JAXA (Japan Aerospace Exploration Agency) astronaut Kimiya Yui shaves NASA astronaut Mike Fincke's head on the International Space Station. (Image credit: NASA)

Since 2000, the International Space Station (ISS) has continuously hosted astronauts from countries including the United States, Russia, Japan, Canada and parts of Europe. The station serves as a unique platform for research in fields ranging from physics to human health.

Even though they're far from home, astronauts on the ISS still have normal routines -- including getting regular haircuts.

Living aboard the ISS means living in microgravity, a state where everything is in continuous free fall. To astronauts, this feels like weightlessness, making everything just a bit more complicated, including basic hygiene.

There are no showers on the orbital lab. Instead, astronauts take a sort of "sponge bath" with no-rinse shampoo. Something as simple as trimming nails or cutting hair also takes on new challenges, as without gravity, every tiny clipping would drift around, potentially clogging equipment or entering astronauts' eyes or lungs.

The ISS is located at an average altitude of 248 miles (400 kilometers) above Earth.

During long stays aboard the ISS, astronauts' hair grows just as it does on Earth. This means regular haircuts are essential for multiple reasons. Here, JAXA (Japan Aerospace Exploration Agency) astronaut Kimiya Yui uses a razor with a vacuum hose to shave NASA astronaut Mike Fincke's hair, with the hose collecting the hair.

Regular haircuts are beneficial for an astronaut's overall health (it can be uncomfortable or a safety hazard if it's too long) and for the crew's morale (bringing people together for a common goal).