Dynamic modeling to assess hip loading for martian space exploration

Astronaut performance of locomotion and falls in a partial gravity environment similar to Mars (3/8 G) was simulated. An astronaut loping in Mars gravity while wearing a space suit was modeled. Preliminary calculating of factor of risk indicate that both locomotion and falls have a significant fracture risk level following long-term space flight if bone loss occurs at the rates currently observed in space flight studies (1-2% bone mineral density loss per month). This applies to astronauts performing activities on Mars following a 6-12 month journey in weightlessness, and to astronauts performing activities on Earth following 6 months or more of weightlessness. Given the significant level of fracture risk associated with both traumatic activities (falls) and activities of daily living (locomotion) for astronauts, there exists a serious need for countermeasures to bone loss associated with weightlessness.