Author Topic: Skepticism about reusability  (Read 26103 times)

Offline yg1968

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Re: Skepticism about reusability
« Reply #120 on: 12/15/2015 02:59 AM »
There was studies about how many flights it takes for reusability to be worth it. I forget the exact number but I think that it's in the order of once per month.
That's for partial reuse. Full reuse is about an order of magnitude greater.

I've seen figures of 8 launches/year for partial reuse to make sense and 40 launches per year for full reuse to make sense. Both of these are lower-bounds, but still there's a LOT of assumptions that go into them.

I find them as useful orders of magnitude to guide discussion. Obviously there's no physical law about 40 launches per year, but it's better than saying it's like 10,000 or 3 flights, just arbitrarily.

Yes. That's it. I remember that you were the ones linking these studies. I was hoping that you would jump in.

These numbers kind of make sense to me too. Blue's initial objectives for orbital flights is once per month. I think that is the reason that they have no intention of reusing their second stage. 
« Last Edit: 12/15/2015 03:02 AM by yg1968 »

Offline Robotbeat

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Re: Skepticism about reusability
« Reply #121 on: 12/15/2015 04:05 AM »
Liquid oxygen costs about 4 cents per kilogram in bulk (or less). Natural gas costs $0.10/kg right now.

If you somehow get launch costs down to mostly the propellant costs, then launching something into orbit would cost about as much as mailing something across the country.

That's what reusability is about. If reusability can be made to work, then chemical rockets are sufficient for expansion into space (combined with other common tech used on modern spacecraft).
« Last Edit: 12/15/2015 04:09 AM by Robotbeat »
Chris  Whoever loves correction loves knowledge, but he who hates reproof is stupid.

To the maximum extent practicable, the Federal Government shall plan missions to accommodate the space transportation services capabilities of United States commercial providers. US law http://goo.gl/YZYNt0

Offline Coastal Ron

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Re: Skepticism about reusability
« Reply #122 on: 12/15/2015 04:07 AM »
My background is in manufacturing operations, which has included factory scheduling.
Then I can't believe you brought as an example to have people essentially paid for doing nothing, you know it doesn't work.

I brought it up purely from a cost standpoint, since the topic was business models, not how to use employees to their full potential.

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But all that expensive equipment they bought for a factory at that capacity and all the capital cost associated with that investment, that's not going away.

What "expensive equipment"?  How much do you think Falcon 9 1st stage tooling costs?

And again, remember that for every launch they have to build a 2nd stage, so their production line will be in continuous use, and even more so if they are able to expand the launch market with more launch business.

So they will be amortizing their Falcon 9 tooling for years to come.


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The SpaceX business model for reusability makes far more sense than the ULA one.
Actually I'm pretty sure neither of them really has a detailed business model, yet. This is a development program.
SpaceX will try it, believes it's worthwhile and will then decide how to proceed.

If we want to leave planet Earth in any numbers, then reusability has to be perfected.  So based on Musks publicly stated goals about settling Mars, and his publicly stated goals about reusability, reusability is not a question for SpaceX - it's a mandatory goal.

And based on their experience building and launching 18 successful Falcon 9, I have no doubt that they already know what the financial numbers could be.

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There is no single 20-year masterplan to world domination because that's not how the world works. There's just trying and learning and keep going. And that's what they do.

SpaceX was formed 13 years ago to make humanity multi-planetary - and that goal won't be met by the year 2022.  So I'd say that according to Musk there is a multi-decade plan.  And he has been very consistent about the goal.

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So this whole discussion is moot because nobody does yet know whether this will pay. QuantumG is right, "skepticism" is exactly the correct word. Skepticism about "hurray they will change the world with this" as well as skepticism towards "we know it will never work".

Nothing wrong with being a skeptic, and we should all be skeptics for the right things.  But skeptics don't create the future, dreamers do.

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But at least they try it, you get nowhere if you don't try.

Yep.
If we don't continuously lower the cost to access space, how are we ever going to afford to expand humanity out into space?

Offline WindyCity

Re: Skepticism about reusability
« Reply #123 on: 12/15/2015 04:32 AM »
Skepticism is healthy, and I have heard a number of rocketry experts question the feasibility of using chemical propulsion to achieve the goals Musk has set for his company. Those doubts rest mainly on estimates of the cost. That said, I think it's probable that he and his engineers have thought harder about these problems than most other people in the business. After all, the man has staked billions on developing reusability, and the only reason for that is to reduce the expense of launching from earth to a level where his ambition to colonize Mars makes economic sense. If building a successful satellite launch company were all that he wanted to do, the cost reductions he's achieved through vertical integration and efficient design already give him a competitive advantage. Why strive for reusability unless he thinks it stands a reasonable chance of lowering launch costs even more dramatically? It's not about making bigger profits. He apparently likes money, but money isn't what drives him. It's his vision. Skepticism is called for. That's a hallmark of the scientific spirit, and necessary for advancement. But so is hope. The odds may be slim that Musk will succeed, but he must have a path in mind, and have numbers to back it up.

Offline pippin

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Re: Skepticism about reusability
« Reply #124 on: 12/15/2015 04:32 AM »
What "expensive equipment"?  How much do you think Falcon 9 1st stage tooling costs?
Engine tooling. Stage production. And then there's the whole McGregor test facility.

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And again, remember that for every launch they have to build a 2nd stage
With 1/9th to 1/27th the number of engines.

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So they will be amortizing their Falcon 9 tooling for years to come.
Sure. And stop to innovate? So that they don't need new investment? I don't see that.
You should know you don't amortize over time but over the usage time of equipment.

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If we want to leave planet Earth in any numbers, then reusability has to be perfected.
Sure. Didn't argue about that.
And we will then see the flight rates required to make the business case work.
I'm afraid, though, that you and me and Musk won't live to see that happen because the investment is simply way, way beyond what a private endeavor can handle from donations and I currently see neither a business case nor a government paying for that.
Reuse or not.

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So based on Musks publicly stated goals about settling Mars, and his publicly stated goals about reusability, reusability is not a question for SpaceX - it's a mandatory goal.
Not really. If Musk is going to mars he's not going there on current equipment so there is little need to reuse that if it was just about Mars. Reuse of F9 and FH is for his current launch business, mostly government launches and a few comsats. Maybe more comsats if the business models for global LEO sat networks compute this time.
There is growth here, sure. Maybe twice the flights seen today, maybe three times. That's the range of launch rates that need to support the case for reuse. Not Mars.

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And based on their experience building and launching 18 successful Falcon 9, I have no doubt that they already know what the financial numbers could be.
Well, I know what they _could_ be... What they _will_ be remains to be seen.

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SpaceX was formed 13 years ago to make humanity multi-planetary - and that goal won't be met by the year 2022.  So I'd say that according to Musk there is a multi-decade plan.  And he has been very consistent about the goal.
A goal is not a plan. A goal is where the planning starts.
The plan is how you get there and that plan seems to change every two years for SpaceX. Which is actually fine. It's good that way because you know, if they hadn't learned anything in these 13 years that would be pretty lame and if they had learned something but not updated their plans that would be stupid.

Again: this is how progress is being made. you learn and evolve. Progress rarely ever happens through revolutions.
People always think all these people who realize big breakthrough developments start out with this great genius plan but that's not what happens. They start with a goal and some rough idea and then 90% of them fail and the other 10% revise their plans over and over again and get lucky and that's how they reach their goal.
And with hindsight it then all looks so easy because you don't look at all the others who tried the same thing and failed not because they were so much more stupid but just because a few things didn't come together.
« Last Edit: 12/15/2015 04:36 AM by pippin »

Offline WindyCity

Re: Skepticism about reusability
« Reply #125 on: 12/15/2015 04:40 AM »
Reuse of F9 and FH is for his current launch business, mostly government launches and a few comsats. Maybe more comsats if the business models for global LEO sat networks compute this time.

I have had the impression that reusability for the F9 and FH is an incremental developmental step for the construction of the Mars system. Why would reusability be required for ISS resupplies and human transport, or for satellite launches?

Offline pippin

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Re: Skepticism about reusability
« Reply #126 on: 12/15/2015 04:45 AM »
Because they want to reduce cost and they hope it does that. Isn't that what this whole discussion is about?

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