什么是太空垃圾？它有多危险？

American and European officials sharply criticized Russia's recent missile test that exploded an orbiting satellite into many pieces. Scientists said this orbiting debris will increase risks to humans and their efforts in space for years to come.
美国和欧洲官员严厉批评了俄罗斯最近进行的导弹试验，这次试验将一颗在轨卫星炸成了碎片。科学家们表示，这些轨道碎片将在未来几年增加人类及其太空活动的风险。

But, what is this debris – also called space junk -- and what are the safety threats it presents?
但是，这些也被称为太空垃圾的碎片是什么？它会带来什么安全威胁？

Space debris is anything humans have placed in space but no longer use. The junk floats around hundreds of kilometers above Earth. Experts say the main worry is that such debris will hit a space station, satellite or other equipment.
太空垃圾是人类送入太空但是不再使用的任何物体。这些垃圾漂浮在地球上方数百公里处。专家表示，人们主要担心这些碎片会撞击空间站、卫星或其它设备。

Space debris orbits around the Earth very fast - about 25,000 kilometers per hour in low-Earth orbit. The junk could cause major damage if it hits satellites or spacecraft.
太空碎片绕地球运行的速度非常快，在近地轨道上的速度约为每小时2.5万公里。如果这些碎片撞上卫星或航天器可能会造成严重损害。

"Every satellite that goes into orbit has the potential of becoming space debris," said Professor Hugh Lewis, with Britain's University of Southampton. Lewis, who heads the university's Astronautics Research Group, spoke to Reuters news agency.
英国南安普顿大学的休·刘易斯教授表示：“进入太空的每颗卫星都有可能会成为太空碎片。”刘易斯领导了该大学的航天研究小组，他接受了路透社采访。

With the number of satellite deployments rising, near-Earth space will likely see more space debris in the coming years. Russia is not the only country to have destroyed a satellite. China, the United States and India have also carried out anti-satellite missile tests.
随着卫星部署数量的增加，未来几年近地空间可能会出现更多太空碎片。俄罗斯并非唯一一个摧毁卫星的国家。中、美、印也进行过反卫星导弹试验。

How big is the debris?
太空碎片有多大？

The U.S. government tracks about 23,000 pieces of debris larger than a softball orbiting the Earth. About 500,000 pieces of debris are larger than one centimeter and 100 million pieces are about one millimeter or larger.
美国政府追踪了大约2.3万块比垒球大、绕地球运行的碎片。大约有50万块碎片大于1厘米，还有1亿块大约1毫米或更大。

Holger Krag is head of the European Space Agency's Space Safety Program Office. He told Reuters that if the build-up of debris continues, some areas of space might become unusable.
霍尔格·克拉格是欧洲航天局空间安全项目办公室的负责人。他对路透社表示，如果碎片继续累积，某些空间区域可能无法使用。

What was the effect of the latest test?
这次试验的影响如何？

The satellite Russia just destroyed had been launched in 1982. It weighed more than 2,000 kilograms. American officials said the test created more than 1,500 pieces of "trackable orbital debris." The U.S. Space Command said the missile strike likely created hundreds of thousands of additional smaller pieces of debris.
俄罗斯刚刚摧毁的卫星是在1982年发射的。它重达2千多公斤。美国官员表示，这次试验产生了1500多块可追踪的轨道碎片。美国太空司令部表示，这次导弹攻击可能造成了数十万块额外的小碎片。

Crew members aboard the International Space Station (ISS) were directed to take shelter in their attached spaceship capsules for two hours after the test. The safety measure was taken in case the crew had to leave because of possible damage from debris.
在这次试验之后，国际空间站的机组人员被指示进入其附属的太空舱中躲避了两个小时。采取这种安全措施是为了防止碎片可能造成损害，导致机组人员不得不离开国际空间站。

Can space debris be removed?
太空碎片是否可以清除？

The American space agency NASA says debris in orbits 600 kilometers or less from Earth will fall back to the planet within several years. But space junk above 1,000 kilometers is expected to continue circling for a century or more.
美国宇航局表示，距离地球不高于600公里的轨道上的碎片将在几年内落回地球。但1000公里以上轨道的太空碎片预计将盘旋一个世纪或更长时间。

"If we want to try and solve the space debris problem, we have to start to remove that type of object," said professor Lewis of the University of Southampton. Japan's Aerospace Exploration Agency (JAXA) and the European Space Agency (ESA) have partnered with private companies to find ways to remove space debris.
南安普顿大学的刘易斯教授表示：“如果我们想要尝试解决太空碎片问题，我们必须开始清除这类物体。”日本宇宙航空研究开发机构和欧洲航天局已经跟私营企业合作，寻找清除太空碎片的办法。

In addition to being a threat to space property and astronauts, debris also increases the cost for satellite operators. Industry experts have estimated that protection and reduction efforts dealing with space junk make up about 5-10 percent of satellite mission costs. One study by the Organization for Economic Co-operation and Development (OECD) found that the costs for lower-Earth orbits were even higher.
除了对太空财产和宇航员构成威胁之外，碎片还增加了卫星运营商的成本。行业专家估计，应对太空垃圾的防护和缩减措施约占卫星任务成本的5%到10%。经合组织的一项研究发现，更近地轨道的成本甚至更高。

I'm Bryan Lynn.
我是布莱恩·林恩。