1 Introduction
Remote Sensing Satellite (RSS) networks deployed in non-geostationary orbits have increasingly gained recognition as important infrastructures that support various applications [1]. Remote sensing consists of two stages. In the collection stage, satellite sensors gather radiation or reflected signals from the target. In the transmission stage, satellites acting as sources send the collected data back to the Earth Station (ES). Many remote sensing applications, such as forest fire monitoring, need to send a large volume of data to the ground with low delay. Hence, the cooperation transmission [2], which relies on cooperations among satellites to achieve continuous transmission, emerges as an indispensable technique. However, the dynamic topology and time-varying available resources in RSS networks deeply complicate the cooperation transmission scheme, since it needs to be dynamically adjusted to optimize delay. As a result, the delay-optimal cooperation transmission in the RSS networks becomes a critical but difficult problem.