What is a cubesat?
It consists of a modular cube of 10x10x10 cm with a mass of 1.33 kg, which is known as 1-unit (1U) CubeSat.
Cubesats were created to provide a low-cost, flexible and quick-build alternative to reach the space, in a few words a cubesat is a satellite with a cubic form.
Cubesat are now affordable tools for teaching and researching for Universities and Research Centers. Although they are simple platforms, their complexity can be increased. Simulation of the capability of these subsystems is the first step to assess the convenience to include such subsystems in a platform. In this case, Implementation of sensor and actuator models in a CubeSat Simulator and visualization.
Software and hardware specifications and parameters:
The parameters were selected by Javier Sanz Lobo in his master thesis “ Design of a Failure Detection Isolation and Recovery System for Cubesats“
Leo ( Low earth orbit) was selected by its highly demanding orbit maintenance and pointing accuracy. The satellite selected to perform is a 2U CubeSat.
Therefore, its size is 10x20x10 cm, and it weights 2.66 kg. The image illustrates the relative position of the main elements with respect to the body axis, the Earth and the orbit motion. The propulsion system was placed in the opposite face to the orbit motion to counteract the drag and the optical payload pointing to nadir(a selected face to always be syncronized to Earth).
Example proposed in master thesis:
Internally and intrinsically how does the software work?
Attitude and Orbital Control System Elements included for calculations summary:
1.1 Attitude control:
1.1.1 Attitude controller, magnertorquer, reaction wheel allocation, reaction wheel controller and reaction wheel model.
1.2 Orbit Controll:
1.2.1 Thruster allocation, orbit controller and thruster model
2.1 Six degree of freedom model: attitude dynamics and kinematics(with quaternions evolution)
2.2.1 Atmospheric drag, gravity gradient torque, J2 perturbation, magnetic torque and third body perturbation
2.3 Keplerian Orbit: Vectors normalizations
3. FDIR: with frozen and/or sudden death signals included if desired
3.1Gyroscopes FDIR (Control panel included)
3.2 Reaction Wheels FDIR (Control panel included)
3.3Thrusters FDIR (Control panel included)
4.1 Directions cosine matrix to quaternions (positive and negative traces included)
5. Navigation: Sensors and actuators included.
5.1 Attitude Filter, GNSS, Gyroscope, Orbit Filter, and startracker
6. Visualization: 3D orbit, groundtrack and COE
Interface created with improved and modifiables 3D models:
Output interface results:
Expected Visualization Results: