Better approach to commerical Crew

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DarkenedOne

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Recently there has been a great deal of fuss about NASA's requirements for commercial crew vehicles. Many people justifiably are worried that the many of the same problems with HSF under NASA will erase the benefits of private HSF, particularly the innovation and the cost.

The problem lies in the unique environment that HSF operates in. In other industries such as the airline business, the car business, and especially the software industry the costs of experimentation are not that high. Cars and airplanes for example are able to log thousands of hours over hundreds of test runs long before they ever get into wide scale use. Unfortunately rockets on the other hand are very expensive, thus it is impractical for new rockets to be tested hundreds of times before they are put into service. Of course the components of the rockets can be throughly tested individually, but ultimately testing of the entire system is very limited.

The solution to this problem is simple. The fact of the matter is that human spaceflight is not very different from our unmanned satellite launchers and is even less different then cargo carriers. Therefore if you design your rockets with the intention of putting human on them you effectively are able to use the unmanned launches of satellites as tests for your human-rated vehicles. Of course this leaves the actual human spacecraft itself, however if you do cargo services like those for the ISS based on your human spacecraft you can test this component as well.

Using the same hardware for both manned and unmanned launches reduces the costs of both as greater production largely justifies more automation and cost-effective production processes. Every rocket system from the Falcon 9, to the EELVs, to even the space shuttle gets cheaper per launch as the number of launchers go up do to the fact that in the rocket business the fixed costs of factories, launch pads, infrastructure, and highly trained personal are usually significantly higher than the incremental costs consisting of mostly the material and fuel costs.

This approach has been used by every space agency with the exception of NASA when conducting HSF. The Soyuz evolved from an unmanned launcher to manned launcher with a few modifications. At the same time the Progress resupply spacecraft is largely based on the same components as the manned Soyuz spacecraft. The same goes for the Chinese with their Shenzhou human spacecraft which launches on an manned rated version of their Long March 2E unmanned rocket. Same goes for the Europeans who are considering a manned launcher based on the Ariane V rocket and their ATV.

Now going back to commercial crew my point is that you can use a similar approach to insure that commercial launchers are safe. SpaceX is doing this with their Falcon 9 and Dragon spacecraft. By the time they put humans into their Dragon spacecraft it will have already had extensive experience as a cargo carrier for the Space Station. There is no need for strict regulations and requirements when spacecraft are sufficiently tested as a cargo carrier.
 
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bdewoody

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That's my point with my idea to use the Delta IV booster and a manned version of the X-37 both of which will be proven technology by the time Boeing could have a privatized version up and running.
 
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samkent

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My hunch is that human rated rockets are not as efficient as dedicated sat rockets. That’s above the extra hardware needed for redundancy. When you combine both the price for a sat launch would go up.

Hopefully an expert will jump in and set us all straight.
 
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DarkenedOne

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samkent":27riraj5 said:
My hunch is that human rated rockets are not as efficient as dedicated sat rockets. That’s above the extra hardware needed for redundancy. When you combine both the price for a sat launch would go up.

Hopefully an expert will jump in and set us all straight.
This goes back to my post about launch abort systems.

Fact of the matter is that is you have a satellite launcher that is trusted to launch million dollar payloads, and has done so with a very high reliability rating it makes no sense that you need extra redundancy.

There are significant differences between a manned launch pad and an unmanned launch pad, however I do not see how these in any way affect the vehicle.
 
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believer_since_1956

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Additional systems for safety drive the cost up. Also the parts program require "S Level" parts which is the highest reliability rating and require extensive screening which is expensive. These parts are utilized on long duration space craft also such as weather satellites, Geo-Sync Communications satellites, etc.
 
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oldAtlas_Eguy

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believer_since_1956":9qttqblt said:
Additional systems for safety drive the cost up. Also the parts program require "S Level" parts which is the highest reliability rating and require extensive screening which is expensive. These parts are utilized on long duration space craft also such as weather satellites, Geo-Sync Communications satellites, etc.
What usually shows up for man rating a LV is additional redundant sensors and redundant computer systems. Even non man-rated LV’s use ‘S’ parts. It just makes sense when you make such small quantities that you use the best parts. The difference is that NASA has forced that each manufacturer of the part, sub assembly and assembly, test extensively before delivery to the higher level assembler and they are required to test all parts they receive from other manufactures again. Some parts may be tested 4 to 10 times as it changes hands from manufacturer to manufacturer. This is the typical NASA contractor methods for doing man-rated hardware. In Space X case they can reduce the over testing because the discrete ‘S’ components would be tested when they are received and then when the complete assembly or subassembly is finished it would be tested again where parts would be tested just 2 or 3 times reducing the costs by 2 to 3 times without really affecting the quality or safety. Redundant testing does not improve quality. NASA instituted this policy because it didn’t trust the contractors and wanted two or more tests results for each part to determine if a contractor was testing correctly or had QC problems. And contractors went along with it to protect themselves legally from their suppliers and suppliers from their customers.
 
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vulture4

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Really good point, Atlas. Redundancy is not equivalent to reliability. The NASA approach is based on a blanket requirement imposed by safety managers with no real hardware experience, that all Constellation systems would be "failure tolerant", without any knowledge of the actual failure rates and modes. This requires essentially every system to be redundant and made the vehicle too heavy and expensive to fly. To see how inappropriate this is we need only look at Challenger. It had a primary and a backup O-ring. Both failed. The whole concept of redundancy as a way of achieving reliability is based on the assumption that failures are random, due to stochiastic, normally-distributed processes like mechanical wear. But launch vehicles have a design lifetime measured in minutes and there is no time for wear. The vast majority of LV failures are deterministic, design or procedural problems which often cause all the redundant systems fail at once. In the case of Challenger the low temperature caused both O-rings to fail simultaneously.

Yet incredibly NASA planned only one or two launches of the Ares before putting people on it. SpaceX will have at least a dozen launches, giving more time to find and correct any design problems, and will be able to get actual flight experience with any design change before using it for human flight. This was the approach used for Mercury and Gemini, which "man-rated" the Atlas and Titan II with little if any change in the hardware, but these were rockets that had been launched many times. As Chang notes in "Space Launch Vehicle Reliability", the only consistent predictor of launch vehicle reliability is how many times the design has flown.

SpaceX's all-in-house approach also cuts down on the tangle of RFPs, subcontracts, interface documents, etc. We are still spending money on interface documents for the Ares 1/Orion that have taken over a year to write.
 
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oldAtlas_Eguy

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Here is another item that doesn’t make much sense and that is that NASA requires that reports and analysis is done on new launchers before they can take a NASA scientific satellite payload. These reports will take 3 years and more than $25 million. The two new launchers under eval are Falcon 9 and Taurus II, but wait isn’t Space X and Orbital launching scientific and critical payloads as part of COTS? So why is NASA paying for something it will basically not read anyway just so that an old policy is followed. NASA needs these boosters to take the satellites starting in 2013 and 2014 because the existing Delta II is being retired at the end of next year. A two year gap will result with the possibility of slipped launch schedules and increased costs for scientific robotic missions.
 
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Skyskimmer

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oldAtlas_Eguy":1kvtme2y said:
Here is another item that doesn’t make much sense and that is that NASA requires that reports and analysis is done on new launchers before they can take a NASA scientific satellite payload. These reports will take 3 years and more than $25 million. The two new launchers under eval are Falcon 9 and Taurus II, but wait isn’t Space X and Orbital launching scientific and critical payloads as part of COTS? So why is NASA paying for something it will basically not read anyway just so that an old policy is followed. NASA needs these boosters to take the satellites starting in 2013 and 2014 because the existing Delta II is being retired at the end of next year. A two year gap will result with the possibility of slipped launch schedules and increased costs for scientific robotic missions.
My guess is it's nasa, and makes the soviet union look adventurous. I remember trying to understand how they got so much done so cheaply, as a adult I realize it's pretty basic, even socialist state can out perform nasa, :lol:
 
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