Design of the fault tolerant command and data handling subsystem for ESTCube-1

Abstract

This paper presents the design, implementation, and pre-launch test results of the Command and Data Handling Subsystem (CDHS) for ESTCube-1. ESTCube-1 is a one-unit CubeSat, which will perform an electric solar wind sail experiment. The development process of the CDHS for ESTCube-1 was focused on robustness and fault tolerance. A combination of hot and cold hardware redundancy was implemented. Software, including a custom-written internal communications protocol, was designed to increase the system's fault tolerance further by providing fault detection and fall-back procedures. Tests were carried out to validate the implementation's performance and physical endurance. The final CDHS design is operational within the set requirements. Tests that verify fault tolerance of the system in orbit are suggested.

ESTCube-1 nanosatellite for electric solar wind sail in-orbit technology demonstration

“…For both the CDHS and the EPS, fault tolerance is being addressed at a software level as well. More detailed descriptions of all fault-tolerant methods used in the CDHS and the EPS can be found in [17][18][19].…”

“…The following system level tests were carried out to qualify for the launch: sine vibration, random vibration, shock, thermal cycling, and thermal vacuum. Individual tests performed separately on subsystems can be found in the relevant articles [12,14,15,17,19].…”

“…The FreeRTOS operating system is used to fulfil requirements of realtime operations, processing capacity, and memory footprint. The CDHS is described in detail in [17].…”

“…The peak power consumption should be less than 6 W. A 12 V power bus should be provided. To mitigate the risk of mission failure, high levels of redundancy and fault tolerance have been provided in a command and data handling subsystem [17] and an electric power subsystem [18,19]. In this article, we analyse the mission, describe the satellite design, and present the results of system level tests.…”

“…The satellite design provides a detailed system level description and an overall subsystem level description, which includes the purpose, upper level requirements, and technical solutions. Detailed subsystem level descriptions and characterizations are presented in other articles in this issue [12,14,15,17,19].…”