除了装有轻巧的塑料信号镜、精心设计的哨子、可单手使用的打火石外，每个救生包中还有一个特种火源——即所谓的WetFire。
In addition to packing lightweight plastic signal mirrors, well-designed whistles and flints that can be used one-handed, each kit contains a special type of tinder called WetFire.
宇宙飞船的位置可以根据追踪它的无线电信号来确定，也可以用望远镜和雷达来确定。
A spaceship's position can be located by following its radio signal, or by using telescopes and radar.
为了避免干扰，保持望远镜的灵敏度，无线电望远镜被建在没有人为的无线电波或电子信号的地方。
To avoid interferences, and keep the telescopes sensitive, radio telescopes are built in places where there are no human radio waves or electronic signals.
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