Design of a deployable optical payload for CubeSat platform

Abstract

As demands for CubeSat increase, the need for optical payloads that provide better performance characteristics also increases. Deployable Structures offer an excellent advantage to smaller form CubeSat in order to have larger on orbit volume. This increased on orbit volume can be utilized by optical payloads through either providing longer focal length, or larger aperture size. Compared to the traditional CubeSat optical payloads, a payload that utilizes the increased volume of a deployable CubeSat could provide better optical performance whether in terms of Ground Sampling Distance (GSD) or Modulation Transfer Function (MTF). However due to the optical system structure complexity and sensitivity, payloads in deployable CubeSat brings up another challenge for payload engineers, more specifically, in regards to the optical system parameters or opto-mechanical structure design. Unlike traditional CubeSat missions, deployable CubeSat missions consist of a structure that once launched in space, its structures is expanded allowing for the CubeSat to become larger in size. In order to determine the improvement from such mission, the mathematical model to characterize the performance parameters of the system is established. A study regarding for the various optical design and selects the most suitable design with respect to a deployable optical system concept. This thesis presents a design of a Solid Catadioptric optical system in a 6U deployable CubeSat in order to determine the performance improvement. The design is established based on a detailed study of each optical system sensitivity as well as a prototype model to test the concept of deployment and the capability of restoring the image quality after degradation due to deployment. Analytical results as well as software simulation is presented as a reference to verify the optical capability of the system as well as to check the feasibility of the design in a 6U Mechanical Envelope. Moreover, a comparison with Space Heritage Payload is used to compare the performance. It was found that the Solid Catadioptric deployable optical payload can provide an advantage to envelope reduction compared to the current space solutions without a significant compromise in performance.