running since 2023

Number of students:

Benjamin Åkerlund


FENRIR (Free fall Experiment uNit for Reduced-gravity Investigations and Research) is a student experiment based at LTU, which will fly on board one of the cycle 15 REXUS rockets in March 2025. It offers an easy-to-use platform for future free-falling experiments that need to be ejected from sounding rockets.

A free-falling unit (FFU) will be ejected from the rocket just before its apogee (∼ 70 km), ensuring about 70 seconds of reduced gravity. To increase the quality of the reduced gravity conditions, an attitude stabilisation system (ATSS) consisting of three reaction wheels will also be included in the FFU. 

Students aiming to conduct micro-gravity research are seen as potential end-users: thanks to FENRIR’s apparatus, they will have the opportunity to focus only on the mission’s experiment and accompanied electronics, without having to design the entire structure from scratch.


FENRIR is a part of the REXUS/BEXUS programme and is set to fly on the RX34 sounding rocket in March 2025. REXUS/BEXUS is a student experiment programme financed by the Swedish National Space Agency and the German Aerospace Centre with support from the European Space Agency – ESA, the Swedish Space Corporation – SSC, ZARM and more.


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