Design and Development, Musculoskeletal Modeling and Experimental Evaluation of the Enhanced Dynamic Load Sensor for the International Space Station
Roedolph Opperman, PhD Candidate, MVL
Prolonged exposure to the microgravity environment of space leads to a reduction in bone mineral density, muscle mass, strength and endurance. Such deconditioning may impede critical astronaut functions and activities including emergency egress and extravehicular activity during a mission. Furthermore, a compromised musculoskeletal system presents an increased risk of injury after flight when exposed to increased gravity like that of Earth or Mars.
Exercise countermeasures are used extensively on board the International Space Station (ISS) to mitigate musculoskeletal deconditioning among crewmembers during long duration spaceflight missions. However, despite vigorous exercise protocols, bone loss and muscle atrophy is often observed even when countermeasures are in effect.
Currently these exercise countermeasure systems have a significant limitation in that they do not provide any means for on-orbit biomechanical data collection and analysis. Such a capability would advance the efficiency of these systems in mitigating the incidence of bone and muscle loss by quantifying loading intensity and distribution during exercise in microgravity, thus allowing for cause-effect tracking of ISS exercise regimes and biomechanics. By measuring these forces and moments on the exercise device and correlating them with the post-flight fitness of crewmembers, the efficacy of various exercise devices may be assessed, advancing system efficiency. More importantly, opportunities for improvement, including optimized loading protocols and lightweight exercise device designs will become apparent.
This research improves the understanding of astronaut joint loading during resistive exercise in a microgravity environment through the use of rigorous quantitative dynamic analysis, simulation and experimentation. This is accomplished with the development, simulation and evaluation of a self-contained load sensing system, the Enhanced Dynamic Load Sensor for the International Space Station (EDLS-ISS).
The sensor assembly augments existing countermeasures, specifically by interfacing with the ISS Advanced Resistive Exercise Device (ARED) and measuring ground reaction forces imparted by the crew while exercising. Aspects of sensor development, musculoskeletal modeling and parabolic flight testing are discussed.
By validating the EDLS-ISS sensors a unique contribution is made in expanding NASA’s capability to continuously record and quantify crew loading during exercise on ISS. Data obtained through the EDLS-ISS system is used to characterize joint loading, optimize exercise protocols to mitigate musculoskeletal deconditioning and may lead to the design of improved, lightweight exercise equipment for use during long-duration spaceflight, including future missions to Mars.