That's because, since 2000, at least a few humans have been living aboard the International Space Station (ISS), which has been continuously inhabited by astronauts for the past quarter-century.

Left: A drop of protein solution less than two and a half centimeters in diameter formed in the RSD onboard the International Space Station. Right: An image showing a computed Newtonian flow diagram ...

A Soyuz capsule carrying two Russian cosmonauts and one American astronaut safely landed Sunday in Kazakhstan, concluding a 220-day mission aboard the International Space Station ...