This paper gives a general overview of the development of new miniaturized gas sensors for in situ measurements of molecular and atomic oxygen, carbon dioxide, carbon monoxide and hydrogen applicable for space experiments and instruments. Due to space driven miniaturization and a reference-free measurement principle, these screen printed ceramic gas sensors enable in situ measurements of partial pressures and flow rates in physicochemical processes and environmental control systems (air renewal/control, fuel cells, control of medical/biological processes, human respiratory investigations, etc.). Also, first experiences have been gained in low pressure, under high vacuum and other extreme/unconventional environments, i.e. in pure hydrogen or pure oxygen conditions. The first space application is the space qualified sensor system FIPEX (Flux-φ(Phi)-Probe- Experiments) that has been in operation on ESA's external platform EuTEF on the International Space Station for about 18 months. Based on some selected results, this paper is intended to illustrate the performed development steps and the broad applicability of these systems. Hence, measurement principles of the sensors, typical calibration characteristics and measurement ranges are presented for the different terrestrial and space related applications