By: Davan Mulligan
Travelling beyond our planet has been a dream for many people for generations. We may be ready for this fantasy to become a reality, but are our bodies ready? For 50 years, NASA’s Human Research Program has studied the effect space travel has on the human body… and the findings may be surprising.
The acronym “RIDGE,” (which stands for space Radiation, Isolation, Distance from Earth, Gravity fields, and closed Environments), helps us remember the problems we face before committing to long-term space travel.
Radiation is known to cause health issues like cancer, degenerative diseases, cataracts, and more. Space radiation exposure has a harsher impact on our health than radiation we face on Earth, as there is a lot more of it. This may cause negative effects for those who spend prolonged time in space.
Small crews travelling long distances over large time spans may feel very isolated. Additionally, having to get along with such a small group of people and almost zero contact to the outside world could pose a lot of problems for a crew.
Distance from Earth
Astronauts travelling further and further from our home planet could run into many potential problems. Unlike on the ISS, help from those on the ground may not be possible with crews so far from Earth. If there’s ever a medical emergency on the ISS, crews can return to Earth in just a matter of hours. This is not the case travelling to a place like Mars. As we reach further and further into space, there may not even be a way to communicate with those on Earth.
Gravitational Fields and Microgravity
Different gravitational fields can impact humans more significantly than one may think. Different gravitational fields affect spatial orientation, hand-eye coordination, balance, and many other things we take for granted on Earth. Some astronauts report motion sickness from being in space. Microgravity also has effects on human biology. Microgravity is when the effects of gravity are not apparent, but it is not quite zero-gravity. Loss of bone mineral density, muscle mass, deteriorated muscle function and muscle physiology are all found to occur in prolonged microgravity. Brain damage is also expected to come with longer time in space. Astronauts took an MRI before and after a year of space flight in a study at the University of Texas Health Science Centre. Scientists reviewed the MRI scans and found that the brain swells in space, and that these effects still remained after a year back on Earth.
In closed habitats like spaceships, germs transfer more easily from person to person. A crew member carrying an illness would spread it very quickly to the others onboard.
The Twin Study
NASA’s “Twin Study” involved identical twin astronauts Scott Kelly and Mark Kelly. This study compared the differences in Scott Kelly, on the ISS, and Mark Kelly, who stayed on Earth. During the time Scott Kelly was in space, scientists did many biomedical studies on him and his twin back home. NASA found Scott Kelly suffered from DNA damage, change in metabolism, dehydration, and cognitive decline. Several months after returning to Earth, Scott Kelly still suffered these effects.
“Space blindness,” clinically known as Visual Impairment Inter Cranial Pressure Syndrome (VIIP), is a syndrome that causes visual impairment due to microgravity. This is because low gravity environments cause a “flattening” of the eyeballs and inflaming of the optic nerves. Astronaut John Phillips went from 20/20 vision to 20/100 vision in just six months due to this phenomenon. Strangely enough, female astronauts do not exhibit clinically significant visual impairment, whereas 82% of male astronauts suffer from “space blindness.” However, this may be due to the fact that only a limited amount of female astronauts have been studied for VIIP.
So far, there has been no solutions to this “space blindness” problem. As very few astronauts have spent more than a year in space, scientists do not know if more prolonged zero-gravity exposure will cause this syndrome to worsen. We must continue to study “space blindness” and the other challenges our bodies face as we journey deeper into space.