1983年４月７日，美國＂挑戰者＂號航天飛機在太空飛行期間，兩名航天員在太空自由自在地飄飛行走了3個多小時．這是人類首次不系繩索自由地在太空行走．
　　航天員為何能在太空行走呢？原來，航天員從飛船或航天飛機進入太空時，除了要穿上特制的航天服外，還要背上飛行器，有了它，航天員才能在太空自由＂行走＂。美國宇航員的第一次太空行走

【英文文本】

Twelve men have walked on the moon. And now you can, too. Virtually, that is. Because planetary researchers are enlisting everyday citizens in scientific exploration of the surface of the moon.

At the Web site moonzoo.org, you can check out new high-resolution images taken by NASA’s Lunar Reconnaisance Orbiter Camera. And the team at Citizen Science Alliance, based at Oxford University, says you’ll then be one of the first to see the moon’s surface in what they call unprecedented detail.

This lunar project is a spin-off of the popular Galaxy Zoo, which has gotten more than 250,000 people around the world involved in actual astronomical research. For the moon exploration effort, you might, for example, count craters as you stroll. The researchers say that’s important because it can help them determine the age and depth of the lunar surface. Newer craters could give them clues about recent meteor impacts—and hints about what might be in store for us on Earth. And remember the podcast from April 27th, about a Soviet reflector found on the moon’s surface after forty years? Who knows what strange object you might find. That’s at moozoo.org.