18. October 2017
BEXUS 24/25: German-Swedish programme for balloon experiments

Stu­dents re­search the strato­sphere in the Arc­tic

Launch of BEXUS 24 on 18 Oc­to­ber 2017
Image 1/5, Credit: DLR.

Launch of BEXUS 24 on 18 October 2017

The strato­spher­ic re­search bal­loon BEXUS 24 was suc­cess­ful­ly launched from the Es­range Space Cen­ter in Kiruna, Swe­den, on 18 Oc­to­ber 2017 at 13:39 CEST. The gon­do­la of the bal­loon housed four sci­en­tif­ic ex­per­i­ments to be car­ried out un­der mi­cro­grav­i­ty de­signed by stu­dent teams from Swe­den, Italy and Spain.
BEXUS 25: Team HAM­BURG prepar­ing their ex­per­i­ment
Image 2/5, Credit: ZARM.

BEXUS 25: Team HAMBURG preparing their experiment

BEXUS 25: The goal of the stu­dent team HAM­BURG (High Al­ti­tude Me­teroids-dust-catch­ing Bal­loon con­strUct­ed by a Rev­o­lu­tion­ary Gen­er­a­tion) from the Tech­ni­cal Uni­veristy of Ham­burg-Har­burg was to au­to­mat­i­cal­ly col­lect iron-nick­el con­tain­ing mi­crom­e­te­orites.
Launch plat­form ‘Her­cules’ trans­port­ing the BEXUS 24 gon­do­la
Image 3/5, Credit: DLR (CC-BY 3.0).

Launch platform ‘Hercules’ transporting the BEXUS 24 gondola

Pre­cious car­go: The gon­do­la of the BEXUS 24 re­search bal­loon hous­es four ex­per­i­ments from stu­dent teams from Italy, Spain and Swe­den. One day be­fore launch, the gon­do­la is trans­port­ed to the bal­loon us­ing the ‘Her­cules’ trans­port and launch plat­form.
The launch plat­form ‘Her­cules’ fea­tur­ing all par­tic­i­pants of the BEXUS 24/25 cam­paign
Image 4/5, Credit: SSC.

The launch platform ‘Hercules’ featuring all participants of the BEXUS 24/25 campaign

Re­search is an in­ter­na­tion­al thing: Stu­dent teams from Ger­many, Swe­den, Great Britain, Italy and Spain took part in the dou­ble BEXUS 24/25 re­search cam­paign. The pho­to shows this cam­paign's par­tic­i­pants at the Es­range Space Cen­ter in Kiruna, Swe­den. From here, the re­search bal­loons, made pos­si­ble by DLR and the Swedish Na­tion­al Space Board, are launched to­wards the arc­tic sky.
The Lo­tus_XD team prepar­ing for launch
Image 5/5, Credit: ZARM.

The Lotus_XD team preparing for launch

The Lo­tus_XD team (Light pow­er and Op­ti­cal Trans­mis­sion ex­per­i­ment of Uni­ver­si­ty Stu­dents - eX­tra Da­ta) from the Tech­ni­cal Uni­ver­si­ty of Dres­den de­signed an ex­per­i­ment to test so­lar cells un­der re­duced grav­i­ta­tion­al con­di­tions to be launched on BEXUS 25. These types of so­lar cells could be used for the laser trans­fer of en­er­gy to rovers on the Moon or Mars.

  • The BEXUS 24 research balloon was launched from the Esrange Space Center in Sweden on 18 October.
  • On board the joint mission by DLR and the Swedish National Space Board were four science experiments designed by student teams from Spain, Italy and Sweden.
  • On Friday 20 October, the BEXUS 25 balloon followed with four more experiments built by student teams from Germany, Sweden and Great Britain – the scientific focus of these experiments is on subjects such as solar radiation.
  • Focus: Space, research under space conditions, junior research programme

The BEXUS 24 research balloon was launched from the Esrange Space Center in Sweden at 13:39 Central European Summer Time on Wednesday 18 October 2017. The balloon reached its maximum altitude of 24.6 kilometres at 15:25 at which point the gondola separated from the balloon (in a procedure called 'cut down'). The gondola landed back on Earth at 17:22 local time. On board the joint mission by the German Aerospace Center (Deutsches Zentrum für Luft- und Raumfahrt; DLR) and the Swedish National Space Board (SNSB) were four science experiments designed by student teams from Spain, Italy and Sweden.

The BEXUS 25 balloon followed its predecessor on Friday 20 October with four more experiments on board, the focus here being on solar radiation, micrometeorites and other scientific topics. Two student teams from Germany and one team each from Sweden and Great Britain took part in this campaign. Michael Becker, head of the BEXUS programme at the DLR Space Administration, adds: "All the experiments were planned, put together, built and tested by the students themselves. In this way, the REXUS/BEXUS programme offers students a unique opportunity to carry out their own spaceflight project under real conditions."

BEXUS 24: On the hunt for cosmic radiation

The Spanish CADMUS (Cloud chamber for high Altitude Detection of Muons Under Special relativity effect) team from the Polytechnic University of Catalonia aimed to measure elementary particles (muons) that travel at almost the speed of light in the atmosphere. Muons are a major component of secondary cosmic radiation. Using a cloud chamber, they pick up muon traces and calculate, during the balloon’s ascent, the quantity of these particles detected at each altitude range. These data will be used to obtain the mean lifetime of a muon, which will then be compared to the value predicted by Albert Einstein’s special theory of relativity.. By making the decay visible, the half-life of elementary particles can be determined and information on the products of cosmic radiation and their composition at high altitudes can be acquired.

The NEMESYS (Neutron Effects on MEmory SYStems) team from the University of Rome Tor Vergata is looking into the effects of cosmic radiation on electronic storage systems. This experiment was designed to study how particle impacts affect a memory card – in other words, how the radiation environment influences the storage error rate (bit flips). The experiment included measurements of the altitude, position, temperature and the detection of impacts. Electronic storage systems are critical components in satellites, for example.

The Italian DREX (Deployable Reflector Experiment) team from the University of Padua tested the stability of a spring-based reflector antenna in the stratosphere. The advantage of the antenna is its very low weight and its ability to unfold a reflector in the lower layers of the atmosphere. Such an antenna could be used for future satellites and suborbital missions.

The students from EXIST (Examination of Infrasound in the Stratosphere and Troposphere), the team from the University of Luleå, studied infrasound in the stratosphere and troposphere in the Arctic region. The frequency of infrasound is between 16 to 20 Hertz and lies below the human hearing threshold. Infrasound occurs everywhere in nature, but is also generated artificially, for example through mining or by wind turbines. The EXIST team used special instruments on BEXUS 24 to record infrasound and analyse the infrasound spectrum in the arctic region, to subsequently determine the origin of the signals. Measuring infrasound can, for example, help in the prediction of extreme weather conditions and earthquakes.

BEXUS 25: Collecting micrometeorites in the stratosphere

The aim of the HAMBURG (High Altitude Meteoroids-dust-catching Balloon constrUcted by a Revolutionary Generation) student team from the Technical University of Hamburg-Harburg was the automated collection of micrometeorites that contain iron and nickel.

Micrometeorites are extraterrestrial particles with a size of less than 100 micrometres that can be scattered into the atmosphere by the wind. Micrometeorites that contain iron and nickel are ferromagnetic and so could be captured using strong magnets. During the BEXUS 25 flight these micrometeorites were captured at altitudes of five to 20 kilometres and 20 to 30 kilometres to determine their density distribution in the stratosphere. "In addition, we are analysing the composition of the micrometeorites in the laboratory. This information is used not only to determine the age, but also the origin of the micrometeorites, and enable a better understanding of the particles in the atmosphere. The biggest challenge here was to prevent contamination by Earth particles," explains team leader Ihsan Kaplan.

The LOTUS_XD (Light power and Optical Transmission experiment of University Students – eXtra Data) team from the Technical University of Dresden tested solar cells under space conditions. During the flight with the stratospheric balloon, they investigated how solar cells that are suitable for laser-based energy transfer from a satellite in orbit to an exploration vehicle on the surface of, for instance, the Moon or Mars behave as the temperature fluctuates. They did so by exposing the solar cells and associated electronics to temperatures as low as minus 60 degrees Celsius. "The experiment is expected to show that it is possible to use the energy from solar cells to freeze the electronics of an exploration vehicle or a satellite in space when it is not needed, and reactivate it again as necessary," explains team leader Jan Walter. "At the same time, the solar cells are expected to be available for transferring scientific data."

Team IRIS (Infra-Red albedo measurements In Stratosphere) focused on climate research. The Swedish team from the Technical University of Luleå used its experiment on board BEXUS 25 to study the behaviour of Earth's incident and reflected solar radiation, i.e. the level of Earth's reflectivity. The data gained will enable better error analysis of measurements by satellites, as the BEXUS measurements were carried out directly in the thin atmospheric layers. The results also support studies on the extent of ice melting in the polar regions, and hence the question of whether reduced reflection of solar radiation is contributing to global warming.

Also participating on board BEXUS 25 was a team from Great Britain. The SUNBYTE team from the University of Sheffield built an especially stable telescope to track the Sun automatically and then photograph the structure of the outermost layer of the Sun in the H-alpha spectral line. The experiment delivered images to the ground station during the flight itself.

BEXUS: a programme for junior researchers

The German-Swedish BEXUS programme (Balloon Experiments for University Students) allows students to gain practical experience in the preparation and implementation of space projects. The Calls for Proposals for the BEXUS 26/27 programme, which will be launched in the autumn of 2018, and the rocket equivalent, REXUS 25/26, foreseen for March 2018, are already open. Both programmes will again be organised by the DLR Space Administration in Bonn, the European Space Agency (ESA) and the Swedish National Space Board (SNSB).

Half of the balloon payload is being made available for experiments undertaken by students from German universities and higher education facilities. The Swedish National Space Board (SNSB) has also opened up their programmes to students from other ESA Member States. The German team of students receive technical and logistical support from the Cen­tre of Ap­plied Space Tech­nol­o­gy and Mi­cro­grav­i­ty (ZARM) in Bremen. The flights will be carried out by EuroLaunch, a joint venture between DLR's Mobile Rocket Base (MoRaBa) and the Esrange Space Center of the Swedish Space Corporation (SSC).

  • Elisabeth Mittelbach
    Me­dia in­quiries Ger­man Space Agen­cy
    Ger­man Aerospace Cen­ter (DLR)
    Com­mu­ni­ca­tions, Ger­man Space Agen­cy at DLR
    Telephone: +49 228 447-385
    Fax: +49 228 447-386
    Königswinterer Str. 522-524
    53227 Bonn
  • Michael Becker
    Ger­man Aerospace Cen­ter (DLR)
    Ger­man Space Agen­cy at DLR
    Re­search and Ex­plo­ration
    Königswinterer Straße 522-524
    53227 Bonn
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