NASP Re-Entry Profile: Effects of Low-Level +Gz on Reaction Time, Keypad Entry,and Reach Error

摘要

The National Aerospace Plane (NASP) is projected to have a reentry profile whichmay generate a maximum of +2.5gz for up to 30 minutes. Very little is known about the effects of this type of acceleration profile on human performance. Thus, 8 subjects were exposed to +2gz for 40 minutes on the DES centrifuge, during which time they performed a choice reaction time task, a keypad entry task, and a reach task. The tasks were based on one of many preliminary NASP cockpit designs. Results indicated that for simple reaction time tasks no performance decrements were found; in fact a slight increase in performance occurred. For the keypad task, however, performance decrements were found throughout the entire profile. The reach task showed decrements early in the exposure, but towards the end performance reached baseline levels. This suggests a recalibration of gross motor movement during long exposure to low-level acceleration. Results indicated that input devices which require large arm/hand movements should be mounted no farther than 21 from the floor and 35 away from the intersection of the seat back/pan of an ACES. II-type seat. Keypad entry devices should have button sizes of at least 3/4 by 3/4, and should be mounted on a swivel mount to reduce uncomfortable wrist angles.