Before humans travel to deep space destinations like Mars, it’s important to understand how their bodies will be affected by spaceflight.
Onboard the International Space Station (ISS), astronauts’ bodies are subtly affected by the microgravity environment. The ISS orbits approximately 240 miles above Earth and has maintained a continuous human presence for over 15 years.
When some astronauts return to Earth after spending time on the ISS, their vision has changed from being in space. About a dozen or more astronauts went through ultrasound exams after returning and learned that their eyeballs had flattened in the back.
During their time in space, swelling of the optic nerve and changes to the structure of both the retina and choroid were found. This is known as VIIP, or visual impairment and intracranial pressure.
What is the root cause of the change? Researchers are trying to find out using a new method utilizing noninvasive measurements while the astronauts were in space.
Ultrasound Eye Imaging on ISS. Credit: NASA
Do astronauts have a higher intracranial pressure (ICP) while in space? There were two techniques used on the ISS to estimate ICP.
One checked the pressure of fluid in an astronaut’s ear. This would allow estimations of ICP to be compared to measurements made on Earth. The fluids of the inner ear are connected to intracranial fluids in most people.
The other technique estimated low-intensity sound waves which were produced by the inner ear as a way to investigate ICP.
While data from the astronauts’ missions continue to be studied, the current results indicate that ICP does not dramatically increase while astronauts are in space.
Ongoing research continues to investigate astronauts in space using non-invasive methods. On Earth, invasive techniques are performed when ICP is high. But onboard the ISS, if the noninvasive devices and techniques are effective, they could be used on Earth instead of the current invasive processes. This is just one of the many ways research on the ISS contributes to life on Earth.
The ISS orbits Earth at around 17,000 miles per hour. The orbiting laboratory is key to expanding human presence for extended periods of time beyond low Earth orbit where the ISS is located. It is a unique platform enabling us to learn about human spaceflight in-depth before embarking on future human missions into deep space.
Curious to learn more about the International Space Station? Check out NASA.gov.