How would you improve current launch vehicles?

[Kryten]

So no new materials except nanotubes or somesuch ever ? O RLY ?

Pretty much. You won't get significant results without massive improvements in tensile strength, given the aforementioned balloon tanks. They're already less than a cm thick, no normal material is going to go much less than that with a useful pressure.

No he didn't. Quite the opposite. Quoting his first post.

Major improvements-things like SSTO-aren't viable without majorly increased demand. The expendable, multistage rocket paradigm is around for a reason.

Emphasis mine.

He's just stating that 'build them and they will come' doesn't work in this business. Given the number of people that have gone bust banking on it that's basically an established fact.

So there are no other cost reduction options than increased demand, and no options to increase demand, in short, there are no cost reduction options.

There's no way for the launch provider to increase demand. That's not the same as saying demand can't increase.

[MBobrik]

Pretty much. You won't get significant results without massive improvements in tensile strength, given the aforementioned balloon tanks.

This might be your personal opinion, but unless you pull a theoretical maximum of non-nanotube material strength/weight ratio calculation akin to the maximum theoretical ISP calculation from somewhere ( don't bother. we both know that no such thing exists ), you have no right to claim I am ignorant and failed to do my research.

Major improvements-things like SSTO-aren't viable without majorly increased demand.

Again, show me a calculation of minimum theoretical manufacturing and operating costs at current level of demand, and that we are actually approaching those, otherwise it is just your personal skepticism.

He's just stating that 'build them and they will come' doesn't work in this business.

True but irrelevant.

There's no way for the launch provider to increase demand.

Again, evidence ? Calculation ?

[Kryten]

This might be your personal opinion, but unless you pull a theoretical maximum of non-nanotube material strength/weight ratio calculation akin to the maximum theoretical ISP calculation from somewhere ( don't bother. we both know that no such thing exists ), you have no right to claim I am ignorant and failed to do my research.

Show me something that's not nanotubes that can do an order of magnitude or more more tensile strength than existing alloys; and cheaply. That's the kind of stuff you're asking for here.

Again, show me a calculation of minimum theoretical manufacturing and operating costs at current level of demand, and that we are actually approaching those, otherwise it is just your personal skepticism.

SpaceX. If somebody had a robust model for lower operating costs, they'd be using it.

Again, evidence ? Calculation ?

You just admitted 'build it and they will come' isn't true in this case-in other the launch provider can't create the demand.

[Nibb31]

Remember that composite tanks are more expensive. Using them for disposable tankage might improve performance, but it also increases manufacturing cost. In some cases, it might also impact operational cost (maintenance, repairs) and safety or reliability, because those materials are less well known and trusted. Increased risk means higher insurance costs, which again negatively impacts the launch price.

Composite tanks are not a new idea. Aerospace companies have known about them for decades. They don't make rockets out of aluminium because they are stupid. The reason they use the materials they use is because they offer the best combination of various factors. In most cases, it will be cheaper to increase performance through other means with trusted technology: bigger engines, bigger tanks.

Engineering is about finding compromises between a multitude of requirements: cost, performance, flexibility, reliability, safety, logistics, schedule, infrastructure, etc...

Which is why my first answer to the OP's question "How would you improve current launch vehicles?", was "Improve how?". Because improving one parameter is always going to negatively affect a whole bunch of other parameters.

[MBobrik]

Show me something that's not nanotubes that can do an order of magnitude or more more tensile strength than existing alloys; and cheaply.

First, the an "order of magnitude or more" is your arbitrary condition. I think it is obvious that even a less than order of magnitude increase would result in the corresponding dry mass decrease, payload weight increase and thus cost per kg decrease.

Second, I am just an ignorant bloke on the internets who got no idea and failed to research even the most basic stuff on the topic, according to you. But my inability to name you a new and better material, right now, would prove general impossibility only if I were in fact omniscient. Which, I am surely not.

SpaceX. If somebody had a robust model for lower operating costs, they'd be using it.

As matter of fact, neither SpaceX is. And their very appearance and success, and their plans for the future clearly show that the current status quo is not the best physically possible.

And the "if it were possible, somebody would already do it" variant of the arfument from ignoracne fallacy*, you and Nibb are reiterating like a mantra, ought get its own name. **

I've searched on the internet and found nobody named it yet.

So I name it The omniscient problem solver fallacy.

You just admitted 'build it and they will come' isn't true in this case-in other the launch provider can't create the demand.

You are overlooking something as obvious as decreasing cost at current demand level which in turn causes future demand to increase.

"Improve how?". Because improving one parameter is always going to negatively affect a whole bunch of other parameters.

This is true only if you already reached the global optimum though all design variables, and no new options will exist for the rest of the ethernity.

* the claim may be rephrased as "better solutions are not known so they don't exist"

** Gonna find a pillow, because if you are going to counter that it is not a fallacy by saying "if it were a fallacy, someone would have already named it", I will facepalm so hard that I might hurt myself.

Edited December 17, 2014 by MBobrik

[Frozen_Heart]

Updating original post with suggestions from the thread. Do people agree or disagree that these could work to even slightly shave down costs?

[shynung]

My two pence:

-Standardization: already tried, considered successful. SpaceX's Falcon 9 used 9 identical engines on its lower stage, and a modified variant on the same engine for its upper stage. Greatly simplifies manufacturing tools, and reaps the benefits of mass production despite lower launches.

-Kerosene fuel: already used, considered successful. Numerous launch vehicles, among the Falcon 9 and Soyuz rocket, used a Kerosene/LOX mixture as propellant.

-Fuel Crossfeed: not tried yet IRL successfully demonstrated in the Space Shuttle Orbiter. Planned in the upcoming Falcon Heavy.

-Advanced nozzles: no significant development IRL so far. Successfully demonstrated in KSP, but actual engine specs may vary.

-Composite tanks: already used, but mainly as tank insulation rather than main structural part. May be developed if prices come down, but unlikely for the moment.

Feel free to correct me if I'm wrong.

Edited December 18, 2014 by shynung

[King Arthur]

-Fuel Crossfeed: not tried yet IRL, successfully demonstrated in KSP. Planned in the upcoming Falcon Heavy.

The Space Shuttle fed its three SSMEs from its EFT (external fuel tank), I think that counts as a form of crossfeeding.

[magnemoe]

The Space Shuttle fed its three SSMEs from its EFT (external fuel tank), I think that counts as a form of crossfeeding.

Yes, however the engines shut down before tank was ejected, else you have the same issues as crosfeed, you has to close of flow from the tank, vent the fuel or oxidizer in the pipes then decouple. This might work on crossfeed too as the falcon engines can be restarted with fuel from the internal tank, else the problem is to switch fuel source without disrupting the flow.

[Bill Phil]

Actually, little development of rocket engines has taken place in the last few decades... Kind of bad if you ask me.

[fairytalefox]

Actually, little development of rocket engines has taken place in the last few decades... Kind of bad if you ask me.

Can I ask you for some details?

[Whirligig Girl]

So there are two concepts for improving launch vehicle cost efficiency.

1) Make them reusable

2) Make them Big and Dumb.

If your engine is super expensive and advanced, you don't want to throw it away (That's why the Space Shuttle mounted the engines on the orbiter). If it's really basic and cheap, then what's the point in adding all the other gizmos and gadgets to make it return or be reused? The Space Shuttle was our first try at reusability. SpaceX's Falcon rockets are the next step, even tomorrow they will attempt a flyback of the rocket stages to a floating barge. Skylon is perhaps the ultimate goal. People liken throwing away rockets to throwing away airplanes. Well, the Skylon is an airplane, and it's not being thrown away. Pretty darn big payload capacity too!

Or you could stop comparing rockets to planes, and just build a really big, really simple, really cheap to produce rocket, and mass produce them. This has the added benifit of making a rocket explosion/failure not such a big deal as far as vehicle availability goes.

To see why the space shuttle program wasn't successful, look here.

As to how I'd improve current launch vehicles, like those from the ULA, I'd try and make them reusable. Making them mass-produced and cheap might actually be considerably harder due to the fact that their components aren't that. You'd practically have to just start over.

As for russian vehicles, there's only one thing I can say. REDESIGN THE PROTON LOWER STAGE! That hypergolic fuel mix is a considerable problem downwind of the launch site, and it's not even efficient!

[Whirligig Girl]

-Advanced nozzles: no significant development IRL so far. Successfully demonstrated in KSP, but actual engine specs may vary.

KSP Doesn't actually simulate advanced nozzle designs. It's just a model and a number for Isp. The devs could have made the Aerospike 20 times more efficient or made it half as efficient. The use of the aerospike in KSP is not really a demonstration of real world uses.

[78stonewobble]

I would create the demand, that would drive any development and improvements. So basically sink money into it, rather than save them.

Permanent presence on the moon for maintaining a far side astronomical station. Ie. moon side of VLBI, large optical observatories and what not.

A permanent asteroid and comet ressource and space borne manufacturing industry.

A permanent long term viable human population on space stations that is self sufficient.

Supported, initially, by the mass produced rockets that launch the equivalent of 4-6+ saturn V payloads a year. Every year, for the forseeable future.

PS: I think the cost of a saturn V in 2014 dollars were around 1,9 billion USD, rounding up to 2 billion. 6 launches a year for 12 billion USD is "just" 0,8 percent of the yearly revenue for the ten largest automotive producers put together.

[Steambirds]

Much like the planned manned mission to Venus by America, we could probably make things more efficient by turning an empty fuel tank into a crew compartment.

[shynung]

KSP Doesn't actually simulate advanced nozzle designs. It's just a model and a number for Isp. The devs could have made the Aerospike 20 times more efficient or made it half as efficient. The use of the aerospike in KSP is not really a demonstration of real world uses.

Hence the line, "actual engine specs may vary".

[TythosEternal]

Yes, however the engines shut down before tank was ejected, else you have the same issues as crosfeed, you has to close of flow from the tank, vent the fuel or oxidizer in the pipes then decouple. This might work on crossfeed too as the falcon engines can be restarted with fuel from the internal tank, else the problem is to switch fuel source without disrupting the flow.

My contacts at SpaceX indicate that they have not found a working solution for the crossfeed problem in the F9H design. Most likely, in my judgment, we will see throttling profile similar to the Delta IV: boosters burn at full while main stage throttles back after launch, then back up after booster separation.

[Aghanim]

How do you do crossfeed in real life anyway? Like the stresses, and the pump needed... What powers the crossfeed pump?

And this: http://en.wikipedia.org/wiki/Aquarius_%28rocket%29

You go cheaper by accepting that failure is an option. Needless to say it was a weirdly bad idea

Edited December 18, 2014 by Aghanim

[cantab]

My contacts at SpaceX indicate that they have not found a working solution for the crossfeed problem in the F9H design. Most likely, in my judgment, we will see throttling profile similar to the Delta IV: boosters burn at full while main stage throttles back after launch, then back up after booster separation.

Interesting. I do recall that crossfeeding wasn't going to be "standard" operation on the F9H, but rather only employed to loft the heaviest payloads that would need it.

But it's a reminder that KSP is not a remotely realistic rocket design simulator. SpaceX believe they can land a rocket stage on its engines on a boat, but they can't do the real-world equivalent of placing a fuel line.