ESTCube-2: The Experience of Developing a Highly Integrated CubeSat Platform

Here we present the development and qualification of the highly integrated satellite avionics stack of ESTCube-2, a three-unit CubeSat carrying various in-orbit demonstration payloads. The primary payload is the Plasma Brake (PB), which is novel deorbiting technology for low Earth orbit (LEO) satellites. The Earth observation payload (EOP) consists of two cameras imaging the planet in 660 nm and 857 nm spectral bands. Finally, the Corrosion Testing in Space (CTS) experiment will study the behavior of a nanostructured coating in the LEO environment. A major innovation of the satellite's design is a highly integrated avionics stack platform, to be demonstrated in LEO as a prototype of future interplanetary nanospacecraft platforms. The electrical power system, the communications, the on-board computer, and the attitude and orbit control solution together occupy a volume smaller than one CubeSat unit. The avionics stack electronics firmware uses a unified and custom hardware abstraction layer (HAL) for STMicroelectronics STM32F7 and STM32L4 microcontrollers. This paper presents the integrated design of the satellite avionics stack, preliminary results of functional and qualification tests, and discusses the engineering challenges that the team has been facing.