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保持华盛顿领空安全并非易事

Being the home of all three branches of the U.S. federal government makes Washington, D.C., the prime target for those who want to make their messages and ideas heard. Unfortunately, many of them choose to deliver them in unorthodox ways, including from the air, as a recent incident clearly showed involving a gyrocopter landing on the Capitol’s West Lawn.

作为美国政府三大分支机关的所在地，首都华盛顿成为了那些希望以各种手段传递信息、发表意见的人们的首要目标。不幸的是，有人会选择另类手段。例如最近降落在国会大厦外西草坪的旋翼飞机事件。

When Florida Postal¹ Service worker Doug Hughes landed his homemade gyrocopter on the west lawn of the U.S. Capitol, in a daring bid to deliver a political message to the lawmakers, the security services were taken by surprise.

佛罗里达州的邮递员道格?休斯(Doug Hughes)把自制的旋翼飞机降落在国会大厦外西草坪上，希望以这种大胆的方式向立法者们传达政治信息。他的从天而降让安全部门措手不及。

He was quickly surrounded and taken away by police, his aircraft was checked for explosives, and now he faces several years of prison.

警察迅速将他包围并带走，对飞机进行了爆炸物检测，现在他面临着几年的监禁。

But his stunt²  highlighted once more that the airspace around most of the public buildings is easily penetrated³ by drones and light piloted aircraft, too small and flying too low to be safely prevented from reaching their goals.

但是他此番特技再一次凸显了很多公共建筑周边的空域很容易被无人机或是轻型有人驾驶飞机闯入。这些飞行器体积太小、飞行高度太低，因此无法安全地阻止他们达到目标。

Difficult detection

John Hansman a professor of Aeronautics⁴ and Astronautics at Massachusetts Institute of Technology, said small, flying vehicles are not easy to detect and stop.

约翰?汉斯曼是麻省理工学院航空航天专业的教授。他说小型飞行器不容易被探测和阻止。

“If you have a very small target, like a gyrocopter, which doesn't have a very large radar⁵ cross-section, so it's not reflecting much energy back, and it's close to the ground, you might get some signal coming there, but you may actually think it's a building or a car moving on the ground, not a helicopter," he said.

他说：“如果目标很小，例如旋翼飞机，雷达有效截面不大，那么反射回来的能量也不多，而且这类飞机靠近地面，可能会有一些信号从那个方向过来，但是你可能会认为这是一栋楼或是地面上移动的一辆车，不会认为是直升机。”

Hansman noted⁶ that heavy traffic in downtown Washington makes it even more difficult.

汉斯曼说华盛顿市区繁忙的交通让这变得更困难了。

“If you have a complex environment like an area around Washington where you have lots of other vehicles on the ground, you have vehicles in the air, and you have something very small like this, it's actually not that difficult for it to slip through the protection,” said Hansman.

他说：“如果环境很复杂，就像华盛顿周边地区这样，地面上有很多很多车，空中也有飞行器，还有像这样很小的东西，所以混过保护设施并不难。”

Inadequate⁷ systems

The chairman of the American Leadership and Policy Foundation, David Stuckenberg, is a former military pilot who writes about the airspace security. Speaking via Skype, he said the present safety systems are inadequate.

美国领袖与政策基金会主席戴维?斯达肯伯格曾任军队飞行员，现在写领空安全方面的文章。他通过通讯软件Skype说，现有的安全系统是不够的。

“We need to understand that we've been lucky and as technology increases and as drones proliferate⁸ people will increasingly look at these as weapons of opportunity or technologies that can be adapted for ill intent,” he said.

他说：“我们需要认识到，一直没出大事我们很幸运。随着技术发展、无人机激增，人们会越来越多地把这些看作是伺机而动的武器，或是用于不良意图的科技。”

Stuckenberg said a lot more needs to be done before such systems are in place, such as conducting thorough analyses and bringing new regulations.

斯达肯伯格说，在更完备的安全系统到位前还需要做很多事情，例如实施彻底的分析以及出台新的规定。