Author Topic: Refurbishment of Used Stages/Vehicles  (Read 161569 times)

Offline envy887

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Re: Refurbishment of Used Stages/Vehicles
« Reply #540 on: 03/13/2017 05:35 PM »

This will be the first RE-FLIGHT of an orbital main stage.

No, Columbia qualifies as the first

I have a hard time calling something that doesn't carry it's own fuel and can't get off the ground by itself a main stage. What Columbia did (orbit and back while and carrying people!) was far more impressive but obviously quite different than the Falcon 9 booster.
No, Jim is correct. The orbiter, along with the ET was the main stage of STS. The only difference from a "regular" rocket is that upon MECO the tankage was separated from the propulsion unit.

That definition is fine, but Columbia never re-flew an ET. So SES-10 is still the first re-flight of an orbital main stage, just not the first re-flight of the propulsion section of a orbital main stage.

STS's first stage is the SRBs.  They were reflown.
STS's second stage is the ET + SSME's.  The SSME's were reflown.
STS's third stage is the OMS system.  It was reflown.

I would argue that the conversion from STS to Falcon looks like this:

SRBs = Falcon 9 first stage
ET = Falcon 9 second stage tank
SSME's = MVAC
OMS system (and orbiter) = Dragon.

So, STS did one thing Falcon 9 will never do (re-fly second stage propulsion system), and STS did everything Falcon 9 will soon do (hopefully), with the exception of the first-stage landing destination (sea versus barge or land).  Someday, hopefully, Dragon will make its first land landing.

I don't think a particular Shuttle solid booster assembly was ever re-flown. The "airframe" was disassembled into segments, which were refurbished and had propellant re-cast, and new SRBs (complete with new serial numbers) were built out of new and refurbished components. In theory they could have reassembled all the same components and have the "same" booster (and even given it the same serial number), but I don't think that ever actually happened (particularly the serial number part). The process actually worked better by NOT re-flying a particular assembly, and is in large part why SRB reuse wasn't cost-effective.

Exactly what Falcon 9 refurbishment consists of isn't clear yet, but it's intended to get as close to gas-n-go as reasonably possible. Replacing engines and other components will happen, but I can't see them completely disassembling the airframe between flights as a matter of course. SpaceX apparently isn't even bothering to rebuild Block 3 and 4 boosters into Block 5's.

Offline Jim

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Re: Refurbishment of Used Stages/Vehicles
« Reply #541 on: 03/13/2017 05:41 PM »
SRBs = Atlas V SRMs=F9 N/A
ET/Orbiter = Atlas V core= F9 core
SSME's = RD-180= 9 Merlins
OMS system  = Centaur= F9 second stage

Offline mn

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Re: Refurbishment of Used Stages/Vehicles
« Reply #542 on: 03/13/2017 05:50 PM »
I hope this is the right thread for my two cents on this whole 'first to be reused' argument.

Cent 1: I think it's fair to say that SES-10 would be the first time 'something' that is typically discarded will be reused, and this 'something' happens to cost lots of money to build. It is definitely a significant step, regardless of how many other 'things' have been reused in the past.

Cent 2: It's too early to tell (at least to those of us without inside information) whether this will be cost effective in the long term.

Hopefully this is something everyone can agree on.

Offline intrepidpursuit

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Re: Refurbishment of Used Stages/Vehicles
« Reply #543 on: 03/13/2017 06:04 PM »
I'll throw in my 2 cents as well. There have been many pieces of space hardware reused in the past and whether F9S1 is more or less noteworthy than, say, STS is debatable (though so far F9S1 is clearly a smaller achievement than STS IMHO FWIW).

What IS noteworthy about F9S1 is that it is the first time an ENTIRE purpose built first stage including all engines and tankage that were used for the first leg of flight will be recovered from an operational, orbital mission and reused for such. It is also noteworthy that this is the first time something anything like this has been developed on an orbital scale in decades, and that it is a commercial endeavour (yes, NASA was instrumental, but they never asked for F9S1 reuse).

History will ask whether it becomes operational and economical, which we simply don't know yet. Every step toward that (GH, GH2, Orb2, SES-10, etc.) is a good sign though, and that is why we get excited.

SRBs = Atlas V SRMs=F9 N/A
ET/Orbiter = Atlas V core= F9 core
SSME's = RD-180= 9 Merlins
OMS system  = Centaur= F9 second stage

Edits for clarification bolded.
« Last Edit: 03/13/2017 06:36 PM by intrepidpursuit »

Offline jcliving

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Re: Refurbishment of Used Stages/Vehicles
« Reply #544 on: 03/13/2017 06:28 PM »
My "2 cents" statement is the past while interesting is a moot point.  The reuse of an active launch platform is important.  A cost effective method for reuse of an active launch platform would be a significant achievement.

Offline Space Ghost 1962

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Re: Refurbishment of Used Stages/Vehicles
« Reply #545 on: 03/13/2017 07:31 PM »
Returning to Shuttle for a moment - STS-1 was a narrow thing, with lots of learning for the launch system, orbiter, and recovery of vehicle. It was a laboratory experiment, where we learned more of "what not to do".

Would not begrudge SX/BO on early reuse here. NS/F9 are the smallest reusable booster systems ever, and the margins are the smallest they'll ever be. Flight history here tells you much in the puzzle of "how you thought it would work" vs "how it works".

"Waterfall" and "agile" play this quite differently from my direct observation. Typically waterfall is looking for adequate margins against design validation. Agile on the other hand has a bunch of stochastic guesses where they were under/over margin.

What I like about the first is adherence to schedule/pressure (some may say "hide bound") . What I like about the second is that you get more exposure to pushing the bounds beyond the firsts implied "safe limits" (some may say "reckless").

So those four months of reprocessing ... does it result in a vehicle that achieves rapid reuse (e.g. less than a week) ... or just three months of reprocessing? The former is likely economic, the latter is not. And why Shuttle taught us all to doubt economic reuse.

That's how to "grade" effectiveness IMHO.

Offline spacenut

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Re: Refurbishment of Used Stages/Vehicles
« Reply #546 on: 03/13/2017 07:39 PM »
Will the processing time decrease with experience?  This was the first one, and they probably went over everything with a fine toothed comb.  That might not be necessary in the future.  Refurbishing the shuttle and rebuilding the solid rockets was a wash, so it didn't decrease costs.  Don't yet know if refurbishing a F9 stage will be cost effective, as wash, or actually decrease costs.  If it decreases costs by just 25% it would be worth it.  I think it will be more, and if the rocket can be reused multiple times, then it decreases even more.  There will come a point where too many times and it will not be cost effective as more parts wear out.   

Online macpacheco

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Re: Refurbishment of Used Stages/Vehicles
« Reply #547 on: 03/13/2017 08:45 PM »
(Not an expert)

SSME and M1D have huge fundamental differences- propellant being an obvious one, but also a completely different engine cycle. So the actual components are doing different jobs, a bit like the difference between a petrol and a diesel engine. SSME was also designed in the 70s, Merlin can draw on another three decades of development (perhaps not as big an advantage as it should be)

I don't personally know what refurbishing each of these engines entails, but a few points to consider:
1) where do you draw the line between refurb and inspection? You might not replace a component, but you might still want to whip it out and check e.g. tolerance on a bearing seal.
2) There will be a trade between the hassle and cost if inspection/refurb, and the hassle and cost of engine failure. That scale will be weighted massively in favour of not losing the vehicle.
3) There may also (and I'm starting to speculate a little here) be a trade between cost, performance, and service intervals. Is it worth building a no-refurb engine if it comes at the cost of performance loss? Would you buy a car that didn't need refuelled until the next service interval- of course not, that would mean driving around lugging 20,000 miles worth of fuel with you. Absurd example but I hope it illustrates the point.
SSME was designed in a pre CFD, pre CAD world, when Supercomputing power was measured in MIPS, today its measured in 6+ orders of magnitude higher.
SSME was designed with reuse in mind but not with economic reuse as an essential goal.
The technical resources SpaceX has put on Merlin and on Raptor towards reuse is orders of magnitude more effective.
Being skeptical is free in general, but I believe being skeptical at SX efforts towards reuse is also being foolish.
« Last Edit: 03/13/2017 08:45 PM by macpacheco »
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Offline vanoord

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Re: Refurbishment of Used Stages/Vehicles
« Reply #548 on: 03/13/2017 09:08 PM »
What's a Merlin these days? About $2m apiece?

Well worth the costs of recovery and refurb.

Offline pippin

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Re: Refurbishment of Used Stages/Vehicles
« Reply #549 on: 03/14/2017 03:02 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?

Offline MP99

Re: Refurbishment of Used Stages/Vehicles
« Reply #550 on: 03/14/2017 09:10 AM »
Returning to Shuttle for a moment - STS-1 was a narrow thing, with lots of learning for the launch system, orbiter, and recovery of vehicle. It was a laboratory experiment, where we learned more of "what not to do".

Would not begrudge SX/BO on early reuse here. NS/F9 are the smallest reusable booster systems ever, and the margins are the smallest they'll ever be. Flight history here tells you much in the puzzle of "how you thought it would work" vs "how it works".

"Waterfall" and "agile" play this quite differently from my direct observation. Typically waterfall is looking for adequate margins against design validation. Agile on the other hand has a bunch of stochastic guesses where they were under/over margin.

What I like about the first is adherence to schedule/pressure (some may say "hide bound") . What I like about the second is that you get more exposure to pushing the bounds beyond the firsts implied "safe limits" (some may say "reckless").

So those four months of reprocessing ... does it result in a vehicle that achieves rapid reuse (e.g. less than a week) ... or just three months of reprocessing? The former is likely economic, the latter is not. And why Shuttle taught us all to doubt economic reuse.

That's how to "grade" effectiveness IMHO.

Previous booster designers have had to design with margin, and then rely on telemetry and failure investigations to validate those margins.

I wonder to what extent block 5 is matured based on inspecting the actual flown stage? It seems to fit well with the agile methodology.

Cheers, Martin

Edit: better > well.
« Last Edit: 03/14/2017 09:10 AM by MP99 »

Offline vanoord

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Re: Refurbishment of Used Stages/Vehicles
« Reply #551 on: 03/14/2017 11:35 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?

No idea  :)

Given that the engines appear able to be re-used with minimal work - the JCSAT-14 core has (apparently) had 8 (?) full-duration firings since recovery - that *suggests* there is value in recovered engines?

The proposed Vulcan recovery method also suggests that engines are the driving force behind recovery and re-use.

From a personal - and yes, uninformed - point of view, I suspect we may see re-use of stages a lot fewer times than is currently being touted, e.g. two or three uses in Recovery mode, then a final flight in Expendable configuration. That means there's still going to be a need to build new engines; and the fixed costs will still keep being covered.

Online JamesH65

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Re: Refurbishment of Used Stages/Vehicles
« Reply #552 on: 03/14/2017 11:51 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?

No idea  :)

Given that the engines appear able to be re-used with minimal work - the JCSAT-14 core has (apparently) had 8 (?) full-duration firings since recovery - that *suggests* there is value in recovered engines?

The proposed Vulcan recovery method also suggests that engines are the driving force behind recovery and re-use.

From a personal - and yes, uninformed - point of view, I suspect we may see re-use of stages a lot fewer times than is currently being touted, e.g. two or three uses in Recovery mode, then a final flight in Expendable configuration. That means there's still going to be a need to build new engines; and the fixed costs will still keep being covered.

Rocket = aluminium alloy tube with Things bolted on to it.

Things = Engines, grid fins, hydraulics, legs, plus some electronics and connectors, some pipes 'n stuff.

Really Expensive things subset = engines, legs.

To me, the cost of the engines is the major component of the cost of the stage. Recovering them seems a no brainer, however you do it.

Offline rsdavis9

Re: Refurbishment of Used Stages/Vehicles
« Reply #553 on: 03/14/2017 12:48 PM »
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?

No idea  :)

Given that the engines appear able to be re-used with minimal work - the JCSAT-14 core has (apparently) had 8 (?) full-duration firings since recovery - that *suggests* there is value in recovered engines?

The proposed Vulcan recovery method also suggests that engines are the driving force behind recovery and re-use.

From a personal - and yes, uninformed - point of view, I suspect we may see re-use of stages a lot fewer times than is currently being touted, e.g. two or three uses in Recovery mode, then a final flight in Expendable configuration. That means there's still going to be a need to build new engines; and the fixed costs will still keep being covered.

Rocket = aluminium alloy tube with Things bolted on to it.

Things = Engines, grid fins, hydraulics, legs, plus some electronics and connectors, some pipes 'n stuff.

Really Expensive things subset = engines, legs.

To me, the cost of the engines is the major component of the cost of the stage. Recovering them seems a no brainer, however you do it.

Also I expect man-hours to refurbish to be a big ticket item at least at first. Once they know what doesn't have to be checked each launch the human costs should go down considerably. This is the big advantage that recovering a complete stage has over just the engines (like ula) or everything but the tank like the shuttle. They will always require "some assembly required".
With ELV best efficiency was the paradigm. The new paradigm is reusable, good enough, and commonality of design.
Same engines. Design once. Same vehicle. Design once. Reusable. Build once.

Offline Lee Jay

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Re: Refurbishment of Used Stages/Vehicles
« Reply #554 on: 03/14/2017 01:42 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.

Offline wannamoonbase

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Re: Refurbishment of Used Stages/Vehicles
« Reply #555 on: 03/14/2017 01:44 PM »
Yes the engines are the most costly part of a booster.  However, the cost of the entire booster as an assembly that doesn't need to be rebuilt and transported across the country is a huge savings too.

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.
Excited to be finally into the first Falcon Heavy flow, we are getting so close!

Offline mn

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Re: Refurbishment of Used Stages/Vehicles
« Reply #556 on: 03/14/2017 01:54 PM »
... So those four months of reprocessing ...

Where does this reference to four months of processing come from? Did SpaceX tell us how much time went into 'processing' and how long the stage was just sitting there?

Offline whitelancer64

Re: Refurbishment of Used Stages/Vehicles
« Reply #557 on: 03/14/2017 02:04 PM »
... So those four months of reprocessing ...

Where does this reference to four months of processing come from? Did SpaceX tell us how much time went into 'processing' and how long the stage was just sitting there?

Peter B. de Selding‏ of Space Intel Report:
Shotwell: Took us 4 months to refurbish the stage that we'll refly at end of this month. Going forward, it'll be sub that.

https://twitter.com/pbdes/status/839598801375608832
« Last Edit: 03/14/2017 02:06 PM by whitelancer64 »
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Offline mn

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Re: Refurbishment of Used Stages/Vehicles
« Reply #558 on: 03/14/2017 02:06 PM »
... So those four months of reprocessing ...

Where does this reference to four months of processing come from? Did SpaceX tell us how much time went into 'processing' and how long the stage was just sitting there?

Peter B. de Selding‏ of Space Intel Report:
Shotwell: Took us 4 months to refurbish the stage that we'll refly at end of this month. Going forward, it'll be sub that.

Missed that. Thank you

Offline tdperk

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Re: Refurbishment of Used Stages/Vehicles
« Reply #559 on: 03/14/2017 02:50 PM »
Peter B. de Selding‏ of Space Intel Report:
Shotwell: Took us 4 months to refurbish the stage that we'll refly at end of this month. Going forward, it'll be sub that.

https://twitter.com/pbdes/status/839598801375608832

I have not seen where we can justify this supposition  -->  4 months was an all but complete (or a complete) teardown/uninstall, inspect/blueprint, rebuild.

That is my supposition

Presumably they will not be doing complete teardown, inspect, rebuilds in the future.  Or at least they intend to learn what they do not need to refurbish, or at least the refurbishment per flight rate they need?

Speculation, they should do a complete teardown/rebuild on all reused stages before reflight for at least the first 100+ re-uses to get a feel for what needs to be done?

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