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Will
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« Reply #4125 on: 01/09/2009 04:16 PM » |
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If a contractor can actually build the ultalightweight EDS claimed by Direct, Ares V will not need 5.5 segments.
This assumes NASA is willing to let contractor build such an EDS. So far NASA wanted to do it "their way", and considering that NASA does not have required experience, no wonder "NASA way" EDS is worse.
The NASA EDS is heavier. If lightness is the only figure of merit, all stages will have common bulkheads. They don't, and it isn't because the contractors don't know how to do it. Boeing's new upper stage for Delta IV doesn't have one.
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luke strawwalker
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« Reply #4126 on: 01/09/2009 04:18 PM » |
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PS The pro-Ares arguments kind of remind of the current Microsoft Mojave commercials, which essentially say, "Windows Vista, it doesn't suck nearly as bad as you think, so get behind it and purchase a copy because you don't have an alternative!"
- John
EXACTLY!!!
When did things in this country get so screwed up that elimination of competition and lack of an alternative, forcing one to adopt the existing plan/product no matter how bad it is, is somehow touted as "the best choice"?? Lack of an alternative means there IS NO CHOICE... Ignoring, downplaying, and villifying alternatives is a BAD CHOICE, and is intellectually dishonest. If something is the best choice, it would logically stand up to scrutiny and win on it's own merits-- not through elimination of any alternatives or competition FORCING it to be adopted even though it might be the worst alternative there is...
(throws up hands in disgust)-- OL JR 
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jarmumd
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« Reply #4128 on: 01/09/2009 04:40 PM » |
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I just don't understand what's so mysterious about the Direct 2.0 numbers. It seems like people are just fishing for a problem. Everything is derivative on the Jupiter:
* Core fuel tank is the Shuttle ET.
* Engines are from the Delta IV.
* SRBs aren't even derivative, they're the SRBs.
* Upper stage is a resized Atlas Centaur.
* J2-X is a modified J2.
Direct 2.0 does have the burden of explaining the numbers and reasoning, but I find the level of skepticism a bit excessive.
My complaint is simply that the amount of work required to make Jupiter seems to be low-balled. In the case of the ET, absolutely it uses the same manufacturing techniques, infrastructure, and procedures. But it IS a different tank, the only component NOT modified will be the intertank, and that will probably need to be modified so as to adjust the cross beam stiffness for TO (remember it is a vehicle resonance). Not saying anything about the value of doing it (cost/time), but its not the Shuttle ET (I know you said "derivative"). And with the Centaur upper stage, yes the design is a derivative, but tell me what its mass is after a few design evolutions. What will make the highest loads on the centaur - and how will this affect it's design? I know you aren't advocating the "Lego" LV design, but to simply say LM has more experience with this and can make their claims is to say that it's a Lego upperstage and won't need to be re-designed for Jupiter loads. (BTW, no issue with LM, but I hope that their Centaur upper stage is designed with more clarity than the Orion). Marc
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Will
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« Reply #4129 on: 01/09/2009 04:51 PM » |
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One additional point to be made regarding the production of Jupiter vs Aries.
Direct would require 3 production lines: Shuttle RSRB, Core stage, EDS
Aries would require 5 produciton lines: 5Seg RSRB, 5.5 Seg SRB, Aries I US, Aries V Core, Aries V US
The Shuttle RSRB lines exist, the Direct core stage line reuses a lot of ET production equipment, and the Jupiter EDS is a new line
All 5 production lines for Aries are new
----------------
As far as the JUS being a magical stage, at least one company thinks they can make it. All the Direct team is looking for is a review of the designs on an even playing field.
On an operating basis the savings aren't as great as you might think, since most of the cost is in the propulsion and avionics, not the structure. Based on the contract cost, the savings from entirely eliminating the Ares I US production is about $90 million a year. That's not a very large share of the cost of the entire program. Against this Jupiter requires man-rating the RS-68 and Jupiter core, both of which will raise costs for those components considerably. Also, marginal cost will be higher on the ISS mission since you are buying more liquid engines and more SRB segments.
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HIP2BSQRE
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« Reply #4130 on: 01/09/2009 05:31 PM » |
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Hope posting a link to another site won't get me in trouble:
http://www.nasawatch.com/archives/2009/01/transition_team_4.html
"Word has it Buzz was going with them"
Now that is interesting. I know Buzz has his own ideas, but if DIRECT can get his endorsement it would be a big boost in credibility.
As for the "other site", that dude harbors over-the-top hostility towards DIRECT. I suppose he must have his reasons, but even in the very first DIRECT article archived on his site, he comes down hard on DIRECT and any favorable posts. Someone must have really p*ssed in his lemonade.
Mark S.
Please change the tone. Please be constructive. Everyone has their own view. Saying rude things about anyone does not help matters.
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TrueBlueWitt
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« Reply #4131 on: 01/09/2009 05:39 PM » |
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I just don't understand what's so mysterious about the Direct 2.0 numbers. It seems like people are just fishing for a problem. Everything is derivative on the Jupiter:
* Core fuel tank is the Shuttle ET.
* Engines are from the Delta IV.
* SRBs aren't even derivative, they're the SRBs.
* Upper stage is a resized Atlas Centaur.
* J2-X is a modified J2.
Direct 2.0 does have the burden of explaining the numbers and reasoning, but I find the level of skepticism a bit excessive.
My complaint is simply that the amount of work required to make Jupiter seems to be low-balled. In the case of the ET, absolutely it uses the same manufacturing techniques, infrastructure, and procedures. But it IS a different tank, the only component NOT modified will be the intertank, and that will probably need to be modified so as to adjust the cross beam stiffness for TO (remember it is a vehicle resonance). Not saying anything about the value of doing it (cost/time), but its not the Shuttle ET (I know you said "derivative").
And with the Centaur upper stage, yes the design is a derivative, but tell me what its mass is after a few design evolutions. What will make the highest loads on the centaur - and how will this affect it's design? I know you aren't advocating the "Lego" LV design, but to simply say LM has more experience with this and can make their claims is to say that it's a Lego upperstage and won't need to be re-designed for Jupiter loads. (BTW, no issue with LM, but I hope that their Centaur upper stage is designed with more clarity than the Orion).
Marc
I believe that Ross or Chuck stated, a little while ago in this thread, that they already have an extra $2.5 Billion added in the figures they published just to deal with potential development cost overruns. Do you think that is not enough?
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mike robel
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« Reply #4132 on: 01/09/2009 05:41 PM » |
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Ross or Chuck do not control the budget of the United States
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TrueBlueWitt
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« Reply #4133 on: 01/09/2009 05:46 PM » |
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Ross or Chuck do not control the budget of the United States
No kidding.. What is this comment about? Chris? I just stated that the numbers the DIRECT team is quoting already have, I believe, an extra $2.5 Billion included to deal with cost overruns. What about that do you have a problem with?
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GraphGuy
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« Reply #4134 on: 01/09/2009 05:48 PM » |
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The Ares SRB is totally new, completely untested, untried, and in strict terms, is an experimental motor. Given the climate for this kind of big-ticket purchase, it is not really a surprise that it would cost more, without even knowing all the technical reasons why. Does anyone out there honestly believe that if we built a Mercury spacecraft for use next year, that it would only cost $1.2 million? I'd expect it to cost about $5-7 million or so, which is four times what the originals cost, even allowing for what the dollar is today, as opposed to 1959-60.
The SRBs in use right now are all known quantities.
Yep. I also forgot to mention the possibility of a composite SRB for Ares V which would be a wholly different "SRB" and be completely different than what Ares I uses. So imagine if you could take all the R&D money for new SRBs and just use that to build other parts. It saves quite a bit of time and money.
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William Barton
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« Reply #4135 on: 01/09/2009 06:19 PM » |
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Hope posting a link to another site won't get me in trouble:
http://www.nasawatch.com/archives/2009/01/transition_team_4.html
"Word has it Buzz was going with them"
Now that is interesting. I know Buzz has his own ideas, but if DIRECT can get his endorsement it would be a big boost in credibility.
As for the "other site", that dude harbors over-the-top hostility towards DIRECT. I suppose he must have his reasons, but even in the very first DIRECT article archived on his site, he comes down hard on DIRECT and any favorable posts. Someone must have really p*ssed in his lemonade.
Mark S.
Please change the tone. Please be constructive. Everyone has their own view. Saying rude things about anyone does not help matters.
I believe everyone in the space advocacy/development community needs to take this to heart, from those of us cheering from the sidelines right up to NASA Administrators. Sounding like a bunch of Internet jerks doesn't do the cause any good. Regardless of how we feel about rockets and personalities, at rock bottom, we all want the same thing: a future for humanity off-earth.
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William Barton
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« Reply #4136 on: 01/09/2009 06:24 PM » |
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This assumes NASA is willing to let contractor build such an EDS. So far NASA wanted to do it "their way", and considering that NASA does not have required experience, no wonder "NASA way" EDS is worse.
This gets back to an earlier criticism of mine (and many others with industry experience): NASA does NOT need to do detailed design! Their highest, best role in the process should be as an overseer of the prime contractors selected. The recent PDR debacle demonstrates that clearly. NASA should focus its limited resources on generating top-level mission requirements and level one design requirements and then getting out of the way until PDR except in a general way.
CLES? That would be the Commercial Lunar Exploration Services program...
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Mark S
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« Reply #4137 on: 01/09/2009 06:31 PM » |
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Hope posting a link to another site won't get me in trouble:
http://www.nasawatch.com/archives/2009/01/transition_team_4.html
"Word has it Buzz was going with them"
Now that is interesting. I know Buzz has his own ideas, but if DIRECT can get his endorsement it would be a big boost in credibility.
As for the "other site", that dude harbors over-the-top hostility towards DIRECT. I suppose he must have his reasons, but even in the very first DIRECT article archived on his site, he comes down hard on DIRECT and any favorable posts. Someone must have really p*ssed in his lemonade.
Mark S.
Please change the tone. Please be constructive. Everyone has their own view. Saying rude things about anyone does not help matters.
I believe everyone in the space advocacy/development community needs to take this to heart, from those of us cheering from the sidelines right up to NASA Administrators. Sounding like a bunch of Internet jerks doesn't do the cause any good. Regardless of how we feel about rockets and personalities, at rock bottom, we all want the same thing: a future for humanity off-earth.
So it is now considered rude to point out the obvious? I didn't call him names or cast aspersions about his parentage or mental capacity. I simply made the observation that his site is hostile to DIRECT. How is that a problem? I didn't even include any veiled insults, like "prominent ego", "vocal advocacy group", or even "input is of marginal ... value". Mark S.
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Pheogh
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« Reply #4138 on: 01/09/2009 06:41 PM » |
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Hope posting a link to another site won't get me in trouble:
http://www.nasawatch.com/archives/2009/01/transition_team_4.html
"Word has it Buzz was going with them"
Now that is interesting. I know Buzz has his own ideas, but if DIRECT can get his endorsement it would be a big boost in credibility.
As for the "other site", that dude harbors over-the-top hostility towards DIRECT. I suppose he must have his reasons, but even in the very first DIRECT article archived on his site, he comes down hard on DIRECT and any favorable posts. Someone must have really p*ssed in his lemonade.
Mark S.
Please change the tone. Please be constructive. Everyone has their own view. Saying rude things about anyone does not help matters.
I believe everyone in the space advocacy/development community needs to take this to heart, from those of us cheering from the sidelines right up to NASA Administrators. Sounding like a bunch of Internet jerks doesn't do the cause any good. Regardless of how we feel about rockets and personalities, at rock bottom, we all want the same thing: a future for humanity off-earth.
I couldn't agree more. I would like to see the events of this week as DIRECT advancing into more considerate echelon of debate. Far away from the "guy in the basement of his mom's house" blog-o-sphere.
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Herb Schaltegger
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« Reply #4139 on: 01/09/2009 06:50 PM » |
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Hope posting a link to another site won't get me in trouble:
http://www.nasawatch.com/archives/2009/01/transition_team_4.html
"Word has it Buzz was going with them"
Now that is interesting. I know Buzz has his own ideas, but if DIRECT can get his endorsement it would be a big boost in credibility.
As for the "other site", that dude harbors over-the-top hostility towards DIRECT. I suppose he must have his reasons, but even in the very first DIRECT article archived on his site, he comes down hard on DIRECT and any favorable posts. Someone must have really p*ssed in his lemonade.
Mark S.
Please change the tone. Please be constructive. Everyone has their own view. Saying rude things about anyone does not help matters.
I believe everyone in the space advocacy/development community needs to take this to heart, from those of us cheering from the sidelines right up to NASA Administrators. Sounding like a bunch of Internet jerks doesn't do the cause any good. Regardless of how we feel about rockets and personalities, at rock bottom, we all want the same thing: a future for humanity off-earth.
So it is now considered rude to point out the obvious? I didn't call him names or cast aspersions about his parentage or mental capacity. I simply made the observation that his site is hostile to DIRECT. How is that a problem?
I didn't even include any veiled insults, like "prominent ego", "vocal advocacy group", or even "input is of marginal ... value".
Mark S.
I agree with you. Folks, the criticism of Mark's post is unfair. He made no insults, just pointed out what is, in fact, obvious to many. Further, Keith updated his site an hour or two ago to point out that "the DIRECT fanboys" (his phrase) were upset with him.
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