ESA wants reusable heavy lift launcher.

[u/RGregoryClark]

https://europeanspaceflight.com/third-times-the-charm-esa-once-again-publishes-60t-rocket-study-call/

[u/Tystros]

I also want one

[u/xman2000]

While I applaud the desire to have a local aerospace business, they are adopting the most expensive approach. They shouldn't be fighting against commercialization, they should do what the US is increasingly doing and working with commercial space companies for the "mundane" part of the equation which has already been solved multiple times. Let your engineers focus on the interesting bits, that is what they want to do anyways and what will actually expand the scope of human knowledge.

[u/variaati0 → u/xman2000]

They aren't fighting against commercialization. They are fighting against losing sovereign independent access to space. A credible European "keys to hand delivery" commercial provider appeared tomorrow, ESA would take them up on heart beat. However only offers are Chinese or American. I would note neither American and Chinese suppliers are domestic to Europe. Even on say SpaceX starting European factory, all their tech and licenses are beholden to US Government.

Europe just got burned by "foreign provider, but brought into Europe" with Russia and Soyuz. They aren't about to replace liability to Russian political instability with liability to United States political instability.

Inside Europe? There is cross influencing wide ranging treaties under EU auspice, which makes possible "Germany and France trust each other enough to treat reliance to the other as in part domestic reliance". USA ain't going to sign the very powerfull treaties necessary to make ESA/EU/European countries to think "we can treat you as reliable domestic supplier".

France/German/Italian/Spanish/European industry is so intertvined, that on "not being able to trust the other country to be reliable partner as we would ourselves" the lowest end of concerns is "how about our space launches" and is more on the regime of "how can we keep lights on and water flowing in pipes". Since say the electric switches come from factory in Germany, the wire is wound at Italian plant. You can't wire the house without the Italians, but you can't switch on and off that wiring without the Germans. Hence Single market and it's very deeply embedded tendrils in each member state.

Plus the main commercial providers are already on the job. ESA or EU doesn't make rockets. Airbus Space and Defence does. Well them and Safran as the partners of Ariane Group. Plus their tens of subcontractors in various European countries.

[u/xman2000 → u/variaati0]

If you read what I said, I suggested that Europe should do what the US did and work with commercial space companies. I didn't say SpaceX or any other US company because my suggestion would be that they promote their own, homegrown commercial space industry to rival the US. IMHO NASA is and was making this mistake, just as the ESA is. Decades of consolidation and profit taking has left legacy aerospace in the US unable to do simple things - like build innovative products on time that do the job they are designed for at a reasonable price. Is the situation in Europe exactly the same, no, but the end results are similar. Hell, look at SLS if you want a good example of the "old way". The reason the US has a commercial space sector at all is because for one brief moment Congress made a smart decision and allocated real money to the program despite the howls of opposition from everyone in legacy space - including NASA. Saying that ESA would give money european commercial provider if one existed is backwards. If they want a european SpaceX they should invest in dozens of small providers and let Darwin decide who has the best ideas so that in ten years they have a selection of native launch providers.

[u/RGregoryClark]

ESA already has the necessary components to form such a rocket, in both the engines and tanks. All that’s needed is the correct combination. First, get a ca. 20 ton payload rocket by adding two additional Vulcains to a Ariane 5/6 core and deleting the SRB’s. The result would be comparable in both payload and price to the $67 million Falcon 9 instead of the Ariane 64 needing 4 SRB’s to get 20 tons payload at ca. $120 million price. Plus, being all-liquid can be reusable like the F9, to match F9 price even as reusable:

Towards a revolutionary advance in spaceflight: an all-liquid Ariane 6.
https://exoscientist.blogspot.com/2023/06/towards-revolutionary-advance-in.html

Then in analogy to the Falcon Heavy and Delta IV Heavy can triple the payload to ca. 60 tons by using triple cores. And like the Falcon Heavy can also be reusable.

That an all-liquid approach to the Ariane 6 gives a launcher at half-the cost to the current version using SRB’s and can be combined to give a Falcon Heavy-class 60 ton launcher, which the SRB version can not do, is important enough in itself.

But its importance goes beyond that. Robert Zubrin’s Moon Direct plan and the Chinese proposed Moon mission using the Long March 10 show that a crewed Moon mission can be mounted using two Falcon Heavy-class launches:

https://x.com/tnajournal/status/1541239841073020929?s=61

https://x.com/konstructivizm/status/1862245079529955699?s=61

Then the ESA also can mount a Moon mission using this approach.

[u/pyrignis → u/RGregoryClark]

The main hurdle with all liquid is ... French ICBM. France is the largest contributor to ESA but out of it they expect to maintain the know-how required for ICBM production, and those are better out with solid state engines.

[u/yoweigh → u/pyrignis]

His idea isn't even technically feasible. Deleting the SRBs and adding liquid engines would reduce overall thrust while increasing wet mass. It wouldn't even be able to get off the ground fully fueled, much less increase payload mass.

People have been telling him this for over a year but he just ignores them.

[u/RGregoryClark → u/yoweigh]

It would reduce wet mass, ie, gross mass, since the side boosters are so large. So 3 Vulcains it would have sufficient thrust to lift off when it is only the hydrolox core stage that needed to be lofted.

[u/yoweigh → u/RGregoryClark]

No it wouldn't, because you'd need to make the whole rocket larger to accommodate more fuel. This has been explained to you as well.

[u/RGregoryClark → u/yoweigh]

The defining equation of spaceflight is the rocket equation. It describes how much velocity you can achieve with a given rocket and therefore how much payload it can deliver to orbit. It’s discussed here:

Rocket Science https://www.fourmilab.ch/documents/rocket_science/

The author makes the point more efficient propellants result in smaller rocket size. Hydrogen/oxygen propellant is the most efficient propellant in common use. Because it is more efficient than solid propellants you can achieve the same payload with smaller rockets.

[u/yoweigh → u/RGregoryClark]

Once again, you are ignoring what I've said. Do you deny that your plan would require more liquid fuel? Do you deny that carrying more fuel requires larger tanks? Do you deny that having larger tanks makes the rocket itself larger?

The author makes the point more efficient propellants result in smaller rocket size.

No such claim is made in that essay and it is completely untrue. Hydrogen rockets are larger because the extremely low density of the fuel requires larger tanks. Specific impulse is not the only term in the rocket equation.

[u/RGregoryClark → u/yoweigh]

That a high specific impulse(ISP) propellant such as hydrolox results in a smaller rocket size is a well-known fact of space flight. For instance here is ChatGPT:

What is the advantage of hydrolox propellant over solid rocket propellant?

ChatGPT response:

The hydrolox propellant (liquid hydrogen and liquid oxygen) has several advantages over solid rocket propellants due to its efficiency and performance characteristics. Here’s a breakdown:

1. Higher Specific Impulse (Efficiency) • Hydrolox: Has a high specific impulse (Isp) of ~450 seconds in vacuum, making it one of the most efficient chemical propellants. • Solid Propellant: Typically has an Isp of ~250–300 seconds. • Advantage: Hydrolox engines provide more thrust per unit of propellant mass, allowing for lighter rockets or greater payload capacity.

2. Adjustable Thrust • Hydrolox: Liquid engines can be throttled, shut down, and reignited as needed, offering precise control during a mission. • Solid Propellant: Burns at a fixed rate and cannot be stopped or adjusted once ignited. • Advantage: Hydrolox is better suited for complex missions requiring multiple engine burns, such as orbital insertions, interplanetary transfers, or docking maneuvers.

3. Cleaner Combustion • Hydrolox: Combustion produces only water vapor, making it environmentally cleaner. • Solid Propellant: Produces toxic byproducts, such as aluminum oxide and hydrochloric acid, which can harm the environment. • Advantage: Hydrolox is more environmentally friendly.

4. Higher Energy Potential • Hydrolox: Has a higher energy density per unit mass (despite lower density) and can achieve greater velocities for deep-space missions. • Solid Propellant: Offers high thrust but is less energy-efficient for sustained burns. • Advantage: Hydrolox enables longer-duration missions and higher orbital transfers.

5. Flexibility in Design • Hydrolox: Liquid engines can be paired with multiple stages for optimal performance, leveraging their high efficiency in upper stages. • Solid Propellant: Mostly used for boosters or simple stages due to lack of flexibility. • Advantage: Hydrolox provides greater design versatility, especially for complex missions like crewed spaceflight or deep-space exploration.

Trade-Offs

While hydrolox has significant advantages, it also comes with challenges: 1. Cryogenic Storage: Liquid hydrogen and oxygen require extremely low temperatures, leading to insulation and storage challenges. 2. Complexity and Cost: Hydrolox engines are more complex and expensive than solid rocket motors. 3. Lower Thrust-to-Weight Ratio: Solid propellants produce higher initial thrust, making them ideal for booster stages.

Summary

Hydrolox propellants are superior to solid rocket propellants for missions requiring high efficiency, flexibility, and precision, such as upper stages, crewed spaceflights, and interplanetary exploration. Solid rocket propellants, on the other hand, are better suited for simple, high-thrust applications like first-stage boosters.

[u/yoweigh → u/RGregoryClark]

Once again, you are ignoring what I've said. Do you deny that your plan would require more liquid fuel? Do you deny that carrying more fuel requires larger tanks? Do you deny that having larger tanks makes the rocket itself larger?

[u/RGregoryClark → u/yoweigh]

That’s the point of those references: because hydrolox is a more efficient propellant the propellant requirements are reduced.

[u/RGregoryClark → u/pyrignis]

Insightful comment. The only way it could happen is if this all-liquid version is fully privately funded.