International Space Station Acoustic Measurement Program (ISS Acoustics) - 05.13.15
The International Space Station Acoustic Measurement Program (ISS Acoustics) is responsible for ensuring a safe, healthy and habitable acoustic environments on the ISS, in which crews can live, communicate, and work. This means ensuring that space vehicle environments are not too noisy, do not have irritating audible sounds and do not have startling bursts of acoustic energy. Science Results for Everyone
Space may be silent, but spaceships can be pretty noisy. That creates problems for those who live and work in space, particularly on the busy space station. This project measured noise levels throughout the station. The data will help the ISS acoustics team safeguard crewmembers’ hearing, develop work-arounds for excessive noise and provide a secure, productive and comfortable environment for crewmembers to live and work. Results indicate that daily noise exposure limits aboard the station should be at or close to 70 A-weighted decibels, based on crew experience and variability in response to noise. Noise monitoring, abatement and restricting crew exposure during a mission will help achieve those limits. Experiment Details
Samuel A. Denham, Ph.D., The Boeing Company, Huntsville, AL, United States
S. Reynold Chu, Ph.D., Lockheed Martin, Houston, TX, United States
Christopher S. Allen, Johnson Space Center, Houston, TX, United States
Sponsoring Space Agency
National Aeronautics and Space Administration (NASA)
Human Exploration and Operations Mission Directorate (HEOMD)
ISS Expedition Duration
September 2000 - March 2010
Previous ISS Missions
The ISS Acoustics program has been operated on many Space Shuttle missions and Mir.
- The International Space Station Acoustic Measurement Program (ISS Acoustics) utilizes one Sound Level Meter (SLM) and three audio (acoustic) dosimeters to monitor the ISS acoustic noise environment.
- Periodic SLM surveys across the ISS and crew-worn/static audio dosimeter measurements are used for noise trend tracking, acoustic diagnosis, and development of noise abatements/acoustic remedies.
The ISS is a noisy place. To better characterize the acoustic environment as it changes with assembly, the International Space Station Acoustic Measurement Program (ISS Acoustics) has collected data from before a permanent crew occupied the ISS. The experiment utilizes one B&K Type 2260 Sound Level Meter (SLM) and three Ametek Mark I audio (acoustic) dosimeters to monitor the ISS acoustic noise environment.
There are two types of SLM activities, the SLM survey of ISS and acoustic engineering evaluation. An SLM survey is performed once every two months to measure the acoustic spectral levels at specified locations. An acoustic engineering evaluation is performed to: diagnose acoustic abnormalities; investigate crew complaints and evaluate effectiveness of newly-installed noise reduction measures.
Noise exposure levels are measured by crew-worn dosimeters and dosimeters deployed at fixed locations to determine work, sleep, and 24-hour noise exposure levels. Periodic reports of SLM surveys and dosimeter measurements are generated for noise trend tracking, acoustic diagnosis, and development of noise abatements/acoustic remedies.
Information from ISS Acoustics is used to ensure safe and habitable noise levels for crewmembers living and working aboard the ISS. ISS Acoustics data are used to compare with noise level predictions for upcoming spaceflight missions.
Data resulting from measuring acoustics on the ISS are useful in other extreme environments on Earth, such as submarines or underwater laboratories.
The program deploys one B&K Type 2260 SLM and three Ametek Mark I audio dosimeters to monitor ISS acoustic noise environment. The SLM survey is performed once every two months. The first survey of each increment is a survey of the entire ISS measuring at about 40 locations. Subsequent surveys during the increment are a survey of only the Service Module (SM) and US Laboratory, Destiny, about 25 locations. Measurement data are transferred from the SLM to the medical equipment computer (MEC) for subsequent downlink.
Audio dosimeter measurements are also performed once every two months. The first day of the activity deploys the dosimeters for crew-worn measurements during work and sleep hours. The second day of the activity deploys the dosimeters at static locations. Measurement data are either downlinked or called down to Mission Control Center.
At the beginning of each SLM survey, the crew unstows the SLM from the Acoustic Countermeasures Kit, powers up the SLM, and performs some setup procedures. Additional checkout procedures are performed if a resupplied SLM is used for the first time. Then, the crew proceeds to measure acoustic spectral levels at locations designated by the Acoustics Office, prior to the survey. The crews are instructed not to talk and to turn off music while making measurements. Also, the SLM survey is not to be scheduled during exercise and ground communication sessions. These guidelines prevent the measurements from being corrupted by unintended noises. The measurements are saved on the hard drive of the SLM during the survey, and then transferred to MEC immediately after the survey.
For crew-worn dosimeter measurements, each crewmember attaches a dosimeter to their waist or pocket, and attaches the microphone to their lapel or collar. The crew records the measurements after approximately 16 hours of work, and 8 hours of sleep.
The ISS presents a significant acoustics challenge considering all of the modules and equipment that make it an on-orbit laboratory and home with long-duration crew occupation. The acoustic environment on board the ISS has become one of the highest crew habitability concerns. The acoustics mission support function, including training, mission control support, and data analysis, is necessary to monitor crew exposure and ensure that the crewmembers' hearing is not at risk. Without accurate on-orbit data, all preventative ground efforts are rendered ineffective. Mission monitoring and support is critical to the control and mitigation of acoustic noise on the ISS. ISS Acoustics preserves crewmembers' hearing and provides for a safe, productive, and comfortable noise environment.
The Acoustics Office at Johnson Space Center performs valuable management oversight over acoustic activities. The JSC acoustics team provides beneficial support of modules, payloads, and GFE requirements definition, design and development, consultation, and applies proactive efforts to help hardware providers achieve compliance. The acoustic team also manages predictions for flight readiness, on-orbit measurements, and maintains a database of measurements, and distributes reports and assessments of the data. It is important that the ISS noise be in compliance with current specifications. This is important to ensure acceptable crew communications, health, and well-being. Data collected from the Space Shuttle and Mir programs indicate that levels at or close to 70 dBA should be considered ISS daily exposure limits. These limits are justified in view of crew experience, especially considering the variability in crew member physiological and psychological response to noise (Goodman 2003).
ISS Acoustics develops measures to safeguard the crewmembers' hearing, ensures there are work-arounds for excessively noisy areas or mission events, and provides for a secure, productive, and comfortable noise environment. This is aided by module noise monitoring, noise abatement, and restricting crew noise exposure during a mission (Pilkinton 2003). (Evans et al. 2009)
Goodman JR. International Space Station Acoustics. Noise Conference, Cleveland, OH; 2003
Pilkinton GD. ISS Acoustics Mission Support. Noise Conference, Cleveland, OH; 2003
Allen CS, Denham SA. International Space Station acoustics - a status report. 41st International Conference on Environmental Systems, Portland, Oregon; 2011 July 17-21 21 pp.
Limardo JG, Allen CS. Analysis of noise exposure measurements acquired onboard the International Space Station. 41st International Conference on Environmental Systems, Portland, Oregon; 2011 July 17-21 16 pp.
Ground Based Results Publications
Grosveld FW, Goodman JR. Design of an Acoustic Muffler Prototype for an Air Filtration System Inlet on International Space Station. Noise Conference, Cleveland, OH; 2003
Allen CS, Goodman JR. Preparing for Flight - The Process of Assessing the ISS Acoustic Environment. Noise Conference, Cleveland, OH; 2003 Jun 23-25
Tang P, Goodman JR. Testing, Evaluation, and Design Support of the Minus Eighty-Degree Laboratory Freezer (MELFI) Payload Rack. Noise Conference, Cleveland, OH; 2003
Phillips EN, Tang P. ISS Human Research Facility (HRF) acoustics. Noise Conference, Cleveland, OH; 2003
Habitability and Environmental Factors Division Labs and Facilities
NASA Image: ISS003E329018 - Expedition Three Mission Commander Frank L. Culbertson holds the Sound Level Meter (SLM) in the U.S. Laboratory / Destiny. The SLM is part of the Acoustic Countermeasures Kit (ACK).
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NASA Image: ISS005E12372 - Flight Engineer, Sergei Treschev takes measurements with an SLM in the U.S. Laboratory during Expedition Five.
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NASA Image: ISS007E08990 - Expedition Seven Science Officer, Ed Lu, poses for a photo in the Zvezda Service Module while wearing the audio dosimeter.
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