1 Parabolic Flight as a Spaceflight Analog

24 25 Ground-based analog facilities have had wide use in mimicking some of the features of space 26 flight, in a more controlled and less-expensive manner. One such analog is parabolic flight, in 27 which an aircraft flies repeated parabolic trajectories that provide short-duration periods of free 28 fall (0g) alternating with high-g pullout or recovery phases. Parabolic flight is unique in being 29 able to provide true 0g in a ground-based facility. Accordingly, it lends itself well to the 30 investigation of specific areas of human space flight that can benefit from this capability, which 31 predominantly includes neurovestibular effects, but also others such as human factors, 32 locomotion, and medical procedures. Applications to research in artificial gravity, and to effects 33 likely to occur in upcoming commercial suborbital flights, are also possible. 34