2015年6月3日 星期三

NASA Celebrates 50 Years of Spacewalking


For 50 years, NASA has been "suiting up" for spacewalking. In this Feb. 7, 1984 photograph of the first untethered spacewalk, NASA astronaut Bruce McCandless is in the midst of the first "field" tryout of a nitrogen-propelled backpack device called the Manned Maneuvering Unit (MMU). via NASA http://ift.tt/1K9NJRo

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