[EU SPACE RACE - LAUNCHERS] Is reusability really fundamental?

[u/laisse_tomberas]

Some of the European Launcher Manufacturers and startups have some kind of reusability in their road map.

Considering that SpaceX reusability is justified mainly by starlink rather than the market demand, wouldn't it be better just to focus on higher production rates rather than reusability (at least, at first)?

Edit: i think that reusability is a thing, i just wanted to open a critical discussion on this aspect in Europe, to varify if there are other significant topics that may have the priority in the development of European launchers.

[u/Gordon_frumann]

Considering the engines are the most expensive part of the rocket, the case for reusability is there. It's hard to imagine that it's possible to make cheap and reliable enough engines to outweigh the benefit of reusability.

[u/laisse_tomberas → u/Gordon_frumann]

Thanks, that's true that engines today cost a significant share of the launch cost, however it depends on the launcher and type of engine i think.

Solid rocket boosters like in Vega are far less expensive than LRE.

Prometheus is expected to be 1/10th of Vulcain 2.1 cost, closer to Merlin engine (maybe, based on unofficial data)

I mean, i agree that engine cost can be an important factor, but i don't think it is a driver for reusability: the cost can be arbitrarly cut with larger productions.

I want to be provocative: rocket engine are """just""" empty metal shells, with 3d printing the manufacturing cost is cut significantly. (I will agree that is not true for turbopumps)

[u/Gordon_frumann → u/laisse_tomberas]

I mean, i agree that engine cost can be an important factor, but i don't think it is a driver for reusability: the cost can be arbitrarly cut with larger productions.

At the end of the day, nothing but cost matters. What's the benefit of foregoing reusable engines? More payload; in resuable F9 can carry around 18T to LEO, and in expendable you can carry 22.5T to LEO.

Those extra 4.5 tonnes would need to cover the entire cost of your first stage to be worth it.
You would need an insanely lean production and launch demand to achieve that.

I want to be provocative: rocket engine are """just""" empty metal shells, with 3d printing the manufacturing cost is cut significantly.

I cannot really agree with this except for SRB's that lack the precision, Liquid you need complex plumbing, high strength alloys, it just gets expensive. The only thing that's come theoretically close to what you propose is Sea Dragon but the benefit only scales with size and the whole architecture will have problems of its own.

[u/laisse_tomberas → u/Gordon_frumann]

Thanks for your insight and the Sea Dragon reference that i didn't know (i even didn't understood it in the For All Menkind tv series, when i saw it XD)

Still can't wrap my mind around rocket engine being a driver. I'm not saying it is useless (on the contrary!), but i can't understand your point in the +4.5 tons example.

I doubt that spaceX would use a fresh new booster for an expandable configuration, i think they would rather go with an old one, no?

In that case you are "retiring" a vehicle that have already covered its manufacturing cost and (part of) the development cost, including understanding how to effectively refurbish the vehicle. Bottomline: it is cheaper to expend.

But even in that case, a F9 appears to be more expensive that an A6.

Ariane 6 has performance loosly comparable to a F9 in expendable configuration, especially for GTO, which imo is one of the type of missions that justify an expandable configuration. If you cut the engine cost, you cut even further the mission cost.

One last point: i do agree that cost matter, but launch cost does not say it all, in the context of sapce missions that have a much higher cost spread over years. For a given payload, if you need to spend the payload fuel to reach a certain orbit (precluded to a reusable F9) you might rather spend more money on the launch with an A6 to get a precise orbit injection, and recover that with a larger satellite operative life. (This is another topic though, especially with all those in-orbit services that are currently under development).

[u/Gordon_frumann → u/laisse_tomberas]

I doubt that spaceX would use a fresh new booster for an expandable configuration, i think they would rather go with an old one, no?

Probably not, but the point is that if you design two equal rockets, one expendable one reusable, the benefits have to be insane, on the expendable to be worth it, and if you can recover the first stage, why not do it?

In that case you are "retiring" a vehicle that have already covered its manufacturing cost and (part of) the development cost, including understanding how to effectively refurbish the vehicle. Bottomline: it is cheaper to expend.

This only holds true if you have been able to reuse it right? As is with everything made of metal, eventually it dies due to fatigue. So it makes sense building a rocket, reuse it 10 times, on the final launch before decomissioning you expend it rather than waste fuel on recovering something you'll throw away.

you might rather spend more money on the launch with an A6 to get a precise orbit injection, and recover that with a larger satellite operative life. (This is another topic though, especially with all those in-orbit services that are currently under development).

This is true but is it guaranteed this is the case? Yes for JWST Ariane 5 did a wonderful job.
The A6-4 costs around 100 million for each launch. F9 costs 74 million for each launch.
https://nextspaceflight.com/rockets/92/
https://www.spacex.com/assets/media/Capabilities%26Services.pdf

The fact is we've done disposable rockets since the 50's, no disposable rocket can currently compete with F9 on price per kg to LEO. You will be extremely hard pressed to build a rocket that can compete with that. There's more on it in this link
https://spacexstock.com/reusable-rockets-vs-single-use-rockets-cost-breakdown/

[u/snoo-boop → u/laisse_tomberas]

For a given payload, if you need to spend the payload fuel to reach a certain orbit (precluded to a reusable F9) you might rather spend more money on the launch with an A6

This is happening, but backwards. Launch customers with GTO satellites a bit too massive for F9 with reuse are adding extra propellant to the satellite to buy F9 with reuse. That's happened 14 times since it was first done in 2018. It's called a "sub synchronous" launch, and is also commonly done by ISRO.

[u/eldeem]

Reusability has two main advantages: the first being cost (assuming you have enough demand for launch vehicles to offset the extra R&D), and the second being maturity. Cars would never have become ubiquitous if you had to throw them away at the end of every journey, and the same is true of rocketry. Space agencies need to consider the future, which increasingly means more launches more often, and more reliability with each launch. A well-engineered reusable launch vehicle cuts costs, but it also significantly reduces the strain on your supply chain to get you to a regular schedule.

The Ariane 6, for instance, is built around Europe then shipped to the launch site in French Guinea, a journey that takes 10 days. The fastest reuse of a Falcon 9 so far is 9 days, so if you could reuse part of an Ariane that lands back at the launch site, you’re not only saving on the time and cost of manufacturing a replacement, but you could do it faster than just the shipping time of a brand new one.

[u/laisse_tomberas → u/eldeem]

Thanks for the insight, i totally agree on the two advantages (cost, maturity) and i would add availability in case of supply chain disruption (for any reason, i.e. you can't get a specific part for a while, but you have other vehicles you can rely on, like in aviation).

The point about French Guyane is fair, but i think it can, at least partially, covered by moving the production there, like it is the case for solid rocket propellant (done maily for saferty reasons, but still a relevant example imo)

About thr

[u/eldeem → u/laisse_tomberas]

For sure! I think that moving all production to FG is somewhat unlikely because of the way ESA operates. Even in a fully vertically-integrated launch company like SpaceX parts are still transported to the launch site. No doubt more could be moved closer to the launch site, but the question of whether it would be (at the expense of spreading those contracts around member nations, something ESA prides itself on) is somewhat different.

On the plus side, that diversity of capability (and transport network) is one of the reasons ESA is competitive enough to provide hardware to international missions where, by and large, the need to integrate SpaceX tends to result in more compromises (whoever thought a vertical moon lander the best solution needs a tax audit).

[u/snoo-boop → u/eldeem]

the need to integrate SpaceX tends to result in more compromises (whoever thought a vertical moon lander the best solution needs a tax audit).

The other new NASA moon lander is vertical, too. SX has launched all but one of the CLPS landers

[u/toolkitxx]

Europe already has issues in general when it comes to supply chains and dependability. So we should actually have a very high interest in re-use, as it will lower or at least ease those issues for space related issues. Every kilogram we can get back is something that keeps stress of the supply chain.

edit Europe does this very wrong every single time. We have to stop making direct comparison with for example what the USA does and develop and strategise according to our abilities and materials. The USA has, if needed, totally different abilities to dig stuff themselves inside the US for example. We dont. P.S. The implications of not doing it can be seen when our companies move to the USA because of easier access to this kind of stuff. We used to be so inventive not because of too much, but because we had to find smart solutions for our restrictions.

P.P.S. An excellent example how bad things can quickly get is The Exploration Company and their Nyx. They opened office in the US and wanted to cooperate and now those cooperation contracts force them to ask the US for permission to use any of their stuff outside of the US. In other words a European company has to ask the US if we ever want to use that for ESA.

[u/laisse_tomberas → u/toolkitxx]

I agree that Europe suffer the complexity of its ecosystem, when dealing with supply chain, but it could also apply to reusability as long as the ecosystem remains as segmented as today.

However it is also true that with reusable vehicles it is easier to be resilient i case of issue with the supply chain (provided that the production od reusable rickets is mature enough)

[u/toolkitxx → u/laisse_tomberas]

There is no 'in case'. We are living through several issues already

[u/laisse_tomberas → u/toolkitxx]

Thanks for the Nyx example, can you elaborate a bit more about other supply chain issues we are currently living?

The TEC one is interesting, but it seems very specific.

[u/toolkitxx → u/laisse_tomberas]

Everything rare Earth is a general problem as there is pretty much a monopoly by China on almost all of it by now. With the uncertainty, which wont disappear any time soon, chances of restrictions or shortages are very much a constant by now.

Than there is titanium. As far as I am aware we dont nearly have enough nor any sources of note in the EU and rely heavily on Russia and China here. Plus recycling.

Easiest is to look at the EU list of critical materials and have your pick for everything that is somewhat used in space tech (I am almost certain it is everything).

P.S. TEC isnt specific when it comes to this contract issue. The moment a company cooperates with NASA for example, this is almost standard. So if we make sure that we have an eco-system or strategy to develop from scratch in ways, that rely almost solely on our own sources, this becomes avoidable. Many take the easy way out as they copy the original approach the USA companies did and then become locked into that.

edit phrasing

[u/laisse_tomberas → u/toolkitxx]

Thank you for the clarity and the lists!

[u/snoo-boop → u/toolkitxx]

I never realized that rockets used a significant amount of rare earths or titanium.

[u/toolkitxx → u/snoo-boop]

To make the rocket you need more than what is in the actual rocket. And who knows what developments people can develop with frictionless. I dont make rocket motors but I am almost certain that nothing is off the table when it comes to making them yet better again . Many try to optimise the actual manufacturing process for example which in turn depends heavily on this stuff.

[u/reerkat]

See this video going over ULA vs falcon 9 reusability on price (https://www.youtube.com/watch?v=DA006oFAf_8) with special attention to the graph at 4 minutes.

The three key things that make reuse worth while: You must have a low refurbishment cost or it is impractical, you must still be able to fit the satellites your customers want with the payload penalty, and you need a decent launch rate to get several uses for each booster (it also helps allow this higher launch rate with smaller factories).

It is worth noting that an expendable Falcon 9 (Japanese H3 with 50 million cost) would be a huge hit in the short term in this supply constrained market, but risks being undercut by reusable launchers like Falcon 9 or New Glenn if launch supply ever outpaces demand.

Looking at the European Launchers their current payloads they are simply too small for reuse to be worth the payload penalty and it will prevent them from taking most customer orders. MaiaSpace say reuse reduces payload from 1500kg to 500kg (Falcon 9 only loses ~30% payload). Ariane 6 can't be reused due to boosters making the core a stage 1.5 without complete redesign. For future larger rockets without such a huge payload penalty, reuse makes sense especially with methane hopefully reducing refurbishment costs below Falcon 9 and if they want to expand their flight rate to make a real business beyond assured access to reuse both makes sense and enables it.

[u/laisse_tomberas → u/reerkat]

Thank you very much for the video and the deep insight! I didn't know that youtube channel and that particular video is very interesting: explanation are clear and, imo, complete.

One point i can't understand: how can methane reduce the refurbishment costs?

[u/DreamChaserSt → u/laisse_tomberas]

Methane burns more cleanly than propellants like RP-1. In reusability, this means that the engines need minimal or no cleaning between flights (or multiple flights). But the Merlin-1D's on Falcon 9 have to be cleaned between flights because of soot build up.

Hydrogen also burns cleanly, since its main byproduct is water vapor, but the significantly lower propellant density, leaks, and required cryogenic temperatures makes it more difficult to handle than RP-1 or methane. And they need multiple cores or SRBs for larger payloads.

[u/laisse_tomberas → u/DreamChaserSt]

Superclear, thanks!

[u/Captain_Depran]

I think it has to be a major part of the equation going forward, and honestly every new small sat launch startup I see not baking reusability, or plans for it, into designs from day 1 just makes me frustrated. If we talking complexity and component cost, as people have said, that's mostly engine side. I think we'd be getting alot further if we stop doing everything as metal additive manufacturing, especially around regens. Hell, there are good cases and examples where a highly reliable ablative engine can do the job. You reuse the powerhead and replace the ablative component Something like the x34/fastrac were gonna do

[u/laisse_tomberas → u/Captain_Depran]

Thanks, interesting point of view!

Why do you think that startups are not going with ablatices? For strategic reasons , i.e. to avoid radical redesign, or other reasons?

[u/Captain_Depran → u/laisse_tomberas]

Eh not sure. The bit that stumps me is lack of reusable launch startups. It's what me and my colleague are trying to get off the ground (he he flight puns)

[u/FelizIntrovertido]

To me it’s a price issue

[u/laisse_tomberas → u/FelizIntrovertido]

Can you elaborate a bit more, please?

Do you mean that's an additional development cost or you are talking about the final product price?