THE International Space Station will be so noisy that astronauts may struggle
to communicate, suffer poor health, and even miss crucial warning tones that
signal an emergency. According to documents obtained by 快猫短视频
under the US鈥檚 Freedom of Information Act, the constant clatter of equipment
aboard Russian-built station modules could disrupt work and sleep鈥攁nd
perhaps even damage astronauts鈥� hearing.
The first element of the station, known as Zarya, was launched last November.
Yet as long ago as September 1997, the Khrunichev State Research and Production
Space Centre in Moscow warned that noise generated by fans, air filters, dust
collectors and pumps would result in a 鈥減robable worsening of the health of
cosmonauts and in unintelligibility of voice communications鈥�.
In parts of Zarya, astronauts could be subjected to a perceived noise level
of 72.5 decibels (dBA). That鈥檚 louder than an air conditioner in a closed room,
says Robert Lilkendey of Jaffe Holden Scarbrough Acoustics in Norwalk,
Connecticut. 鈥淚t鈥檚 not something that鈥檚 intolerable, but you鈥檝e got to raise
your voice.鈥� Even the quietest parts of Zarya exceed the space station鈥檚 design
requirements of 50 to 55 dBA.
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Under normal circumstances, these noise levels are too low to cause hearing
damage, but experience with long, constant exposures in Russia鈥檚 Mir
station鈥攚hich is of similar design to Zarya鈥攚orries NASA engineers.
鈥淭here鈥檚 an indication that a significant number of astronauts have lost hearing
in Mir,鈥� says Jerry Goodman, who works on the acoustics of the space station.
Goodman declines to give further details, citing medical confidentiality, but
says that the astronauts later recovered a percentage of their hearing loss.
Even if astronauts鈥� hearing is not damaged, noise could have other
undesirable effects. 鈥淐rew ability to sleep, work, communicate will be
impaired,鈥� warns one NASA document, dated July 1998. Another document, dated
November 1998, notes that the warning tones that signal an emergency would be
鈥渕inimally audible鈥� in Zarya.
Rich Patrican, a NASA official responsible for safety aboard the space
station, says that the launch of Zarya went ahead despite the problem because
foam covers and other devices would be installed later to dampen the noise. 鈥淚t
will be under control,鈥� he says. But other NASA documents predict that the
installation of acoustic mufflers will be 鈥渕inimally effective鈥�, reducing the
noise by only a few decibels. And Goodman admits he can鈥檛 be sure the mufflers
will work.
Less than a month before Zarya鈥檚 launch, the Russians and Americans were
still arguing about the solution to the noise problem. In October 1998, a team
from Khrunichev suggested that astronauts spend no more than four hours a day in
Zarya and no more than two hours a day in the noisiest segments. They also
suggested wearing earplugs. However, documents from the Johnson Space Center in
Houston brand the time restrictions 鈥渦nacceptable鈥�, and say that earplugs should
be prohibited because they would interfere with astronauts鈥� ability to hear
warning signals.
With Zarya already in orbit, the focus of the arguments has now shifted to
the Russian service module, currently scheduled for launch in September, which
will serve as the astronauts鈥� living quarters during much of the station鈥檚
construction. At a meeting in January this year, Russian officials announced
that noise levels in the service module will be as high as 74 dBA. This did not
include the added rumbles of refrigerators and other equipment.
Goodman says that NASA is now paying additional attention to the acoustics within its station
modules, to provide astronauts with quiet havens. 鈥淲hen you鈥檙e locked up in a
spacecraft, you can鈥檛 get away from the noise unless you have a good sleep
station,鈥� he says.
