Satellites use wavelengths in the near-infrared (NIR) spectrum, primarily around 1550 nm (1.55 µm), for laser communication due to its low atmospheric attenuation, suitability for optical amplifiers, and invisibility to the human eye, though other bands like 800-1064 nm are used for beaconing and research. The 1550 nm band is common because it aligns with terrestrial fiber optics, offers high data rates, and has reduced noise making it ideal for high-speed, secure space-to-ground or inter-satellite links.