This section concerns the appropriate design atmosphere of [[Getting to Space]] and looking at #spaceadaptation Factors considered here 1. General design goals [[Payload Design]] 2. Atmospheric composition and pressure limits 3. Monitoring and control of the cabin atmosphere [[Cabin Pressure]] 4. Limits on contaminants and toxins. ## Atmospheric Design Considerations Crewmembers in the system must be provided with an environment to enable them to survive and function as a system component in space. An artificial atmosphere of suitable composition and pressure is the most immediate need. Humans are accustomed to breathing an atmosphere that contains 21% oxygen [[Space Oxygen]] by volume at sea-level. Solution - Considering crew needs only, space cabin pressure is sufficient in the range between 190 and 380 mm Hg (3.75 - 7.3 psia). In this range, crewmembers need not wear protective equipment, and as long as the amount of oxygen in the vehicle cabin provides an alveolar partial pressure of O2 (pO2) of at least 103 mm Hg (1.9 psia), the blood will have an oxygen level equivalent to that at sea level. Advantage - The use of low ambient pressure and 100% oxygen at the above pressure saves weight, simplifies engineering and monitoring, and reduces atmospheric gas leak rates. #Kareena