经济学人下载:航空航天:可执行卫星作业的高空无人机 (1)

On August 6th a flimsy-looking pilotless aircraft, the Zephyr S, came slowly in to land at an undisclosed location in Arizona,
8月6日，一架薄得像纸一般的无人驾驶飞机Zephyr S在美国亚利桑那州的一个未知地点缓慢着陆，

and was caught by a group of people jogging along beside it.
在该地附近慢跑的人发现了这架无人机。

The reception committee was needed because the craft, which weighs less than 75kg, lacks an undercarriage
由于这架重量不足75公斤的航空器没有着陆装置，因此需要接待委员会的介入

—or, indeed, anything else that would add unnecessary weight.
—确实，任何其他装置都会给这架无人机增加不必要的重量。

The touchdown meant the Zephyr S had set a new flight-endurance record for a drone, of 25 days, 23 hours and 57 minutes.
此次着陆意味着Zephyr S创下了无人机飞行耐力的新纪录—25天23小时57分钟。

The point of doing so was to show that solar-powered aircraft of this sort
此次飞行的意义在于展现这种太阳能航空器

can compete with satellites in the markets for Earth observation and telecommunications.
可以与市场上用于地球观测和通讯的人造卫星相竞争。

This has led some people to dub them "pseudo-satellites". The idea is that eventually they will stay aloft for months.
这让一些人将它们称为“伪卫星”。他们的想法是，最终让它们在空中待上几个月。

The previous endurance record for drones, of just over14 days, was set in 2010 by the Zephyr 7, an earlier version of this aircraft.
早前的无人机耐力记录是14天，创造该纪录的是2010年的Zephyr 7，Zephyr S的初期版本。

The Zephyr 7 was developed by QinetiQ, a British defence company.
Zephyr 7的发开者是一家英国防御公司—奎奈蒂克。

In 2013 QinetiQ sold the Zephyr programme to Airbus, a European aerospace firm.
2013年，奎奈蒂克将Zephyr项目卖给了一家欧洲航空航天公司—空中客车公司。

Airbus has now built, at Farnborough, in Britain, a factory to make them.
空中客车公司现在在英国法恩伯勒建了一家制造该航天器的工厂。

The model S, with a wingspan of 25 metres, will soon be joined by a bigger, more advanced version, the model T.
模型S的翼幅为25米，很快将推出一个更大更先进的版本—模型T。

Zephyrs fly in the stratosphere. During daylight hours they cruise at an altitude of about 21km.
Zephyrs在平流层飞行。在白天，它们在海拔约21千米的地方巡航。

At night, when solar energy is unavailable and they must rely solely on their batteries,
夜间没有太阳能可用的时候，它们必须也只能依靠电池，

they make a slow but powered and controlled descent to 16.7 km.
它们缓慢地通过有力控制将高度降至16.7千米。

That, though, is still well above troublesome weather, and also clear of commercial aircraft.
尽管如此，这样的高度仍然可以避免麻烦的天气情况，还能避免碰到商用飞机。

They are powered by a pair of propellers driven by electric motors.
它们由一对螺旋桨提供动力，螺旋桨由电动装置驱动。

Airbus says the craft are fitted with batteries which use an "advanced chemistry" and are recharged by "novel" solar cells that cover their wings.
空中客车公司表示这种航天器所配备的电池使用的是一种“高级化学成分”，通过覆盖在机翼上的“新型”太阳能电池充电。