1、Lessons Learned Entry: 1109Lesson Info:a71 Lesson Number: 1109a71 Lesson Date: 1999-02-01a71 Submitting Organization: HQa71 Submitted by: David M. LengyelSubject: International Space Station Program/Crew/Radiation Exposure Description of Driving Event: Reduction in the Annual Limit for Radiation Exp
2、osureLesson(s) Learned: In the ASAP Annual Report for 1997, the Panel expressed concern for the high doses of radiation recorded by the U.S. astronauts during extended Phase I missions in Mir. Subsequent and continuing review of this potential problem revalidates that unresolved concern. The current
3、 NASA limit for radiation exposure is 40 REM per year to the blood-forming organs, twice the limit for the U.S. airline pilots and four times the limit for Navy nuclear operators (see also Finding #23).Recommendation(s): In the ASAP Annual Report for 1997, the Panel expressed concern for the high do
4、ses of radiation recorded by the U.S. astronauts during extended Phase I missions in Mir. Subsequent and continuing review of this potential problem revalidates that unresolved concern. The current NASA limit for radiation exposure is 40 REM per year to the blood-forming organs, twice the limit for
5、the U.S. airline pilots and four times the limit for Navy nuclear operators (see also Finding #23).Evidence of Recurrence Control Effectiveness: NASA concurs with the recommendation. However, in keeping with the “as low as reasonably achievable“ (ALARA) radiation protection principle, NASA is propos
6、ing a set of administrative spaceflight exposure limits which are significantly below the NCRP recommended annual limits. The administrative limits are designed to improve the management of astronaut radiation exposures and ensure that any exposures are minimized. The proposed administrative BFO exp
7、osure limits Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-range from 5 cSv (REM) for a one month exposure period to 16 cSv (REM) for a twelve month exposure period. These limits have been proposed for inclusion in section B14 of the Flight Rules a
8、nd are currently awaiting concurrence from Energia and the Russian Space Agency.The National Council on Radiation Protection and Measurements (NCRP) developed these limits in 1989 for NASA. The NCRP is a congressionally chartered organization responsible for developing radiation protection limits. T
9、he NASA Administrator, OSHA, and the Department of Labor approved these limits.NASA has adapted 30 day and annual dose limits of 0.25 Sv and 0.5 Sv, respectively. The purpose of these limits is to prevent acute health effects, such as nausea, vomiting, etc. NASA also maintains career limits intended
10、 to limit the probability of cancer below 3% excess cancer mortality. These career limits are comparable to the US career limits for other radiation workers. Furthermore, the annual limits also serve to spread out career radiation exposure over time.The NCRP completed a re-evaluation of astronaut ex
11、posure limits in 1998 using the most recent results from longitudinal studies of Japanese atomic bomb survivors. Currently, the NCRP has a draft report undergoing full NCRP review and approval, which is expected to be released in the fall of 1999. When this report is released, NASA will consider its
12、 recommendations and, if appropriate, will proceed to implement any recommended reductions.Documents Related to Lesson: N/AMission Directorate(s): a71 Exploration Systemsa71 Space Operationsa71 Aeronautics ResearchAdditional Key Phrase(s): a71 Aerospace Safety Advisory Panela71 Medicala71 Policy & P
13、lanninga71 Research & DevelopmentAdditional Info: Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-Approval Info: a71 Approval Date: 2002-02-12a71 Approval Name: Bill Loewya71 Approval Organization: HQa71 Approval Phone Number: 202-358-0528Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-
