As part of the Extravehicular Activity (EVA) Project, the NASA Glenn Research Center is responsible for Communications, Avionics, and Information (CAI) subsystems for next-generation exploration space suits. Part of this effort involves prototypical development and testing of various CAI subsystems. This particular effort included the development of an EVA audio laboratory and digital signal processor (DSP) voice interface, an EVA crew display subsystem, an EVA suit information subsystem, and an EVA sensor subsystem.
Glenn’s Space Audio Development and Evaluation Laboratory (SPADEL) is useful for precise characterization of in-suit acoustics and the evaluation of forward and return speech channels for prospective and operational systems. Audio system technology development of headset and DSP-based voice interfaces (helmet-mounted microphones and speakers) may improve outbound speech quality, in-suit noise levels, and duplex channel feedback levels. The SPADEL supports evaluation of speech quality through creation of an utterance database for jury testing, as well as objective evaluation of speech quality using International Telecommunications Union- (ITU-) recommended algorithms. The portability of SPADEL’s test equipment allows for low-cost and low-risk environmental testing at various EVA operating pressures. A successful demonstration and field testing of suit-mounted microphones, speakers, and DSP-based noise suppression in the Mark III suit took place during the 2006 Desert Research and Technology Studies (D-RATS) outing. In addition, an improved headset concept is being developed to mitigate current EVA audio limitations.
SPADEL and DSP subsystem.
Another effort at Glenn involved the development of EVA crew displays. EVA design constraints were evaluated for various display concepts. Optical characteristics were evaluated for both displays inside the EVA helmet and displays located on the crewmember’s arm. An optics analysis for a Glenn-developed internal helmet mounted display concept yielded promising results. A detailed prototype design is currently in progress. System design must allow for the required low volume, power, and safety considerations for operating in a pure oxygen environment.
Snapshot of EVA information system.
PUMA and integration testing.
Development is underway of an EVA suit information system prototyping platform that integrates displays, voice interfaces, computers, sensor systems, and software for evaluation of advanced EVA information system concepts. Candidate applications include using voice recognition for command and control of anon-suit computer, tracking and monitoring suit life support consumables such as oxygen and battery, displaying timeline procedures and checking off tasks, displaying crew biomedical information such as heart rate and metabolic rate for pacing of work activities, and navigating and tracking during surface operations.
The fourth CAI effort at Glenn involves development of a sensor system that promotes autonomous crew performance and health monitoring, such as heart rate and metabolic rate determination. Although Apollo-era metabolic rates were calculated on the ground, future EVA systems need to be able to operate autonomously. For the sensor system, CO2 sensors are being developed with reduced size, power, and mass. This activity also supports near-term ground-based integrated testing activities such as walk-back testing to determine safe EVA traverse requirements. This technology is also coupled with the system requirements definition of an EVA information system.
Finally, the Portable Unit for Metabolic Analysis (PUMA) was upgraded to increase accuracy and portability to support EVA integrated testing. This technology development is also being evaluated for inclusion into the EVA system for real-time metabolic determination while astronauts are operating on the Moon.
Glenn contact: David A. Carek, 216-433-8396, David.A.Carek@nasa.govLast updated: December 14, 2007
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