SERA-III (Supersonic Experimental Rocket Ares) is a supersonic rocket designed by French students, that will be launched on 26th April 2017 in Sweden, north of the Arctic Circle. This rocket is part of the PERSEUS project («Projet Etudiant de Recherche Spatiale Européen Universitaire et Scientifique»: Undergraduate, European and Scientific Project for Space Research). Swedish high school students will participate by loading an experiment.
The SERA rockets are the first supersonic ones designed entirely by French students since 1998. They are part of the ARES family of rockets, which contributed to develop technology and techniques for supersonic flight.
SERA, in its first version, was successfully launched in April 2015, reaching an altitude of 5 km and mach 1.4 (the mach number is the speed of the rocket divided by the speed of sound). SERA-II was also a success, launched in April 2016. Now the goal is to reach higher altitudes while respecting the flight conditions of industrial rockets such as Arianne, and to improve technology such as for the separation between two stages.
The main innovation of SERA-III is to use three motors in a cluster configuration, whereas the previous rockets had only one. This marks a real gap and has led to new issues concerning the mechanical design (the rocket must be able to handle the thrust) and the reliability study (what happens if one motor does not ignite? How will the trajectory be modified? Will the rocket fall into the launch site?).
The main axes of the project are the following:
- Project management. It is necessary to build up a timetable, coordinate the students working on different fields, review what has been done and what needs to be done, and report the progress to the CNES team supervising the students on the project.
- Electronic subsystems. Since the rocket must collect large quantities of data, the electronic team is in charge of designing and developing the electronic architecture and the different sensors. It is essential for the measurements but also for both parachutes opening system.
- Mechanical subsystems. This team is in charge of the CAD (computer-aided design) and the mechanical problems, and makes sure that every component finds its place in the rocket.
- Safety and reliability. SERA-III is the first rocket of its lineage to need a safety team, because of the issues explained above. The team uses digital tools to investigate these issues, and also control the release of the parachutes. The goal is to convince the launch site safety team that the students have full control of the trajectory of the rocket and that it is safe to launch.
- Digital simulation. To design the nose-cone and the stage-coupler properly, the team uses computational tools.