Sending stem cells into space turns out to be an incredible way to study human biology because the lack of gravity profoundly changes how these cells grow, divide, and transform. By launching mini-organs and tissue models built from stem cells up to the International Space Station, scientists are discovering that the space environment actually accelerates the aging and disease processes, allowing them to study things like tissue breakdown in fast-forward. Furthermore, without gravity pulling them down, stem cells can grow and form complex 3D tissues much faster and more naturally than they do in labs on Earth, opening up a whole new field of “space-manufacturing” for future medical treatments. While this research is vital for protecting astronauts on upcoming long-distance missions to the Moon and Mars, it also introduces tricky new hurdles regarding safety regulations, ethics, and the specialized training needed to run a biotech lab in orbit.