The REXUS / BEXUS program is the result of a collaboration between the Swedish National Space Agency (SNSA) and the German Space Agency (DLR) in collaboration with the European Space Agency (ESA).

In 2019 we decided to apply for the program, respectively, in the BEXUS modality. After participating in the Selection process in November, our project was one of those selected with the scheduled flight date in October 2020.

Stay tuned to our blog for more news!

The Experience

The STRATOSPOLCA project has the scientific objective of measuring the background radiation of gamma rays.

Let us imagine an old radio that, if it is not at the right frequency, produces that well-known background noise. But in order to know which music channel is, we need to know what the noise is. In our experience, we do just that: we measure background radiation in gamma rays, noise, so that we can “hear the music” that comes from distant celestial bodies.

Our detector is made up of a set of 25 “pixels”. They are made of Cadmium Telluride, a semiconductor very sensitive to photon energy levels. When a photon encounters the semiconductor an event occurs and it generates an electrical signal. These signals, and their properties, are the target of our study; they allow us to extract information, such as the energy amount of the photon.

Another very interesting phenomenon, which is part of our study and is essential to fulfil the goals of our mission, is that when a photon interacts with a pixel, it can “jump” to another pixel. That’s why it’s so important that the pixels are next to each other. If we receive two signals, from two interactions within a short time frame, a “double event” has occurred. Ever so often, it may happen that the photon interacts with a pixel more than twice within a short time frame, we call this a “multiple event”.


Experiment Objectives

Measure the level of single, double and multiple events, drawing a profile of such events as a function of the altitude.
Reach a wide non-technical audience. 

Improve future polarimetric experiments Signal-To-Noise Ratio
Compare data acquired to pre-flight simulations.
Measure the energy of the interactions.