BEXUS 32/33 stratospheric balloons launched
Last week 63 university students participating the Swedish-German REXUS/BEXUS programme got the unique opportunity to travel to Northern Sweden, where they participated in a launch campaign for two stratospheric balloons BEXUS 32 and 33. But they have not been there as visitors: the students were members of eight university teams, each having built their own experiment to be flown on the balloons. Six of those teams were sponsored by the Swedish National Space Agency (SNSA) and ESA, two were sponsored by the German Space Agency (DLR).
The preparation
The REXUS/BEXUS programme allows university students to participate in a full space project in a relatively short time. The student teams participating in the BEXUS 32/33 launch campaign successfully defended their experiment ideas in front of a selection panel made of experts from space agencies and industry in December 2021. After being selected , they went through all typical phases of a professional space project. Student teams refined their experiment design throughout multiple reviews, and then manufactured, integrated, and tested their experiments. All along the way they were closely followed and supported by professional experts from SNSA, DLR, ESA, the Swedish Space Corporation (SSC), the Center of Applied Space Technology and Microgravity (ZARM) and DLR’s Mobile Rocket Base (MORABA).
After almost 2 years of experiment development, it was finally time to travel to the long-awaited launch campaign, which took place from 15-25 September 2023 at the Esrange Space Center in Northern Sweden. Two balloon gondolas, each carrying four experiments, where prepared in parallel. In the first few days of the campaign, the student teams made final preparations of their experiments and went through rigorous testing with the balloon flight systems, making sure all equipment works nominally.
The launch
The gondola of the BEXUS 33 balloon was ready to fly first. But just as all preparations were done, snow and rain arrived at the Esrange Space Center making it difficult to find a launch opportunity. In the early morning of 21 September conditions looked good and the opportunity to launch was taken. After a four-hour countdown, the BEXUS 33 balloon was released at 05:41 local time and began its journey to the stratosphere. It reached an altitude of 27.7 km, where it stayed almost 2 h before the balloon was cut and the gondola flew back to ground under a parachute. Recovery operations commenced immediately after touch down, and the experiments were back in the students’ hands shortly before midnight.
Four student experiments were on board of BEXUS 33. Three of them were sponsored by SNSA and ESA:
- ALMA (Atmospheric Laser Measurement of Aerosols) from Luleå University of Technology, Sweden
- SPACIS (Sound Propagation in the Atmosphere using Complex Infrasonic Signals) from University of Porto, Portugal
- TOTORO (Test Observations of Transient Objects and RadiO) from Warsaw University of Technology, Poland
A fourth experiment was sponsored by DLR:
- CASTOR (Combined Analysis Sensor for Trioxygen and Oxygen Richness) from Technische Universität Dresden, Germany
For BEXUS 32, the weather conditions continued to put launch operations on hold. Students and campaign personnel were waiting patiently for a gap in the rain and for the wind to slow down, with all equipment ready to go once the opportunity would arise. Even a first launch attempt was done, unfortunately it had to be stopped at the last possible moment.
Then finally, in the morning of 24 September, the last day of the campaign’s launch window, BEXUS 32 was released at 08:07 local time. It reached an altitude of 27.6 km, where it stayed for 1.5 hours. Again, the experiments were recovered after the flight.
Three SNSA/ESA sponsored experiments on board of BEXUS 32 were:
- HERCCULES (Heat-transfer and Environment Radiative and Convective Characterization in a University Laboratory for Experimentation in the Stratosphere) from Universidad Politécnica de Madrid, Spain
- HERMES (Habited Exoplanet Research Measured by Eminence Stokes) from Hautes Ecoles Spécialisées Genève, Switzerland
- ROMULUS (Radio Occultation Miniaturized Unit for LEO and Upper Stratosphere) from Sapienza University of Rome, Italy
Again one additional experiment was sponsored by DLR:
- SBGA (miniaturised multi Sensor Box for spaceborne Geodetic Applications) from Technical University of Munich, Germany
The results
During both balloon flights, experiments worked as expected. Further analysis of the acquired data will be done at the students’ home universities and a first preliminary presentation of the results is planned in the week after the campaign. Then, following a more detailed analysis of the experiment data, the students will get the opportunity to present their findings at a related conference.
The BEXUS launch campaign also marked a significant milestone for the REXUS/BEXUS programme. In total, more than 100 student-built balloon experiments – 102 to be exact – have been launched since the inception of the REXUS/BEXUS programme in its current form.
The REXUS/BEXUS programme is realised under a bilateral Agency Agreement between the German Aerospace Center (DLR) and the Swedish National Space Agency (SNSA). The Swedish share of the payload has been made available to students from other European countries through a collaboration with the European Space Agency (ESA). EuroLaunch, a cooperation between the Swedish Space Corporation (SSC) and the Mobile Rocket Base (MORABA) of DLR, is responsible for the campaign management and operations of the launch vehicles. Experts from DLR, SSC, ZARM and ESA provide technical support to the student teams throughout the project. REXUS and BEXUS are launched from SSC, Esrange Space Center in northern Sweden.
