Flying Squirrels

The Fly Your Thesis! programme

The European Space Agency (ESA) Education Programme has the objective to inspire and motivate young people to enhance their literacy and competence in science, technology, engineering and mathematics (STEM disciplines), and to pursue a career in these fields, in the space domain in particular. To this end, it offers a number of exciting activities that range from training and classroom activities that use space as a teaching and learning context for school teachers and pupils, to real space projects for university students.

The Fly Your Thesis! (FYT) programme gives master and PhD candidates the opportunity to fly their scientific experiment or technological research in microgravity conditions. The experiments can be related to fluid physics, chemistry, biology, material sciences, heat transfer and astrophysics. The parabolic flight campaign takes place on the Airbus A310 Zero-G, which is operated by Novespace from Bordeaux, France. Each campaign consists of a series of three flights of 30 parabolas each. These will provide about 20s of microgravity each.

Learn more about Fly Your Thesis!

The team

Flying Squirrels team, from left to right: Antoine Brunet, Hélène Evain, Thomas Solatges and Adrien Dias Ribeiro.

Our team is composed of:

• Daniel Alazard is our endorsing professor from ISAE SUPAERO.
• Hélène Evain is a French PhD student, funded by ONERA (the French aerospace lab) in the DCSD department and CNES (the French Space Agency) in Toulouse (France), and academically affiliated with ISAE SUPAERO. Her PhD topic is the study of new configurations of Control Moment Gyro clusters and design of the steering and attitude control laws. Therefore, this experiment is integrated in her PhD. She is the team leader of this project, defines the scientific objectives, and develops the control laws and the maneuvers to be tested. After the campaign, she will analyse the experimental data and publish with the teams the results in journals and conferences.
• Thomas Solatges is a French PhD student at SITIA company (Nantes, France) and affiliated with ISAE SUPAERO and ONERA. He works on the design, building and control of a large scale and highly dynamic flexible robotic arm intended to launch and recover small fixed wing planes (5kg to 10kg) from a moving ship. He has designed and built many systems such as fixed wing and multirotor drones. He handles the mechanical design, system design of the nanosatellite and builds the prototypes. He is the technical leader of the team.
• Antoine Brunet is a French PhD student, funded by ONERA (the French aerospace lab) in the DESP department and CNES (the French Space Agency) in Toulouse (France), and academically affiliated with ISAE SUPAERO. His PhD topic is the study of new multiscale numerical schemes to simulate the impact of solar generators on the electrostatic charging of a satellite. In this team, he is in charge of the software development, both for the embedded computer and the monitoring system. He is also in charge of the experiment operations.
• Adrien Dias Ribeiro is a French MSc student, studying at EI.CESI Toulouse and University Paul Sabatier. He is studying electrical engineering, embedded systems and robotics at the university. He is also an apprentice at ONERA (The French Aerospace Lab) in the DESP department, he is working on the automation of test bench (vacuum chambers) for space applications. On this project, he is doing the electronics of the system. He will design electronics board for power conversion, communication and electrical safety. He is also in charge of project management.

Our experiment design

The main objective of the experiment is to test a new attitude control system (system to control the orientation) for small satellites (nanosatellites). This system includes a Control Moment Gyro cluster composed of six actuators, and a new in-house steering law that controls the actuators.

The nanosatellites have more and more needs for agility and accurate pointing, and Control Moment Gyro clusters have proven to be very power-efficient and have more torque capabilities than other attitude actuators for the same mass and electrical power in satellites. For micro-satellites, their use is not common because of the complexity of steering a cluster, and few technologies are available in the market. We therefore propose a new mechanical design of a CMG cluster, fitting in a nanosatellite, with equipment available in the market, and to test in microgravity the performance of the new steering law by carrying out typical maneuvers a nanosatellite may have to perform, with tests of reliability in case of actuators failures.

The Control Moment Gyro cluster contains six identical CMGs. Each CMG has two actuators: one flywheel motor will rotate the flywheel at a high constant velocity, and one gimbal motor will be controlled to provide the required gyroscopic moments.

The main controller of the nanosat is a Raspberry Pi 3 with a PCB shield holding electronic components and connections to sensors and other electronic systems such as one I2C IMU.

Planned maneuvers

During the flights, the cubesat will perform several different maneuvers to assess the performance of the CMG cluster and of its control law.

At the beginning of each parabola, one maneuver will be asked to the nanosat, and it will have to perform it during the 20 seconds of microgravity. The three types of maneuvers are:

• Fixed pointing: the nanosat will have to stay fixed in a given orientation despite the external perturbations during the whole parabola. This simulates a mode where a satellite in space has to keep its solar panels fixed towards the Sun to charge its batteries, or when a satellite needs to keep its antennas fixed towards the Earth to communicate with the ground stations. The goal is to remain pointed in a fixed direction, by rejecting the outside perturbations.
• Rapid large reorientations of the nanosatellite : the nanosatellite will have to rapidly turn around itself to point in a different orientation.
• Follow a target: it models a space debris inspection mission where a nanosatellite has to keep its camera fixed relatively to a moving object. To do so, a camera will be placed inside the nanosat that will track a target (for our experiment, probably a ball of foam).

Each maneuver will also be tested with simulated failures of one or two actuators switched-off during these parabolas.