How many sets of tools does an astronaut need to change a light bulb?
Stories from Physics for 11-14 14-16
Answer: two if you are in the International Space Station (ISS) and don’t know which module the bulb is in!
Yet again, space is the arena where units are mismatched. But this time, everyone knows to be prepared.
The first component of the ISS was launched into orbit in 1998. It was built by an international consortium which fostered collaboration but also led to some practical quirks.
The modules built by the United States are designed using Imperial units, whilst the European, Russian and Japanese modules use metric units. Both metric and imperial tools are therefore available for the astronauts.