Presentation of space travel numerous challenges, not the least of which has to do with astronaut health and safety. And the more adventurous these Earth missions get, the more important they become.
Beyond Earth’s protective atmosphere and magnetosphere lies the threat of long-term exposure to solar and cosmic radiation. But while radiation exposure can be mitigated with proper shielding, few strategies are available to deal 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, loss of bone density, organ function, vision, 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 deep space locations will need to be equipped with artificial gravity. This study examined the effects of microgravity on fruit flies aboard the ISS and showed that artificial gravity provides partial protection against these changes.
Artificial gravity to the rescue
The study was conducted by researchers from institutions such as the Space Biosciences Division at NASA Ames Research Center, the COSMIAC Research Center at the University of New Mexico, and the University Space Research Association (USRA) . Their findings were published Sept. 6 in the journal Cell Reports.
In this study, the team conducted a month-long investigation using the Multipurpose Variable Gravity Platform (MVP), a commercial centrifuge-based test bed that arrived at the ISS in 2019. This experiment has different compartments and provides the flies with fresh food. while they live and reproduce.
This allowed the team to house different generations of flies separately and under different levels of gravity, with one exposed to microgravity (like their astronaut counterparts aboard the ISS) and another exposed to gravity similar to Earth (9.8 m/s2, or 1 g). .
The research team monitored their behavior using cameras embedded in the hardware. At various points, some of the flies were frozen and returned to Earth to be analyzed to see how the different levels of severity affected their gene expression and impact on their nervous system. As Janani Iyer, USRA project scientist at NASA Ames Research Center, explained in a recent NASA press release:
“Microgravity poses risks to the central nervous system, suggesting that countermeasures may be needed for long-duration space travel. As we venture back to the Moon and Mars, reducing the harmful effects of microgravity will be key to keep future explorers safe. This study is a step in the right direction to explore the protective effects of artificial gravity in space and to understand adaptation to conditions on Earth after returning from space.”
Why fruit flies?
Fruit flies are the ideal organism for this type of research because of their similarities to humans in terms of cellular and molecular processes and their short lifespans and reproductive cycles (two months and two weeks, respectively ).
Nearly 75 percent of the genes that cause disease in humans are shared by fruit flies, meaning that changes in their gene expression will resemble potential changes in humans. Also, three weeks in space is equivalent to about thirty years of a human’s life, allowing scientists to observe decades of biological information in a short time.
After the experiment was completed, the flies were returned to Earth aboard a SpaceX Dragon capsule and transported to NASA’s Ames for further analysis. For two days, the scientists carried out biochemical and behavioral tests on these “flyonauts”, which consisted of monitoring their movements within their habitat, cellular changes in the brain, how changes in gene expression were affect your nervous system and more.
They then combined their observations with images from the MVP cameras and compared the results to a control group that had remained on Earth.
Among the behaviors studied, the scientists examined how the flies climbed the walls of their container, a natural response that fruit flies have when touched. They found that flies in microgravity were more active than those exposed to artificial gravity, but experienced difficulty during the climbing test upon their return to Earth.
Post-flight analysis also revealed that flies exposed to microgravity experienced neurological changes, while those exposed to artificial gravity aged differently and faced less severe challenges to acclimate once they returned.
Planning future flights
These results suggest that spaceflight causes stress that causes negative neurological and behavioral effects, as well as changes in gene expression in the fly brain. They also suggest that artificial gravity can mitigate these effects during spaceflight, although there are still long-term challenges when it comes to reacclimating to Earth.
Although these results cannot accurately predict human health effects, they provide an approximation and a good starting point for future research. As summarized by Dr. Siddhita Mhatre, senior scientist at KBR Wyle in Ames and author of the paper:
“With upcoming long-duration deep space missions where astronauts will be exposed to varying levels of gravity, it is imperative that we understand the impacts of altered gravity on neurological function. If we can use artificial gravity to delay the deficits space-related, we may be able to extend future mission timelines. And flies in space, along with astronauts, will help increase our efforts to keep astronauts healthy.”
NASA is currently researching centrifuges and artificial gravity for space stations and deep space missions. Examples include NASA’s concept study titled “Non-Atmospheric Universal Transport for Long-Term Exploration of the United States” (NAUTILUS-X), a rotating bull-shaped module that would provide artificial gravity.
NASA further proposed that a demonstration module (the ISS Centrifuge Demonstration) could be converted into a sleep module for the ISS crew. This module would measure 9.1 m (30 ft) in diameter, have an inner diameter of 0.76 m (2.5 ft), and provide between 0.08 and 0.51 g of partial gravity.
It was also intended to provide a proof of concept for a larger torus that could be integrated into a possible spacecraft known as the Multimission Space Exploration Vehicle (MMSEV). This concept and similar research studies highlight the importance of astronaut health and safety measures for long-duration space flights.
As NASA and other space agencies send astronauts to the Moon (to stay this time) and conduct manned missions to Mars and beyond, artificial gravity may become a regular feature of spacecraft, stations spatial and even surface habitats.
This article was originally published on Universe Today by Matt Williams. Read the original article here.
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