NASA guide to wiring

[Mark Hennessy]

Fancy improving your constructional techniques? Here's a fascinating document...

[Skywave]

My goodness: no stone left unturned, eh? Obviously, on account of just what NASA does, I fully understand and fully appreciate the very detailed lengths that are necessary, as stated in that document. But if I was on Day One as a wireman working for NASA and had that document thrust in front of me with the instruction "Read that - and comply!", I think I would resign on the spot! Quote: "A man's got to know his limitations!"

Al.

[Nick]

Awesome! Takes me back to my apprenticeship (actually my degree internship) at STL, Harlow.

Even though I was designing cutting edge (for the time) digital filters, I still had to learn how to produce perfect wiring looms - one mistake and the instructor, a gruff old sod, would just cut the waxed cord and you had to re-do from scratch.

I'd like to say, "Happy days", but although the work was great, Harlow was a real dump

[Mark Hennessy]

Can you still buy the waxed cord these days? I did buy some from Maplin 20+ years back, but it was PVC coated, and didn't work any better than regular wire!

EDIT: It appears you can: http://uk.rs-online.com/web/p/cable-lacing/3031697/

[Nick]

Can you still buy the waxed cord these days...

Its also known as "Whipping Twine" and can be bought from Yacht Chandlers - its used to finish the ends of rope splices.

http://www.marlowropes.com/leisure-marin...twine.html

http://www.amazon.co.uk/Kingfisher-Whipp...8NRZ4D3Q9F

Many a happy afternoon spent splicing & whipping - I can just about still do a mean "Turks Head"...

Lot cheaper than buying it from RS... (and available in different colours too!)

[Alan Douglas]

I still like the look of a wire harness, and would occasionally do it for an instrument I was building. But you couldn't give me waxed cord. On teflon wire (which was all we used) that's like chasing a greased pig. I always used flat rubberized nylon lacing tape. I do have linen cord here at home for when I need to match something I'm restoring.

I just paged through that document. Looks like normal practice where I worked (except it was self-inspected).

[Kalee20]

Generally looks like normal practice to me, too. Instructions about if a tool breaks, all bits must be accounted for are perfectly understandable. For spacecraft applications, it is quite usual for each joint to be double-inspected, ie inspected by two different people, before being covered over by heatshrink, connector backshell, etc.

A job where this specification is applicable, will be heavily managed, and the customer would expect to see evidence that relevant sections have been complied with. The benefit of documenting it all, is that it then becomes a contractual condition giving cause for rejection if the wiring is not to spec. And you can be sure that NASA Quality representatives would be frequent visitors, whether such a job was being done in-house or by external subcontractors.

[Refugee]

They are right about foreign objects in space equipment.
There were a number of false UFO sightings in space in the early 1970s.
They would have been flecks of dust floating about weightless in lenses.

[Skywave]

One extract from that document caught my attention:

6.9.3 Part Marking Permanency. Solvent and cleaning systems have the potential of removing marking information from parts.

Oh yes! I think that most of us have been tripped up by that!

Al.