Astronomy Picture of the Day——在太空自由飞翔

To Fly Free in Space 
Image Credit: NASA, STS-41B

Explanation: What would it be like to fly free in space? At about 100 meters from the cargo bay of the space shuttle Challenger, Bruce McCandless II was living the dream -- floating farther out than anyone had ever been before. Guided by a Manned Maneuvering Unit (MMU), astronaut McCandless, pictured, was floating free in space.McCandless and fellow NASA astronaut Robert Stewart were the first to experience such an "untethered space walk" during Space Shuttle mission 41-B in 1984. The MMUworked by shooting jets of nitrogen and was used to help deploy and retrieve satellites. With a mass over 140 kilograms, an MMU is heavy on Earth, but, like everything, is weightless when drifting in orbit. The MMU was later replaced with the SAFER backpack propulsion unit.

在太空自由飞翔

在太空中飞翔是一种什么样的体验？在挑战者号航天飞机货仓外约100米的地方，Bruce McCandless和同伴觉得自己正在梦境当中，因为这时他比以往的任何人都漂浮得更远。通过载人机动装置(MMU)，图中的宇航员McCandless实现了自由悬浮在太空中。在1984年航天飞机41-B任务中，McCandless和另一名NASA宇航员Robert Stewart首次体验了这种“无系绳太空行走”。MMU利用喷射氮气的原理来工作，帮助部署和回收卫星。140千克的MMU在地面上显得非常沉重，但在进入轨道之后，像其他所有的物体一样，都处于失重状态。MMU在之后几年被更加安全的背包推进装置所代替。

NASA

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