1、Lessons Learned Entry: 1117Lesson Info:a71 Lesson Number: 1117a71 Lesson Date: 1999-02-01a71 Submitting Organization: HQa71 Submitted by: David M. LengyelSubject: International Space Station (ISS) Program/Extravehicular Activity (EVA)/Prereathe Protocol Description of Driving Event: Modification of
2、Prebreathe Protocol for Extravehicular Activity (EVA) OperationsLesson(s) Learned: There is an initiative to modify the prebreathe protocol for EVA operations on the ISS. The target is a 2-hour prebreathe from any pressure with the same or better bends risk than the protocol currently used in Space
3、Shuttle operations.Recommendation(s): Prior to authorizing any reduction in prebreathe protocol for EVA on the ISS, NASA should conduct a study to ensure that there is no increase in the risk of bends associated with the special circumstances of the proposed new protocol.Evidence of Recurrence Contr
4、ol Effectiveness: NASA concurs with the ASAP recommendation, and believes that the recommended study efforts have already been initiated. In 1997, the EVA IPT initiated a Prebreathe Reduction Program (PRP) to address the risk of decompression sickness (DCS) associated with reduced prebreathe protoco
5、ls. The PRP Team developed a detailed 2-year plan to:1. Develop and test an operationally implementable 2-hour prebreathe protocol2. Perform a detailed risk assessment of acceptable DCS risk to provide prospective accept/reject criteria so that there was a clear metric by which to judge the success
6、or failure of the laboratory trialsProvided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-3. Develop improved methods for treating DCS on orbit4. Develop flight rules to document in advance the specific actions that would be taken to manage a DCS contingenc
7、y should one occur.Items 2,3,and 4 from above form the NASA “DCS Risk Definition and Contingency Plan.“Effort required by that plan has been completed and favorably reviewed by an external review committee chaired by Dr. C. J. Lambertsen. Accept/reject criteria developed from the above plan was used
8、 in an extensive, multi-phase laboratory-testing program of an operationally implementable 2-hour prebreathe protocol. This effort was initiated in November 1997 as a multi-center effort led and managed by NASA and involving three external laboratories (Duke University, the Canadian Defense and Civi
9、l Institute of Environmental Medicine, and the University of Texas Hermann Hospital).A review of the multi-phased laboratory-testing program results and the entire PRP project conducted by medical experts of the International Partners (the Multi-Lateral Medical Operations Panel subcommittee for EVA)
10、 resulted in a committee recommendation that the 2-hour protocol should be safe to implement for EVAs from the ISS. Furthermore, additional internal and external reviews of the laboratory data are planned for June 1999. Pending the recommendations of that review, NASA believes there to be no increas
11、e in the risk of bends associated with the special circumstances of the proposed new protocol, and the 2-hour protocol will be implemented for operations on ISS Flight 7A, which includes the first U.S. space walks from the ISS joint airlock.The PRP Team has also developed a 5-year operational resear
12、ch plan with the goals of providing a better understanding of the underlying science of DCS in microgravity and the possibility of further reductions in prebreathe without compromise to safety. This 5-year research program will include four external laboratories, including the Brooks Air Force Base
13、Armstrong Laboratory and the onsite NASA JSC facilities. Finally, NASA is committed to continued investigative/research efforts to address any relevant data obtained from past, current, or future testing in order to assure no increase in the risk of bends associated with the special circumstances of
14、 current or proposed new protocol.Documents Related to Lesson: N/AMission Directorate(s): a71 Exploration Systemsa71 Space Operationsa71 Aeronautics ResearchAdditional Key Phrase(s): a71 Aerospace Safety Advisory PanelProvided by IHSNot for ResaleNo reproduction or networking permitted without licen
15、se from IHS-,-,-a71 Extra-Vehicular Activitya71 Medicala71 Research & Developmenta71 Safety & Mission AssuranceAdditional Info: 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-,-,-
