Earlier this month, NASA announced that it had to cancel a scheduled spacewalk, citing a “medical situation” affecting a “single crew member who is stable” on board the International Space Station. “All crew members remain stable,” the space agency reassured. There’s a lot to still learn about providing care during medical emergencies, particularly when it comes to long-duration space exploration missions into deep space. Spending prolonged periods in a microgravity environment has also been shown to affect astronauts’ vision and blood pressure. More on the evacuation: Entire Space Station Down to Skeleton Crew After NASA Evacuation