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#21
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Keith Cowing Makes His Move
Revision wrote:
"Jim Davis" I'll be damned. That's what I thought. One of the bigger dumb ass moves the govt ever made. G Accounting O made sense. Accountability is a completely different meaning. The government is going bankrupt because of corruption, cronyism and incompetence, and you are worried about what the name of the government organization entrusted with investigating itself should actually be? Right. Got it. Thanks! |
#22
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Keith Cowing Makes His Move
"Len" wrote in message ... On Jan 15, 2:15 pm, "Jeff Findley" wrote: "Len" wrote in message ... On Jan 15, 11:47 am, wrote: That isn't an architecture. just a bunch of engines Actually, engines are where most aerospace designers have started for over a 100 years. A lot of home built aircraft used to use air cooled VW engines, but a used Beetle is still a *long* way from a finished home built aircraft. Yes, and "long" way includes the engine itself. The potential advantages of converted auto engines seems to evaporate quite quickly in the face of reality. That's part of my point. The same can be true when designing a launch vehicle around existing engines. A particularly problematic one that springs immediately to mind is a launch vehicle which was intended to be based on the 4 segment shuttle SRB topped by an air started SSME powered upper stage. It was supposed to be "safe, simple, soon". It didn't work out when it was placed under close scrutiny. In other cases, existing engines have been tweaked to produce new variants for new launch vehicles. The above example morphed into Ares I, which is currently based on a new 5 segment SRB topped by a J-2 derived engine for the upper stage. It's now a new vehicle based on new engines. Jeff -- A clever person solves a problem. A wise person avoids it. -- Einstein |
#23
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Keith Cowing Makes His Move
Pat Flannery wrote: Over at NASA Watch, the ESMD PAO has said they are reviewing Cowing's questions and expect to get a reply to him within 48 hours. Pat And here's their reply: http://www.spaceref.com/news/viewnews.html?id=1266 Pat |
#24
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Keith Cowing Makes His Move
And here's their reply: http://www.spaceref.com/news/viewnews.html?id=1266
They didn't answer all of Cowing's questions, but they answered many of them. |
#25
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Keith Cowing Makes His Move
On 17 Jan 2008 22:07:15 -0500, in a place far, far away, Jim Kingdon
made the phosphor on my monitor glow in such a way as to indicate that: And here's their reply: http://www.spaceref.com/news/viewnews.html?id=1266 They didn't answer all of Cowing's questions, but they answered many of them. Not very well, in my opinion: http://www.transterrestrial.com/arch...96.html#010396 |
#26
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Keith Cowing Makes His Move
"Pat Flannery" wrote in message ... Pat Flannery wrote: Over at NASA Watch, the ESMD PAO has said they are reviewing Cowing's questions and expect to get a reply to him within 48 hours. Pat And here's their reply: http://www.spaceref.com/news/viewnews.html?id=1266 From their reply, "These longitudinal forces may increase the loads experienced by the Ares I during flight, and may exceed allowable loads on various portions of the vehicle and allowable forces on the astronaut crew. ", followed later by, "Thrust oscillation forces may be reduced by vehicle structures, as is the case with the space shuttle and Titan IV", and later by, "The Orion and Ares teams are holding detailed discussions and developing a plan to fully characterize Ares I thrust oscillation, assess any design changes that may be proposed, and manage sensitive design parameters with additional tests, trade studies and analyses". So they're still trying to characterize the thrust oscillation and see how it impacts the design. Unfortunately, experience from Titan IV and shuttle isn't quite directly applicable since both of those use twin SRB's side mounted to a central, liquid, core. Ares I is a distinct departure from this design with only one SRB and one upper stage on top of the SRB. And I absolutely love this little gem from near the end of the NASA response, "Thrust oscillation is a new engineering challenge to the developers of Ares". Maybe this is new to upper management, but I'm sure that there are a few propulsion engineers at Thiokol and NASA who saw this one coming. It's a problem that would have manifested itself with any inline design using a shuttle derived SRB for the first stage. Considering the weight issues associated with Ares I and Orion, there isn't much in the way of excess mass which can be spared to throw at this problem. It's starting to look like Ares I is a real pig of a design. Large segmented SRB's ought not be used on any new launch vehicle. Their drawbacks aren't worth their perceived advantages. Jeff -- A clever person solves a problem. A wise person avoids it. -- Einstein |
#27
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Keith Cowing Makes His Move
Jeff Findley wrote:
"Pat Flannery" wrote in message ... Pat Flannery wrote: Over at NASA Watch, the ESMD PAO has said they are reviewing Cowing's questions and expect to get a reply to him within 48 hours. Pat And here's their reply: http://www.spaceref.com/news/viewnews.html?id=1266 From their reply, "These longitudinal forces may increase the loads experienced by the Ares I during flight, and may exceed allowable loads on various portions of the vehicle and allowable forces on the astronaut crew. ", followed later by, "Thrust oscillation forces may be reduced by vehicle structures, as is the case with the space shuttle and Titan IV", and later by, "The Orion and Ares teams are holding detailed discussions and developing a plan to fully characterize Ares I thrust oscillation, assess any design changes that may be proposed, and manage sensitive design parameters with additional tests, trade studies and analyses". So they're still trying to characterize the thrust oscillation and see how it impacts the design. Unfortunately, experience from Titan IV and shuttle isn't quite directly applicable since both of those use twin SRB's side mounted to a central, liquid, core. Ares I is a distinct departure from this design with only one SRB and one upper stage on top of the SRB. And I absolutely love this little gem from near the end of the NASA response, "Thrust oscillation is a new engineering challenge to the developers of Ares". Maybe this is new to upper management, but I'm sure that there are a few propulsion engineers at Thiokol and NASA who saw this one coming. It's a problem that would have manifested itself with any inline design using a shuttle derived SRB for the first stage. Considering the weight issues associated with Ares I and Orion, there isn't much in the way of excess mass which can be spared to throw at this problem. It's starting to look like Ares I is a real pig of a design. Large segmented SRB's ought not be used on any new launch vehicle. Their drawbacks aren't worth their perceived advantages. Wow, and it only took you two and a half years to figure that out. I left for the Bahamas in the spring of 2005 confident that not only would Griffin not be confirmed, but that this vehicle would be excluded on first principles physics arguments alone. Was I ever surprised and horrified after I dragged my sorry ass back to the states after the two worst hurricane seasons I have ever experienced, and the ensuing two and a half years have been just one nightmare after another with this thing. At least the hurricanes have been cooperating since then. I'm surprised it took Cowing so long to figure this out. |
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