It has been long known that long-term exposure to zero-gravity or microgravity results in negative health effects on astronauts.
A good example of this is the Twins Study conducted by NASA’s Human Research Program (HRP), which researched the effects on astronaut Scott Kelly’s body after he spent a year aboard the International Space Station – using his twin brother, Mark Kelly, as the control.
Studies have been conducted aboard the ISS (International Space Station) to determine the extent of these effects and how to prevent them.
These health effects include:
- Muscle atrophy
- Loss of bone density
- Diminished organ function
- Circulation problems
- Genetic changes
A team of NASA and JAXA-funded researchers showed how artificial gravity is needed for long-term plans in space. Their research paper, which appeared in the International Journal of Molecular Sciences, confirmed that exposure to microgravity can not only affect bone density and muscle mass, but also immune-function, blood oxygenation and cardiovascular health.
Genomic and cognitive changes due to exposure to space radiation is well known and documented. However, eyesight degradation, a discovery that is the result of years of research and study into microgravity and its effects on eyesight, is also possible and is the result of less circulation and oxygen making it to the eyes.
Reports from astronauts as it relates to impairment of vision are also common:
- 30% of astronauts on short-term space shuttle flights (roughly two weeks) to the ISS
- 60% on long-duration missions to the ISS
To this end, Dean of the College of Human Sciences at Florida State University (FSU) and a co-author on the paper, Professor Michael Delp and his colleagues recommend that plans be made to generate artificial gravity on future space missions as noted in a Florida State University release by Dr. Delp, quote: “The problem is the longer the astronauts are in space, the more likely they are to experience visual impairment. Some astronauts will recover from vision changes, but some don’t. So this is a high priority for NASA and space agencies worldwide. With this application of artificial gravity, we found it didn’t totally prevent changes to the eye, but we didn’t see the worst outcomes.”
So what exactly did this study reveal?
Spaceflight and artificial gravity – Astronauts need Gravity to see better
In their study, Professor Michael Delp teamed up with researchers from:
- JAXA (Japan Aerospace Exploration Agency)
- Professor Xiao Wen Mao (the study’s lead author) from Linda Loma University
- Researchers from the University of Arkansas for Medical Sciences
- Researchers from the Arkansas Children’s Research Institute
- Researchers from the University of Tsukuba
To determine if artificial gravity would lessen these effects, the team then examined changes in the ocular tissues of mice after they spent 35 days aboard the ISS. The test subjects consisted of 12 nine-week-old male mice that were flown from the Kennedy Space Center.
They were housed in the mouse HCU (Habitat Cage Unit) in the JAXA “Kibo” Laboratory on the ISS. Over the course of their stay, the mice were divided into two groups:
- One group lived in ambient microgravity conditions
- One group lived in a centrifugal habitat unit that produced 1 g of artificial gravity, equivalent of Earth’s gravity)
From this, the research team found that the former group in the ambient microgravity conditions suffered damage to the blood vessels that are important for the regulation of fluid pressure within the eyes. In addition, the team noted that protein expression profiles had also changed in the mice’s eyes.
By comparison, the mice that spent their time in the centrifuge did not experience nearly as much damage to their ocular tissues. These results indicate that artificial gravity, likely in the form of rotating sections or centrifuges, will be a necessary component for long-duration space missions.
The explanation by Dr. Delph is quite interesting, as he said “When we’re on Earth, gravity pulls fluid down toward our feet,” said Phelps. “When you lose gravity, the fluid shifts toward the head. This fluid shift affects the vascular system throughout the body, and now we know it also affects the blood vessels in the eye.”
So know that the research confirms what was long suspected, what can be done for future missions?
Artificial Gravity and Long Term Spaceflight – Rotating Space Stations or Stellar Engine
The use of artificial gravity in space is not something new and can be best seen in the Stanford Torus Space Settlement, a principal design that was considered by the 1975 NASA Summer Study.
The 1975 NASA Summer Study was a ten-week program consisted of professors, technical directors and students from NASA’s Ames Research Center and Stanford University. They designed a vision of how people might someday live in a wheel-like space station that would rotate. This idea, which has often been portrayed in movies and anime series, would provide the sensation of either Earth-normal or partial gravity.
Still, this would be no good for travel, as this is more suited for an orbital space station, for mining the moon and Mars as described in Why Mining the Moon for Rocket fuel with AI and Robots aids Mars Exploration travel across the solar system and into interstellar space.
Nautilus-X (Non-Atmospheric Universal Transport Intended for Lengthy United States Exploration) was developed in 2011 by engineers Mark Holderman and Edward Henderson of NASA’s Technology Applications Assessment Team as a multi-mission spacecraft concept.
Still even better, rather than move a few astronauts, why not move the entire solar system? After all, with something out there to kill us, we could, in a distant future, move our solar system out of harm’s way while exploring the solar system by using Stellar Engines.
Thoughts to ponder as we design the next generation of spacecraft to preserve our eyesight and make it possible to see the stars.