Remanufactured is a more approptiate term. I do apologize once again for my choice of language.
Right, so it doesn't cost much more to build 30 than it does to build 5. Even if you're largely hand-building the things (vs using CNC), you still need dies and templates. Besides, with any halfway modern CADD system, the CNC codes are just another output.
The original reply gave benefit to the current setup due to cost reduction through volume. My point was it isn't cost reduction through volume. I was not implying mass manufacturing is more expensive. Instead I was illustrating that due to current techniques in manufacturing, the benefits would only arrive after several hundred units were built. Not a plus for either side here. I just disagree with the cheaper by shear volume example.
No, you're talking about replacing simple, rigid plumbing fixtures with something combining flexible plumbing and electric motors, adding at least five points of failure
I do agree that complexity is not favorable in harsh environment applications. ie space. I was referring only the training necessary for service technicians. I never said that replacing the entire system with one unit was wise. In fact, I believe I point out the need for a failsafe. As for redundancy I do agree with you there. It is far safer to have a backup system.
Several grams can cost on the order of thousands of dollars to reach high earth orbit.
NASA has always been weight aware which is why so many satellites have been built twice. One is for operational checks and the light*expensive* version goes into space. Low launch weights are a necessity for monetary and equipment reasons. Personally, I think this system is far better suited to non-manned vehicles. Granted the proposal was for manned craft; however, the system doesn't seem well suited for that use. The system would need to be massive. Lighting the motor under launch conditions would be catastrophic due to the off axis loading on the single motor. I believe that high orbit or deep space flight is the only real use for the joint system. IMHO.
Apologies if my post came across as vague. I was in a rush between meetings. The joint is a unique kinematic innovation of which I feel is greatly important. Our current method of sending things into low-earth orbit has worked well for many years and for good reason. 50 years of engineering practice as you say. I think the use of this technology lies farther out in our space ventures.
It was meant more for small craft travel vector correction. Hence the attachment to CEV. Not main craft repetitive flights like the space shuttle. Sorry I gave that as an example but its something everyone can relate to.
I do have to disagree with you in terms of your analysis of engineering economics however. How many space shuttles do you think they mass produce? Most parts are one offs from precision manufacturing facilities. The only parts which are repeat manufactured are SRBs and those are extremely simple. The dies and CNC code is what is costed most in manufacturing. The mass production just makes the profit/cost ratio more favorable to the consumer... aka NASA. If you only make 30 pieces. There really isn't a mass production method in place.
And technicians are much faster at servicing one part instead of 4. That's part of the reasoning behind the system. We are talking about replacing multiple pieces with one piece therefore they still have the same learning curve for servicing the system.
As for redundancy I do agree with you there. It is far safer to have a backup system. However, even with the multiple booster positioning systems in place today. If one fails entirely, there is still a serious impairment to the craft. They just don't send up unused pieces with a space vehicle. Weight costs money. Several grams can cost on the order of thousands of dollars to reach high earth orbit. Once again the system that weighs less wins especially with funding reductions in the program as of late.
Just my 2 cents...;)
OUT
I am a Mechanical Engineering Undergraduate who attends TTU and does research for the department in which this design originated. I work in the lab where the device was first prototyped. Just as an FYI, the device is revolutionary because of the elimination of repetitive structures. Granted the bearing are an issue but the gimble can achieve a full 360 degree spherical change in attitude with only the use of 3 stepper motors. Nothing else does exactly that at this time. That's why the device is interesting to NASA. Think of replacing the current arrangement of 5 motors with just one. Can you say cost savings? Just thought I would post my 2 cents since I have had to demo the device on several occassions and have first hand experience with the mechanism.
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Remanufactured is a more approptiate term. I do apologize once again for my choice of language.
Right, so it doesn't cost much more to build 30 than it does to build 5. Even if you're largely hand-building the things (vs using CNC), you still need dies and templates. Besides, with any halfway modern CADD system, the CNC codes are just another output.
The original reply gave benefit to the current setup due to cost reduction through volume. My point was it isn't cost reduction through volume. I was not implying mass manufacturing is more expensive. Instead I was illustrating that due to current techniques in manufacturing, the benefits would only arrive after several hundred units were built. Not a plus for either side here. I just disagree with the cheaper by shear volume example.
No, you're talking about replacing simple, rigid plumbing fixtures with something combining flexible plumbing and electric motors, adding at least five points of failure
I do agree that complexity is not favorable in harsh environment applications. ie space. I was referring only the training necessary for service technicians. I never said that replacing the entire system with one unit was wise. In fact, I believe I point out the need for a failsafe. As for redundancy I do agree with you there. It is far safer to have a backup system.
Several grams can cost on the order of thousands of dollars to reach high earth orbit.
NASA has always been weight aware which is why so many satellites have been built twice. One is for operational checks and the light*expensive* version goes into space. Low launch weights are a necessity for monetary and equipment reasons. Personally, I think this system is far better suited to non-manned vehicles. Granted the proposal was for manned craft; however, the system doesn't seem well suited for that use. The system would need to be massive. Lighting the motor under launch conditions would be catastrophic due to the off axis loading on the single motor. I believe that high orbit or deep space flight is the only real use for the joint system. IMHO.
Apologies if my post came across as vague. I was in a rush between meetings. The joint is a unique kinematic innovation of which I feel is greatly important. Our current method of sending things into low-earth orbit has worked well for many years and for good reason. 50 years of engineering practice as you say. I think the use of this technology lies farther out in our space ventures.
OUT
It was meant more for small craft travel vector correction. Hence the attachment to CEV. Not main craft repetitive flights like the space shuttle. Sorry I gave that as an example but its something everyone can relate to. I do have to disagree with you in terms of your analysis of engineering economics however. How many space shuttles do you think they mass produce? Most parts are one offs from precision manufacturing facilities. The only parts which are repeat manufactured are SRBs and those are extremely simple. The dies and CNC code is what is costed most in manufacturing. The mass production just makes the profit/cost ratio more favorable to the consumer... aka NASA. If you only make 30 pieces. There really isn't a mass production method in place. And technicians are much faster at servicing one part instead of 4. That's part of the reasoning behind the system. We are talking about replacing multiple pieces with one piece therefore they still have the same learning curve for servicing the system. As for redundancy I do agree with you there. It is far safer to have a backup system. However, even with the multiple booster positioning systems in place today. If one fails entirely, there is still a serious impairment to the craft. They just don't send up unused pieces with a space vehicle. Weight costs money. Several grams can cost on the order of thousands of dollars to reach high earth orbit. Once again the system that weighs less wins especially with funding reductions in the program as of late. Just my 2 cents... ;)
OUT
I am a Mechanical Engineering Undergraduate who attends TTU and does research for the department in which this design originated. I work in the lab where the device was first prototyped. Just as an FYI, the device is revolutionary because of the elimination of repetitive structures. Granted the bearing are an issue but the gimble can achieve a full 360 degree spherical change in attitude with only the use of 3 stepper motors. Nothing else does exactly that at this time. That's why the device is interesting to NASA. Think of replacing the current arrangement of 5 motors with just one. Can you say cost savings? Just thought I would post my 2 cents since I have had to demo the device on several occassions and have first hand experience with the mechanism. OUT