Case 1 When NASA began the launch of astronauts into space, they found out that the pens wouldn"t work at zero gravity (ink won"t flow down to the writing surface).

例一当美国航空航天局准备将宇航员送往太空时，他们发现钢笔在零重力情况下写不出来（墨水无法流出来印到书写材质上）。

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The four current NASA pilots who can operate the modified 747 are ex-military aviators who split their time flying other planes including zero-gravity aircraft and T-38 supersonic jets.

MSN: What it's like to fly a plane carrying shuttle - Technology & science - Space | NBC News

Watch Kirobi's zero gravity training below, come back, and then tell us you didn't at least crack a smile.

ENGADGET: Alt-week 3.9.13: Sunstones, knotted vortices and a zero-g robot