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Popular articles about the handheld power tools used on EVA by astronauts usually focus substantially on how much specialized engineering goes into making these tools. And there definitely are a lot of engineering concerns to make them reliable and efficient in space.

But I wonder whether cheaply-modified commodity power tools could be made to work practically at all, or if they would just be a complete no-sell.

The proposed modifications would include:

  • Start with an ordinary commodity drill/driver or impact driver that uses a lithium-ion battery and a brushless motor (the latter have become common and inexpensive in the last couple of years)

  • Regrease everything that is greased with krytox or other high vacuum lubricant

  • Wrap the tool in shiny thermal-control tape (like the actual NASA Pistol Grip Tool is), possibly after adding some insulation

  • Get some small vapor heat pipes, add some heat sinks to them, and stick the other ends of them to the stator of the motor and to the power controller with the most thermally-conductive metal-filled epoxy you can find

  • Package with a scrap of space blanket and a hot pack to warm up the battery in case you're in the shade.

Obviously this bodged monstrosity would never be qualified for any modern space-program flight. But I am curious whether anything is noticeably missing, whether this would work well enough to be worth not just using a screwdriver, or whether it just would completely fail due to thermal or vacuum effects.

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    $\begingroup$ I imagine that thermal control would be the biggest problem. Brushless drills are designed from the ground up to include air cooling; typically the rotor directly drives a fan to blow air. Retrofitting heat pipes and heat sinks would be difficult but it also depends on the load. Are you tightening screws or are you drilling steel plates? $\endgroup$
    – Dragongeek
    Commented Mar 10, 2020 at 10:22
  • $\begingroup$ I don't know, but I agree with Dragongreek: machines designed around air cooling are going to be hard to modify to work in the absence of air. One interesting thing to look at would be how well to such tools perform at very high altitudes on Earth? $\endgroup$
    – user21103
    Commented Mar 10, 2020 at 10:49
  • $\begingroup$ A brushless motor using a DC supply voltage needs an electronic semiconductor circuit for operation. These semiconductors need cooling too to prevent overheating. $\endgroup$
    – Uwe
    Commented Mar 10, 2020 at 11:21
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    $\begingroup$ Step 4 sounds complicated. $\endgroup$
    – Organic Marble
    Commented Mar 10, 2020 at 13:48

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Thermal control, as mentioned in the comments, is a big problem.
Next, many of the power tools currently in use in space are designed to be reactionless (counter-torquing) to reduce the difficulty of the user staying in place.

Battery cooling (getting cold) is not a problem since the battery has no "cold air" around it to lose heat to. It can only radiate energy, and a shiny case will mediate that just fine. By the same token, battery heating is a problem. Designing and building heat-sink systems that work in a vacuum and in zero-g is a seriously nontrivial (and expensive) task.

If it were easy, NASA (and all the other world-wide space consortiums) would long ago have switched to cheaper toolsets.

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