Team Aiolos at the European CanSat Competition in Bologna

We were really looking forward to the European CanSat competition, although we had to improve and repair a lot of things on our CanSat during the previous week. Fortunately, we got everything done by Sunday evening and were able to board the train on Monday morning with a big travel suitcase full of tools, spare parts and of course our CanSat.

The congress center where the competition was held is located just outside of Bologna, where we arrived around afternoon. Many of the other teams were already there, so we were able to socialize for the first time. Around 19:00 we were invited to the "Opening Ceremony", where we were officially welcomed together with the 24 other teams from all over Europe and from Canada. The dinner (like all other meals) was taken at very internationally mixed tables. The meals were a highlight every day, because we could talk to other students from all over Europe about our CanSats and the school, but also about completely different things. It was very exciting to hear how other national competitions went or how the school system in other countries differed from ours. In the evenings we often played soccer together, went out for ice cream or talked until late at night.

Of course we also worked on our CanSat. On Tuesday, the "Technical Inspections" were carried out, i.e. checking whether the dimensions and mass of our CanSat are correct. The parachute together with a "dummy" CanSat was brought up to 50 meters on a drone and dropped to test the required fall speed. We passed all tests on the first try, even our last check of the sensors and gas collection bags of our CanSat did not reveal any problems or errors.

On Wednesday, the time had finally come and the launch was about to take place. At 12:30 we were brought to a small airfield where the rocket for the CanSats would start. Before the launch, we were able to check our CanSat briefly - everything was fine. At 14:55 our CanSat was launched together with that of the Canadian team with a solid fuel rocket.

Launch of our CanSat in Bologna

After a total flight time of 128 seconds, our CanSat landed safely in a sugar beet field. Although our CanSat was printed from orange PLA, it took us quite a long time to find it again. When we finally had it, we were very disappointed because the gas collection bags were not filled with air.

Unfortunately, after recovering our satellite, we had to start the error analysis. After ruling out a hardware failure, we checked the software. This was where the error was located: after the German competition, we had replaced the air pressure sensor and exchanged it for a faster and more accurate one. Unfortunately, the new sensor measured in hectopascals instead of pascals like the old one. This meant that our algorithm, which determines the highest point of the flight and thus triggers the filling of the bags, did not work.

The primary mission, on the other hand, worked very well. Due to the new pressure and humidity sensor, the data is much more accurate compared to the German competition and with only a smaller offset (due to the reaction times of the sensors).

Humidity-height diagram

Thursday was completely filled with the presentations of all teams. Each team was allowed to present and explain their results as well as their mistakes for eight minutes. An international jury consisting of prominent figures in European spaceflight as well as professors of aerospace engineering evaluated the successes of the individual teams. We also presented our data from the primary mission, the error analysis and what we would have expected from the samples.

Friday was the last day of this very eventful week in Bologna. In the morning the award ceremony of this year's European CanSat competition took place. The team from Switzerland won the prize for the best CanSat project fully deserved. Congratulations!

Due to our failed secondary mission, we did not win a prize. Nevertheless, we will not forget this week in Bologna. At first, all teams were a bit unsure what to expect. But since very few of the students learned English as their native language, at least the language was not an obstacle: because it meant that everyone spoke English equally well (or poorly). From the beginning, we were a great community where everyone helped one another. If a certain component broke or you needed a certain tool, you could be sure that another team would help and support you as much as possible.

We would like to thank ESA and all the other teams for this unforgettable experience!


1st place at the German CanSat competition!

Our final presentation for the German CanSat 2021/2022 competition took place on May 12 via video conference. At this event, the participant teams presented their elaborated data of the launch campaign in front of the jury and the other teams. This was followed by an evaluation of each team in relation to the entire project, scoring on the criteria of learning progress, scientific work, technical implementation, professionalism and public relations. Afterwards, the first four places were named, where we can proudly announce to have scored as the best team in the German CanSat competition this year!

With this result we have been qualified to participate in the European CanSat competition and will travel to Bologna (Italy) from June 20th to launch our satellite once again, this time against international competition. Until then we have a lot of work to do, e.g. repairs or optimizations of the CanSat based on recent discoveries from the launch campaign. In addition, we have to write a comprehensive report for the European competition and install a radio system in the CanSat, which we can use to send data to a ground station on site.

The realization of the project would not have been possible without the active support of our Sponsors und Betreuer nicht möglich gewesen, weshalb wir uns in diesem Sinne nochmals ausdrücklich bei diesen Bedanken wollen!


Update 09.05.2022

On Monday, May 9, we focused on the analysis of our gas samples, and for this purpose we had an appointment with Dr. Saathoff at the KIT . At the Institute for Atmospheric Aerosol Research (AAF) he explained us how the proton transfer mass spectrometer works and how the measured values are analyzed. In addition, we enjoyed a very interesting guided tour through the institute, especially the impressive cloud simulation chamber within the facility. Thereby, we were able to follow the analysis of our gas samples at close range, learning a lot about atmospheric aerosol research. We received the final results shortly after our visit in the following days.

We would like to thank Dr. Saathoff and Yanxia Li for the evaluation of the gas samples and the detailed insight into the IMK-AAF.

Measuring instruments at IMK-AAF
Cloud Simulation chamber (outside)


Update 10.04.2022

In the meantime we have got our CanSat back. First things first: all sensors and actuators worked as planned and we were able to read out the data on the SD cards. In addition, the gas collection bags are filled.

Due to a defect on the rocket, our CanSat flew twice, because on the first flight the release mechanism did not work. Therefore, we now have two data sets that we can evaluate. What is not so good, however, is that the two flights have mixed up the samples in the gas collection bag. Together with KIT, we will check to what extent the air samples can still be used and what insights can be gained from them.

We have already started to evaluate the collected sensor data. On 12 May 2022, the virtual final event of the competition will take place, where we will present our results. Here is a first preview of the evaluation:

temperature-altitude profile

The temperature-altitude profile shows the temperature at different altitudes. It can be seen that, as expected, it is significantly warmer at ground level than at higher altitudes. In addition, the temperature decreases rather quickly and reaches its minimum at about 500 metres altitude. Surprisingly, the temperature increases by another 1 degree Celsius at about 600 metres.


Many 3D-printed Parts

Our CanSat has a shell made of PET-G, a plastic that can be processed very well with the 3D printer. In the course of the project, we created a 3D model for the shell, but it kept changing. New sensors were added or more space had to be created for the gas collection bags at a certain point.

All models printed during the competition

In order to test the individual components, we have printed them out frequently; on the picture you can see all the test prints. We are surprised ourselves how many there have been in the course of the last six months. Of course, we will shred all the test prints and have them processed into new filament so that we can reuse them.

PS: The different colours are different filaments, some of which print faster.


Start campaign 05.04.2022

On Tuesday afternoon, we eagerly followed the rocket launch of our probe via livestream. The live stream started at 5 pm and presented the participating teams in just under 40 minutes, as well as summaries of the pre-recorded rocket launches and recoveries of the CanSats. The individual teams were able to present themselves and their project via self-created videos. The replay of the official livestream and our team presentation are linked below:

After we got back our probe together with the gas samples, our project is not over yet. Before the virtual final presentation on 12 May, the samples will be analysed with the help of a KIT proton transfer mass spectrometer. How useful the collected data will ultimately be therefore remains to be seen.


Update 30.03.2022

At the weekend we completely assembled and tested our CanSat. Those were some exhausting hours, as some 3D-printed parts didn't quite fit and some connectors were a bit loose. In the end, however, we managed to produce a stable and fail-safe CanSat.

The finished CanSat. For testing still without top cover

28.03.2022 was the last possible day for shipping the satellite, which we of course kept. Due to the express shipping, the CanSat was also in Bremen the very next day.

Wednesday, 30.03.2022 was one of the most important days of the competition: the virtual conference. Here, all teams presented their mission, implementation and difficulties to the jury and the other participants. We are impressed by the achievements of the other teams, the inventiveness of the missions and the creative implementations! Therefore, we are very much looking forward to the start day next week.

We wish all teams a successful flight and a safe landing!


Update 19.03.2022

The deadline for sending our CanSat to the launch campaign is approaching, which is why we met again at the weekend to put the "final touches" to our probe. After the structure had to be reduced by a few millimetres and reprinted accordingly in order to comply with the required external dimensions of the CanSat, it was now time to finally place all the components inside in their finished state. However, before we also installed the pump system, we subjected the entire system to a final test in which we once again used the used and no longer sterile test bags. The following video shows the complete test using all the electronics installed on the launch day:

Sequence of the test:

0:00 When the power source is connected, the probe starts directly with the self-test programme of the electronics. In the finished state of the CanSat, this only happens after pressing the on/off switch, which is already permanently installed in the casing and was therefore not used for this test. The checking of the individual components one after the other is initiated by a long beep of the acoustic signal generator and returns the signal for "component functional" by a double beep.

1:07 Now the programme sequence for the case of the probe begins, which can be recognised by the humming sound of the pump. Actually, this part is only carried out after the launch and ejection of the probe from the rocket has been detected and the sensor system has been read out regularly in the meantime. For the test, however, we shortened this part and went directly to filling the gas collection bags in the programme sequence.

The filling of the gas collection bags starts with the first bag at the top left and then continues counterclockwise with bags two and three. Two factors are decisive for the filling time during which air is actively fed into the corresponding bag via pump and valves: the air pressure and the height calculated with it, as well as a maximum time interval that may not be exceeded. The former ensures that air samples from different layers are collected by the valves switching to the next bag at certain distances from the floor. The second stops the filling of the bag when the height intervals for filling a single bag are so long that continuous pumping into the bag could damage it if the internal pressure is too high. Since the ambient air pressure in the test setup is approximately constant, each bag is filled according to the second factor for just under 15 seconds. This is followed by a short venting of the system, during which all valves are switched to output. This is to minimise the mixing of gas samples from different heights by the air remaining in the hoses and valves between the filling of two gas collection bags. A short beep signals the switching to the next bag and the process repeats.

In the video it is difficult to see the filling of the gas collection bags. This is because we only take small air samples and the test bags used in the video are already very crumpled and not completely empty of air due to frequent use.


Update 27.02.2022

As we are slowly approaching the submission of our CanSat for the launch campaign, we continued with the completion of the probe last Saturday. For the first time, we were able to fully integrate the pump system, for which all components were finally available to us, into a test print of our structure. As a result, we noticed a need for optimisation of the outer shell in some places, which would not have been possible during the planning in the CAD model, as the dimensions of individual components often deviate from the specified ideal value in reality. In addition, it was difficult to plan the hose routing of the pump system in advance, as we had to bend the hoses inside a lot without them kinking and thus reducing the inner diameter. This revealed clear space problems inside. Especially in places where cable management and pump system cross each other, we had to spend some time trying to fit everything in. We can now use the knowledge we have gained to design another and possibly final version of our structure.

The illustration shows the pump system inside the designated segments of our structure. The top level in which there is a holder for the pump, as well as the three threaded rods for connecting all the segments, have been omitted for better clarity.

You can see the three two-way valves (dark blue and white) and the pump above them (black and grey). Three transparent gas collection bags can be seen at the edge of the orange outer shell.

We also completed the parachutes for 11 m/s and 15 m/s fall speeds, which until now had been missing the attachment of the parachute to the probe via eight nylon cords. We used a lighter to fuse them together under heat at the knots.

We were also able to continue working on the electronics of our CanSat. First, we assembled the industrially manufactured circuit board that we had received from Tesat by soldering on the Arduino, connectors and other components. We then checked the functionality one by one by linking all the sensors and other components to the Arduino via the board and running our test programmes. Fortunately, no problems were encountered.

The picture shows our finished board with the Arduino soldered on.
Some of our components are connected via provisional plug connections for testing.

We are already working on the correct cable connections to ensure a secure connection between the sensors and our board..


Support from Tesat-Spacecom

To control the electronics of our probe, we need a lot of cables and smaller components like transistors, which would take up a lot of space inside the shell. Therefore, we use a circuit board from which we can connect all electronic components to the microcontroller and our power source in a space-saving and clearly arranged way.

Since the PCB plays a central role in our CanSat, it is important to us that it is optimally designed and manufactured with professional equipment. We would therefore like to thank the German aerospace engineering company Tesat-Spacecom for their kind offer to support us with valuable expertise and an industrially manufactured PCB. Thank you very much for your support!

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