As opposed to putting a tape measure back in a drawer when it is not needed, NASA used one as part of the Body Measures experiment aboard the International Space Station in 2014. The study involved astronauts taking body measurements at different points during their missions to understand how the human body changes during extended exposure to microgravity. NASA's Integrated Extravehicular Activity Human Research & Testing Plan: 2019 lists a tape measure among the equipment used for the study, alongside an anthropometer and weight scale, with digital still photography, video imaging, and 3-D whole-body scanning also used to collect information about body shape, size, and posture. The same plan says that preflight, inflight and postflight anthropometry data from the completed Body Measures study were incorporated into the requirements for the Exploration Extravehicular Mobility Unit, or xEMU.
The experiment was not simply about finding out whether an astronaut's spine became longer in space. NASA was interested in changes in body dimensions, neutral posture, and spinal elongation during long-duration exposure to microgravity, because these factors can affect the way an astronaut fits inside a spacesuit. The 2019 plan describes the study as measuring changes in anthropometry that were important to suit-sizing parameters. That made the project less about one particular measurement and more about understanding how the human body changes as a mission progresses.
