BUBBLE 2 successfully launched!

BUBBLE 2 successfully launched!

On June 17, 2021, the long-awaited day had come, BUBBLE 2 could finally launch after a year’s delay due to Corona!

30°C outside temperature in Stuttgart and the team gathered, with negative Corona tests, at the university in Vaihingen to do the last preparations for the balloon launch. Changing batteries, preparing the ropes, gondola and parachute and to finish setting up the ground station. In the process, the software from the mobile ground stations still had to be set up on enough laptops so that tracking of the balloon was possible in each of the three tracking cars. 

Around 12:30 the preparations were finished, all things were packed and the gondola and the helium were brought to the launch site. There the team set up a pavilion for some protection from the sun and started to assemble the gondola and check all the functions. At the same time, the balloon was filled.  Shortly before 4 pm everything was ready and BUBBLE 2 was launched.

A flight time of roughly 3 hours was calculated with an approximate landing site north of Bretten. On a windless day the balloon does not fly too far away, which makes the chase more comfortable, so there was enough time for cleaning up, filling the water bottles and eating an ice cream before setting out. Using the tracking systems integrated in the gondola, the position of BUBBLE 2 could now be pinpointed and the flight route followed. Both the mobile and stationary ground stations were able to receive good data. At an altitude of almost 36km, the balloon burst and the gondola fell in free fall until the parachute was able to brake in the denser atmosphere. BUBBLE 2 glided gently to the ground at 5 m/s for the last few kilometers. The cars drove to the approximate landing site from different directions to increase the chance of recovering the gondola quickly. This is important if, for example, there is a river nearby to be able to rescue the systems in time.

All three chase cars had gathered near the expected landing site shortly before the landing and one of them could even watch the gondola descending. It was an unspectacular landing in the field, far away from roads and towns and during recovery no damage to the gondola or electronics could be detected. So it was a successful flight.

The entire flight was filmed by our GoPro, provides stunning footage and can be viewed in full on Youtube.

The data evaluation now also brings BUBBLE 3 a lot further, as we now know which of our systems worked well and where there are still weak points. Our goal to develop a plug-and-play system for high-altitude balloons, has come a lot closer this day!

BUBBLE 2 successfully performed its system test – ready for launch!

BUBBLE 2 successfully performed its system test – ready for launch!

As temperatures are rising, and winter winds are finally gone, BUBBLE 2 has successfully performed its system test – a critical milestone in the launch preparations. During the 2.5 hour long test run, every functionality such as a strong radio down link connection, battery performance and reliable data recording was tested, and no issues were found. Additionally, the team took the opportunity to work on final launch preparations. A final launch date is yet to be chosen and will be selected quite spontaneous as the launch is dependent on good weather and a promising flight track prediction – however, the team is looking for a launch in June 2021.

BUBBLE is the very own high-altitude program and balloon of the Small Satellite Student Society of the University of Stuttgart. BUBBLE 2 is, similar to the flight of BUBBLE 1, equipped with a sky brightness sensor which is an experiment performed in cooperation with the Institute of Space Systems at the University of Stuttgart. The high altitude balloon will lift a 2 kg gondola carrying the experiment to a maximum altitude of approximately 35,000 m where the balloon will burst and the gondola starts to descend safely on a parachute. The BUBBLE team on the ground will receive radio transmissions from the balloon to localize and recover the gondola after landing.

BUBBLE Team Practices Tracking & Recovery

BUBBLE Team Practices Tracking & Recovery

The BUBBLE team practised for their upcoming launch today by helping to track and recover another private high altitude balloon. The payload was a camera, along with a few personal items. After a launch near the University of Stuttgart and a 2 hour flight with a maximum altitude of 34.8 km, the balloon landed in a forest and got stuck in a tree. With some patience and a 15m long telescopic stick they were able to successfully recover the balloon and its payload. Participating in this kind of operation gives the team a chance to practice for their own launches, and helps to ensure a smooth tracking and recovery later.

Corona and the impact on KSat projects

Corona and the impact on KSat projects

The corona virus currently leads to massive restrictions in public life in Germany and Europe. The University of Stuttgart will close down almost completely until 20 April 2020, which will delay some of our projects, which we summarize below.

This article will be updated if there are further changes.

Update 2020-03-19: Currently all meetings of clubs are prohibited in Germany. We are taking the opportunity to expand our server infrastructure with voice chat and other teleworking services.


Our rover mission was to be launched in March on board a REXUS rocket. The launch was postponed indefinitely in order to ensure satellite operation at the launch pad and as no medical care could be provided locally. REXUS/BEXUS and the organisers DLR and SNSA are looking for an alternative date.


Our CubeSat project is currently in phase C. Due to the closure of workshops and laboratories at the university there are some delays in production and tests.

Some work, especially software development and documentation is actually progressing faster now, as team members have much less other obligations. The schedule will not be changed for the time being.

The Critical Design Review was scheduled for April 20. Since this is now announced as the first day of lectures we are looking for a new date – and in case the shut down will be extended a good solution for a remote review.


The second balloon in our BUBBLE balloon series was scheduled to launch in April. As there are no production and launch preparations possible at the moment, the schedule will not be able to be kept. As soon as university operations are resumed, we will look for a new launch date.


Our CanSat-Challenge is running and nearing the end. Since no production and launch preparations are possible at present, the schedule will not be able to be kept. As soon as university operations are resumed, we will look for a new launch date.


Hannover Messe

The fair has been postponed by the organizer to 13 – 17 July 2020.

Yuri’s Night Stuttgart

The Yuri’s Night 2020 was cancelled by the organizer.

Tag der Wissenschaft

The Science Day was cancelled by the organizer.

PiAndMore 12 ½

The PiAndMore 12 ½ has been postponed, a new date has not been fixed yet.

Update 2020-03-24


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