Space Travel Gifts many challenges, not the least of which is related to the health and safety of astronauts. And the farther these missions get from Earth, the more important they become.
Beyond Earth’s protective atmosphere and magnetosphere, there is the threat of long-term exposure to solar and cosmic radiation. But while radiation exposure can be mitigated with proper shielding, there are few strategies 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 wasting, loss of bone density, 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 places 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 that artificial gravity provides partial protection against these changes.
Artificial gravity to the rescue
The study was conducted by researchers from institutions including the Space Biosciences Division of NASA’s Ames Research Center, the University of New Mexico’s COSMIAC Research Center, and the Space Research Association of Universities. (USRA). Their findings were published September 6 in the journal Cell reports.
In this study, the team conducted a month-long investigation using the Multi-Purpose Variable Gravity Platform (MVP), a centrifuge-based commercial test bed that arrived on the ISS in 2019. This experiment has separate compartments and provides flies with fresh food. as 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 Earth’s gravity. (9.8m/s2or 1 g).
The research team then monitored their behavior using cameras built into the hardware. At different times, some of the flies were frozen and sent back to Earth for analysis to see how the different levels of severity affected their gene expression and its impact on their nervous systems. 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 return to the Moon and Mars, reducing the harmful effects of microgravity will be essential to ensure the safety of future explorers.This study is a step in the right direction to explore the protective effects of artificial gravity in space and to understand adaptation to Earth conditions after return from space.
Why fruit flies?
Fruit flies are the ideal organism for this type of research due to their similarities to humans in terms of cellular and molecular processes and their short lifespan and reproductive cycles (two months and two weeks respectively). ).
Nearly 75% of genes that cause disease in humans are shared by fruit flies, meaning changes in their gene expression will resemble possible changes in humans. Moreover, the three weeks they spend 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.
When the experiment was complete, the flies were returned to Earth aboard a SpaceX Dragon capsule and transported to NASA Ames for further analysis. For two days, scientists conducted behavioral and biochemical tests on these “flyonauts”, which consisted of monitoring their movements inside their habitat, cellular changes in their brains, how changes in the expression of genes affected their nervous system, etc.
They then combined their observations with images from the MVP cameras and compared the results to a control group that remained on Earth.
Among the behaviors studied, the scientists looked at how the flies climb the walls of their container – a natural response that fruit flies have when tapped. They found that the flies in microgravity were more active than those exposed to artificial gravity but struggled in the climbing test when they returned 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 acclimatize upon return.
Future flight planning
These results suggest that spaceflight causes stress that results in negative behavioral and neurological effects, as well as changes in gene expression in the fly’s 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 do not accurately predict human health effects, they provide an approximation and a good starting point for future research. As summarized by Dr. Siddhita Mhatre, KBR Wyle Senior Scientist at 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 delaying space-related deficits, we may be able to extend the timelines of future missions, and spaceflight alongside astronauts will help continue our efforts to keep astronauts healthy.
NASA is currently studying centrifuges and artificial gravity for space stations and deep space missions. Examples include NASA’s concept study titled “Non-Atmospheric Universal Transport for Extended Exploration of the United States” (NAUTILUS-X), a rotating torus-shaped module that would provide artificial gravity.
NASA further proposed that a demonstration module (the ISS Centrifuge Demo) could become a sleep module for the ISS crew. This module would be 9.1 m (30 ft) in diameter, have an inside diameter of 0.76 m (2.5 ft) and provide between 0.08 and 0.51 g of partial gravity.
It also aimed to provide a proof of concept for a larger torus that could be integrated into an eventual spacecraft known as a Multi-Mission Space Exploration Vehicle (MMSEV). This concept and similar research studies highlight the importance of astronaut health and safety measures for long-duration spaceflight.
As NASA and other space agencies send astronauts to the Moon (to stay this time) and pursue crewed missions to Mars and beyond, artificial gravity may become a regular feature of spacecraft, space stations and even surface habitats.
This article was originally published on Universe today by Matt Williams. Read the original article here.