I was watching one of the broadcasts of a space walk on the ISS. I noticed the Pistol Grip Tool (Thanks Courageous Potato) looks like its made of polished stainless steel. Why do these tools have shiny metalic surfaces? Is it for visibility or heat dissipation?

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    $\begingroup$ If we pain them and after some time the tool releases paint flakes, that may become a problem I suppose $\endgroup$
    – zephyr0110
    Commented Oct 18, 2019 at 14:31
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    $\begingroup$ Probably a thermal control coating like 'AZ-2100-IECW' with low heat absorption to prevent the tool from catastrophically heating up due to direct solar exposure. I don't know specifically which coating though, as the one I've linked is white. Here's a list of other examples. $\endgroup$ Commented Oct 18, 2019 at 14:41
  • $\begingroup$ Note this was not a plug for the company, just one of the many companies used by NASA in certain designs. $\endgroup$ Commented Oct 18, 2019 at 18:26
  • $\begingroup$ The answer is always "thermal control".... $\endgroup$ Commented Oct 19, 2019 at 11:13
  • $\begingroup$ For your reference: this is the Pistol Grip Tool (PGT) $\endgroup$ Commented Oct 19, 2019 at 18:54

1 Answer 1


It's not "heat dissipation", but rather, the opposite: preventing excessive heat absorption or dissipation.

Shiny metal surfaces (or surfaces covered with shiny metal paint or tape, as its stated that the PGT itself is made of plastic) reflect most of the heat of the Sun when exposed to the sun, so they only slowly warm up. And when they are in the shade, they only slowly emit radiation and cool down. This is also true of white surfaces, which are simply diffusely reflective rather than specularly reflective.

This is also the reason why many spacecraft are covered with a crumpled shiny foil material -- multiple layers of shiny non-emitting, non-absorbing material form a strong heat insulator when in the vacuum of space.

(There is also a more prosaic reason for space equipment to be made of shiny metal. The vacuum environment tends to favor metallic and ceramic materials, and these types of high-quality custom equipment are often going to be made out of metal that is machined and then polished, nickel-plated, coated with clear anodize or iridite that leaves it shiny, etc.)


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