KINGSTON, R.I. 鈥� March 16, 2026 鈥� NASA鈥檚 goal is to send astronauts to Mars as early as the 2030s. Marie Mortreux, an assistant professor in the 溏心vlog免费B站鈥檚 , is part of an international team of researchers studying how the Red Planet鈥檚 gravity would affect astronauts鈥� skeletal muscle.
Skeletal muscle is the most abundant tissue in the body鈥攔epresenting more than 40% of the total body mass鈥攂ut it is especially sensitive and a loss of gravity and can result in substantial loss of muscle strength, size, and performance. Since Mars鈥� gravity is about 38% of Earth鈥檚, it鈥檚 important to determine how the muscle would handle the difference.
鈥淲hile we can simulate spaceflight on Earth in humans, it鈥檚 extremely complicated and costly,鈥� said Mortreux. 鈥淲e have centrifuges that can be used to temporarily expose humans to certain gravity levels, but it is not homogenous nor constant.鈥�
Among the dozens of scientists involved in the project, many were from the Japan Aerospace Exploration Agency (JAXA). To determine how skeletal muscle reacts to different levels of gravity, 24 mice were launched from Kennedy Space Center to the International Space Center, where they were tested in the developed by Japan.
The mice were exposed to four different gravity levels using the JAXA-developed, centrifuge-based Multiple Artificial-gravity Research System (MARS) laboratory over a 28-day period.
鈥淲e used gravity levels that were equally separated, to have a better picture of the dose-response of each system to gravity,鈥� said Mortreux, who leads the Metabolism and Muscle Biology Lab in 溏心vlog免费B站鈥檚 Department of Nutrition. 鈥淭he test group that was exposed to 0.33g was extremely close to Martian gravity (0.38g). Our findings for that group can be translated into actions to enable Mars exploration.鈥�
Mortreux wasn鈥檛 available for the pre-flight testing of the mice from January to March 2023, but when the mice returned from space in April 2023 she analyzed their weight, strength, and movement at NASA鈥檚 facilities.
Mortreux became involved in the project while collaborating with Professor Mary Bouxsein at Harvard Medical School as a post-doctoral researcher and instructor, prior to joining the 溏心vlog免费B站 faculty in 2022. She continued with the project after arriving at 溏心vlog免费B站, while protocols were defined and several launches were delayed.
鈥淒r. Bouxsein developed the ground-based mouse model of partial gravity in the early 2010s, and I created the rat model of partial gravity at Harvard, so we were extremely experienced with the impact of different gravity levels on musculoskeletal tissues,鈥� said Mortreux. 鈥淪ince this mission aimed to assess gravity as a continuum, we were perfectly positioned to see if our ground-based results had similar outcomes when reduced mechanical loading was applied in orbit.鈥�
Mortreux was also comfortable working with her Japanese counterparts.
鈥淲orking with an international team was challenging and exciting,鈥� said Mortreux, who earned her bachelor鈥檚 and master鈥檚 degrees and Ph.D. from Paris Diderot University in France. 鈥淚 think my experience working in Italy, France, and the United States prepared me for those big-scale collaborations.鈥�
The results of the research team鈥檚 analysis of how different gravity levels affected the skeletal muscle of the mice is described in a peer-reviewed article in March. Data from the project is still being studied in Mortreux鈥檚 lab and is expected to result in future articles.