The microgravity environment offers the unique chance for creating large controllable interfaces, allowing a number of interesting situations to be considered and studied experimentally and theoretical and numerical models to be more efficiently investigated and validated through suitable microgravity experimentations. This article deals with the most recent advances and developments performed by the authors in three different research areas in the general field of microgravity fluid science: liquid bridges and floating zones; protein crystal growth in evaporating drops; liquid drops with Marangoni effect. The paper gives a critical overview of the experimental, theoretical and numerical works done by different authors on these subjects, pointing out at the different and sometimes contradictory results obtained with different approaches. The discrepancies between the present understanding of these phenomena and the predictions of previous theoretical studies have motivated the research activities of the group in Naples. The results of the present computations allow to interpret and explain a number of theoretical results obtained by different authors and are in agreement with the experimental findings, providing coherent physical explanations of the phenomena. Further investigations proposed for future space experiments will be dedicated to the experimental validation and check of these results.