Operational concepts for selected Sortie missions: Executive summary

An executive summary is presented of a Spacelab concept study conducted from August 1973 to June 1974. Background information and a summary of study conclusions are given. Specific data are reported for the quick-reaction carrier concept, software and mission integration, configuration management, documentation, equipment pool, and integration alternatives. A forecast of the impact of a second launch site, mission feasibility, and space availability for the Spacelab are also discussed

Application Of A Large Computerized Ground System To Shuttle Payload Software Intergration

A concept for the integration of Shuttle experiment/ payload software is proposed. A key element in this software integration process is the Launch Processing System (LPS), being developed by NASA/ KSC. The concept uses the Sortie Lab as a representative experiment carrier. This concept permits the installation and checkout of experiment software prior to hardware installation onto experiment carriers. In addition it assures software compatibility, prior to payload installation, between the various elements, i.e., experiments, carriers, orbiter, and ground support system software

Alkali-independent Anion Redox in LiNaFeS2

Although Na-ion batteries present a promising and more sustainable solution compared to Li-ion batteries, Na-ion batteries have comparatively lower energy density and suffer from irreversible charge storage due to the size and mass of Na+. In recent years, the investigation of Li-rich materials has revealed employing multielectron redox that couples cation and anion redox is a method to improve capacity. Coupling anion and cation redox could be a way to improve the low energy density of Na-ion cathodes, but the influence of the large Na+ on these electrochemical processes is not well understood. Here, we leverage the mixed-alkali nature of LiNaFeS2 to compare its behavior in Li vs. Na half cells. LiNaFeS2 is known to support multielectron redox by virtue of cation and anion redox in Li half cells. We now demonstrate that LiNaFeS2 can also be used as a multielectron Na cathode. Elemental analysis of the cathodes at various states of charge verify Na as the dominant mobile ion after first charge, which correlates to different structural responses that cause deviations in the electrochemistry compared to the material cycled in a Li half cell. Notably, cycling with a Na electrolyte causes the particles to roughen and amorphize. Fe and S K-edge X-ray absorption spectroscopy show that the charge compensation mechanisms from an electronic structure point of view are fundamentally the same independent of cell configuration. The disparate electrochemical behavior is entirely due to structural rather than electronic effects, which is further probed with synchrotron X-ray diffraction studies, scanning electron microscopy, and cyclic voltammetry coupled with b-value analysis. Our work provides a fundamental study on the differences between Li- and Na-based anion redox in the same material