More Space Problems

To predict the effect of long duration space flight on human health, scientists have been studying astronauts on the International Space Station. One thing they found was worsened vision. Some astronauts developed swollen optic nerves and a flattening of the eyes. They thought maybe it was caused by low gravity which allows a buildup of bodily fluids like blood and water in the head.

To test this theory, researchers studied the jugular veins of eleven astronauts. The vein sits in the neck and sends blood from the head back to the heart.

Before astronauts went to space, measurements were taken of their jugulars as they stood or laid down. All were normal. But once in space on the ISS, ultrasounds of the astronauts showed the blood flow in six of the eleven astronauts stagnated. Sometimes the blood sloshed back and forth and by day fifty was not moving in the normal direction. One astronaut even developed a blood clot.

A possible explanation could be the shifting of bodily fluids and organs upward blocking the flow of blood through some veins. Before returning from space, astronauts used a Russian designed suit to move some of their fluids back down in the body which helped. Upon return, almost all astronauts recovered.

For now only physically fit astronauts travel to space but that won't be the case when paying customers start taking commercial space flights. More pressing is how even fit astronauts will endure years of space travel when they attempt the journey to and back from Mars.