## 1 Introduction  
The vigorous development of satellite communication meets the needs of social development. In recent years, with the rise of low earth orbit constellations, the demand for data exchange between satellites is increasing, thus there is a great demand for spectrum resources. The L, S, C, X, Ku, and Ka frequency bands for traditional satellite communication are very scarce. As an undeveloped band of the electromagnetic spectrum, the terahertz band has a frequency between 0.1-10 THz, which has a high spectrum bandwidth to realize high-speed data transmission, and has great application value in satellite communication. At present, International Telecommunication Union has completed the frequency division of satellite services in the frequency range of 100-275 GHz and has made a simple division of the terahertz frequency band above 275 GHz. At the same time, the development of terahertz devices is progressing steadily. The terahertz frequency band has been preliminarily qualified for application in satellite communication. The modeling of inter-satellite terahertz channel is the basis for realizing the application of inter-satellite terahertz wireless communication. The channel through which terahertz waves are transmitted from the transmitter antenna to the receiver antenna is the terahertz wireless channel, and the characteristics of the channel determine the performance of satellite communication systems. The terahertz channel model is the foundation for the design and optimization of terahertz communication systems. Channel modeling is based on data measured by existing channel measurement platforms, using mathematical formulas to characterize various parameters of the channel. There have been many researches on the modeling of terahertz channel in terrestrial communication [1; 2; 3; 4]. [PERSON] et al. [1] provided a detailed explanation of the characteristics of ground terahertz channels. The terahertz frequency is large and the wavelength is short, so the terahertz channel has different channel characteristics compared with the low-frequency channel. As terahertz travels through the atmosphere, molecules such as water vapor, clouds, ice crystals, and dust increase path losses. [PERSON] et al. [2] analyzed the existing terahertz channel models and introduced channel simulators based on these models. IncludingNYUSIM, Cloud RT, EDX Advanced Promotion, etc. These models are mainly applied in ground communication scenarios such as indoor offices and outdoor environments. However, to our knowledge, there is currently a lack of research on channel modeling for inter-satellite terahertz communications, therefore it is necessary to conduct relevant research. In addition, in terms of channel modeling methods, channel modeling methods include deterministic modeling and statistical modeling. The deterministic channel modeling method is based on the analysis of optical and electromagnetic propagation theories in current application scenarios to establish a wireless channel model. [PERSON] et al. [5] used ray tracing technology to model a 300 GHz indoor environment and used a free space path loss formula to model large-scale fading of line-of-sight links. For small-scale fading, the line-of-sight links delay is modeled as \(\tau=\frac{d}{c}\), recursively calculating the delay of each order of reflection path. The line-of-sight links phase is modeled as the first-order function of the delay \(\varphi=-2\pi f\tau\), the phase on the reflection path is uniformly modeled within \(-180^{\circ}\) and \(180^{\circ}\). And model the horizontal angle of arrival (AOA) uniformly, and calculate the horizontal angle of departure (AOD) by adding a difference value on the AOA, which is equal to a multiple of \(180^{\circ}\). The advantage of the deterministic channel modeling method is that it does not require actual measurement, but its disadvantage is that it requires very detailed application scenario information and high computational complexity.