As mentioned in the first part, we can use the stratosphere for several causes. Some applications within research lie in astronomy, weather, biology or ecology. It is easiest to perform this type of science with balloons, as satellites burn when they enter the atmosphere and rockets pass through this layer to quickly.

It also depends on the different missions how much time is needed to perform an experiment: A human jumping from a plane at 36km height takes place over a completely different timescale than the study of fluorine hydrocarbons within the stratosphere. Therefore scientists distinguish between long and short term flights of stratosphere balloons. The flights can take as little as a few hours and up to 3-4 weeks.
The range which can be covered is therefore really wide. For example, to study cosmic background radiation, balloons were heavily used for the first experiments. After that, satellites were used more and more and were able to map the entire sky.

Another important part was played by balloons in the discovery and research of cosmic radiation. They are not only much cheaper than satellites (which in itself is an important advantage!) but they also need much less time be prepared and ready for take off. During the observation of the 1987 Supernova this fact led to the first discovery of gamma rays produced by the supernova. By the time a satellite mission would have been ready to measure the event, any radiation would have long been gone.
Balloons have also proven the existence of holes in the ozone layer, which are caused by fluorine hydrocarbons. They have been used to study a multitude of gases and their interactions within the higher layers of the atmosphere. Today this is mostly done via satellite missions, which can cover a larger area over a longer period of time. Still, balloons can be used to complete data samples or correct for any errors in the satellite measurements.

Is the balloon a historic means to study our atmosphere and should be sent into retirement soon? That is not at all the case! Balloons can contribute to the exploration of Mars and maybe even the further solar system.
The Mars Science Laboratory (MSL, NASA’s next rover on Mars) is going to be equipped with machinery which was developed to study the earth atmosphere. MSL is not the first nor will it be the last mission which makes use of this type of technology. The possibilities to use balloon technology range from the study of our galaxy, the cosmic background radiation and even gravitational waves.
Balloons can not only be used to study the earth atmosphere – they can also be deployed to study the atmosphere on Mars, Titan, Venus… They could also be used to search for ideal landing places for manned missions or take high resolution photographs of the landing area.

Passepartout is of course not quite so technologically advanced. However, the ability of the Austrian Space Forum to build it shows the know how available. In the past, Passepartout carried payloads consisting of cameras, triops eggs, geiger counters (to study the cosmic radiation) and even amateur radio equipment like APRS Transmitter or a Digipeater.
In the past, it has been more of a technical than scientific project, but this will change in the near future, thanks to Passepartouts new transport system “Sherpa”. For example, with an added “Air sampler” it will be possible to catch live forms from the upper layers of the atmosphere and enable the team to study them on the ground. The Forum’s expertise with contamination experiments will come in very handy.

This article is available in: German