CNN News:地球轨道现存4000个退役卫星，存在极大安全隐患

Sputnik One lasted about a year before it reentered Earth`s atmosphere and burned up. The thousands of other objects we`ve launched in the space don`t do that. They just hang out in orbit, spinning around the Earth until they possibly hit something. A lot of you saw the Oscar-winning movie "Gravity". Is it only a matter of time before space junk threatens space travelers?

人造卫星一号在经过一年旅行之后重新返回地球大气层并燃烧。其它我们发射出的数千种发射器并不会有这种行为，他们只会沿着地球轨道保持旋转直到撞击到什么物质。你们中可能很多人都看过奥斯卡获奖电影《地球引力》这部片子，现在有一个问题，在太空垃圾袭击太空旅行者之前仅仅存在一个时间问题吗?

There`s about 5,000 objects in - large objects in Earth`s orbit, and there`s only about 1,000 that are functioning. You have bunch of electronics up there, you`ve got rocket engines that have to be used to put the object in orbit. I published my paper in 1978, which led to this Kessler Syndrome name. It`s a cascading phenomenon in the sense that when things break up, they produce both a very large distribution of small fragments and a smaller number of larger fragments. And those larger fragments are still large enough to go on and get a satellite and totally break it up. And so it cascades into - in increasing number of collisions as - with time. It`s a slow process, it`s not something that would normally happen as quickly as demonstrated in the movie "Gravity," but it`s still a real process.

目前为止，在地球运行轨道上大约存在5000个发射器，但是真正仍继续工作的只有1000个。想要把各种卫星探测器或者什么卫星运送到太空的话你就得需要火箭来发射运输。这就是地球轨道上产生这么多废旧物品的原因。在我1978年发表的论文中，“凯斯勒现象”这一名词引起了轰动。这是一种级联现象，当太空中任何发射器发生分裂时，他们会同时产生非常繁多的细小碎片和少数巨大碎片。并且那些巨大碎片足以撞击卫星至其损坏。然后随着时间的发展，它会越积越多引发更多的撞击碰撞发生。这是一个缓慢的进程，不会像电影《地心引力》里所表现出来的一样，但这仍是一个艰巨的任务，不容忽视。

The film illustrated the larger fragments breaking things up, but at the same time there would have been a lot more small fragments doing things like penetrating suits and causing leaks or penetrating the capsules that the astronauts were in causing leaks, making them uninhabitable. So, and that would be a much more probably thing to happen, actually, than the cascading that.

电影中展现出了事故发生过程，巨大碎片撞击太空飞行物，同样细小碎片也会穿透宇航服造成泄漏，或者破坏宇航员居住的太空舱至其无法居住。所以，这是一种比级联现象更有可能发生的现象。

The space station was one of the first vehicles to be designed to be protected against orbital debris, and consequently, they had - in order to get the safety that they wanted, they had to add shielding to the older habitation modules. And that shielding is to protect them against roughly marble size objects traveling at about ten kilometer per second.

国际空间站是第一个被设计出来防止轨道出现碎片的，但是结果证明为了更好做好保护工作，他们想，不他们不得不对陈旧的居住设施添加防护设施，保护其免受大理石大小大约以每秒十公里移动的太空垃圾的撞击。

They also had to worry about the larger stuff that would totally break up the space station - by satellite. And so they do collision avoidance in order to avoid that. But there`s a region between the one centimeter and a roughly ten centimeter, which is the largest thing that they can track where the space station is totally vulnerable, there is nothing they can do. They can`t see it coming. They can`t maneuver to get out of the way, and it were to hit a module, it would be catastrophic to the people inside that module.

同时他们还必须要担心更大的漂浮物会撞击毁坏空间站。所以他们必须做好防护措施。但是如果存在一个一厘米到十厘米这样一个裂痕的话，他们就会意识到空间站是多么不堪一击，他们将束手无措。他们甚至看不到发生的过程，也逃不出来，如果撞击到任何一个模块的话，对于里面的人员来说是毁灭性的的灾难。