Human spaceflight and space adaptations: Computational simulation of gravitational unloading on the spine

• Published in: Acta astronautica Vol. 145; pp. 18 - 27
• Main Authors: Townsend, Molly T., Sarigul-Klijn, Nesrin
• Format: Journal Article
• Language: English
• Published: Elmsford Elsevier Ltd 01.04.2018; Elsevier BV
• Subjects: Adaptation; Computer simulation; Curvature; Finite element analysis; Finite element method; Gravitation; Gravitational unloading; Gravity; Human body; Human spaceflight; Integrity; International Space Station; Long duration spaceflight; Manned space flight; Mars missions; Mathematical analysis; Mathematical models; Organs; Residual stress; Space exploration; Space missions; Space stations; Spine; Stress analysis; Stress concentration; Stress distribution; Swelling; Terrestrial environments; Three dimensional models; Tissue damage; Finite element method; Tissue damage; Long duration spaceflight; Swelling; Human spaceflight; Gravitational unloading
• ISSN: 0094-5765; 1879-2030
• DOI: 10.1016/j.actaastro.2018.01.015

Living in reduced gravitational environments for a prolonged duration such, as a fly by mission to Mars or an extended stay at the international space station, affects the human body - in particular, the spine. As the spine adapts to spaceflight, morphological and physiological changes cause the mechanical integrity of the spinal column to be compromised, potentially endangering internal organs, nervous health, and human body mechanical function. Therefore, a high fidelity computational model and simulation of the whole human spine was created and validated for the purpose of investigating the mechanical integrity of the spine in crew members during exploratory space missions. A spaceflight exposed spine has been developed through the adaptation of a three-dimensional nonlinear finite element model with the updated Lagrangian formulation of a healthy ground-based human spine in vivo. Simulation of the porohyperelastic response of the intervertebral disc to mechanical unloading resulted in a model capable of accurately predicting spinal swelling/lengthening, spinal motion, and internal stress distribution. The curvature of this space adaptation exposed spine model was compared to a control terrestrial-based finite element model, indicating how the shape changed. Finally, the potential of injury sites to crew members are predicted for a typical 9 day mission. •A finite element model of a whole spine is presented.•Spaceflight-induced mechanical unloading was simulated.•Simulations were validated against experimental measurements of spinal swelling.•Spinal mechanical integrity was investigated to predict potential injury sites.