Yingying Wu, Bomin Mao, Hongzhi Guo, Yijie Xun, Nei Kato
Satellite communications constitute a significant part of 6G to enable ubiquitous connectivity, seamless services, and ultra-high mobility, but pose challenges by long propagation paths and open broadcast environment. Fortunately, Intelligent Reflecting Surface (IRS) can address above challenges by dynamically adjusting the phase, amplitude, and polarization of reflecting signals, thus finally change the wavefront and enable the signal coherent superposition at receivers, resulting in improved signal quality, which can be further adopted to promote the performance of the Integrated Communication, Navigation, and remote Sensing (ICNS). Inspired by these advantages, this article investigates the potential applications of IRS in future satellite constellations. We first provide a comprehensive review of satellite communication systems and IRS, along with their capabilities. By leveraging their respective advantages and specific characteristics, we further explore the applications of IRS deployment in satellites, including the Internet of Everything (IoE), deep space exploration, positioning and navigation, and secret communications. A case study of the IRS-secured satellite framework is presented to prevent air and space Eavesdroppers (Eves), further demonstrating its security advantages. Finally, we discuss the future perspectives of IRS-assisted satellite communication systems.