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SCALAR-6 project: 10 years of passion and a two-stage rocket designed entirely at SCube
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Ten years after the first launch of the Supaéro CAnsat LAuncheR program, the students of the Supaéro Space Section (SCube) have reached a major new milestone with SCALAR-6, the first experimental two-stage rocket designed and built entirely within the club.
Ludovic BASTIEN, head of the SCALAR-V project in 2024 and SCALAR-6 in 2025, talks about his experience.
What is the SCALAR-6 project?
SCALAR-6 is the sixth version of the SCALAR(Supaéro CAnsat LAuncheR) launcher. Designed and built entirely within the SCube(Supaéro Space Section), this project aimed to achieve the program’s ultimate technical goal: to design and fly an active two-stage experimental rocket at C’Space 2025, carrying an experiment in the form of a CanSat ejected at the apogee of its flight. An active two-stage rocket consists of two superimposed stages, each equipped with its own engine, the second being ignited in flight after separation. This active flight requires a so-called passive flight, during which the second stage carries an inert engine serving as a mass simulator.
This project followed in the footsteps of earlier SCALARs, in particular SCALAR-V, the single-stage launcher for C’Space 2024, which made its nominal flight on July 10, 2024, and enabled SCALAR-6 to exist. The club’s aim was to regain the skills lost in the wake of the covid crisis, and even go one step further, which was achieved with SCALAR-V and SCALAR-6.
But let’s not forget the history of the club and the SCALAR project. Indeed, the project celebrated its 10th anniversary with the SCALAR-6 project, since the first SCALAR was built in 2015.
The SCALAR-6 team involved some thirty students, mostly second-year and first-year students, trained at the club. These students came from the engineering and speciality engineering streams, as well as from specialized masters programs. As the project’s name suggests, the rocket carried an experiment in the form of a can-sized “mini-satellite” called CanSat, created by schoolchildren involved in the ISAE-SUPAERO OSE program, with the help of club students.
Photo Credit: CNES 2025 – Planet Sciences – C. Pouilly
What were the objectives of the project and how did it go?
The entire project was carried out over the2024/2025 school year. We designed the rocket at the beginning of the year, then manufactured it in late winter and spring 2026. Then it’s off to the launch campaign,
For the CanSat, 2 sessions of 3 hours were carried out as part of the OSE project with secondary school students. The first session took place on
The Supaero Space Section was present with eight SCALAR members for this launch campaign. This edition was marked by a particular difficulty: the shortage of PRO75 engines. Out of ten teams present, only five were able to obtain one. […] Faced with material constraints and limited time, we had to review our ambitions. In particular, theabsence of vents on the carbon skin– since we forgot about this constraint – made active flight impossible. We quickly decided to concentrate our efforts on passive flight, which was more realistic in the context of the campaign. At the same time, we decided to abandon several secondary experiments (GPS measurement, telemetry, CanSat operation), as setting them up and validating them would have considerably slowed down rocket qualification. Qualification was not without its difficulties. First of all, we encountered stability problems. Having never carried out a test with the rocket fully assembled, we had several unpleasant surprises during the first tests. On the upper stage, two critical points became apparent. The absence of vents in the carbon skin represented a major risk, since in the event of engine failure, excess pressure could have caused an explosion. In addition, the motor was difficult to extract, posing a major safety problem: in the event of non-ignition, the pyrotechnician must be able to remove it quickly and safely. The lower stage was not without its faults either: a gap was found in the motor attachment, which we had to correct urgently using an improvised piece of metal to wedge the thruster correctly. Finally, during the simulated flights – a dress rehearsal evaluated by a member of CNES and planète science before we were allowed to fly – other difficulties arose, in particular with the take-off detection threshold and the programmed time windows for opening the parachutes. Fortunately, we were able to correct these problems and validate SCALAR-6 during the second simulated flight.
From these experiences, we have learned an essential lesson: perform all critical tests upstream to avoid unforeseen problems during official inspections.
What was the SCALAR-6 flight like?
SCALAR-6 finally took off on Wednesday July 9 at 5:52 pm. The flight was semi-nominal:
- thelower level performed according to plan.
- the upper-stage recovery system has failed, probably due to an electronic fault or wiring problem.
A particularly positive point was the success of the inter-stage separation system. Separation was straightforward and perfectly executed, an essential criterion for future active flight. This feedback confirms the reliability of the separation system, but highlights the need to drastically simplify the upper stage electronics, notably by reducing the number of cables.
As the upper floor was not recovered, we only have data from the second floor, which was less instrumented than the second.
What is your feedback on this project?
We didn’t quite reach our target of an active two-stage flight, but SCALAR-6 remains a great success for the club. All the systems required for such a flight have been developed, designed and tested at least once, giving us valuable experience and skills over the year. […]
Over and above the successes and failures, we will remember above all the knowledge and skills acquired by the team members, whether technical or human. On the human side, there’s group work, of course, but also managing the unexpected, sometimes under stressful conditions, and the perseverance needed to achieve our goals. From a technical point of view, the most important lesson is the reality check: this type of project quickly reminds us that practice is far more complex than theory suggests on paper.
This edition of SCALAR is a good illustration of this. After overcoming numerous challenges, correcting a multitude of small problems and successfully qualifying the rocket through a battery of tests, the second stage failed on flight day. The expression “Space is hard” took on its full meaning for the team, with the brutality of seeing their project go ballistic despite all the hours invested.
What does the future hold for the SCALAR project?
SCALAR-6 marked an important milestone for the club. It was SCALAR’s tenth anniversary project. It was also the first flight of a two-stage rocket designed entirely by club students, even if the flight remained passive.
We learned an enormous amount on a technical and human level. We succeeded in qualifying a passive two-stage rocket and demonstrating that inter-stage separation works. We haven’t yet achieved active flight, but the foundations have been laid for the next SCALAR.
The Foundation’s financial support played an essential role. It ensured that the budget was managed and that the students did not have to finance the project out of their own pockets.
With SCALAR-6, we have laid the foundations for the future. The project shows that the club is capable of going further. The next objective will naturally be active flying. The club is back with a new SCALAR edition: SCALAR-7. We’re aiming for an active two-stage rocket.
Do you have a message for the Foundation’s donors?
The Foundation’s support played an essential role in cash management. By making available funds that could be drawn on immediately, without the need for receipts, the Foundation avoided the need for members to advance expenses. The funds thus served as a genuine “working capital budget”, while awaiting reimbursements from the Students’ Association via the Supaero Space Section account, a more time-consuming procedure subject to supporting documents. As certain purchases are not covered by the AE (such as travel to Tarbes or certain purchases in stores without an invoice), the use of the Foundation made it possible to avoid any personal expenditure. Unlike the previous edition, SCALAR-V, where expenses had to be borne individually (last-minute purchases or transport for the campaign), no member had to pay out of pocket this year.
The SCALAR team warmly thanks all the Foundation’s donors. Thanks to your support, we have been able to realize this ambitious project, and we are deeply grateful.