Uitvouwbare telescoop voor kleine satellieten

Small satellites have increased access to space, but their compact form factor limits the performance of optical payloads. This thesis addresses this limitation by developing a deployable telescope for small satellites that deploy once in orbit, increasing both aperture size and focal length while maintaining the stability required for high-resolution Earth observation and astronomy missions. The proposed system is an axis-deployable Cassegrain telescope with a monolithic, stationary primary mirror and a small secondary mirror that deploys along the optical axis away from the main spacecraft. Achieving diffraction-limited performance requires stringent positional tolerances, the most critical is the axial position of the secondary mirror. This requires a deployable structure with high stiffness and positional accuracy in deployed state. To meet these requirements, a coilable-boom structure is developed in which beams deform into a helix, storing the elastic energy needed for deployment. The structure is optimized to achieve a high eigenfrequency in the deployed state, ensuring optical alignment while meeting small satellite mass and volume constraints. A cable-pulley transmission system converts the combined translational and rotational motion of the structure into pure rotation. A centrifugal brake regulates the deployment speed to a safe level, protecting sensitive components from damaging shocks. A dedicated hold-down and release linkage mechanism secures all moving parts during launch and sequentially releases the centrifugal brake before initiating the main structural deployment in orbit. The beams are joined to supporting rings via self-locking hinges that ensure repeatable deployment and high rigidity. Each hinge provides one rotational degree of freedom during deployment and constrains all degrees of freedom when locked. Magnetic and spring-preloaded designs are compared. A novel leaf spring-preloaded locking hinge is developed and implemented. To improve the signal-to-noise ratio, a compact deployable baffle is integrated in the telescope to suppress unwanted stray light. The primary baffle consists of telescopic cylindrical tubes, while the main baffle uses a compact origami-folded foil. Two origami patterns are described in detail: the Yoshimura pattern, which minimizes aperture obstruction but requires an additional rotational degree of freedom, and the Kresling pattern, which allows direct kinematic coupling to the main structure. Two prototypes, tailored to a 6U CubeSat platform with a 4U payload bay, validate the proposed concepts. The first prototype has a stowed height of 70 mm and extends to 510 mm when deployed, demonstrating an approximately 80% reduction in stowed payload volume.