Crew Performance in Spacelab

Abstract

This paper discusses two studies utilizing videotaped footage of crew members working in the micro-g environments aboard two flights of Spacelab. Various aspects of crew restraint, stabilization, manipulation of controls, and moving about were observed, operationally defined, and quantified by observing videotaped scenes of spacelab crew members. In the first study four performance behaviors were quantified in order to provide estimates of their frequency of occurrence and variation over the course of each of the flights: (1) movement between work stations (translation), (2) holding on with one hand to stabilize while working (Hand Hold), (3) use of provided foot restraints while working (Foot Restraint), (4) out-of-control body movements (Struggle). Eighty one-minute segments were randomly chosen of which 59 met the restrictive definitions for coding. Four raters timed all behaviors using stopwatches. Inter-rater reliabilities (Chronbach's ALPHA) varied between .87 and .96 for the four behaviors. The averaged responses of the four raters showed the following mean proportions of time for each of the behaviors: Translating=9.4%, Hand Hold=32.2%, Foot Restraint=35.3%, and Struggle=3.7%. Because more than a third of a crew member's time was spent inefficiently holding on with one hand while trying to work with the other, a second study was conducted exploring the use of foot restraints and hand stabilization. In both flights hand stabilization occurred more often when using a single cloth foot loop than when using two, t(90)=2.37, p < .01. Crew members increased their use of double foot restraints with experience.