>> Thursday, April 30, 2009

Ah, Thieving Thursday. This time, finally, it's a comment from Relax Max' blog Clarity 2009. Someone asked me about extravehicular tools on a post about a different science experiment. The question was if EVA tools were gold plated to prevent oxidation/binding.

I told the questioner, “no.”. There is gold on the sun visor because it's such a good reflector for a wide spectrum of light, but not any of the tools (they are generally reworked Snap-On tools, often with holes cut into the handles to make them lighter, with special tether points added or made to be pressurized-glove friendly). I have never seen one gold plated (the socket wrenches I have seen are clear anodized - they look like metallic silver). Gold would not wear well. There's a PDF document describing some older EVA tools here.

Now, EVA handholds are anodized yellow or gold so they can be differentiated from handholds that are not rated for human mass and loading (which are generally white or silver - you can tether a load to them but not a crewmember). However, they are not gold plated. EVA requirements can be found here and here.

In fact, most metal surfaces are anodized, alodined or painted to (a) protect against corrosion (which isn't an issue for gold) and (b) reduce overheating in the massive thermal extremes, where a gold or other bare metal surface would be bad. (I had mentioned previously in the same comment thread that cold temperatures were a particular concern for EVA crewmembers because they were less likely to detect a dangerously cold surface by touch than a dangerously hot surface).

EVA tools are cool, and there's a great deal to say. There are only two power tools, the Pistol Grip Tool (pictured) and the Power Ratchet Tool. The rest are variations of hand tools, some standard and some completely new. We have tools for cutting, though those must be handled careful to preclude cutting the suit. Tools must be actuated and have handles large enough that using a pressurized glove is (a) possible and (b) not too tiring. Sometimes tools have holes cut in them to facilitate handling an reduce mass. They must pass stringent dimensional tolerance requirements because of the thermal extremes. Most have tether points or bayonet interfaces or velcro (if not all three).

Seriously, if you're a tool junkie or like neat stuff, pay attention to the next Hubble Servicing Mission. No missions use cooler EVA tools than Hubble Servicing Missions.


  • Relax Max

    Although I don't now enough about your occupation to really follow you, this sounds really cool. Like rocket science. Heh.

    You can thieve from me any day. (Espcially when I don't really know what you are talking about. :)

  • Bob Johnson

    Very cool!! love your tool explanation posts. I would love to have that pistol grip one for show and tell at work,lol.

  • soubriquet

    As that commenter, I thank you for your reply and the further info in this post.
    I AM a tool junkie, i love tools, and the human ingenuity that invents them. I have some pretty cool tools, things that not so long ago would have sounded like Sci-Fi. I like the blog "Kevin Kelly's Cool Tools", ...
    recent-ish cool tool purchase that paid for itself in savings in sweat and blood and tears in the first day of ownership, a 24volt cordless impact wrench, which made short work of a job where previously I'd resorted to an oxy-acetlyene curtting torch.
    I appreciate the fact that since its inception, the space program has driven technologies forward in so many fields, spinning on down to end-users such as me...
    Thirty years ago, a mylar gold reflective-coated space-blanket probably saved my life.

    Right... now I'll go read more....

  • soubriquet

    curtting? agh.

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