In 1997, NASA sent 64 desert beetles to Russia’s Mir space station with tiny wheels tracking their every movement; their movements helped scientists understand how light regulates biological clocks in microgravity

In May 1997, NASA sent 64 black desert beetles into space aboard the Space Shuttle Atlantis as part of the STS-84 mission. The shuttle docked with the Russian Mir space station, where the beetles were kept in individual chambers equipped with tiny wheels that turned whenever they moved.

The insects spent about 125 days aboard Mir before returning to Earth on a later shuttle mission in September 1997. During that time, scientists on Earth monitored the revolutions of the miniature wheels to study how the beetles’ activity changed in microgravity.