The closed enviornment experienced by space crews has various effects: - Stress hormone levels are elevated and immune systems are altered which could increase susceptibility to allergies or other illnesses - Spaceflight changes immune systems, which may lead to autoimmune issues, and more ### Current solutions - Nasa monitors air quality of space stations - Thermal control systems are used to maintain temperatures of the space station and keep astonauts comfortable - Molecular techniques to evaluate risk of microbes - Immunisation following flu shots work as well in space as on earth #pn