Abstract
The spacecraft payload operational time (SPOT) is amongst the main critical design considerations that must be optimised and validated during the system engineering analysis of a spacecraft mission. This requirement becomes more demanding for a communication satellite mission that relies on the functionality of the payload for its operation and service delivery. The design principles and performance budgets of the payload module are based on the subsubsystems and subsystems that enable the mission to be accomplished. The SPOT constraint is tied to the spacecraft size, weight and power (SWAP) limitations, operational modes of the subsystems and orbital patterns where the system is being deployed. This paper presents a system-level multicriteria optimisation of POTs for communication satellite (ComSat) missions in low-Earth orbit (LEO). The parameter space investigation (PSI) method was utilised to accomplish the multicriteria optimisation of the payload power and spacecraft mass. In the multicriteria optimisation and vector investigation (MOVI) process, 2048 tests were performed and the PSI was conservatively designed to yield 658 pareto optimal solutions vectors; a pareto optimal solution of 37.119 W for the payload module yielded highly adaptive microsatellite (HAM) mass and power margin of 97.021 kg and 23.366 W respectively. The required maximum subsystem power consumption for the power-storing mode is 25.703 W. From the analysis, the solar array capability was calculated to deliver 116.828 W for the mission; this forms the beginning-of-life design point. The prototype design for the ComSat mission yielded a maximum POT of approximately 494 minutes for the onboard payload processing and communication (downlink and uplink). The findings promise to enhance the design of a reliable and capability-based payload module for real-time digital video and broadband media, mobile services, interactive data transfer and voice communication.
Keywords: Adaptive small satellite, communication satellite, downlink, modelling, multicriteria, operational times, payload module, power budget, power contingency, power modes, space mission, system engineering, uplink.
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