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This paper describes the development of Orbit Fab’s Tanker-001 Tenzing mission, the world’s first orbital propellant tanker. The development of a robust orbital propellant supply chain is critical to accelerating the growth of government and commercial space activities. The widespread availability of spacecraft refueling has the potential to provide a number of revolutionary benefits. High-value space assets could have their operational lives extended, as they would no longer be constrained by the amount of propellant stored onboard for maneuvering. On-orbit servicing missions would become more efficient, as servicing vehicles could be refueled and repeatedly used. A large orbital propellant supply would also enable new mission and business models based on operational flexibility and frequent maneuvering. These benefits would be particularly impactful on small satellites, where the ability to refuel could overcome the operational constraints of having smaller propellant tanks. This will greatly expand the market for small spacecraft as it increases their range of missions and capabilities. Launching no earlier than June 24, 2021, Tenzing is a 35 kg small satellite with an Astro Digital bus carrying a supply of storable propellant, high test peroxide (HTP). Tenzing’s propellant supply is being offered to customers for refueling and used to gather data on propellant storage. In addition to being the first propellant tanker, Tenzing is also an orbital laboratory including a variety of payloads intended to test key technologies for refueling. This includes the first flight of Orbit Fab’s Rapidly Attachable Fluid Transfer Interface (RAFTI), a stereo camera system, and a Halcyon HTP propulsion system designed and built by Benchmark Space Systems for orbital maneuvers. The latter two elements can be used to test rendezvous and flyby maneuvers, providing data to support the development of full rendezvous, proximity operations, and docking (RPOD) systems for future Orbit Fab missions.

Additional file 4. Gene regulation by species, brain region, and cell population.

Additional file 2. Primers utilized in study.

Additional file 1. Human demographics for examined cocaine dependent and non-dependent tissue.

This thesis investigates the effects of aluminates, sulfates, and heterogeneous substrates on the nucleation and growth of synthetic calcium-silicate-hydrates (C-S-H) produced by dropwise precipitation. The use of synthetic C-S-H, separate from other cementitious phases, allows formation mechanisms and kinetics effects to be investigated in a simplified system. The addition of other ions and substrates then allows an approach to the more complicated, multi-phase system of cement and concrete. The first goal of this thesis was to reproducibly synthesize single-phase C-S-H with Ca:Si from 1 to 2. Guidelines were described for collection, drying, and handling of the precipitates to prevent the formation of Ca(OH)2 during synthesis and minimize carbonation. Interlayer spacing in precipitates was studied by transmission XRD to compare the effects of Ca:Si, relative humidity, and time, using the 14Å tobermorite structure as a baseline for synthetic C-S-H. The growth and nucleation kinetics of C-S-H were then investigated with the combined thermodynamic and population balance equation model (PBEM). The surface characteristics of C-S-H, C-A-S-H, and C-S-H + [dollar] were investigated by acoustophoresis to compare the effects of Ca:Si, washing, and dispersion media on zeta potential measurements. Results showed the necessity of full characterization of both solutions and precipitates in order to understand and compare acoustophoresis results. In the final section of the thesis C-S-H, C-A-S-H, and C-S-H + $ were grown on the surface of heterogeneous substrates, quartz and calcite, to approach C-S-H growth in real systems. Overall, the results from this thesis provided helpful information on synthetic C-S-H, C-A-S-H, and C-S-H + at the full range of Ca:Si molar ratios, particularly ratios above 1.5, as observed in Portland cement. As we get closer to understanding and controlling C-S-H in real systems, this work will help provide insight as to how heterogenous substrates and aluminates introduced by SCMs, in addition to sulfates, commonly added to cement via gypsum, affect the early age strength and kinetics of C-S-H formation