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The concept of geomagnetic cutoff rigidities is presented in relation to the determination of radiation dosage from galactic cosmic rays and solar proton events. Examples for both aircraft routes and spacecraft orbits are presented.

The detrimental effects of prolonged sitting during long-duration flights include deep vein thrombosis, pressure sores, and decreased awareness and performance. However, the cushion is often the only component of the ejection seat system that can be modified to mitigate these effects. This study investigated the long-duration effects of sitting in four ejection seat cushions over eight hours. Subjective comfort survey data and cognitive performance data were gathered along with comparative objective data, including seated pressures, muscular fatigue levels, and lower extremity oxygen saturation. Peak seated pressures ranged from 1.22–3.22 psi. Oxygen saturation in the lower extremities decreased over the eight hours. Cognitive performance increased over time regardless of cushion with the exception of the dynamic cushion, which induced a decrease in performance for females.

Two series of tests were conducted to investigate the performance of ejection seat cushions for safety and comfort, respectively. In the safety study, seven operational and prototype cushions were tested on the vertical deceleration tower, where the cushions were placed between the seat pan and the occupant (a 50th percentile Hybrid III manikin) and subjected to +Gz impact at 8, 10, and 12 g, respectively. In the comfort investigation, twenty volunteer subjects (12 females and 8 males) with a range of anthropometry were tested on four operational and prototype cushions over eight-hour durations. The safety performance of a cushion is evaluated by the impact transmissibility from the carriage acceleration to the peak lumbar load, whereas the sitting comfort performance is assessed in terms of the peak contact pressure and subjective survey data.

Side-facing seats are present in a variety of aircraft. During impact, these seats load the occupants in a different manner than typical forward-facing seats, namely the occupants are exposed to a lateral impact. In order to minimize injury during a crash, it is necessary for the occupants to prepare themselves and be situated in a position for maximum protection. In an effort to understand occupant initial position in a side-facing seat, a 3-D rigid-body model was developed of a side-facing seat configuration with three occupants, using the Articulated Total Body (ATB) program. The occupants were seated side-by-side in webbed troop-style seats, and each occupant was restrained by a lap belt. Three different initial occupant positions were studied, and each of the three occupants in a given simulation were seated in the same position. A 10 G lateral pulse with an approximate duration of 200 ms was applied to the vehicle.