This little-known phenomenon has vexed scientists for more than a decade, and it remains a key health dilemma of human space exploration, particularly as Nasa looks towards longer voyages to Mars.
“We don’t know how bad the effects might be on a longer flight, like a two-year Mars operation,” said Dr Benjamin Levine, a cardiologist at UT Southwestern who is working with Nasa to address risks associated with abnormal blood flow in space. “It would be a disaster if astronauts had such severe impairments that they couldn’t see what they’re doing and it compromised the mission.”
The condition, spaceflight-associated neuro-ocular syndrome (SANS), is characterised by the progressive flattening of the eyeball, swelling of the optic nerve, and vision impairment. Studies have shown it is likely to be caused by the constant pressure applied to the brain by body fluids in zero-gravity. On Earth, gravity pulls fluids down into the body when a person climbs out of...