Noise in space is a major problem. This is especially true for long range duration on the International Space Station and future missions to Mars. According to American astronauts, the decibel levels in the Russian portion of the international space station are damaging their hearing (The Los Angeles Times, “U.S. Astronauts Sound Off on Space Noise, Dec. 2, 2001).
Recent data indicate that noise levels on the International Space Station can average more than 70 decibels and that scheduled sleep episodes have recorded over 90 decibels (Risk of Performance Errors due to Sleep Loss, Circadian Desynchronization, Fatigue, and Work Overload, Human Research Program Requirements Document).
There are several implications and consequences from astronauts enduring noise.
There was a large scale study (based on 4.6 million adults across Switzerland). After factoring for air pollution, etc. the researchers found that both the level and duration of aircraft noise drove up the risk of lethal heart attack. One of the researchers in the article pointed out that noise itself regardless of the sources affects blood pressure. Another researcher noted that even if something is not that loud or disturbing, it can become really bothersome if not turned off. He also said that the classic stress response includes a rise in heart rate and blood pressure and although it isn’t usually a problem when short and infrequent bursts, this can lead to significant wear and tear if it continues daily. Finally according to the researchers report in the journal Epidemiology, people exposed to a daily average of at least 60 decibels of noise had a 30 percent greater risk of dying from a heart attack compared with those exposed to less than 45 decibels (Epidemiology online, September 27, 2010).
Another article stated, “Most agree that acute exposure to levels greater than 80-85 dB and chronic exposure to levels greater than 65 dB can cause an increase in blood viscosity, vasoconstriction, heart rate, and blood pressure (Chertoff, Environmental Health, Spring 2010).”
Jay Buckey, a former astronaut now at Dartmouth Medical School in Hanover, New Hampshire, said that both temporary and permanent hearing loss were recorded after flights on the Soviet and Russian Salyut stations, even for stays as short as seven days. The loss was usually at higher frequencies (Young, K., New Scientist, June, 2006)
Professor David Dinges, Department of Psychiatry at University of Pennsylvania, says sleep is critical no matter where humans go and if they don’t get it, performance deteriorates rapidly. When people are awake more than 18 hours, they tend to have psycho-motor impairments equivalent to when they are inebriated (Documentary, “Mars Uprising,” 2007).
Bonnet et al. (2005) found that the discrepancy between sleep in flight and ground-based studies suggests that “not only is sleep quantity reduced during space flight, but also that the restorative component of sleep may be disrupted in space, which may further increase the likelihood that waking neurobehavioral performance deficits will occur.” (Whitmire et al., Jan 2009, Risk of Performance Errors due to Sleep Loss, Circadian Desynchronization, Fatigue, and Work Overload)
Barger and Czeisler (2008), suggest that the amount and quality of in-flight sleep is reduced in comparison to terrestrial sleep behavior for multiple reasons, one of which is noise.
Deprived of sleep, the risk of accidents on the Mars mission will be high.
Noise tends to produce stress. There are numerous environmental variables which can, under certain circumstances, either provoke aggression or increase the likelihood of its occurrence. Astronauts are carefully screened and selected, as was former astronaut Lisa Nowak, who was charged with attempted kidnapping. This may seem difficult to imagine, but putting six astronauts in about the same the space as a small apartment on a 12 month journey to Mars and back that has never been done before, would not be the time to discover in hindsight that this is a problem that had never been addressed. Noise levels above 80 dB are associated with both an increase in aggressive behavior and a decrease in behavior helpful to others (Noise Pollution: A Modern Plague: Adverse Health Effects of Noise, Southern Medical Journal, 2007). This is not something that NASA would want to deal with on the Mars mission.
There is a device that may be able to help provide at least a partial contribution to the solution.
It is a noise level alert system . Astronauts set the threshold noise level so that a notification alert can be given when the threshold noise level is exceeded. For example, if it is decided that the astronauts should be notified when the ambient noise level reaches 75 decibels, then an audio voice system or other alert modes can warn the astronauts when that level is reached. The voice system is programmed to be just above the current ambient noise level so it can be heard.
This can be used to help the astronauts to know when to use ear protection devices and can help them sleep better. The device can also be used to warn the astronauts to use ear protection during waking hours. The threshold can be set to different levels depending on whether the astronauts are sleeping or awake.
In addition, the device could measure how many times specific decibel levels are exceeded and when, which would provide invaluable data for NASA in determining the effects of noise on astronauts.
The idea may sound simple, but it would be one more tool that can at least provide a partial solution to the problem.
The device is patent pending.