NASA seems to have made a startling discovery that could impact our first manned mission to Mars.

A new report has revealed that spaceflight can halt and even reverse blood flow in an astronaut’s upper body.

This health risk was unknown until now and the study has also shown that one astronaut was found to have developed a clot in the internal jugular vein during spaceflight.

Source: https://www.nbcnews.com/science/space/zero-gravity-serious-problem-nasa-study-finds-new-health-risk-n1081701