Personnel Communications in Space. A Study of Speech Transmission and Helmet Comfort

摘要

A program exploring original techniques as well as those currently employed was performed to improve speech com munication and comfort tolerance in the space helmets. A high performance noise-cancelling microphone, the M-93, was investigated. Its superior characteristics were confirmed by psycho-acoustic comparisons with the M-87 and M-101 operational types. A study of microphone arrays was made. A unique space helmet was developed providing freedom of lateral head motion and featuring off-the-head transducers in its communication system. These features make possible predicted long comfort tolerance compared with presently used helmets. The new helmet additionally offers the excellent promise of significant noise reduction, good thermal insulation, and acoustic stability with comfortable sidetone level. A novel method of restoring aural directional perception to a man in space was further developed utilizing cardoid receptors and a specialized network. This method provided an important degree of orientation ability. Conclusions and recommendations for future work are included. (Author)