Space-based radar sensors have transformed Earth observation since their first use by Seasat in 1978. Radar instruments are less affected by daylight or weather conditions than optical counterparts, suitable for continually monitoring the global biosphere. The current trends in synthetic aperture radar (SAR) platform design are distinct from traditional approaches in that miniaturized satellites carrying SAR are launched in multiples to form a SAR constellation. A systems engineering perspective is presented in this paper to track the transitioning of space-based SAR platforms from large satellites to small satellites. Technological advances therein are analyzed in terms of subsystem components, standalone satellites, and satellite constellations. The availability of commercial satellite constellations, ground stations, and launch services together enable real-time SAR observations with unprecedented details, which will help reveal the global biomass and their changes owing to anthropogenic drivers. The possible roles of small satellites in global biospheric monitoring and the subsequent research areas are also discussed.

Accelerated Stress Tests (ASTs) to characterize carbon corrosion were performed on MEAs based on 3 different carbon supports. High surface area carbon exhibited the best initial performance but the fastest degradation rate. On the other hand, highly graphitized carbon exhibiting the slowest degradation rate but had the lowest initial performance. TEM analysis of the MEAs after corrosion indicated Pt particle size growth in all the catalyst layers in addition to significant thinning of the high surface area carbon-based catalyst layers. Voltage loss breakdown identified mass transport losses resulting from a compaction of the catalyst layer porosity as the greatest contributor to performance loss. Three different membrane ASTs were performed on 2 distinct MEAs (designated P5 and HD6) from Ballard Power Systems and the degradation compared to that observed in the field. The membrane chemical degradation AST resulted in significant membrane thinning not observed in the field. The membrane mechanical degradation AST was able to reproduce the degradation phenomenon observed in the field but had little ability to distinguish between various membranes. A combined mechanical/chemical AST was examined to better simulate the degradation rates observed in the field.

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The assembly of 3D printed composites has a wide range of applications for ground preparation of space systems, in-orbit manufacturing, or even in-situ resource utilisation on planetary surfaces. The recent developments in composites additive manufacturing (AM) technologies include indoor experimentation on the International Space Station, and technological demonstrations will follow using satellite platforms on the Low Earth Orbits (LEOs) in the next few years. This review paper surveys AM technologies for varied off-Earth purposes where components or tools made of composite materials become necessary: mechanical, electrical, electrochemical and medical applications. Recommendations are also made on how to utilize AM technologies developed for ground applications, both commercial-off-the-shelf (COTS) and laboratory-based, to reduce development costs and promote sustainability.