All 2015 Content
Abstract
In a previous paper, the feasibility and trade space of a CubeSat with modulated retroreflector optical communications was discussed. In this paper, the design and testing of a surrogate retroreflector payload to assess key components of a modulated retroreflector payload is presented. In addition to passive retroreflectors, the surrogate payload has an optical beacon to aid in acquisition and tracking as well as an optical detector. The payload design is comprised of six subsystems: mechanical structure, optical electrical circuits, flight computer, retroreflectors, optical beacon, and optical detector. The mechanical structure has been tailored to accommodate the retroreflectors, while preserving roughly a 1.5U size. The circuits are designed to perform electrical power conversion, drive a high current optical source, and drive an optical detector. The flight computer will be comprised of a commercially available FPGA and/or a microcontroller on a custom circuit board to interface with the optical beacon and optical detector as well as collect telemetry. Previously developed models are used to design custom retroreflectors to provide a specific returned optical intensity pattern. The optical source and optical detector are commercially available and designed according to link analysis and electrical power restrictions. Individual components will be benchmarked, environmentally tested, and reassessed for performance prior to integration into the mechanical structure.
Design and Testing of a CubeSat-Sized Retroreflector Payload
In a previous paper, the feasibility and trade space of a CubeSat with modulated retroreflector optical communications was discussed. In this paper, the design and testing of a surrogate retroreflector payload to assess key components of a modulated retroreflector payload is presented. In addition to passive retroreflectors, the surrogate payload has an optical beacon to aid in acquisition and tracking as well as an optical detector. The payload design is comprised of six subsystems: mechanical structure, optical electrical circuits, flight computer, retroreflectors, optical beacon, and optical detector. The mechanical structure has been tailored to accommodate the retroreflectors, while preserving roughly a 1.5U size. The circuits are designed to perform electrical power conversion, drive a high current optical source, and drive an optical detector. The flight computer will be comprised of a commercially available FPGA and/or a microcontroller on a custom circuit board to interface with the optical beacon and optical detector as well as collect telemetry. Previously developed models are used to design custom retroreflectors to provide a specific returned optical intensity pattern. The optical source and optical detector are commercially available and designed according to link analysis and electrical power restrictions. Individual components will be benchmarked, environmentally tested, and reassessed for performance prior to integration into the mechanical structure.
