Design of Magnetorquer-Based Attitude Control Subsystem for FORESAIL-1 Satellite

The magnetorquer-based attitude control system capable of attaining high spin rates and precise pointing control is required for a 3U CubeSat satellite FORESAIL-1. The satellite, developed by the Finnish Centre of Excellence, needs to maintain a spin rate of 24°/s and precise pointing of the spin axis toward the Sun for the particle telescope instrument, as well as to reach 130°/s spin rate for the deployment of the plasma brake. Mission requirements analysis and attitude system requirements derivation are presented, followed by actuator tradeoff and selection, with a detailed design of the complete attitude control system, including the air-cored type of magnetorquer actuators and their drivers, made of H-bridge and filtering components. The design is based on several theoretical and practical considerations with emphasis on the high-power efficiency, such as effects of parallel and serial magnetorquer connections, modeling the magnetorquers with equivalent circuit models for finding a suitable driving frequency and extrapolation methods for efficient dipole moment usage. The in-house manufacturing process of magnetorquers, using a custom 3-D-printer setup, is described. Finally, the testing and verification are performed, by measuring the performance of the manufactured hardware, circuit simulations, and attitude control simulations. It is shown that the manufactured attitude control system fulfills all system requirements. Simulations also confirm the capability to satisfy mission requirements.

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Anticipation of Air Pollution Density Patterns Affected by Wind Velocity Based on Fourier Transform Spectrometer Across the Silk Road Countries by Using EcoBeltSat—A 6U CubeSat

EcoBeltSat is a 6U nanosatellite (CubeSat) able to offer access on space for scientists to determine the effects of cross-border air pollution flux, and acquire a more precise understanding of climate change and global warming for the Belt and Road countries. The objective of this CubeSat mission is demonstrated by the use of an onboard atmospheric spectrometer as the first payload. Therefore, a second payload is suggested to estimate and localize renewable energy sources in these countries. The aim of this mission is achieved based on Fourier transform spectrometer (FTS), which is used for wind velocity measurement around the globe by using Cubesats. This data can offer confidence to the investors in the sector of renewable energy projects, for example, wind farms, solar power plants, and other systems. In this article, the association of air pollution measurements by the spectrometer and the wind velocity measurements by FTS instrument is proposed to give an innovative idea and the opportunity for a spaceborne predictive pollution map which avoid the actual implementation of billions of sensors implanted on the ground around the world.

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Software-Defined Radios for CubeSat Applications: A Brief Review and Methodology

CubeSats have revolutionized the way scientists and students perceive space. The majority of CubeSat communication is greatly limited by the AX.25 standards, the small communication window, the available transmission power, and the available bandwidth at VHF/UHF band. As a result, CubeSat radios could only establish low data rate links which restrict the communication capabilities of a CubeSat mission. In this article, a brief review of current software-defined radios (SDRs) used in space missions is given. In addition, two different design methodologies for SDRs for CubeSats are proposed that can be used as a guideline for CubeSat developers. Finally, a high data rate SDR for the UOW CubeSat project is presented that address all the above limitations. The radio operates at S-band, employs quadrature amplitude modulation with a maximum data rate of 60 Mb/s consuming 2.6 Watts in transmit mode and 0.4 Watts in receive mode. The digital signal processing functions and the mode control of the radio are orchestrated by a field programmable gate array system-on-chip. The analog radio frequency domain is accommodated by a 4-layer printed circuit board with dimensions of 92 mm × 88 mm. The goal of the UOW CubeSat radio is an adaptive, on-flight reconfigurable communication platform that will revolutionize the current communication capabilities of the CubeSats and expand nanosatellites mission perspectives.

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