Space Station Mouse Study Finds 0.67 g Needed to Maintain Muscle Function

Overview

• Published in Science Advances on March 13, the study identifies a gravity level that preserved strength and muscle fiber composition in mice living in orbit.
• Researchers launched 24 mice to the ISS in 2023 and used JAXA’s MARS centrifuge to expose them to microgravity, 0.33 g, 0.67 g, or 1 g for up to 28 days, with 23 returning alive for analysis.
• At 0.67 g the mice retained normal grip strength and muscle profiles, while at 0.33 g their muscle size appeared similar yet strength declined, and in lower gravity deterioration was evident.
• Scientists emphasize that rodent data may not directly translate to humans and urge studies on human thresholds, longer exposures, exercise impacts, bone responses, and artificial gravity options.
• With Mars at about 0.38 g and the Moon near 0.17 g, experts indicate those settings alone likely will not prevent muscle atrophy during extended missions.