Ut ProSat-1: A Platform for Testing Lightweight Deployable Composite Structures

This paper details the mission, challenges during the design process, and lessons learned from the development of an upcoming 3U cubesat from Virginia Tech dubbed Ut ProSat-1, scheduled to launch in 2023 on NG-19. This student-designed, -built, and -operated flight is a follow-on from the VT ThickSat launch in February 2021, incorporating lessons learned and upgrading specific experiments. The mission science goal is to demonstrate the reusability of lightweight deployable space structures for solar sails, antennas, and other extended components as well as characterizing the dynamic properties of the deployed structure while in space. In addition, the team has set a goal for this mission to serve as a starting point towards developing a reliable satellite bus to host payloads for Virginia Tech researchers as a continuous learning and improvement program. The inclusion of multiple payloads necessitated a modular approach to spacecraft design that included the development of a standalone payload control module apart from the satellite flight computer. This allows future spacecraft using this design to host multiple payloads operated independently, helping to reduce the cost of a flight for any single payload. Several challenges made the design, test, and build process difficult for the team, including only a year of development time from first design to final delivery, a short operational window in space before de-orbiting, and uncertain launch and power parameters. This put the 20-person team comprised of graduate and undergraduate students to the test with fast-paced parallel development of both the satellite core unit and payloads. This study on the development and design process presents a retrospective of the project and highlights the upcoming mission goals from the perspective of the project manager and development team leads, with the aim to discuss how students can lead the development of small satellites and generate excitement around the mission

A Prototype Virginia Ground Station Network

This paper provides a detailed technical description of a prototype ground station network, the Virginia Ground Station Network (VGSN), developed for the Virginia Cubesat Constellation (VCC) mission. Virginia Tech (VT), University of Virginia (UVA), and Old Dominion University (ODU) have each constructed ground stations to communicate with their respective VCC spacecraft. Initially, each university was responsible for commanding its own spacecraft via its own ground station. As the mission progressed, it was decided to network the ground stations and operations centers together to provide backup communications capability for the overall mission. The NASA Wallops Flight Facility (WFF) UHF smallsat ground station was also included in this network. Implementing the VGSN led to the establishment of successful communications with UVA’s Libertas spacecraft via the VT Ground Station (VTGS), demonstrating the utility of collaboration and of the VGSN. This paper provides a technical overview of the VGSN, details concerning signal processing requirements for the mission, a discussion concerning the radio regulatory process as applied to the VCC mission, and plans for future upgrades of the network to continue to support Virginia (and partner institution) small satellite missions

Hypertonic Saline Enhances Host Response to Bacterial Challenge by Augmenting Receptor-Independent Neutrophil Intracellular Superoxide Formation

OBJECTIVE: This study sought to determine whether hypertonic saline (HTS) infusion modulates the host response to bacterial challenge. METHODS: Sepsis was induced in 30 Balb-C mice by intraperitoneal injection of Escherichia coli (5 × 10(7) organisms per animal). In 10 mice, resuscitation was performed at 0 and 24 hours with a 4 mL/kg bolus of HTS (7.5% NaCl), 10 animals received 4 mL/kg of normal saline (0.9% NaCl), and the remaining animals received 30 mL/kg of normal saline. Samples of blood, spleen, and lung were cultured at 8 and 36 hours. Polymorphonucleocytes were incubated in isotonic or hypertonic medium before culture with E. coli. Phagocytosis was assessed by flow cytometry, whereas intracellular bacterial killing was measured after inhibition of phagocytosis with cytochalasin B. Intracellular formation of free radicals was assessed by the molecular probe CM-H(2)DCFDA. Mitogen-activated protein (MAP) kinase p38 and ERK-1 phosphorylation, and nuclear factor κ B (NFκB) activation were determined. Data are represented as means (SEM), and an analysis of variance test was performed to gauge statistical significance. RESULTS: Significantly reduced bacterial culture was observed in the animals resuscitated with HTS when compared with their NS counterparts, in blood (51.8 ± 4.3 vs. 82.0 ± 3.3 and 78.4 ± 4.8, P = 0.005), lung (40.0 ± 4.1 vs. 93.2 ± 2.1 and 80.9 ± 4.7, P = 0.002), and spleen (56.4 ± 3.8 vs. 85.4 ± 4.2 and 90.1 ± 5.9, P = 0.05). Intracellular killing of bacteria increased markedly (P = 0.026) and superoxide generation was enhanced upon exposure to HTS (775.78 ± 23.6 vs. 696.57 ± 42.2, P = 0.017) despite inhibition of MAP kinase and NFκB activation. CONCLUSIONS: HTS significantly enhances intracellular killing of bacteria while attenuating receptor-mediated activation of proinflammatory cascades