BEXUS 36/37: A stratospheric student experience

Record participation in BEXUS

Following a rigorous selection in late 2024, ten university student teams were chosen, marking the highest level of participation at a balloon campaign since REXUS/BEXUS began. This also highlights the value that students and universities place on these opportunities.

The teams embarked on a challenging journey with the REXUS/BEXUS programme, which provides students with the opportunity to work on hands-on space projects closely resembling a real-world mission. REXUS/BEXUS is carried out under a bilateral Agency Agreement between the German Aerospace Center (DLR) and the Swedish National Space Agency (SNSA), with support from the European Space Agency (ESA).

Seven teams were supported by ESA and SNSA:

• EVE CURiE (Warsaw University of Technology, Poland) – investigating material and radiation effects in the stratosphere.
• GLITCH (Luleå University of Technology, Sweden) – studying single event upsets in SRAM memory during solar maximum.
• SUNFLOWER (University of Padova, Italy) – testing adaptive light and thermal shielding for biological samples.
• SVAROG² (Imperial College London, UK) – validating solar sail deployment models through a scaled membrane experiment.
• OSTRICH (Radboud University Nijmegen, the Netherlands) – imaging atmospheric phenomena with cameras, requiring dark conditions.
• RATATOSK (University of Southern Denmark, Denmark) – testing an X-band (10.0–10.1 GHz) communication link with a ground station.
• SOBER (University of Waterloo, Canada) – calibrating optical and infrared sensors in stratospheric darkness.

Three teams were supported by DLR:

• CRAB (TU Dresden, Germany) – testing a modulating retroreflector laser link and optical gondola tracking.
• SHAREon (EAH Jena, Germany / TU Delft, the Netherlands) – demonstrating optical navigation sensors on a deployable arm.
• SETH (University of Kiel, Germany) – performing spectral measurements of cosmic radiation.

From concept to launch pad

After the selection, the teams refined their designs, passed multiple technical reviews, and prepared their payloads for integration and testing, under the guidance of experts from SNSA, DLR, ESA, the Swedish Space Corporation (SSC), ZARM, and the Mobile Rocket Base (MORABA) of DLR. After nearly a year of intense work, the teams were ready for the launch campaign at Esrange Space Center in Kiruna, Sweden.

“The BEXUS programme is amazing. It gave my team and I truly hands-on experience to idealize, design, build and launch a space mission,” said the team leader of SOBER from the University of Waterloo, Canada. “With over 20 Canadian and European students from multiple countries and cultures, we learnt how to work together as a team and achieve our goals.”

The launch campaign

The overall experience offered the students a valuable opportunity to learn and grow. They experienced first-hand the professional dynamics that characterise the final stages of a launch campaign. Before the actual lift-off of their experiments on board stratospheric balloons, each team successfully completed the individual, interference, and flight compatibility tests, demonstrating the results of their hard work and dedication.

The two BEXUS balloons lifted off from Esrange Space Center under the crisp northern sky, each carrying a set of student-built experiments designed to operate in the harsh environment of the stratosphere.

BEXUS 37 was launched first, on 8 October 2025 at 19:23 CEST, marking the first night-time flight of the programme in many years. Benefiting from exceptionally calm winds, the balloon remained almost stationary, reaching an altitude of 27 km and maintaining a float time of 4h 47’, a new duration record for the campaign. The flight provided ideal conditions for experiments requiring darkness, such as optical imaging and infrared calibration.

“This was the first experience for me being at Esrange. I think the campaign was a great success. I learnt a lot and I hope to be back with a new project,” said the latest member to join the OSTRICH team from Radboud University Nijmegen, the Netherlands.

Two days later, BEXUS 36 arrived at the launch pad carrying another set of experiments. Shortly after inflation, the balloon suffered a failure that caused a termination of the launch attempt. The experiments did not sustain noteworthy damage, but due to the uncertain cause of the failure it was not possible to repeat a launch attempt. A further failure investigation is currently ongoing. Despite the disappointment, the launch campaign provided a powerful learning experience for all the students involved.

“Project SVAROG² had an amazing time at the BEXUS campaign this year. Coming in, we had many challenges to overcome, but the support given by SSC, ZARM and ESA teams really helped us get our experiment into flight-ready condition. Although the launch did not go to plan, the experience was unbelievable and I would recommend BEXUS to any student team who wants to take their project to new heights,” said the team leader of SVAROG² from Imperial College London, UK.

Results and student experience

Preliminary results indicate that most payloads on BEXUS 37 performed as expected. Students began presenting early findings at Esrange, while full data analysis will continue in the coming months at their home institutions.

For the teams whose experiments were hosted on BEXUS 36, the premature end of the mission transformed into a different kind of success, one defined by teamwork, resilience, and shared learning. Students worked side by side with experts from SNSA, DLR, ESA, SSC and ZARM to review the data collected prior to the failure and to understand what happened, turning an unexpected event into a valuable engineering lesson.

“Thinking back on the launch campaign, it's clear that this has been an incredibly intense and challenging experience, not just technically, but also on an emotional level,” said the team leader of SUNFLOWER from the University of Padova, Italy. “Thanks to how the story ended, the journey itself has been profoundly educational, and we’re grateful to the experts and fellow teams who guided and supported us along the way.”

The launch campaign concluded with a shared sense of achievement and growth among all teams. Regardless of whether their experiments reached the stratosphere, every participant left Esrange with new skills, valuable teamwork experience, and the confidence of having crossed the threshold from student to professional.

About the Programme

The REXUS/BEXUS programme is realised under a bilateral Agency Agreement between DLR and SNSA. The Swedish share of the payload is made available to students from other European countries through collaboration with ESA. EuroLaunch, a cooperation between SSC and DLR MORABA, is responsible for campaign management and launch operations. Experts from DLR, SSC, ZARM, and ESA provide technical support throughout the project.

For more information about the REXUS/BEXUS programme, visit: https://www.esa.int/Education/Rexus_Bexus