Field medicine can make equipment dependent upon a stable downward G vector challenging, especially when relying on upward flotation of bubbles in a container of liquid; if a gravity-driven air trap loses its intended orientation with respect to G, air may be infused into the patient. Human spaceflight takes place in an austere, remote, and physiologically challenging environment. Medical provisions are severely limited by considerations of power, weight, volume, and the available skill of the crew. Further, in a 2.5-yr Mars mission involving six crewmembers