Abstract:

Significance The microgravity environment in space causes human musculoskeletal deconditioning to gravity, triggering a number of physiological changes, such as muscle atrophy and bone loss. Such pathologies affect the ability of astronauts to perform their missions and expose them to a higher risk of fracture and disc herniation upon return to earth. There has been widespread interest and concern about how to combat the adverse pathologies caused by the microgravity environment on the human musculoskeletal system. Compression garment is an important medium for generating mechanical interactions on the human body. The desired pressure can be obtained by adjusting the material and structure of the compression garment. In addition, compression garments are lightweight and compact, which have important advantages in space flight. It is significant to explore the current status of research on compression garment against microgravity environments by using a combination of clothing ergonomics and human biomechanical principles. This will help to guard the health of astronauts and promote the development of human spaceflight technology.
Progress This paper specifically analyzes the countermeasure mechanisms and structural efficacy characteristics of existing compression garments for space stations, such as the penguin suit and gravity loading countermeasure skinsuit (GLCS), and related prototype garments reported in the literature. The study concludes that the current compression garments are classified into tension-pressure and gas-pressure countermeasures. The penguin suit selects elastic tension straps to apply axial load on the body. However, the poor comfort limits its cap ability to apply loads to the body. The GLCS applies bi-directional elastic fabric to balance the axial load and circumferential pressure. It can be seen from the performance evaluation of some GLCS versions that GLCS has cut down its mechanical function while continuously improving its comfort. Other prototypes categorized as tension-pressure garments are based on the principle of providing pressure along the vertical axis of the body. Gas-pressure countermeasures, for example, lower body negative pressure (LBNP) garment uses negative pressure to create a ground reaction force on the bottom of the foot. The energy consumption and bulkiness of LBNP is a problem that needs to be solved. Moreover, some harness-type accessories provide resistance to movement and load on the body by combining with other equipment.
Conclusion and Prospect The key technology for compression garments against microgravity environments is to balance loading functionality and wearing comfort. At the same time, the evaluation of human dressing-related indicators should be strengthened. At present, such compression garments have problems such as insufficient gravity loading and incomplete performance testing. This paper proposes the following countermeasures to solve these problems. On the one hand, the consideration of textile process should be enhanced when fabricating garments. For example, the performance of the garment should be improved by introducing different mechanical properties and other functional yarns. Form different functions in each area of the garment by choosing different molding processes. The relationship between the mechanical properties of garments and the load functions required by the human body should be explored in depth, providing a reliable basis for the preparation of garments. On the other hand, the evaluation of compression garments should include three aspects, i.e., loading functionality, wearing comfort and physiological adaptability. The performance assessment of the mechanical interaction between the garment and the human body should be strengthened. The assessment of the human body's physiological adaptation to garment can be reinforced by introducing simulation technology. The future research direction focuses on three aspects: material process, evaluation system and technology transformation. Researchers can focus on developing new materials that are durable, moisture permeable and comfortable, whilst engineers should concentrate on improving the intelligence and accuracy of evaluation methods. Further, efforts can be made to convert this aerospace technology into rehabilitation measures for bedridden patients.

Key words: microgravity, compression garment, musculoskeletal, protective compression garment, anti-G suit, gravity loading suit, spacesuit