Question for the space profesionals here:

[spacefire]

How much of the US hardware that goes in space (bolts, nuts, rivets, screws, washers...., ot just fasteners, but pipes, drains, pumps, consumables) and tools is taken from the aviation industry (thus cheap) and how much is custom built (i.e. prohibitevly expensive, limited series)? <div class="Discussion_UserSignature"> <p>http://asteroid-invasion.blogspot.com</p><p>http://www.solvengineer.com/asteroid-invasion.html </p><p> </p> </div>

 

[erauskydiver]

Depends on the project.

 

[spacefire]

I'm looking for a more detailed answer, with examples.<br />For instance, dealing with fasteners: there are many models suited for various loading conditions, material of the parts that are joined, flushness requirements and so on...<br />Can you find any of the widely used Aviation and Military standard fastener on a rocket or are they all custom-made?<br /> <div class="Discussion_UserSignature"> <p>http://asteroid-invasion.blogspot.com</p><p>http://www.solvengineer.com/asteroid-invasion.html </p><p> </p> </div>

 

[propforce]

It's all from "commercial industry" suppliers which there are HUNDREDS of them. We have what is called "MIL-STD" specifications for bolts, nuts, etc. (actually on everything!!). Any company who can satisfy the specification can provide these hardware. <div class="Discussion_UserSignature"> </div>

 

[vogon13]

I had an actual space shuttle on/off switch for the auxillary power units in my hand once. The levele of 'coolness' was palpable. Switch body seemed to be hermetically sealed, and the device actually seemed kind of 'plump' for just being essentially an on/off device.<br /><br />Strangely enough, I have never (knowingly) had a commercial airliner grade equivelent device in my hands for comparison.<br /><br /> <div class="Discussion_UserSignature"> <p><font color="#ff0000"><strong>TPTB went to Dallas and all I got was Plucked !!</strong></font></p><p><font color="#339966"><strong>So many people, so few recipes !!</strong></font></p><p><font color="#0000ff"><strong>Let's clean up this stinkhole !!</strong></font> </p> </div>

 

[chriscdc]

I've always wondered who decides what goes up. One image that struck me was of an astronaut on the ISS, sitting in a metal chair, with massive headphones. Now I understand that the ISS is noisy and so there needs to be soundproofing, but the metal chair! I know things need to be uber reliable in space, but surely there is a lighter equivalent?

 

[radarredux]

> <i><font color="yellow">How much of the US hardware that goes in space ... is taken from the aviation industry (thus cheap)</font>/i><br /><br />The question is: How much is Commercial Off The Shelf (COTS)? Of course "how much" can be defined in many ways (e.g., how much by mass, how much by volume, how much by percentage of total cost, ...).<br /><br />Another question is "How much is COTS versus how much could be COTS?" In many government organizations employees' time is often considered "free" -- you pay them whether they sit around or are actually working and you have to pay them. So the organization pays for the employees to develop something that could technically be bought commercial off the shelf.<br /><br />For example, instead of buying a commercial software package, the organization will pay for employees to develop or adapt a free version of the software even though if the cost of the employees' time were factored in, this approach costs far more than buying COTS.</i>

 

[spacefire]

<font color="yellow">A lot of things may be virtually identical to aviation hardware but they are produced and tested under more controlled conditions.</font><br /><br />say the part is expected to eprform under the exact conditions as on an airplane. why isn't the manufacturer's QC enough? <div class="Discussion_UserSignature"> <p>http://asteroid-invasion.blogspot.com</p><p>http://www.solvengineer.com/asteroid-invasion.html </p><p> </p> </div>

 

[radarredux]

> <i><font color="yellow">It's all from "commercial industry" suppliers</font>/i><br /><br />I think the question is "How much already existed before being used on a space project versus how much was created to meet a specific need?"</i>

 

[propforce]

<font color="yellow"><i>"...I think the question is "How much already existed before being used on a space project versus how much was created to meet a specific need?" ...</i></font><br /><br />When it comes down to nuts, bolts, fastners.... practically all of them are "commercial off the shelf" (COTS) as long as they meet the MIL-STD specification of metalurgical quality (stainless 316 vs. titantium, for example) and tolerance. Another word, parts made from cheap steels from China would not cut it. There maybe occassionally unique parts that may need to be custom-made, then we'd buy your industry standard aluminum/stainless steel bar stocks/plates and machine them. Of course you realize there are more than a dozen different aluminum, you'll just need to know which one meets your "need" <img src="/images/icons/smile.gif" /><br /><br />Same with electronic circuits when it comes down to resistors, diodes and capacitors, it has its own IEEE specifications (industry standard) as well as MIL-STD/ MIL-SPEC parts. <br /><br />The "non-standard/ non-COTS/ non-OTS/ unique" hardware are really at the "board and/or box" (electronics) or "component/ subsystem" level (mechanical). For example, it would be difficult to go to Walmart and buy your commercial-off-the-shelf (COTS) liquid rocket engines and expect to meet the rigorous standards, or your every day radar jammers. The electronic circuit boards would not only meet the "electrons" performance standard but it has to withstand the rigor of violent vibrations and acoustic levels in flight environment (rocket or military jets), sometime also with extreme heat and cold at the same time (called thermal stresses). Then most also have its own EMC/EMI requirements. Some has radiation hardening requirements as well. Your typical Radio Shack electronic parts do not usually need to survive a nuclear blast and still be able to function. So you have to make it strong but not too stiff, flexible but can't break, and most <div class="Discussion_UserSignature"> </div>

 

[spacefire]

thanks propforce, pretty good explanation! <div class="Discussion_UserSignature"> <p>http://asteroid-invasion.blogspot.com</p><p>http://www.solvengineer.com/asteroid-invasion.html </p><p> </p> </div>