Thowards a new era
Minerva II is the competition project with which the Sapienza Rocket Team competed in the 10,000 ft COTS category of the 2025 International Rocket Engineering Competition (IREC).
The rocket carries a 2 kg scientific payload and, thanks to its structure in composite materials and aluminum, is able to withstand high accelerations and speeds. We precisely reach the target altitude through the use of an airbrake system.
Minerva II is the result of months of design, testing, and collaboration among 84 students united by their passion for space and engineering.
Minerva II’s airbrake system, designed to ensure the precise achievement of the 10,000-foot target altitude, consists of a lightweight aluminum structure, divided into two main sections and equipped with a cam mechanism driven by a KAVAN servomotor.
The load-bearing structure, organized in a cruciform orthogonal configuration, integrates linear guides and a cam-carriage system that converts the actuator’s rotation into linear motion.
The relationship between the cam’s rotation angle and the carriage’s linear extension is described by a linear function.
This precise mechanical control allows for modulated extension of the airbrakes during flight, essential for accurately reaching the desired apogee.
The 6 Degrees of Freedom (6DoF) Simulator developed by the Mission Analysis Department is an advanced numerical simulation tool for the flight analysis of student-built rockets.
The model integrates the rigid dynamics of the prototype, simultaneously considering translational and rotational motions, and applying Newton-Euler equations of motion. It accounts for aerodynamic forces (including the drag coefficient varying with altitude and speed), moments of inertia, gravitational forces (updated Earth gravitational model), and external perturbations.
The simulator is optimized for trajectory analysis, launch accuracy prediction, and safety margin analysis, and is essential for the design and validation of Minerva II.
In the future, the system will be able to model the behavior of control systems other than airbrakes, such as one based on canards, simulating the effect of complex maneuvers during different phases of flight.
Our payload is developed in collaboration with the Department of Geodesy at Sapienza University of Rome, with the goal of tracking the rocket’s trajectory during flight with high precision, measuring velocity variations on the order of just a few millimeters per second.
To do this, GNSS technology is used: a satellite navigation system that allows us to collect highly detailed data on the rocket’s position and speed. Through the use of a variometric technique, we are able to obtain extremely accurate measurements in real time.
The system consists of two GNSS receivers, two antennas, and a microcontroller, all connected to a Raspberry Pi that records data during flight.
All collected data is then analyzed with dedicated software, currently tested on the ground, but designed to be integrated on board in the future, for real-time analysis directly during flight.
Tests conducted show that the system is reliable and able to guarantee a precision of up to 2 mm/s on the horizontal axes and 3 mm/s on the vertical axis.
