Author Topic: Fairing reuse  (Read 434173 times)

Offline Jim

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Re: Fairing reuse
« Reply #340 on: 04/11/2016 01:58 PM »
Since there are four points of attachments on each fairing half it's easy to control twisting. You know how long is each cable. As well as it's easy to measure pressure on the cable. If one is longer that means it should be pulled little bit faster than other ones.

No 6DOF control? Why you need that?

I doubt now we talk about the same they thing? Why should they prevent fairing halves from hitting each other? It's all about hitting each other in controlled manner to reconnect and make shape which is safe in atmospheric heat and can be easily make floatable.



there is no "hitting" of the fairing halves.  they would get damaged.  Fairing mate is a slow and controlled motion.

What four attach points?

6DOF is needed because the cables are going to be tens of feet long and the fairing halves are going to be subject to aero and plume loads which will give them different rotation and translation rates.  They are not going to remain "collinear"  . The cables will be long enough to get twisted or have the fairings halves contact each other in weird attitudes


« Last Edit: 04/11/2016 01:59 PM by Jim »

Offline JamesH65

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Re: Fairing reuse
« Reply #341 on: 04/11/2016 02:19 PM »
I'm still not sure why people want to bring the fairing back together. Why not just attempt to land each half individually. It's going to act more like a leaf when still in halves, rather than a bullet when recombined, which should mean an overall less stressful reentry.

Offline Remes

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Re: Fairing reuse
« Reply #342 on: 04/11/2016 10:46 PM »
I found the comment in the after launch press conference from EM interesting (at 33:33): Each of the fairing halfs cost several millions.

Playing around with numbers: if each fairing half is 2mio (lower boundary), then the complete fairing is 4 mio. If I take 4mio per engine as an absolute upper boundary (then 10 engines would be 40mio, fairing 4 million and leaving 16mio for everything else including launch, testing and perhaps profit), then one fairing would equal the cost of one engine. Which seems somehow odd, given the complexity of an engine. And I would rather guess an engine is less then 4mio (because 16mio for everything else is not too much).

Offline envy887

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Re: Fairing reuse
« Reply #343 on: 04/11/2016 11:18 PM »
For a low temperature, low stress re-entry it helps to increase area, reduce mass, and increase drag coefficient.

Orienting halves individually with the concave side forward helps with all those.

Offline georgegassaway

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Re: Fairing reuse
« Reply #344 on: 04/11/2016 11:34 PM »

BALLUTE

Offline hrissan

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Re: Fairing reuse
« Reply #345 on: 04/12/2016 04:17 PM »
Each half should land independently, that's clear.

Here is how: each half has large parts of each on hinges, so it splits open, obtaining the shape of maple seed, then splashes down into water on autorotation!!! :):):)

Offline Doesitfloat

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Re: Fairing reuse
« Reply #346 on: 04/12/2016 04:48 PM »

BALLUTE

Don't be silly that could be lightweight and practical. :)

Then when they are lower... just catch em


Online wannamoonbase

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Re: Fairing reuse
« Reply #347 on: 04/12/2016 05:59 PM »
I found the comment in the after launch press conference from EM interesting (at 33:33): Each of the fairing halfs cost several millions.

Playing around with numbers: if each fairing half is 2mio (lower boundary), then the complete fairing is 4 mio. If I take 4mio per engine as an absolute upper boundary (then 10 engines would be 40mio, fairing 4 million and leaving 16mio for everything else including launch, testing and perhaps profit), then one fairing would equal the cost of one engine. Which seems somehow odd, given the complexity of an engine. And I would rather guess an engine is less then 4mio (because 16mio for everything else is not too much).

The engines are a volume production product and could be getting cheaper with each one produced.  Depending on material costs.  SpaceX should be getting smarter and more efficient as they continue to crank out these engines, plus development costs get spread out more with each one made.

Fairings are a large structure, lower volume, hard to make, hard to handle, hard to ship. 

I can see the fairings as being more expensive than a single Merlin 1D.

Re-use will put additional pressure on competitors.
« Last Edit: 04/12/2016 06:02 PM by wannamoonbase »
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Offline rds100

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Re: Fairing reuse
« Reply #348 on: 04/12/2016 06:15 PM »

They should just learn how to build these cheaper, say some sort of 3D printing. Nowadays even large structures can be 3D printed.


Offline Kaputnik

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Re: Fairing reuse
« Reply #349 on: 04/12/2016 07:18 PM »

They should just learn how to build these cheaper, say some sort of 3D printing. Nowadays even large structures can be 3D printed.



Composite materials get their strength from the use of (long) directional fibres.
3D printing isn't the answer to everything...
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Offline iamlucky13

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Re: Fairing reuse
« Reply #350 on: 04/12/2016 08:41 PM »
3-D printing is massively over-hyped in the pop-science world. It has a growing, but still small place in the real engineering world, primarily for relatively complex shapes with low tolerances made in low volumes of single materials. 3-D printing as the most people recognize it is not suited for producing rocket fairings.

That said, there is a 3-D printing-like technology for carbon fiber (actually, a couple, but the types that extrude short-fiber+binder mixes like a regular 3-D printer are far from optimal strength or production rate wise): The NASA ISAAC robot definitely can do carbon fiber structure layup on this scale, when combined with rotating tooling. It's a variation of the same technology that produces the 787 fuselage sections. A larger custom gantry machine could do it with static tooling. SpaceX is well aware of this technology.

That only produces the uncured laminate, however. A single step would have been automated. That reduces the labor cost for that step somewhat, but whether it is enough to justify the up-front cost of the robot and more complex tooling is for SpaceX to figure out based on required production rates.

It still requires curing, trimming, stiffener and bracket installation, acoustic panel installation, and systems installation, including the latches and separation pushers, which themselves are relatively expensive parts.

I might as well also point out that SpaceX said a year or two ago that as they transition to higher production rates, they are doing work to streamline production throughout the factory, and part of the result of that should be lower production costs, but the fairings will remain a relatively significant cost that re-use could potentially lessen.

Online Robotbeat

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Re: Fairing reuse
« Reply #351 on: 04/15/2016 09:28 PM »

They should just learn how to build these cheaper, say some sort of 3D printing. Nowadays even large structures can be 3D printed.



Composite materials get their strength from the use of (long) directional fibres.
3D printing isn't the answer to everything...
The relevant tech here would be an automated fiber layup machine like is used for airplanes. It's still technically "Additive Manufacturing," so it's a kind of 3d printing except it uses a mandrel.

Still, SpaceX is better off trying reuse. They need to get good at this sort of thing anyway.

EDIT: Yes, the ISAAC machine. But these kind of machines are actually much better understood and more effectively utilized in industry than at NASA, to be absolutely honest. ISAAC is kind of a "me too!" sort of development, not anything ground-breaking (except in the literal sense since they need to reinforce the floor).
« Last Edit: 04/15/2016 09:30 PM by Robotbeat »
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Offline Space Ghost 1962

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Re: Fairing reuse
« Reply #352 on: 04/15/2016 10:46 PM »

They should just learn how to build these cheaper, say some sort of 3D printing. Nowadays even large structures can be 3D printed.



Composite materials get their strength from the use of (long) directional fibres.
3D printing isn't the answer to everything...

6 months ago I was listening to a presentation on 3D printing composite materials for space/LV application, where they were laying down fibers with long range orientation/registration/no kinks/no twist. (They are thinking about forming them like "pre-stressed" concrete beams, with a programmed distribution of fiber characteristics so as to make structural parts that are otherwise impossible to fabricate any other way ...

Offline cambrianera

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Re: Fairing reuse
« Reply #353 on: 04/18/2016 07:47 PM »
This is how fairing flaps can behave/deploy.
Obviously really simplified  ;)
Oh to be young again. . .

Offline sanman

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Re: Fairing reuse
« Reply #354 on: 04/19/2016 06:04 AM »
This is how the professionals do it - the clamshell way:




Offline Blackjax

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Re: Fairing reuse
« Reply #355 on: 04/23/2016 06:36 PM »

In this post
https://forum.nasaspaceflight.com/index.php?topic=39181.msg1521556#msg1521556

...an idea gets laid out that the F9 might be relegated to more mid-sized payloads well inside its performance envelope once the FH is flying regularly and that this might leave reserve capacity for RTLS.  If you take this idea and run with it on the fairing front, what you might end up with is an improved mass budget for a redesigned & reusable fairing flying on a sandbagged F9 or a FH (which is otherwise overkill for most payloads that the market might produce in the foreseeable future).  Consider also that a redesigned fairing does not need to be optimized for shipping considerations the same way that an expendable would, because shipping logistics complexity and cost are amortized over many flights and you are shipping much fewer of them.

I have often wondered if the point of the FH isn't to loft big payloads, but to enable a combined F9/FH reusable fleet to shift mass margins across the existing market for payloads to maximize reusability and "aircraft like operations".

Offline rds100

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Re: Fairing reuse
« Reply #356 on: 04/23/2016 07:19 PM »

 Consider also that a redesigned fairing does not need to be optimized for shipping considerations the same way that an expendable would, because shipping logistics complexity and cost are amortized over many flights and you are shipping much fewer of them.


Am imissing something here? A reused fairing would need to be shipped many times, since it wouldn't return to the launch site, it would end somewhere in the ocean. Then it need to be retrieved, brought to land, transported by road, etc.



Online launchwatcher

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Re: Fairing reuse
« Reply #357 on: 04/23/2016 07:29 PM »

 Consider also that a redesigned fairing does not need to be optimized for shipping considerations the same way that an expendable would, because shipping logistics complexity and cost are amortized over many flights and you are shipping much fewer of them.


Am imissing something here? A reused fairing would need to be shipped many times, since it wouldn't return to the launch site, it would end somewhere in the ocean. Then it need to be retrieved, brought to land, transported by road, etc.
Short-distance road transport of oversized items from Port Canaveral to various launch pads at the Cape is clearly a solved problem.   




Offline iamlucky13

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Re: Fairing reuse
« Reply #358 on: 04/27/2016 07:06 PM »
The relevant tech here would be an automated fiber layup machine like is used for airplanes. It's still technically "Additive Manufacturing," so it's a kind of 3d printing except it uses a mandrel.

Still, SpaceX is better off trying reuse. They need to get good at this sort of thing anyway.

EDIT: Yes, the ISAAC machine. But these kind of machines are actually much better understood and more effectively utilized in industry than at NASA, to be absolutely honest. ISAAC is kind of a "me too!" sort of development, not anything ground-breaking (except in the literal sense since they need to reinforce the floor).

There might be a bit of "me-too" involved in the decision making to purchase ISAAC, but the stated intent is to allow NASA to prototype structures more easily.

It's somewhat surprising how much work is still going on within the aerospace industry just characterizing the performance of different layup patterns. I have a friend who recently left his aerospace engineering job in part because he was looking for more variety than continuously iterating small variations in fiber orientation, ply thickness, etc, analyzing their strength in various load cases, then sending along the better patterns to the test engineers to fabricate samples of to test and compare to the analysis. He spent several years doing this.

I presume NASA tends to work with different fibers and resins than the aircraft industry, and certainly different part shapes, so they may well have their own justification for on-site prototyping, such as for subscale or truncated fairing and interstage pieces or stiffeners for SLS. Fairings or interstages have large axial loads, but less significant pressure and bending loads. Aircraft fuselages have large pressure and bending loads, but relatively little axial loading, so what is optimal for aircraft is not what is optimal for rockets. I suppose from NASA's point of view, they'll pay for that optimization one way or another: either their suppliers figure it out and factor the development costs into what they charge, or NASA figures it out and shares the data with suppliers and the whole industry benefits.


6 months ago I was listening to a presentation on 3D printing composite materials for space/LV application, where they were laying down fibers with long range orientation/registration/no kinks/no twist. (They are thinking about forming them like "pre-stressed" concrete beams, with a programmed distribution of fiber characteristics so as to make structural parts that are otherwise impossible to fabricate any other way ...

That's automated fiber placement (AFP), like ISAAC. I believe it, or at least automated tape laying (ATL), started to be used for medium-sized aircraft structures in the 90's. NASA is not the only spaceflight organization starting to look at AFP.

It is possible to fabricate large parts in other ways. Hand layup is still an option, but very tedious. Most hand layup is done with woven or stitched multi-directional fiber cloth. Larger pieces can be put down that way, which helps with production efficiency, but you have less ability to play with the fiber direction since the material you're working with has been woven or stitched with fibers in specific orientations relative to each other. Most machine layup is done with ribbon-like "tows", frequently 1/4 to 1/2 inch wide, or for low curvature parts, sometimes with "tape" 6+ inches wide. Each fiber can have its orientation chosen more or less how the engineer wants within the final structure.

As a result of how each company evaluates those trade offs, I know of different aircraft that have similar parts made in different ways (AFP vs. ATL vs. hand layup of multi-directional fibers). So although SpaceX has the option of investing in fiber placement for their fairings, don't assume that it's necessarily the best choice for what they're doing.

Offline mme

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Re: Fairing reuse
« Reply #359 on: 05/16/2016 04:31 AM »
https://twitter.com/elonmusk/status/732042627445460992

Quote
Raket_Mand @bittdk
@elonmusk how did the recovery of the fairings go?

Quote
Elon Musk ‏@elonmusk  1h1 hour ago
@bittdk Better. Not there yet, but a solution is likely.
Space is not Highlander.  There can, and will, be more than one.

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