ON ORBIT DEPLOYMENT OF THE EU:CROPIS SOLAR PANEL BY GFRP TAPE SPRING HINGES

Eu:CROPIS is a compact satellite featuring a biological payload. The Satellite was launched on December 3rd 2018. The cylindrical Satellite of 1m diameter has four deployable panels for power generation. Those panels are connected to the main structure by glass fibre reinforced polymer (GFRP) tape spring hinges. The hinges, comparable to curved metallic measuring tapes, have elastic energy stored when flattened and folded and thus deploy the panels by simply unfolding. When unfolded the hinges snap into their original shape and support the panels with considerable stiffness. No friction or mechanical locking is involved in the deploying process. The presented paper focuses on the practical handling of the hinges and the mechanisms during the final integration and the deployment process. The integration of the panels requires some special consideration. The hinges are not able to support the panels under gravity. The release mechanisms only work at a correct positioning of the panels. The measures taken to ensure the integrity and functionality of the hinges and mechanisms are described and examples are given for a correct and a false outcome. The separation is done by breaking a bolt with a heated bushing from shape memory alloy. Though reliable the separation cannot be timed down to the second and there is no direct feedback of the separation. To prevent an uneven opening of the panels several on orbit pre-tests are performed to ensure the functionality of the mechanisms for the actual deployment. At the actual separation the heating is monitored to ensure that all mechanisms are activated and the separation is working as proposed. Furthermore, a method was developed to detect the successful breaking of the bolts by use of the heating temperature data. The paper describes these checks and surveillance methods. As not all things go as planned some decisions were to be made before and at panel deployment. Also, the unfolding of the hinges was slower than during the on ground. Tests were made to simulate and understand the on-orbit behaviour. Lessons learned for further use of the mechanisms are presented

Deciphering the intracellular metabolism of Listeria monocytogenes by mutant screening and modelling

Background: The human pathogen Listeria monocytogenes resides and proliferates within the cytoplasm of epithelial cells. While the virulence factors essentially contributing to this step of the infection cycle are well characterized, the set of listerial genes contributing to intracellular replication remains to be defined on a genome-wide level. Results: A comprehensive library of L. monocytogenes strain EGD knockout mutants was constructed upon insertion-duplication mutagenesis, and 1491 mutants were tested for their phenotypes in rich medium and in a Caco-2 cell culture assay. Following sequencing of the plasmid insertion site, 141 different genes required for invasion of and replication in Caco-2 cells were identified. Ten in-frame deletion mutants were constructed that confirmed the data. The genes with known functions are mainly involved in cellular processes including transport, in the intermediary metabolism of sugars, nucleotides and lipids, and in information pathways such as regulatory functions. No function could be ascribed to 18 genes, and a counterpart of eight genes is missing in the apathogenic species L. innocua. Mice infection studies revealed the in vivo requirement of IspE (Lmo0190) involved in mevalonate synthesis, and of the novel ABC transporter Lmo0135-0137 associated with cysteine transport. Based on the data of this genome-scale screening, an extreme pathway and elementary mode analysis was applied that demonstrates the critical role of glycerol and purine metabolism, of fucose utilization, and of the synthesis of glutathione, aspartate semialdehyde, serine and branched chain amino acids during intracellular replication of L. monocytogenes. Conclusion: The combination of a genetic screening and a modelling approach revealed that a series of transporters help L. monocytogenes to overcome a putative lack of nutrients within cells, and that a high metabolic flexibility contributes to the intracellular replication of this pathogen

Towards a Reusable First Stage Demonstrator: CALLISTO - Technical Progresses & Challenges

In order to investigate the capabilities of a reusable launch system, JAXA, CNES and DLR have jointly initiated the project CALLISTO ("Cooperative Action Leading to Launcher Innovation for Stage Toss-back Operations"). The goal of this cooperation is to launch, recover and reuse a first stage demonstrator to increase the maturity of technologies necessary for future operational reusable launch vehicles (RLV) and to build up know-how on such vehicles under operational and developmental aspects. As the project has now turned into the detailed design phase, significant technical progresses have been made in definition, analysis and testing of systems and subsystems. The CALLISTO vehicle itself constitutes a subscale vertical take-off vertical landing (VTVL) stage with an overall length of 13.5 m and a take-off mass of less than 4 tons, which is propelled by a throttleable LOX/LH2 engine. It is capable to perform up to 10 consecutive flights during the planned flight campaign in French Guiana. Globally, the development effort on this system is equally shared between the three project partners. This paper presents the recent achievements in development of the key technologies for the reusable launch vehicle. While the design of critical subsystems has reached PDR level, detailed analyses and first breadboard tests have been performed successfully. These results are presented and discussed within the perimeter of the CALLISTO development roadmap. Possible technical challenges are indicated and their resolution methods are examined. Finally, the upcoming development steps are described which are foreseen to move forward to the qualification and maiden flight campaign

<scp>ReSurveyEurope</scp>: A database of resurveyed vegetation plots in Europe

AbstractAimsWe introduce ReSurveyEurope — a new data source of resurveyed vegetation plots in Europe, compiled by a collaborative network of vegetation scientists. We describe the scope of this initiative, provide an overview of currently available data, governance, data contribution rules, and accessibility. In addition, we outline further steps, including potential research questions.ResultsReSurveyEurope includes resurveyed vegetation plots from all habitats. Version 1.0 of ReSurveyEurope contains 283,135 observations (i.e., individual surveys of each plot) from 79,190 plots sampled in 449 independent resurvey projects. Of these, 62,139 (78%) are permanent plots, that is, marked in situ, or located with GPS, which allow for high spatial accuracy in resurvey. The remaining 17,051 (22%) plots are from studies in which plots from the initial survey could not be exactly relocated. Four data sets, which together account for 28,470 (36%) plots, provide only presence/absence information on plant species, while the remaining 50,720 (64%) plots contain abundance information (e.g., percentage cover or cover–abundance classes such as variants of the Braun‐Blanquet scale). The oldest plots were sampled in 1911 in the Swiss Alps, while most plots were sampled between 1950 and 2020.ConclusionsReSurveyEurope is a new resource to address a wide range of research questions on fine‐scale changes in European vegetation. The initiative is devoted to an inclusive and transparent governance and data usage approach, based on slightly adapted rules of the well‐established European Vegetation Archive (EVA). ReSurveyEurope data are ready for use, and proposals for analyses of the data set can be submitted at any time to the coordinators. Still, further data contributions are highly welcome.</jats:sec

DESIGN AND ANALYSIS OF A COMPOSITE SANDWICH SOLAR ARRAY STRUCTURE FOR THE EU:CROPIS COMPACT SATELLITE WITH AS FEW RELEASE MECHANISMS AS POSSIBLE

This paper presents the design and analysis of a composite sandwich solar array panel with internal local stiffeners. The purpose of this investigation is the connection between the panel and the satellite structure. The application for this purpose is the Eu:CROPIS (Euglena and Combined Regenerative Organic-Food Production in Space) compact satellite. The release mechanisms to be used are Frangibolts. A main design driver is the use of as few hold down and release mechanisms as possible. This approach is well founded due to the resulting reduction in complexity of the on board computer, the harness and its connections. Furthermore, the reduction in release mechanisms reduces the power consumption during the detumbling phase after launch. A finite element model is used to calculate the deformations, stresses and strains of the solar panel in different configurations. The numbers of hold down and release mechanisms (HDRM) as well as the layout of the internal panel stiffeners are investigated. The hold down and the bearing forces are evaluated under launch loads to examine the different array configurations

DESIGN OF A GYROSCOPE SUPPORT STRUCTURE MANUFACTURED BY SELEVTIVE LASER MELTING

The presented paper gives a look inside the design and manufacturing of a support structure that carries the four gyroscopes of the attitude and orbit control system (AOCS) of the compact satellite Eu:CROPIS. The special characteristic of the selective laser melting (SLM) process and its impact onto the structural design is described in comparison to a composite design and a classical machined structure. Therefore, advantages and disadvantages of the SLM process are discussed. To evaluate the material properties, in compare to the given datasheet [3], a batch of specimens is tested under tensile loading. Specifically, vertical and horizontal fabricated specimens are tested to investigate the isotopically material behaviour. Furthermore, the porosity of the tensile specimens is estimated by using a colour penetration method. Finally, optical measurements are performed to determine the geometry of the produced structure, to then compare it to the CAD-template. Geometric deviations are thus assessed to prove the AOCS requirements