Rocket Scientist

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.

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