EVA Tools

The EVA power tools we use today are standard battery-powered off-the-shelf tools with a few important modifications:

1. Cleaning - all lubricants are cleaned off the tools and replaced with dry lubricants or unlubricated bearings and bushings. Lubricants tend to freeze up in space.

2. Thermal insulation - a reflective aluminum tape is wrapped around the tool to protect it from temperature extremes.

3. Tether points - rings are added to which astronauts attach equipment tethers.

4. Retractable tether points - some sockets and socket extensions have a little mechanical interface added to accommodate the "McTether" (which is named for its inventor Bruce McCandless). The McTether is a wire which retracts onto a spring-loaded spool. At the end of the wire is a pip pin which will not release until the socket is mounted either on the power tool or the tool board.

5. Serial numbers - part numbers are engraved on all tools, sockets, etc., so folks can keep track of each part and its status. This is used not only for inventory, but to make sure the correct tools are manifested for a flight and the tools are currently flight-qualified. Each tool is cleaned, calibrated, and inspected prior to flight.

Custom equipment, such as the torque reaction fitting and torque multiplier for the standard EVA Power Tool, are designed and manufactured individually at enormous cost to the taxpayer. NASA also has in work a smart power tool which will be able to control the amount of torque and number of turns it has applied.