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Micrometeoroid and orbital debris (MMOD) penetration hazards have been a concern for the large number of EVA’s (Extravehicular Activities) expected during the assembly and operation of the International Space Station (ISS). Earlier studies have shown large uncertainties in estimated spacesuit penetration risks. This paper reports the results of recent tests and analyses that have significantly expanded the Shuttle EMU (Extravehicular Mobility Unit) hypervelocity penetration database and clarified our understanding of the associated risks. The results of testing have been used to develop improved estimates of the cumulative risk of penetration during EVA's through the first ten years after the beginning of ISS construction. These analyses have shown that the risks of MMOD penetration during EVA will be somewhat less than the risk of a critical penetration of the ISS itself over the same ten-year period.

A cooperative program undertaken by Zvezda and Hamilton Standard to address the required walking mobility for future planetary missions has focussed on space suit foot and ankle mobility. It has included the evaluation of the performance of a boot sole metatarsal (toe) joint and two different ankle joint configurations. A field test with a highly mobile space suit prototype by NASA provides data that complement the results of the above study. Experience in traversing a variety of terrain similar to that expected on Mars provides confirmation of the value of pressure suit ankle and boot sole mobility in the field. Taken together, these studies provide useful data for the design of future planetary exploration spacesuits. Laboratory and field test results are presented and some of their implications for planetary space suit designs are discussed.