While the use of Shack-Hartmann wave sensor prevails within the last decade, its bandwidth limitations and saturation losses lead to the development of other early-stage technologies such as modal holographic wave-front sensors based on the Karhunen-Loeve modes [9]. In addition, digital adaptive optics for turbulence mitigation is also considered [10]. Apart from atmospheric scintillations, the minimum amount of FSO power penalties in the presence of most cloud types (Mie scattering) is higher than 30 dB, which is unbearable in terms of optical SatCom links [11]. In comparison to turbulence fading, the key solution for cloud mitigation is building an OGS network with sites that are featured with maximum Cloud-Free Line-Of-Sight (CFLOS) probability. Considering Earth's weather system, the selected sites should be situated at least several hundred kilometers from each other, ensuring enough low correlation levels between them. Based on satellite images, various studies were performed by ESA and NASA [12]. Since each selected site is subject to limited CFLOS availability, a European network, including 12 different OGSs and reaching outage probability of \(10^{-3}\) is assessed in [13]. Nevertheless, the accomplished JPL (NASA) work in [14] offers 96% availability based only on four selected OGS sites, namely Oldstone, CA; Kitt Peak, AZ; McDonald Observatory, TX and Mama Kea, Hawaii. In order to not only measure the atmospheric influences by themselves but also to prove the operation of FSO SatCom systems, few ground-space bidirectional links (e.g., Teide Observatory--ARTEMIS GEO satellite FSO link) offer an actual evaluation of atmospheric turbulence and cloud effects over transmitted optical beam have been established [15]. While those initiatives provide the whole picture by means of testing real FSO systems, this is a costly procedure, and actual measured data are only available for a very limited number of locations. Moreover, those measurement campaigns do not offer any room for improvements in regard to the already installed space-borne equipment. Along with available FSO commercial off-the-shelf (COTS) components, several state-of-the-art space-qualified solutions are developed with a high focus on photodetectors, including APDwith integrated TIA offering superior data throughputs and sensitivity [16]. Furthermore, various modulation techniques, including mostly OOK or DPSK, are implemented [17]. Consequently, a few laboratory prototypes evaluating space-borne FSO transceivers consisting of communication subsystems with photodetectors, optical laser sources, etc., as well as fine and coarse pointing assemblies, have been considered within the last years [18]. Nevertheless, most laboratory tests do not cover the influence of atmospheric impairments consisting of turbulence-induced fading and Mie scattering attenuation (i.e., clouds), which is essential for systems/components evaluation in real-life conditions [8]. Since the above technology concepts are still in an early development stage and still a facilitated unexpansive test method is required, a high-end breadboard for verification of SatCom FSO links is suggested in this work. One of the very first prototypes for verification of high-demanding SNSPD-based (Superconducting Nanowire Single-Photon Detector) deep-space FSO channels, described in [19; 20], allows verification of other scenarios, including terrestrial and near-space links. Its operation is hereby translated to a platform for evaluating near-Earth SatCom links implementing 10 Gbps APD-TIA photodetectors (PD) installed in future OGSs for LEO/GEO data transmission [21]. Having offered capabilities for testing COTS components as well as technologies, the testbed implements a state-of-the-art fiber-based hardware FSO channel emulator representing atmospheric turbulences using RAOBs [7; 8]. The remainder of the paper is organized as follows: Section 2 introduces the design and the operation of the developed FSO channel emulator that represents atmospheric-based disruptions of the transmitted optical beam.