An evaluation of noise and its effects on shuttle crewmembers during STS-50/USML-1

High noise levels can lead to physiological, psychological, and performance effects in man, ranging from irritability, annoyance, and sleep interference to interference with verbal communication and fatigue, and to temporary or permanent threshold shift at more extreme levels. The current study evaluated the acoustic environment of the STS50/USML-1 mission. The major objectives were to gain subjective assessments of the STS-50 noise levels, document impacts of noise upon crewmember performance, collect inflight sound level measurements, compare noise levels across missions, evaluate the current Shuttle acoustic criterion, and to make recommendations regarding noise specifications for SSF and other long-duration manned space missions. Sound measurements indicated that background noise levels were 60, 64, and 61 A-weighted decibels, respectively, on the Orbiter middeck, flight deck, and Space lab. All levels were rated acceptable, with the Spacelab environment rated the most favorably. Sleep stations afforded attenuation from airborne noise sources, although all crewmembers reported being awakened by crew activity on the middeck. Models of distance for acceptable speech communications were generated, identifying situations of compromised verbal communications to be avoided.