Spaceflight rewires the human body. Muscles shrink, bones thin and fluids shift towards the brain – but these changes may help improve life on Earth.

In NASA's current missions, medical risks are manageable. There's the opportunity for emergency evacuations, real-time communications, and the ability to send samples to Earth. However, long-term future missions, such as going to Mars, will take away that ...

Mars is an inhospitable desert planet. Billions of years ago, things were different. In Jezero Crater, for example, fed by a vast river delta, there was probably a considerable body of water roughly the size of Lake Constance.

Mars has two permanent polar ice caps of water ice and some dry ice, and a few patches of ice both on and under the surface. Here on Earth, that ice would be a prime candidate to host life. But on Mars, any life forms in the ice would be exposed to the devastating Martian conditions.