Orthostatic Intolerance Garments for Spaceflight: Posture-Informed Design for Improving Garment Comfort

Astronauts are susceptible to dizziness and fainting when leaving microgravity as the cardiovascular system struggles to maintain cerebral blood flow during orthostatic challenge with the onset of gravity exposure. Orthostatic Intolerance Garments (OIG) are therefore worn to apply compression to the lower body to minimize blood pooling in the abdomen and lower extremities. The Artemis program intends to use OIG to reduce the risk of losing cognitive ability when transitioning to a higher-gravity environment when spacecraft control or physical capability (e.g., emergency egress) may be compromised. NASA s OIG for spaceflight is an abdomen-to-foot garment where the desired compression regime is graduated from 55mmHg at the lower leg to 15mmHg at the abdomen. Currently astronauts are measured for tailor-made compression garments which are donned for Earth re-entry. Challenges for improved OIG design include the preservation of wearer comfort under target compression regimes, especially around the knee in a seated position. Further, even if using a compression garment tailored to the astronaut, the stretch and pressure of the garment after microgravity exposure will be unknown due to anthropometric variance from height changes, muscle atrophy and fluid redistribution compared to pre-flight measurements. The intention of this study is to contribute new ideas towards the development of a new OIG design which allows for comfortable application of ankle-to-abdomen compression, allowing for flexion of the joints while preserving ambulatory capability. This is being achieved by extending anthropometric-centered-design and giving particular importance to the body posture while seated in the spacecraft re-entry chair.