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Atmospheric Ionizing Radiation and the High Speed Civil TransportAtmospheric ionizing radiation is produced by extraterrestrial radiations incident on the Earth's atmosphere. These extraterrestrial radiations are of two sources: ever present galactic cosmic rays with origin outside the solar system and transient solar particle events that are at times very intense events associated with solar activity lasting several hours to a few days. Although the galactic radiation penetrating through the atmosphere to the ground is low in intensity, the intensity is more than two orders of magnitude greater at commercial aircraft altitudes. The radiation levels at the higher altitudes of the High Speed Civil Transport (HSCT) are an additional factor of two higher. Ionizing radiation produces chemically active radicals in biological tissues that alter the cell function or result in cell death. Protection standards against low levels of ionizing radiation are based on limitation of excess cancer mortality or limitation of developmental injury resulting in permanent damage to the offspring during pregnancy. The crews of commercial air transport operations are considered as radiation workers by the EPA, the FAA, and the International Commission on Radiological Protection (ICRP). The annual exposures of aircrews depend on the latitudes and altitudes of operation and flight time. Flight hours have significantly increased since deregulation of the airline industry in the 1980's. The FAA estimates annual subsonic aircrew exposures to range from 0.2 to 9.1 mSv compared to 0.5 mSv exposure of the average nuclear power plant worker in the nuclear industry. The commercial aircrews of the HSCT may receive exposures above recently recommended allowable limits for even radiation workers if flying their allowable number of flight hours. An adequate protection philosophy for background exposures in HSCT commercial airtraffic cannot be developed at this time due to current uncertainty in environmental levels. In addition, if a large solar particle event occurs during flight at HSCT altitudes then passengers and crew may greatly exceed allowable limits unless means are available to reduce exposures.
Document ID
20030063006
Acquisition Source
Langley Research Center
Document Type
Conference Paper
Authors
Maiden, D. L.
(NASA Langley Research Center Hampton, VA, United States)
Wilson, J. W.
(NASA Langley Research Center Hampton, VA, United States)
Jones, I. W.
(NASA Langley Research Center Hampton, VA, United States)
Goldhagen, P.
(Department of Energy New York, NY, United States)
Date Acquired
September 7, 2013
Publication Date
February 1, 2003
Publication Information
Publication: Atmospheric Ionizing Radiation (AIR): Analysis, Results, and Lessons Learned From the June 1997 ER-2 Campaign
Subject Category
Air Transportation And Safety
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.
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