Like its Cousins radar and sonar, lidar (light detection and ranging), works by broadcasting electromagnetic waves towards a target and then building up a picture from the reflection.
Our eyes can only feel the light waves (electromagnetic wave) with wavelengths ranging from 4000 to 7000a, which we call visible light.
人的眼睛只能感受波长范围在4000 - 7000埃的光(电磁)波-我们称为可见光。
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Firstly, spacecraft carries its mission in very severe environment, including varied temperature ranging hundreds centigrade, electromagnetic interference, high-energy cosmic radiation particles etc.