1、Lessons Learned Entry: 0744Lesson Info:a71 Lesson Number: 0744a71 Lesson Date: 2000-03-06a71 Submitting Organization: JSCa71 Submitted by: Larry GreggSubject: Evaluation of Actual Operating Conditions in Hardware Designs Prior To Hazardous Testing/Operations Description of Driving Event: On May 28,
2、1993, a NASA astronaut suffered frostbite on eight fingers during manned thermal-vacuum (MTV) testing in Chamber B, Building 32, at JSC. This test was the second portion of a two-part test designed to evaluate the extravehicular activity (EVA) hand tool functionality and flight crew operations for t
3、he Hubble Space Telescope First Servicing Mission. The actual test lasted 6 hours in the thermal-vacuum chamber with the suited astronaut repeatedly operating a large number of hand tools and hardware at temperatures as low as -140F. At the conclusion of the test, upon removal of his extravehicular
4、mobility unit (EMU) gloves, the astronaut noted to the test director that his hands appeared frostbitten.During this test, the astronaut had reported that his hands were cold and that he was experiencing pain. This report was not made in a way that indicated any concern or alarm, and it went undetec
5、ted by the test team. Astronauts routinely note experiencing cold during MTV and some hand pain is also a normally experienced due to the effort required to function in the pressurized suit gloves. The astronaut never again indicated during the run that he was experiencing pain or cold in his hands.
6、 As the test continued, the astronaut operated virtually all of the flight tools, most of them repeatedly. Temperature of the tools and other items was consistently measured via thermocouples at between -113F and -131F. Furthermore, these tools required hand however, they concentrated on hardware ma
7、lfunctions and did not thoroughly assess hazards associated with the unique human factors in this test run, nor adequately consider operational hazards. The EMU-specific hazard Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-analysis also did not ade
8、quately address hazards associated with exposure to extreme cold. It was also noted during the investigation that certain of the tools did not operate properly, or had not undergone any type of thermal of vacuum testing prior to the MTV tests. Additionally, the thermal effects of these tools on the
9、astronauts hands were not a design consideration. Nothing had been done to reduce thermal conductivity of the hand tools, and most had bare metal surfaces. There was also a lack of specific test data on thermal effects within the EMU gloves. Tests had been done on maximum allowable temperatures for
10、short/light exposure, and on warmer temperatures for longer exposures; but it is difficult to extrapolate from these to actual temperatures, grasp pressures, length (of time) of grasp and cumulative effects. These factors are also affected by a number of variables in EMU sizing and individual astron
11、aut options.Lesson(s) Learned: Failure to consider actual operating conditions in design prior to testing can lead to hazards and injury of those involved in the testRecommendation(s): Actual environmental conditions should be collected and considered in design of tools, equipment, and operations ea
12、rly in the design and development process.Evidence of Recurrence Control Effectiveness: N/ADocuments Related to Lesson: N/AMission Directorate(s): a71 Exploration Systemsa71 Space Operationsa71 Aeronautics ResearchAdditional Key Phrase(s): a71 Configuration Managementa71 Cryogenic Systemsa71 Environ
13、menta71 Flight EquipmentProvided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-a71 Hardwarea71 Hazardous/Toxic Waste/Materialsa71 Medicala71 Personal Protective Equipmenta71 Research & Developmenta71 Risk Management/Assessmenta71 Safety & Mission Assurancea71 Test Facilitya71 Test & VerificationAdditional Info: Approval Info: a71 Approval Date: 2000-04-11a71 Approval Name: Eric Raynora71 Approval Organization: QSa71 Approval Phone Number: 202-358-4738Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-
