ATK push for US space flight independence via Liberty

[joek]

1.  A substantial amount of Orion's weight is prop

No it isn't, unless you consider "Orion" an inseparable CM+SM combination, with some predefined prop load.  Which it isn't.

2.  A composite crew module will offer a mass savings over a traditional aluminum module

Based on what?  The results of NASA's CCM effort suggests otherwise--that was the "no significant mass or cost savings" part of the report.

3. Why ATK chose that is up to them and likely proprietary but it could have to do with so they could also offer the MPLM-like capability

Only if it offered some significant cost or mass savings, which it does not appear to do; see above.

4. The exact differences are again internal to ATK and LM and people here are not owed knowing those details

No, we're not "owed" anything, but that's a poor excuse not asking questions.  Or should we all bite our tongues and simply await the People-Who-Know to grace us poor ignorant sods?

On a completely speculative front from my perspective ...

Piffle.

[Go4TLI]

1.  A substantial amount of Orion's weight is prop

No it isn't, unless you consider "Orion" an inseparable CM+SM combination, with some predefined prop load.  Which it isn't.

2.  A composite crew module will offer a mass savings over a traditional aluminum module

Based on what?  The results of NASA's CCM effort suggests otherwise--that was the "no significant mass or cost savings" part of the report.

3. Why ATK chose that is up to them and likely proprietary but it could have to do with so they could also offer the MPLM-like capability

Only if it offered some significant cost or mass savings, which it does not appear to do; see above.

4. The exact differences are again internal to ATK and LM and people here are not owed knowing those details

No, we're not "owed" anything, but that's a poor excuse not asking questions.  Or should we all bite our tongues and simply await the People-Who-Know to grace us poor ignorant sods?

On a completely speculative front from my perspective ...

Piffle.

1.  The CM and SM are one vehicle.  Just different elements

2 and 3.  NASA's one development effort does not mean there are no savings. Read the report. Again, they have their reasons and I gave you a possibility.

Why does Scaled Composites use them?  Why did Boeing build the 787 this way?

4.  There is a difference between asking questions and demanding answers.  I would say this thread is an excellent example of people demanding things or wanting to fly off the handle half cocked

[Jim]

Why does Scaled Composites use them?  Why did Boeing build the 787 this way?

wrong.
not applicable analogies.  Did not work out for x-33 and it was found on MER to be a waste of effort since it did not save any weight. 

Fuselage shapes are different than a capsule, weight savings do not always translate

[Go4TLI]

Why does Scaled Composites use them?  Why did Boeing build the 787 this way?

wrong.
not applicable analogies.  Did not work out for x-33 and it was found on MER to be a waste of effort since it did not save any weight. 

Fuselage shapes are different than a capsule, weight savings do not always translate

Not wrong Jim.  You are by no means the final authority around here and thus far you have given me absolutely nothing substantial

On X-33, it was very much to be composite tanks for mass savings.  However composite tech had not advanced enough at that time for cyro temps and the stresses of such

[Jim]

Why does Scaled Composites use them?  Why did Boeing build the 787 this way?

wrong.
not applicable analogies.  Did not work out for x-33 and it was found on MER to be a waste of effort since it did not save any weight. 

Fuselage shapes are different than a capsule, weight savings do not always translate

Not wrong Jim.  You are by no means the final authority around here and thus far you have given me absolutely nothing substantial

and you have any authority? 
BTW, you are wrong in this case, there were no real weight savings for Orion

[Go4TLI]

Why does Scaled Composites use them?  Why did Boeing build the 787 this way?

wrong.
not applicable analogies.  Did not work out for x-33 and it was found on MER to be a waste of effort since it did not save any weight. 

Fuselage shapes are different than a capsule, weight savings do not always translate

Not wrong Jim.  You are by no means the final authority around here and thus far you have given me absolutely nothing substantial

and you have any authority? 
BTW, you are wrong in this case, there were no real weight savings for Orion

Ok Jim, thanks. My ego I guess is not so fragile that I will argue with someone who just keeps saying wrong but can provide nothing further

I stand by my points.  Enjoy your night

[Jim]

Where is your proof of your points?  You have nothing to back them up.
As for composite cabin, proof is lack of Orion's use for it.

[pathfinder_01]

and you have any authority? 
BTW, you are wrong in this case, there were no real weight savings for Orion

Yeap. NASA wanted to do composites with Orion, but they found it wouldn't save much weight. There is a report posted by rdale in a thread here:

http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20110020665_2011021823.pdf

“However, first order materials comparisons were made that would suggest that mass between the CCM and the Al-Li Orion would be similar. The CCM was strength driven rather than stiffness driven primary structure. The majority of the structure was sized by multiaxial loads caused by internal pressure. The CCM will also be exposed to possible damage during spacecraft integration and during the mission, so damage tolerance knockdowns were used to accommodate for possible impact damage. These factors combined strength rather than stiffness, multiaxial loading, damage tolerant material properties, and limits the performance benefit a composite
material system might traditionally offer to a design since strength per unit mass of damage tolerant, quasi isotropic composite materials systems are similar to Al-Li properties. Therefore, there were no expected significant mass differences between the CCM and the Orion Al-Li CM.”

One problem is that Compisites are very good at handling forces in one direction, if you apply a force in another direction they snap which in turn requires more composite to deal with. Metal on the other hand bends. This esp. comes into play when you want to do a water landing.

Composites also require a lot of hand work which can make them more expensive than metal for some applications.

[Go4TLI]

and you have any authority? 
BTW, you are wrong in this case, there were no real weight savings for Orion

Yeap. NASA wanted to do composites with Orion, but they found it wouldn't save much weight. There is a report posted by rdale in a thread here:

http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20110020665_2011021823.pdf

“However, first order materials comparisons were made that would suggest that mass between the CCM and the Al-Li Orion would be similar. The CCM was strength driven rather than stiffness driven primary structure. The majority of the structure was sized by multiaxial loads caused by internal pressure. The CCM will also be exposed to possible damage during spacecraft integration and during the mission, so damage tolerance knockdowns were used to accommodate for possible impact damage. These factors combined strength rather than stiffness, multiaxial loading, damage tolerant material properties, and limits the performance benefit a composite
material system might traditionally offer to a design since strength per unit mass of damage tolerant, quasi isotropic composite materials systems are similar to Al-Li properties. Therefore, there were no expected significant mass differences between the CCM and the Orion Al-Li CM.”

One problem is that Compisites are very good at handling forces in one direction, if you apply a force in another direction they snap which in turn requires more composite to deal with. Metal on the other hand bends. This esp. comes into play when you want to do a water landing.

Composites also require a lot of hand work which can make them more expensive than metal for some applications.

Indeed.  And since this was a pathfinder project, margin was added in order to be conservative as well as damage tolerance for potential beyond Earth missions

It is fair to assume that further refinement, analysis and internal corporate knowledge coupled with the fact this vehicle is currently for LEO-only informed the trade leading to the decision made

[Jim]

not necessarily true.  the decision was more likely due to expediency than weight saving.  CCM gives them ahead start in design

[Prober]

2.  A composite crew module will offer a mass savings over a traditional aluminum module

Not true, it was found to have no substantial weight savings

wrong the study was only for that design.    Material not yet open to public knowledge will allow a 20% weight reduction.  Will also add (from another industry) One of the major auto manufacturers will go into mass production of a composite car before 2020.  Mass production of composite parts has been the holy grail.
 

[Go4TLI]

not necessarily true.  the decision was more likely due to expediency than weight saving.  CCM gives them ahead start in design

Again, I stand by my points, and based on the comment above, you clearly do not have the absolute answer either.

I see no expediency in going with anything that was only a pathfinder and then stopped unless they felt it offered an advantage in mass that allowed additional capabilities.

As for Orion not using it, clearly with what I said above and the additional cost to essentially start the design over offered no value at that time. However that was several years ago and clearly LM has much more detailed designs for the CM now and therefore a traditional aluminum structure would seem to be the obvious choice if expediency was truly the only consideration

We will agree to disagree if that is what is necessary and can leave it at that

[Downix]

not necessarily true.  the decision was more likely due to expediency than weight saving.  CCM gives them ahead start in design

Again, I stand by my points, and based on the comment above, you clearly do not have the absolute answer either.

I see no expediency in going with anything that was only a pathfinder and then stopped unless they felt it offered an advantage in mass that allowed additional capabilities.

As for Orion not using it, clearly with what I said above and the additional cost to essentially start the design over offered no value at that time. However that was several years ago and clearly LM has much more detailed designs for the CM now and therefore a traditional aluminum structure would seem to be the obvious choice if expediency was truly the only consideration

We will agree to disagree if that is what is necessary and can leave it at that

It also depends on the task at hand. The composite might have been more than suitable for LEO, but for BEO tasks it would have needed to be beefed up and the added weight for that would have made it as heavy as the Aluminum structure.

[Zachstar]

WTF? A couple of people calling on ATK "to do some tests" in order to "prove them wrong"?

Has it seriously come to this? A bunch of armchair experts telling a massive aerospace company what they need to do to appease their "Solids are bad things" attitude? Do you realize that a) They will not give a crap what you think and b) how embarrassing you all sound?

Up your game, as I can assure you the majority of people read such posts and do this:

Damn and nobody picked up on my create use of "safe, simple, soon" ?

I for one do not care if they do those tests. As in my opinion somehow it will end up spending some kind of taxpayer money or resources. And even a dollar to ATK is a dollar wasted in my opinion.

Chris, in that case what is the appropriate way to discuss worries about the design and potential ways to address those concerns? Either from the perspective of an armchair (or actual) engineer, or a taxpayer who would be funding this hypothetical project.

Simple, let the engineers do their jobs. The three ground tests already have given plenty of data for such work. They will continue to perform such system tests throughout the operational life of the vehicle. The debate over Ares was done by engineers. I have not heard such concerns here for good reason, they learned lessons and applied them.

You mean the same kind of engineering that turned Orion from a large and very capable spacecraft into a puny waste in my opinion?

When they "did their jobs" we got Ares 1...

[vulture4]

Whether metal or composite structures are best is a complex and difficult tradeoff, and depends a lot on the organization's experience and long-term goals. Both continue to advance. Airbus went with mostly metal for the A380, Boeing bit the bullet on development cost and went all-composite on the 787. But ultimately, as we get more experience, NASA is planning to go all-composite for more and more primary structures. Development is underway at Langely for large booster structures and tanks that are all-composite, as is the SpaceShip 2 and the White Knight 2, one of the world's larest (by span) aircraft. Composites have fundamental advantages, and as we learn more, more of them will be used.

[Robotbeat]

Whether metal or composite structures are best is a complex and difficult tradeoff, and depends a lot on the organization's experience and long-term goals. Both continue to advance. Airbus went with mostly metal for the A380, Boeing bit the bullet on development cost and went all-composite on the 787. But ultimately, as we get more experience, NASA is planning to go all-composite for more and more primary structures. Development is underway at Langely for large booster structures and tanks that are all-composite, as is the SpaceShip 2 and the White Knight 2, one of the world's larest (by span) aircraft. Composites have fundamental advantages, and as we learn more, more of them will be used.

Composites have advantages that aren't always useful (like possibly less cycle fatigue compared to aluminum... an advantage for an airliner especially if there are components that might flutter, but much, much less a concern for a capsule that may only be used a dozen times). Having a complex geometry is one instance when aluminum alloys make more sense often. For instance, the interstage/proto-trunk on Dragon COTS 1 was composite (was just a tube). The trunk for COTS 2+ was aluminum alloy because it wasn't just a tube but had a much more complicated geometry (i.e. to accommodate solar arrays) and needed to stay attached to Dragon and had integrated into it the radiators, etc.

I have a feeling ATK primarily choose the composite structure because they had already been paid to do it, and so could put it in their powerpoint with pictures of real hardware. Going with aluminum would mean they'd actually have to expend some of their own money to get pictures of real hardware. Make of that what you wish, either wise use of previous resources, or an example of the sunk-cost fallacy and a LEGO spacecraft/LV stack with loads of PR. I don't really care, much of it is in the eye of the beholder.

But the NASA report clearly shows that if there are advantages to the composite capsule structure, they aren't very great given the circumstances.

[Go4TLI]

I have a feeling ATK primarily choose the composite structure because they had already been paid to do it, and so could put it in their powerpoint with pictures of real hardware. Going with aluminum would mean they'd actually have to expend some of their own money to get pictures of real hardware. Make of that what you wish, either wise use of previous resources, or an example of the sunk-cost fallacy and a LEGO spacecraft/LV stack with loads of PR. I don't really care, much of it is in the eye of the beholder.

That's kind of a ridiculous statement. 

You claim that ATK dictated to LM, who is the OEM for Orion and its derivatives, that they will go with a composite structure because ATK was but a handfull of contractors working with the NESC on a pathfinder project several years ago?

And because of that they sacraficed any engineering judgment or trades and the long term technical and cost consequences associated with that just so they could stick something in a powerpoint presentation?

And that going with aluminum, which is a design LM clearly has advanced in the last several years and is definitely further along than a composite version, would cause ATK to have to spend their own capital funds?

In my opinion, these are the kind of statements that likely keep Liberty personnel from coming on this forum and unfortunately may have something to do with the comments Chris has made in the past about ATK not wanting to advertise here.  I know that would have an impact on me if I was closely associated with or worked for them.  It's just too damn hostile and short sighted.   

[Lurker Steve]

Besides, if they just wanted pictures of an engineering test article, couldn't they put one together much quicker and cheaper using aluminum instead of composites ?

[sdsds]

Somewhere way back up the thread someone pointed out that ATK has corporate expertise, experience and capability with composites. So c'mon ... why wouldn't they choose that approach?

On a lighter topic, can everyone agree their next test flight should be dubbed, "Libert1Y"?

[Robotbeat]

I have a feeling ATK primarily choose the composite structure because they had already been paid to do it, and so could put it in their powerpoint with pictures of real hardware. Going with aluminum would mean they'd actually have to expend some of their own money to get pictures of real hardware. Make of that what you wish, either wise use of previous resources, or an example of the sunk-cost fallacy and a LEGO spacecraft/LV stack with loads of PR. I don't really care, much of it is in the eye of the beholder.

That's kind of a ridiculous statement. 

You claim that ATK dictated to LM, who is the OEM for Orion and its derivatives, that they will go with a composite structure because ATK was but a handfull of contractors working with the NESC on a pathfinder project several years ago?

And because of that they sacraficed any engineering judgment or trades and the long term technical and cost consequences associated with that just so they could stick something in a powerpoint presentation?

And that going with aluminum, which is a design LM clearly has advanced in the last several years and is definitely further along than a composite version, would cause ATK to have to spend their own capital funds?

In my opinion, these are the kind of statements that likely keep Liberty personnel from coming on this forum and unfortunately may have something to do with the comments Chris has made in the past about ATK not wanting to advertise here.  I know that would have an impact on me if I was closely associated with or worked for them.  It's just too damn hostile and short sighted.   

Hey, when everything in the whole powerpoint presentation comes from various other projects, you have to question if the design choices are based primarily on what's most efficient on first principles /or/ if it's based significantly on what's most convenient in selling the project by showing (at least at the surface level, if not on other levels... a question that is up for debate) that they're "just one step away" from implementing it.

It's not ridiculous. Look at it:

First stage: Ares I heritage.
Second Stage: Ariane V heritage.
Capsule: Orion-side-project heritage.
Launch abort: MLAS heritage.

Are all these really the best options from first principles, or were they chosen significantly because it is something that ATK has built and has a picture of and so can argue it's very close to fielding? This is clearly NOT a clearly conceived from the start, clean-sheet vehicle (that doesn't mean it's not a good one). But ATK apparently is taking to heart the concept that one "goes to war with the army you have, not the army one would like to have."

All of these things are things (other than the upper stage) that NASA started building and then rejected, either because the program got canceled or because the "alternative" way was shown to not have a significant advantage (in the judgement of those at NASA who make such decisions) over the conventional method. Obviously, ATK believes in their own PR, and I don't think they're being dishonest (except about the blackzone myth), but quite obviously NASA doesn't think MLAS is way better or that composite is way better for a capsule.