By Bryan Lynn

20 November 2021

美国和欧洲官员严重批评俄罗斯反导实验所产生的太空碎片。科学家称这些碎片在未来几年对人类构成威胁。

太空碎片即太空垃圾是什么?有什么安全威胁?

太空碎片是人类留在太空中的无用的任何东西。浮游在地球上空数百公里外。专家称主要的担忧是这些碎片将撞击太空站，卫星和其它设备。

这些碎片在低地球轨道快速运行，运行速度是25000千米每小时。如果撞击卫星或航天器太空垃圾将发生巨大危害。

Britain's University of Southampton. Lewis大学Hugh Lewis教授称每个进入轨道的卫星都有成为碎片的可能。

随着卫星的增加，未来几年近地球太空碎片越来越多。俄罗斯仅仅是一个反导实验的国家，中国、美国、印度都在进行反导实验。

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.

But, what is this debris – also called space junk -- and what are the safety threats it presents?

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.

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.

"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.

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.

碎片有多大?

美国政府追踪到约23000个比垒球大的碎片，约500000个直接大于1厘米和1000万个1毫米以上的碎片。

"the European Space Agency's Space Safety Program Office”的领导"Holger Krag ”称随着碎片的增加，太空有的空间将无用。

How big is the debris?

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.

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.

最近的实验效果是什么？

俄罗斯最近摧毁了1982产的重2000千克的导弹。美官员称产生1500个可追踪碎片，太空司令部称产生了成千上万个小碎片。ISS他们的工作人员为了安全必须躲避这些碎片。

What was the effect of the latest test?

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.

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.

太空垃圾可以移除吗?

NASA说离地球600千米以下的碎片在几年内会落下。但是1000千米以上的会遨游一个多世纪。如果我们想解决太空垃圾问题，我们必须开始移除某些物体。日本(JAXA) 和欧洲(ESA) 发现移除垃圾的方法。太空碎片增加太空成本5－10%，近地球成本更高。

Can space debris be removed?

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.

"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.

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.