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Editor\u2019s Note: This article was updated Nov. 20, 2024 shortly after BioSentinel\u2019s mission marked two years of operation in deep space<\/em><\/strong>.<\/p>\n Astronauts live in a pretty extreme environment aboard the\u00a0International Space Station. Orbiting about 250 miles above the Earth in the weightlessness of microgravity, they rely on\u00a0commercial cargo missions\u00a0about every two months to deliver new supplies and experiments. And yet, this place is relatively protected in terms of\u00a0space radiation. The Earth\u2019s magnetic field shields space station crew from much of the radiation that can damage the DNA in our cells and lead to serious health problems. When future astronauts set off on long journeys deeper into space, they will be venturing into more perilous radiation environments and will need substantial protection. With the help of a biology experiment within a small satellite called BioSentinel, scientists at NASA\u2019s Ames Research Center,\u00a0in California\u2019s Silicon Valley,\u00a0are taking an early step toward finding solutions.<\/p>\n To learn the basics of what happens to life in space, researchers often use \u201cmodel organisms\u201d that we understand relatively well. This helps show the differences between what happens in space and on Earth more clearly. For BioSentinel, NASA is using yeast \u2013 the very same yeast that makes bread rise and beer brew. In both our cells and yeast cells, the type of high-energy radiation encountered in deep space can cause breaks in the two entwined strands of DNA that carry genetic information. Often, DNA damage can be repaired by cells in a process that is very similar between yeast and humans.\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/p>\n BioSentinel\u00a0set out to be\u00a0the\u00a0first long-duration biology experiment\u00a0to take place beyond where the space station orbits near Earth. BioSentinel\u2019s spacecraft is one of 10 CubeSats that launched aboard\u00a0Artemis I, the first flight of the\u00a0Artemis\u00a0program\u2019s Space Launch System, NASA\u2019s powerful new rocket. The cereal box-sized satellite traveled to deep space on the rocket then\u00a0flew past the Moon\u00a0in a direction to orbit the Sun.\u00a0\u00a0Once the satellite was in position beyond our planet\u2019s protective magnetic field, the BioSentinel team triggered a series of experiments remotely, activating two strains of the yeast Saccharomyces cerevisiae to grow in the presence of space radiation. Samples of yeast were activated at different time points throughout the six- to twelve-month mission.<\/p>\n One strain is the yeast commonly found in nature, while the other was selected because it has trouble repairing its DNA. By comparing how the two strains respond to the deep\u00a0space radiation environment, researchers will learn more about the health risks posed to humans during long-term exploration and be able to develop informed strategies for reducing potential damage.<\/p>\n During the initial phase of the mission, which began in December 2022 and completed in April 2023, the BioSentinel team successfully operated BioSentinel\u2019s BioSensor hardware \u2013a miniature biotechnology laboratory designed to measure how living yeast cells respond to long-term exposure to space radiation \u2013 in deep space. The team completed four experiments lasting two-weeks each but did not observe any yeast cell growth. They determined that deep space radiation was not the cause of the inactive yeast cells, but that their lack of growth was likely due to the yeast expiring after extended storage time of the spacecraft ahead of launch.\u00a0<\/p>\n Although the yeast did not activate as intended to gather observations on the impact of radiation on living yeast cells, BioSentinel\u2019s onboard radiation detector \u2013 that measures the type and dose of radiation hitting the spacecraft \u2013 continues to collect data in deep space.<\/p>\n NASA\u00a0extended BioSentinel\u2019s mission in 2023\u00a0by up to an additional 18 months, or as late as November 2024, and again in 2024 by up to an additional 10 months, or as late as September 2025, to continue collecting valuable deep space radiation data in the unique, high-radiation environment beyond low Earth orbit.<\/p>\n Solar activity is\u00a0expected to increase\u00a0as we head into a solar maximum period in the Sun\u2019s 11-year cycle. Activity on the Sun,\u00a0\u00a0involving solar flares and\u00a0giant eruptions called\u00a0coronal mass ejections\u00a0are predicted to peak in 2025. These events send powerful bursts of energy, magnetic fields and plasma into space which causes the aurora, interferes with satellite signals.\u00a0\u00a0Solar radiation events from particles accelerated to high speeds can also pose a threat to astronauts in space.<\/p>\n The BioSentinel project builds on Ames\u2019 history of carrying out biology studies in space using CubeSats \u2013 small satellites built from individual units each about four inches\u00a0cubed. BioSentinel is a six-unit spacecraft weighing about 30 pounds. It houses the yeast cells in tiny compartments inside microfluidic cards \u2013 custom hardware that allows for the controlled flow of extremely small volumes of liquids that will activate and sustain the yeast. Data about radiation levels and the yeast\u2019s growth and metabolism will be collected and stored aboard the spacecraft and then transmitted to the science team back on Earth.<\/p>\n A reserve set of microfluidic cards containing yeast samples will be activated if the satellite encounters a solar particle event, a radiation storm coming from the Sun that is a particularly severe health risk for future deep space explorers.\u00a0<\/p>\n In addition to the pioneering BioSentinel mission that will traverse the deep space environment, identical experiments take place under different radiation and gravity conditions. One ran on the space station, in microgravity that is similar to deep space, but with comparatively less radiation. Other experiments took place on the ground, for comparison with Earth\u2019s gravity and radiation levels. These additional versions show scientists how to compare Earth and space station-based science experiments \u2013 which can be conducted much more readily \u2013 to the fierce radiation that future astronauts will encounter in space.<\/p>\n Taken together, the BioSentinel data will be critical for interpreting the effects of space radiation exposure, reducing the risks associated with long-term human exploration, and confirming existing models of the effects of space radiation on living organisms.\u00a0<\/p>\n Partners:<\/strong><\/p>\n Learn more:<\/strong><\/p>\n For researchers:<\/strong>\u00a0<\/p>\n For news media:<\/strong><\/p>\n\n
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