Laser communication offers high data rates and more bandwidth capacity compared to radio but is also advantageous in terms of power and volume. However, the required pointing accuracy and atmospheric influence pose stringent requirements on the system which form the main challenges for this type of communication. This is where laser ranging could make a difference. Laser ranging is more mature than laser communication but both technologies share many commonalities. A synergy of the two could therefore be beneficial to small satellites that are constrained by volume, power or cost. Alternatively, it could expand the capabilities of existing optical communication systems without significant modifications. The latter is considered as the main driver for investigating combined laser ranging and communication capabilities between CubeCat and the TNO optical ground station. CubeCat, currently being developed by TNO, is an example of a cubesat-sized terminal that will demonstrate in-orbit high-speed satellite-to-Earth laser communication.

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.