Energy security plays a major role for satellites and space stations due to their isolated places of operation. Since solar energy is often used to operate these spacecraft, reliable energy storage systems are crucial to compensate for fluctuations in direct solar radiation. These storage systems need to have a very long service life as well as a high operational safety in order to sustainably reduce resource-intensive replacement missions as well as hazards for humans and equipment. However, the battery systems currently used in spacecraft have significant deficits in these areas. That’s why, with »SpaceFlow«, a new energy storage concept for space applications is being presented, which completely fulfils the requirements. »SpaceFlow« is an incomparably long-lasting, charge-cycle-stable, safe and reliable redox flow battery system based on porous metal foam electrodes and zinc-polyiodide electrolytes. The innovative design allows the pressure-stable yet flexible battery cells to be integrated directly into the spacecraft support structures, so that, in addition to energy storage, other functions such as module stiffening or thermal management can be realised with an efficient use of space.