The average worldwide internet traffic demand in 2022 is projected to be over 1200 Terabits per second. A fifth of this data would be transmitted using mobile networks. One of the technologies used for this is radio frequency (RF) telecommunication, but this technology is reaching its limits. Despite ongoing development, typical data rates are still in the order of Gigabits per second per link. TNO is working on a telecommunication link (called TOmCAT) that can reach data transfer rates of a Terabit per second. The high data rate is achieved using a very promising alternative to RF telecommunication: optical telecommunication, which is also known as laser communication. In order to reach the intended data rates, the data needs to be spread over multiple optical frequencies. These signals need to be combined into one transmitted beam using a free-space optical bulk multiplexer. The laser beams that are transmitted by their collimators need to be aligned with respect to each other in order to reach the satellite as one beam. The footprint available for the required alignment mechanisms is very limited. Furthermore, the system needs to achieve a good thermal and mechanical stability in order to meet the strict specifications. The aim of this thesis is two-fold: to show the need for achieving state-of-the-art alignment specifications with strict footprint constraints, and to defend the steps taken to achieve these requirements. The research spans the entire design process of the alignment assembly: from higher/system level trade-offs and calculations, to the derivation of the design specifications, to the conceptual and detailed design, and concluding with the manufacturing and testing of the first prototype.