Author Topic: Refurbishment of Used Stages/Vehicles  (Read 153425 times)

Offline pippin

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Re: Refurbishment of Used Stages/Vehicles
« Reply #560 on: 03/14/2017 05:08 PM »
That means there's still going to be a need to build new engines; and the fixed costs will still keep being covered.

Well, but that's the point, isn't it: how many new engines will be built to "cover" these fixed costs.
If flight rates don't go up dramatically the result of re-use will be that these newly built engines will become more expensive than before, so "how much does an engine cost" will no longer be the same.
These metrics are more important than average figures at some current state.

You can attribute these costs wherever you like but they won't go away, it's not like "oh, SpaceX now reuses engines 90% of the time so they are saving 90% of the cost". In Reality, between fixed costs, refurbishment etc. it will probably be closer to 50% or so.
There's a reason SpaceX estimates the overall cost savings through reuse at about 30%.


Offline AncientU

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Re: Refurbishment of Used Stages/Vehicles
« Reply #561 on: 03/14/2017 05:55 PM »
SRBs = Falcon 9 first stage
ET = Falcon 9 second stage tank
SSME's = MVAC
OMS system (and orbiter) = Dragon.

Since people disagree, I guess I should explain my thinking.

The STS SRBs are both tank and engine (like Falcon 9 stage 1) which provide most of the thrust for first-stage flight and which stage at about the same speed at which the Falcon 9 first stage separates from the second stage when Falcon is used in reusable mode.

The ET and SSME's each achieve orbital velocity, just like the Falcon 9 second stage and the MVac.  This is an enormously higher speed than SRB staging/Falcon stage 1 sep.

The orbiter and its OMS pods do the same thing as Dragon and its RCS system - allow small delta-V changes on orbit to the cargo/person carrying system, and achieve re-entry.

Technical comparison is always going to be dicey -- STS and Falcon are such different systems. 
ITS and STS are closer, so maybe we wait a bit on technicalities.

I think the key comparison is that NASA abandoned reuse as not economical and the industry bought that conclusion.  EM wasn't smart enough to accept their wisdom, so he foolishly tried a different approach. 

Most of the laughing has now subsided...
« Last Edit: 03/14/2017 05:56 PM by AncientU »
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Offline JamesH65

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Re: Refurbishment of Used Stages/Vehicles
« Reply #562 on: 03/14/2017 05:57 PM »
That means there's still going to be a need to build new engines; and the fixed costs will still keep being covered.

Well, but that's the point, isn't it: how many new engines will be built to "cover" these fixed costs.
If flight rates don't go up dramatically the result of re-use will be that these newly built engines will become more expensive than before, so "how much does an engine cost" will no longer be the same.
These metrics are more important than average figures at some current state.

You can attribute these costs wherever you like but they won't go away, it's not like "oh, SpaceX now reuses engines 90% of the time so they are saving 90% of the cost". In Reality, between fixed costs, refurbishment etc. it will probably be closer to 50% or so.
There's a reason SpaceX estimates the overall cost savings through reuse at about 30%.

Don't you have to assume that by now they have covered the fixed (ie tooling) costs? Maybe not for block 5 changes, but they have been flying for some years, and have made a lot of engines. So, if they have a lower required build rate, they can actually move manufacturing staff elsewhere because they don't need as many - it's a man hours to build thing. You now have more man hours to build it in, so you need less 'man'. So cost per engine might actually lower. You also need less production line (if they have more than one).


Offline Space Ghost 1962

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Re: Refurbishment of Used Stages/Vehicles
« Reply #563 on: 03/14/2017 06:05 PM »
SX doesn't need complete reuse to succeed with Falcon. Nor do they need BO overscaling. What they need is enough reflights/gradual cost reduction/cadence/consumption of manifest/reliability ... to shift the global market by about %20 aggregate annual reduction. In this, they will be their own worst enemy, as they'll be competing mostly with themselves and their own mixed agendas.

What is meant by "gradual cost reduction" is that the portion of fixed costs has a recurring benefit - ironically, when you start with recovery/reuse, it has a negative benefit (absent R&D bonus of examining flown articles). This is also where "agile" gains ground on "waterfall". Shuttle RLV partially benefitted from reflight, but was drastically bounded by political/economic realities, some of which curse the ELV SLS as well.

The point of Falcon is to change global launch markets. Which will benefit certain providers at the cost to other providers. Suggest this is where the "new space" (benefit) / "old space" (cost) metaphor belongs, not in age or heritage of the provider, but in the ability to handle this form of uncertain change.

Offline AncientU

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Re: Refurbishment of Used Stages/Vehicles
« Reply #564 on: 03/14/2017 06:06 PM »
That means there's still going to be a need to build new engines; and the fixed costs will still keep being covered.

Well, but that's the point, isn't it: how many new engines will be built to "cover" these fixed costs.
If flight rates don't go up dramatically the result of re-use will be that these newly built engines will become more expensive than before, so "how much does an engine cost" will no longer be the same.
These metrics are more important than average figures at some current state.

You can attribute these costs wherever you like but they won't go away, it's not like "oh, SpaceX now reuses engines 90% of the time so they are saving 90% of the cost". In Reality, between fixed costs, refurbishment etc. it will probably be closer to 50% or so.
There's a reason SpaceX estimates the overall cost savings through reuse at about 30%.

I suspect there is a wide hysteresis in the cost curve.  On the way up, economies of higher production rates can significantly decrease unit costs.  On the way back down (decreasing production rate after production process is mature), the increase in unit cost should be much less than the efficiencies on way up.

Think of it this way... on way up, a manufacturer fully automates the production process (or nearly so).  Robots, tooling, 3D printers, whatever are bought and manufacturing process debugged to get required quality and production rate.  Once there, a cutback in production doesn't necessarily increase the unit cost at all.
« Last Edit: 03/14/2017 06:12 PM by AncientU »
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Offline macpacheco

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Re: Refurbishment of Used Stages/Vehicles
« Reply #565 on: 03/14/2017 06:52 PM »
That means there's still going to be a need to build new engines; and the fixed costs will still keep being covered.

Well, but that's the point, isn't it: how many new engines will be built to "cover" these fixed costs.
If flight rates don't go up dramatically the result of re-use will be that these newly built engines will become more expensive than before, so "how much does an engine cost" will no longer be the same.
These metrics are more important than average figures at some current state.

You can attribute these costs wherever you like but they won't go away, it's not like "oh, SpaceX now reuses engines 90% of the time so they are saving 90% of the cost". In Reality, between fixed costs, refurbishment etc. it will probably be closer to 50% or so.
There's a reason SpaceX estimates the overall cost savings through reuse at about 30%.

I suspect there is a wide hysteresis in the cost curve.  On the way up, economies of higher production rates can significantly decrease unit costs.  On the way back down (decreasing production rate after production process is mature), the increase in unit cost should be much less than the efficiencies on way up.

Think of it this way... on way up, a manufacturer fully automates the production process (or nearly so).  Robots, tooling, 3D printers, whatever are bought and manufacturing process debugged to get required quality and production rate.  Once there, a cutback in production doesn't necessarily increase the unit cost at all.
Except SX still needs to make lots and lots and lots of 2nd stage engines and fairings. Those productivity gains can now be redirected to making perhaps 3x as many 2nd stage/fairings. Booster / regular M1D resources can be reallocated to making more 2nd stages / M1Dvac.
Eventually factory space might be reallocated towards making Raptors and shipping those to the ITS factory, or even building a F9R sized Raptor rocket or at least 2nd stages.
Your logic barely holds if SX doesn't capture more launches, which is highly unlikely. SX won't monopolize launches but it might have >50% of worldwide commercial launches.
And although not yet proven, there's the expectation that cheaper launches can increase commercial satellite launches.
Looking for companies doing great things for much more than money

Offline pippin

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Re: Refurbishment of Used Stages/Vehicles
« Reply #566 on: 03/14/2017 06:57 PM »
That means there's still going to be a need to build new engines; and the fixed costs will still keep being covered.

Well, but that's the point, isn't it: how many new engines will be built to "cover" these fixed costs.
If flight rates don't go up dramatically the result of re-use will be that these newly built engines will become more expensive than before, so "how much does an engine cost" will no longer be the same.
These metrics are more important than average figures at some current state.

You can attribute these costs wherever you like but they won't go away, it's not like "oh, SpaceX now reuses engines 90% of the time so they are saving 90% of the cost". In Reality, between fixed costs, refurbishment etc. it will probably be closer to 50% or so.
There's a reason SpaceX estimates the overall cost savings through reuse at about 30%.

I suspect there is a wide hysteresis in the cost curve.  On the way up, economies of higher production rates can significantly decrease unit costs.  On the way back down (decreasing production rate after production process is mature), the increase in unit cost should be much less than the efficiencies on way up.

Think of it this way... on way up, a manufacturer fully automates the production process (or nearly so).  Robots, tooling, 3D printers, whatever are bought and manufacturing process debugged to get required quality and production rate.  Once there, a cutback in production doesn't necessarily increase the unit cost at all.
Well, in reality, due to inflexibilities in your workforce and asset use it's typically the other way around. You have to invest and add costs before you take in economies of scale and the costs don't go away as quickly if you reduce production.
It's why even highly efficient companies often go bankrupt under a demand shock (negative) when margins are low and it regularly hits manufacturing companies of all kinds.

Online guckyfan

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Re: Refurbishment of Used Stages/Vehicles
« Reply #567 on: 03/14/2017 07:41 PM »
I am confident the workforce can mostly switch to building Raptor without losing the ability to build Merlins. So the cost per unit should not go up too much. I do believe that they will switch to all methane Raptor vehicles not too far in the future, less than 10 years.

Offline Coastal Ron

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Re: Refurbishment of Used Stages/Vehicles
« Reply #568 on: 03/14/2017 07:54 PM »
I am confident the workforce can mostly switch to building Raptor without losing the ability to build Merlins.

I have zero concern about their ability to build large volumes of one engine and small volumes of another.  Zero.  The skillsets required for building engines of any type are going to be similar enough that it won't be an issue.  The aircraft Airframe & Powerplant industry is able to handle this just fine with all the new and old engines there are in the airline industry, so I don't know why rocket engines would be any different.

Even the supply chain for Merlins and Raptors should be close enough that it should not be a concern.

Quote
So the cost per unit should not go up too much.

That will depend on the supply chain, and whether Merlin sustaining engineering keeps up with obsolescence and other supply chain design challenges.

I don't expect it will be enough to change their business model, it will just end up being part of their pricing - which if they do get 40+ launches per engine, their pricing should be pretty stable over time.

Quote
I do believe that they will switch to all methane Raptor vehicles not too far in the future, less than 10 years.

Not for Falcon 9 of course, since that is engineered for RP-1 and not methane.  But the Falcon 9 could be retired after 10 years in favor of one or more successors.
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 pippin

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Re: Refurbishment of Used Stages/Vehicles
« Reply #569 on: 03/14/2017 11:08 PM »
And let's not forget a Raptor powered stage needs to be pretty large to land.

Offline envy887

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Re: Refurbishment of Used Stages/Vehicles
« Reply #570 on: 03/14/2017 11:09 PM »
And let's not forget a Raptor powered stage needs to be pretty large to land.
New Glenn sized should do nicely.

Offline pippin

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Refurbishment of Used Stages/Vehicles
« Reply #571 on: 03/14/2017 11:13 PM »
And let's not forget a Raptor powered stage needs to be pretty large to land.
New Glenn sized should do nicely.
Can Raptor throttle that deep? Isn't Raptor quite a bit bigger than BE-4?
« Last Edit: 03/14/2017 11:13 PM by pippin »

Offline envy887

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Re: Refurbishment of Used Stages/Vehicles
« Reply #572 on: 03/14/2017 11:49 PM »
And let's not forget a Raptor powered stage needs to be pretty large to land.
New Glenn sized should do nicely.
Can Raptor throttle that deep? Isn't Raptor quite a bit bigger than BE-4?
Much deeper than Merlin. Supposedly to 20%

Offline Prettz

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Re: Refurbishment of Used Stages/Vehicles
« Reply #573 on: 03/15/2017 12:29 AM »
What's a Merlin these days? About $2m apiece?

Well worth the costs of recovery and refurb.
And since you seem to have insight into SpaceX's cost structure: how much of these 2mil are fixed costs (tooling, minimum staff,...) that you don't save on if you build one less?
It needn't be about building less of them. They can build the same number of them with the existing factory line yet fly far more missions. In fact, I think that is actually the plan.

It may take SpaceX another 4-5 years to get to 10+ flights per core and a 1-2 month turn around, which will still be worth it.
If it takes them another 4-5 years to get to that stage, then something has gone terribly wrong. Perhaps wrong enough that it means they've been on the wrong track.

Offline pippin

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Re: Refurbishment of Used Stages/Vehicles
« Reply #574 on: 03/15/2017 12:30 AM »
And let's not forget a Raptor powered stage needs to be pretty large to land.
New Glenn sized should do nicely.
Can Raptor throttle that deep? Isn't Raptor quite a bit bigger than BE-4?
Much deeper than Merlin. Supposedly to 20%
The question is: deeper than BE-4?

Offline envy887

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Re: Refurbishment of Used Stages/Vehicles
« Reply #575 on: 03/15/2017 01:11 AM »
The question is: deeper than BE-4?
BE-4 can probably throttle way below what's needed for hovering NG. I've heard as low as 18% minimum throttle, while I estimate New Glenn needs 33% of one engine just to hover while empty, since the booster should mass about 80 tonnes.

Raptor would need to throttle to 25% to hover a 80 tonne stage, and Musk has said it will throttle to 20%. Plus, Merlin can't throttle enough to hover Falcon 9, and that lands just fine.

Offline Lar

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Re: Refurbishment of Used Stages/Vehicles
« Reply #576 on: 03/15/2017 01:11 AM »
A lot of these questions like how deep Raptor can throttle are not exactly  on topic, but are covered in depth in other threads. Ditto the hypothetical Raptor upper stage which has at least one thread just for it.

So let's stay on topic or some of your posts may not survive refurbishment.
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Offline Navier–Stokes

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Re: Refurbishment of Used Stages/Vehicles
« Reply #577 on: 03/22/2017 08:12 PM »
A few interesting quotes from Ricky Lim (SpaceX's senior director of launch operations) in Dave Berman's Florida Today article on the SpaceHab building lease.

Quote from: SpaceX 'super-excited' about Port Canaveral complex
Lim said, with the new process in place, SpaceX no longer will have to send boosters to a company facility in Texas for testing.

"They will be staying in Florida — outside of a quick trip to outer space," Lim said.

Within a few months, rocket refurbishing times will be cut to two to four weeks, down from the current six to eight weeks, Lim said.
« Last Edit: 03/22/2017 08:15 PM by Navier–Stokes »

Offline AncientU

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Re: Refurbishment of Used Stages/Vehicles
« Reply #578 on: 03/22/2017 10:18 PM »
Hard to imagine 2-4 weeks not being 'economically viable.'
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Offline Norm38

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Re: Refurbishment of Used Stages/Vehicles
« Reply #579 on: 03/22/2017 10:52 PM »
SpaceX has 4 Florida launches lined up over the next 8 weeks. With a 4 week process, two boosters could handle that rotation. 3 to allow margin.

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