Delfi-Twin ADCS

AE4897-25: Space Engineering Practical (2026)

Abstract

The Delfi Program is TU Delft’s initiative to develop and demonstrate novel space technologies. As part of this program, the twin satellites of the Delfi-Twin project are planned to become the fourth project to join their predecessors in space. Specifically, the mission aims to deploy and operate two identical satellites as a technology demonstrator, with the goal of achieving formation flying using differential drag, while also investigating the poorly understood spontaneous E-layer in support of laser communication between ground stations and spacecraft. By providing students with the opportunity to develop their engineering skills in a real mission setting, this document captures the work concerning the testing and verification of the Delfi-Twin Attitude Determination and Control System subsystem.

As part of the Space Engineering Practical course (AE4897-26), this subsystem has been under development for two consecutive years, each covering a period of two quarters. During that time, two student teams, ours included, have worked on the subsystem. Each team first contributed to the design and development phase during the Space Engineering Detailed Design Project, followed by verification and testing in the subsequent quarter. Improving upon the work of the previous year, we focused on advancing subsystem-level integration by verifying the functionality of the implemented software. In particular, this concerned the algorithms used to detumble the spacecraft after release into orbit and to orient its instrument towards Earth during operation. Additionally, thorough work has been invested in integrating the hardware and software interfaces with one another, in order to achieve a data pipeline that takes in real-world data and provides appropriate commands for spacecraft actuation.

In this document, the entire process regarding the testing and verification of 3 specific requirements can be found, which were written during detailed design and derived from high-level requirements into technical, verifiable requirements. In logical order, the design of the test article and test jig are first shown. This is followed by the software design, after which the experimental configuration and test setup are presented and elaborated on. Specifically, the documentation concerns a modular, convertible test setup with which a rotating breadboard model of the spacecraft is used to verify detumbling and nadir pointing which were developed during detailed design (AE4904). The setup captures real-world sensor data from Earth Horizon Sensors, represented by IR sensors, and uses magnetometer measurements of the changing local magnetic field to support the verification of the spacecraft’s attitude determination and control functionality. Other, relevant requirements are also listed and explained in relation to the experimental design, including what data is to be acquired and processed further on. Finally, the test results can be found in the final quarter of the document, together with the conclusions that can be drawn based on these results.