Space travel presents numerous challenges, not the least of which have to do with astronaut health and safety. And the farther these missions venture from Earth, the more significant they become. Beyond Earth’s protective atmosphere and magnetosphere, there’s the threat of long-term exposure to solar and cosmic radiation. But whereas radiation exposure can be mitigated with proper shielding, there are few strategies available for dealing with the other major hazard: long-term exposure to microgravity.
Aboard the International Space Station (ISS), astronauts rely on a strict regimen of exercise and resistance training to mitigate the physiological effects. These include muscle atrophy, bone density loss, organ function, eyesight, and effects on cardiovascular health, gene expression, and the central nervous system. But as a recent NASA study revealed, long-duration missions to Mars and other locations in deep space will need to be equipped with artificial gravity. This study examined the effects of microgravity on fruit flies aboard the ISS and demonstrated artificial gravity provides partial protection against those changes.
Can humans reproduce in space? The short answer is that we don’t know. The long answer is maybe, but there are significant barriers to overcome to make zero-gravity pregnancy safe, and research into the subject is only just beginning.
In his book, Endurance, astronaut Scott Kelly described the arduous task of readjusting to life on Earth after spending a year in space. As part of NASA’s Twins Study, Kelly lived and worked aboard the International Space Station (ISS) while his identical twin (astronaut Mark Kelly) remained on Earth. While the results of this study revealed how prolonged exposure to microgravity could lead to all manner of physiological changes, the long and painful recovery Kelly described in his book painted a much more personal and candid picture.
As it turns out, astronauts who spend extended periods in space may never fully recover. At least, that is the conclusion reached by an international team led by the University of Calgary after they assessed the bone strength of multiple astronauts before and after they went to space. They found that after twelve months of recovery, the astronaut’s bones had not regenerated completely. These findings could have significant implications for proposed future missions, many of which involve long-duration stays in space, on the Moon, and Mars.
Ever since childhood, we were all told to never play with fire. Despite it being relevant to our everyday lives, to include heating our homes and water, cooking our food, producing electricity, and more, fire is extremely dangerous. We were all indoctrinated more with how to put out fires instead of how to start one. We’ve all been told about its destructive properties if mishandled, and that fire needs to be controlled. One of the perks of adulthood, and especially being a scientist, is you get paid to play with fire. Despite fire’s complexities, there’s still a lot we don’t know about its behavior. With more and more of humanity traveling to space and living in microgravity, it’s important to learn about how fire behaves in this unique environment to better prepare ourselves for worst case scenarios. But what if we could also control fire so it’s not as dangerous and less destructive to the environment back here on Earth?
There are plenty of processes that might be easier in lower gravity. So far, the biggest hindrance to developing those processes has been the expense of launching equipment to the low gravity environments of the ISS or other space-based research stations. Testing on the ground would be preferable both for ease of use and much lower cost, but the Earth’s gravity usually puts a stop to that. Some scientists see another way. Using magnetic fields can artificially simulate a zero-gravity environment, and now a team from Florida State University’s (FSU’s) National High Magnetic Field Laboratory has developed a system that can hold a much larger sample than previous iterations.
In 1972, the Space Race officially ended as NASA sent one last crew of astronauts to the surface of the Moon (Apollo 17). This was the brass ring that both the US and the Soviets were reaching for, the “Moonshot” that would determine who had supremacy in space. In the current age of renewed space exploration, the next great leap will clearly involve sending astronauts to Mars.
It’s not easy living and working in space for extended periods of time. As NASA’s Twins Study illustrated, microgravity takes a toll on human physiology, which is followed by a painful transition back to normal gravity (just ask Scott Kelly!) Aside from muscle and bone degeneration, there’s diminished organ function, effects on cardiovascular health, the central nervous system, and “subtle changes” on the genetic level.
Until now, the biggest unanswered question was what the underlying cause of these physical impacts was. But after reviewing all of the data accumulated from decades of research aboard the International Space Station (ISS) – which included the Twins Study and DNA samples taken from dozens of astronauts – an international team of researchers came to the conclusion that mitochondria might be the driving force for these changes.
The ESA has a science lab on the International Space Station called Columbus. Inside that lab is the Fluid Science Laboratory, dedicated to studying the behaviour of fluids in microgravity. Currently, that lab is being used to study a substance most of us probably don’t spend much time thinking about: foam.
Ever since astronauts began going to space for extended periods of time, it has been known that long-term exposure to zero-gravity or microgravity comes with its share of health effects. These include muscle atrophy and loss of bone density, but also extend to other areas of the body leading to diminished organ function, circulation, and even genetic changes.
For this reason, numerous studies have been conducted aboard the International Space Station (ISS) to determine the extent of these effects, and what strategies can be used to mitigate them. According to a new study which recently appeared in the International Journal of Molecular Sciences, a team of NASA and JAXA-funded researchers showed how artificial gravity should be a key component of any future long-term plans in space.
On March 1st, 2016, American astronaut Scott Kelly returned to Earth after spending a total of 340 days aboard the International Space Station (ISS). As part of NASA’s goal to send astronauts on long-duration space flights to Mars and beyond, this record-setting stay in space was designed to test the limit of human endurance in a microgravity environment.
Also known as the Twin Study, this experiment consisted of Kelly spending nearly a year in space while his identical twin (Mark Kelly) remained on Earth. Since Kelly’s return, the two have been subjected to medical tests to see what long-term effects microgravity has had of Scott’s Kelly’s physique. The final results of this test, which were just released, reveal that Scott has experienced changes at the genetic level.
The study was conducted by NASA’s Human Research Program, and the preliminary findings were released at their Investigator’s Workshop on the week of January 23rd, 2017. According to these findings, Scott Kelly showed indications of inflammation, changes in his telomeres and telomerase (parts of the chromosonal system related to aging), a decrease in bone density and gastrointestinal changes – all of which were expected.
As NASA reported in their preliminary findings:
“By measuring large numbers of metabolites, cytokines, and proteins, researchers learned that spaceflight is associated with oxygen deprivation stress, increased inflammation, and dramatic nutrient shifts that affect gene expression… After returning to Earth, Scott started the process of readapting to Earth’s gravity. Most of the biological changes he experienced in space quickly returned to nearly his preflight status. Some changes returned to baseline within hours or days of landing, while a few persisted after six months.”
At the same time, the study took into account possible genomic and cognitive changes between the two brothers. These findings were recently clarified by NASA, which indicated that 93% of Scott Kelly’s genes returned to normal after he returned to Earth while the remaining 7% points were missing. These were attributed to “longer-term changes in genes related to his immune system, DNA repair, bone formation networks, hypoxia, and hypercapnia.”
In other words, in addition to the well-documented effects of microgravity – such as muscle atrophy, bone density loss and loss of eyesight – Scott Kelly also experienced health effect caused by a deficiency in the amount of oxygen that was able to make it to his tissues, an excess of CO2 in his tissues, and long-term effects in how his body is able to maintain and repair itself.
At the same time, the report indicated that Scott Kelly experienced no significant changes when it came to cognitive performance. The preliminary findings touched on this, indicating that Scott showed a slight decrease in speed and accuracy when undergoing cognitive performance testing compared to his brother. This decrease was more pronounced when he first landed, but was attributed to readjustment to Earth’s gravity.
Mathias Basner – a professor at the University of Pennsylvania, Philadelphia, who was in charge of conducting the tests – also found no real difference in cognition between 6 month and 12 month missions. This is especially important since typical stays aboard the ISS last six months, whereas long term missions to Mars would take 150-300 days – depending on the alignment of the planets and the speed of the spacecraft.
A two way trip to Mars, as well as the time spent in Mars lower-gravity environment (37.6 % that of Earth’s), could take multiple years. As such, the Twin Study was intrinsic to NASA’s efforts to prepare for its proposed “Journey to Mars“, which is expected to take place sometime in the 2030s. These and other studies being conducted aboard the ISS seek to determine what the long-term effects on astronaut health will be, and how they can be mitigated.
The NASA Twin Study was the result of a partnership between 10 individual investigations, 12 colleges and universities, NASA’s biomedical labs and the National Space Biomedical Research Institute Consortium.
Scott Kelly’s stay in space and the Twin Study will also be the subject of a PBS documentary titled “Beyond a Year in Space“. Be sure to check out the teaser trailer here: