Quote from: DarthVader on 01/16/2009 04:34 amAh it's in the February issue! I was looking all over the newsstands for it, but it's not yet out.You can find it in some places. I know people were able to pick copies up last Friday in Providence CT, Seattle WA and Washington DC, so its 'out there' already.Ross.
Ah it's in the February issue! I was looking all over the newsstands for it, but it's not yet out.
QuoteIf Bernard Kutter says the mass estimate for the JUS is reasonable, I give that opinion considerable respect. I still have to ask what the production cost penalty is for a common bulkhead design , since Boeing has rejected that alternative in spite of the obvious payload benefit on the Delta IV. Also, if pressurization is required at any point prior to launch for a Centaur derived JUS, since that has been such a fundamental feature of the Centaur design to date.There is a higher cost during the testing phase of the development program, to ensure the common bulkhead design is stable (anyone recall the S-II common bulkhead which 'inverted' during testing?). But it is quite marginal compared to the total development expenditure (<1%).In production though, the materials and labor cost is actually LESS because it deletes all of the intricate hardware items which make-up the Intertank area. Manufacturing costs can actually be cut by between 10-20% by utilizing a common bulkhead design instead of a separate-bulkhead, though again, compared to the total development cost this is pretty small.Ross.
If Bernard Kutter says the mass estimate for the JUS is reasonable, I give that opinion considerable respect. I still have to ask what the production cost penalty is for a common bulkhead design , since Boeing has rejected that alternative in spite of the obvious payload benefit on the Delta IV. Also, if pressurization is required at any point prior to launch for a Centaur derived JUS, since that has been such a fundamental feature of the Centaur design to date.
Quote from: kraisee on 01/16/2009 03:56 amQuoteTo note that Lockheed hasn't flown a structurally stable hydrogen powered upper stage in decades isn't a criticism of Mr. Kutter. They just weren't able to close the business case.Actually that isn't correct. Lockheed-Martin build the Shuttle External Tanks, which are the largest structurally stable hydrogen tanking structure in the world today. To say they don't have experience with such systems is therefore incorrect -- they actually have experience with one of the most challenging of such systems.Ross.The ET isn't a full stage, and if it was it wouldn't be an upper stage, since the engines it fuels start on the pad. It doesn't use a common bulkhead and it was designed decades ago.
QuoteTo note that Lockheed hasn't flown a structurally stable hydrogen powered upper stage in decades isn't a criticism of Mr. Kutter. They just weren't able to close the business case.Actually that isn't correct. Lockheed-Martin build the Shuttle External Tanks, which are the largest structurally stable hydrogen tanking structure in the world today. To say they don't have experience with such systems is therefore incorrect -- they actually have experience with one of the most challenging of such systems.Ross.
To note that Lockheed hasn't flown a structurally stable hydrogen powered upper stage in decades isn't a criticism of Mr. Kutter. They just weren't able to close the business case.
Granted, there have been more recent tweeks, but they don't constitute new stage designs.
Also, I still want to know why the Direct team think they can develop their EDS for significantly less than NASA's, considering that it's larger, more complex, and needs to absorb the cost of J-2 development.
[image of J130 (?) model built from LEGO]
Quote Also, I still want to know why the Direct team think they can develop their EDS for significantly less than NASA's, considering that it's larger, more complex, and needs to absorb the cost of J-2 development.Simple; because we worked with the industry that has been doing it for 45 years knows what it’s doing and NASA doesn’t have a clue on how to design this kind of a stage. Short and to the point.
If they decide they like your upper stage design and want to use it, the same things happens, yes?
Quote from: Will on 01/16/2009 04:02 pmQuote from: kraisee on 01/16/2009 03:56 amQuoteTo note that Lockheed hasn't flown a structurally stable hydrogen powered upper stage in decades isn't a criticism of Mr. Kutter. They just weren't able to close the business case.Actually that isn't correct. Lockheed-Martin build the Shuttle External Tanks, which are the largest structurally stable hydrogen tanking structure in the world today. To say they don't have experience with such systems is therefore incorrect -- they actually have experience with one of the most challenging of such systems.Ross.The ET isn't a full stage, and if it was it wouldn't be an upper stage, since the engines it fuels start on the pad. It doesn't use a common bulkhead and it was designed decades ago.Will,I’m almost twice Ross’s age and have a lot less tolerance for BS than he does, so let me just cut to the chase here.
With Ares NASA picks a design, does a detailed review of it and hands it to the contractors to execute,
I have this theoretical question: if you were to optimize Jupiter-120, could you reach Constellation goals with 3 launches of it?
Quote from: Will on 01/16/2009 05:26 pmWith Ares NASA picks a design, does a detailed review of it and hands it to the contractors to execute, That's the way it used to be, but not under Mike Griffin. Under his leadership, NASA is not "picking a design and doing a detailed review of it". They are doing the actual detail design using designers that have never done it before with no design input from the contractors with the experience. Don't get me wrong, these are smart designers, among the best in the world. But there is design and there is design. What Griffin has done is similar to taking a bunch of exceptionally good jet fighter aircraft designers, putting them in a room behind locked doors and telling them to design a nuclear-powered submarine. They don't know how. Will they come up with a working design? Yes. Will it be anywhere near as technically good and cost efficient as what they could get from industry directly? Not a snowball's chance in hell.
And why would they stop doing that just because they chose to build Direct?
Quote from: Will on 01/16/2009 05:49 pmAnd why would they stop doing that just because they chose to build Direct?Because it isn't working and LM is the ET expert