Quote from: Go4TLI on 07/09/2012 05:51 amQuote from: Robotbeat on 07/09/2012 04:38 amI 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.
Quote from: Robotbeat on 07/09/2012 04:38 amI 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.
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.
Quote from: Robotbeat on 07/09/2012 06:47 amFirst stage: Ares I heritage.Second Stage: Ariane V heritage.Capsule: Orion-side-project heritage.Launch abort: MLAS heritage....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.Well, such criticism is not unwanted of. Let's see what the Atlas V is made of:First stage: Titan IV core stage heritage.First stage engine: Zenit / Energia heritage.Second Stage: Atlas III heritage.Second stage engine: Atlas II/III heritage.Control system: Atlas heritage.Fairing: Atlas/Ariane 5 heritage.Yet somehow this was seen as a bad, bad thing....
First stage: Ares I heritage.Second Stage: Ariane V heritage.Capsule: Orion-side-project heritage.Launch abort: MLAS heritage....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.
Quote from: Chris Bergin on 07/08/2012 06:52 pmProblem is there's also a few "Elon didn't invent it, so it sucks" or "It looks like Ares 1, uh oh!" posts too. That's my problem and also problem that whenever I try to keep the noise down, someone's always going to come out with the "oh, so you don't want negative posts then", which fraks me off.My memory doesn't go back that far, so can your remind me: did you make comments like this back in the DIRECT days when every second comment was about how much Ares-1 is a window maker and anyone who advocates for it is Dr Death?Cause it seems a lot of opinions were formed back then that will never be shaken. (not even with the full acoustic load of an SRB).
Problem is there's also a few "Elon didn't invent it, so it sucks" or "It looks like Ares 1, uh oh!" posts too. That's my problem and also problem that whenever I try to keep the noise down, someone's always going to come out with the "oh, so you don't want negative posts then", which fraks me off.
Ares-1-X was not representative of Ares 1 or Liberty in the least.
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.
Quote from: Go4TLI on 07/09/2012 05:51 amIn 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. It was false advertising (safe, simple, soon) that turned people
The biggest problem I have with ATK's offering is that solids cannot be shut down, and that imposes some serious design consequences on the abort system. This one is a showstopper for me, all by itself.
Quote from: anonymous1138 on 07/09/2012 01:41 pmThe biggest problem I have with ATK's offering is that solids cannot be shut down, and that imposes some serious design consequences on the abort system. This one is a showstopper for me, all by itself. Then you'll have a problem with CST-100 too, which would fly on a solid-boosted Atlas.ATK said that the abort system would be designed to clear any first stage failure, so the company must be using the vehicle's excess capacity to address the design challenges. - Ed Kyle
Quote from: anonymous1138 on 07/09/2012 01:41 pmThe biggest problem I have with ATK's offering is that solids cannot be shut down, and that imposes some serious design consequences on the abort system. This one is a showstopper for me, all by itself. When would you deliberatly shut down a single motor stage during flight and would not cause mission failure? On lift-off I can see you may want ot shut it down but, it does take liquids much longer to become flight operational than solids b/c of their complexity and nature. That's why they need to be shut down. Solids are much simpler in the way thrust is provided.
Quote from: Stephan on 07/09/2012 11:08 amAnd the infamous EELV blackzones, still in their briefing years after it was debunked (see last ATK conference).Ares I was cancelled nearly two and a half years ago. Let's leave it be. Liberty is not Ares I.
And the infamous EELV blackzones, still in their briefing years after it was debunked (see last ATK conference).
but, it does take liquids much longer to become flight operational than solids b/c of their complexity and nature.
Quote from: Adam K on 07/09/2012 02:14 pmbut, it does take liquids much longer to become flight operational than solids b/c of their complexity and nature. Not true.
Quote from: Jim on 07/09/2012 02:35 pmQuote from: Adam K on 07/09/2012 02:14 pmbut, it does take liquids much longer to become flight operational than solids b/c of their complexity and nature. Not true.Why are liquid started sooner than solids on every vehicle then?
Quote from: Adam K on 07/09/2012 02:42 pmQuote from: Jim on 07/09/2012 02:35 pmQuote from: Adam K on 07/09/2012 02:14 pmbut, it does take liquids much longer to become flight operational than solids b/c of their complexity and nature. Not true.Why are liquid started sooner than solids on every vehicle then?Because once you start the solids you can't turn them off, and you can't really instrument them very well. With liquids you start them, allow for all the transients and take second to see that everything is nominal, then commit to flight (which you are once you started the solids). If something is off nominal with the liquids, you turn them off and you have an intact abort. If something is off nominal with the solids, you'd probably have a LOM/C.
