A bistable composite tape-spring is a thin-walled, laminated open slit tube, which is stable in both the extended and coiled configurations. For its lightweight and multifunctional nature, there is a growing interest in its application to shape-adaptive and energy harvesting systems for aerospace. The governing factors of the bistability have been well-understood; while there is rare research on the fundamental of its microstructural failure modes under extreme conditions. Thus, we bring together materials scientists, structural engineers and mathematician to tackle this challenge. The aim of this research is to investigate in-situ, the temperature- and strain-dependent phase evolutions and failure mechanisms of the bistable tapes, using the dedicated Engin-X facility at ISIS. These will profoundly benefit industrial applications of the composite tape-springs in aerospace engineering.