydrolox engine to the H-IIA core for ca. $200 million demonstrates this:

In point of fact it’s probably even cheaper than this just to add the second engine. The transition from the H-IIA to the H-IIB actually involved multiple systems:

 

 Then conceivably the cost just for adding the engine only might be only $100 million or less. But when there is no multi-billion dollar development cost, any of the ESA member states could afford to add an additional engine to an Ariane 5/6 core on their own. It’s so low that even the member states that spent billions developing the solids could also adapt a Ariane core to have two Vulcains at this low cost.

  At such a low development cost and each per rocket cost being even lower than the Falcon 9 each ESA member state could have their own independent all-liquid Ariane launchers. And then without the safety issue of solids, each ESA member state would have their own independent manned flight capable rockets.

   Robert Clark

Edited June 7, 2023 by Exoscientist

[tater]

4 hours ago, Exoscientist said:

  At such a low development cost and each per rocket cost being even lower than the Falcon 9 each ESA member state could have their own independent all-liquid Ariane launchers. And then without the safety issue of solids, each ESA member state would have their own independent manned flight capable rockets.

How many decades and billions to have a crew vehicle to put on top?

Also, comparing retail launch services costs doesn't really help here (as in the other thread). What matters is actual cost. I have seen numbers all over the place both for projected Ariane 6 cost to customer, and SpaceX cost to customers. Their website lists a cost at X, then you read that a given customer paid 1.3X (or whatever). Until we see what is actually bid someplace public for a competition between 2 vehicles, the actual costs are not transparent.

Also, the 2 booster version has a low mass to LEO for a capsule, and the 4 SRB version has more than enough, so with a launch into ISS plane, it likely needs closer to the 4 SRB version (also with LES mass, etc).

Edited June 7, 2023 by tater

[SunlitZelkova]

It seems like it would be easier to build F9 production and launch infrastructure in French Guiana or Scotland or wherever these European states would launch from.

Europe is already pretty dependent on the US for defence equipment, why not space too?

[linuxgurugamer]

5 minutes ago, SunlitZelkova said:

It seems like it would be easier to build F9 production and launch infrastructure in French Guiana or Scotland or wherever these European states would launch from.

Europe is already pretty dependent on the US for defence equipment, why not space too?

They don't want to be totally dependent on the US, also national pride, etc

[Exoscientist]

 On the national pride issue, great importance to have an all European crewed rocket to reach orbit.  Consider, the time SpaceX took to add one or more Raptors to Starship for their landing tests was weeks to  months. So adding a second or third Vulcain probably could be done in less than a year.

  Robert Clark

[tater]

1 hour ago, Exoscientist said:

 On the national pride issue, great importance to have an all European crewed rocket to reach orbit.  Consider, the time SpaceX took to add one or more Raptors to Starship for their landing tests was weeks to  months. So adding a second or third Vulcain probably could be done in less than a year.

For SpaceX.

in less than a year Arianespace could arrange some meetings, which might result in commissioning a white paper (might take a few years of such meetings, but let's be optimistic). Maybe a year later, they present the paper, and decide, yesiree, we're gonna do it! Submit paperwork for funding, member states seeing SRBs going away get POed, and delay, some years later it gets funded... they launch the first test vehicle some time after SpaceX has landed on Mars. (note that I am not optimistic about a Mars landing happening any time soon )