Assessing Thickness Accommodation Techniques for Deployable Hexagonal Origami Space Arrays

Origami-based and origami-inspired designs provide paths to achieve highly compact, stowable designs, that can be deployed to large surface areas. This potential is highly beneficial to the area of space antennas and LIDAR as these require compact stowing in a launch payload, but large apertures when deployed in space. Because the engineering materials used to build these antennas are thick, thickness accommodation techniques must be applied to realize the same folding motions as the zero-thickness models. This paper presents a hexagonal twist origami pattern in thick materials using three different thickness accommodation techniques. These techniques are compared. The metrics used for comparison are packing efficiency, usable area, benefit to stability, and deployment methods. These metrics have also help to determine trends that can benefit the designer when selecting thickness accommodation techniques

The KiHM-9: A Novel Self-Deploying PicoSat Antenna Design for Reflectarray Antennas

Reflectarray antennas are popular on satellites for their ability to achieve similar performance to parabolic antennas in a more compact volume. This project shows how integrating novel technologies achieves the benefits of larger antennas while maintaining the advantages of small satellites. The objective of this research is to create a reflectarray antenna for a holographic metasurface that utilizes the volume surrounding a CubeSat when stowed, incorporates a novel pin-less hinge, includes a self-deploying and stabilizing joint, and is manufactured out of space-grade materials. By using hinges embedded with membranes and magnets, issues with lubrication and outgassing may be avoided, and the same motion and stability of pin-joints may be maintained with no external structure required. These technologies also result in a self-deploying and self-stabilizing design. The Radii Controlled Embedded Lamina (RadiCEL) hinge design was incorporated into the final model and allows the geometry of the hinge joint to be specifically tuned to control the stress in the hinge membrane while minimizing required hinge volume. Metal meshes were used as membrane joints, increasing the durability and robustness of the hinge. Feasibility of the RadiCEL joint is shown through fatigue testing of various materials at a range of hinge radii. The testing shows the viability of metal meshes, as well as other common membranes. Magnets were used in a MaLO configuration, which allowed for a smaller footprint in the antenna and required no external actuation or power source to deploy and stabilize the antenna. Various prototypes of the system were manufactured and are presented. Modeling and testing efforts presented create various opportunities to build on current research to improve mission capability by increasing antenna gain while eliminating peripherals required for antenna deployment

Morfología y germinación de semillas de Euphorbia heterophylla L.

El conocimiento de las características morfo-fisiológicas de frutos y semillas es importante para estudiar la forma reproductiva y la posibilidad de domesticar una especie nativa de interés agropecuario o farmacéutico. El propósito de este estudio fue determinar las características morfológicas y la capacidad de germinación de las semillas de Euphorbia heterophylla L., debido a su importancia agropecuaria y económica. Se realizaron análisis morfológicos con 20 frutos y 50 semillas recién cosechadas y seleccionadas al azar. Se determinaron las características morfológicas del embrión, así como su desarrollo. Adicionalmente, se estudiaron las características fisiológicas de las semillas a través del contenido de humedad, la viabilidad y la germinación a diferentes fotoperiodos. El fruto maduro de E. heterophylla es una cápsula de tres lóbulos con un promedio de 3 semillas por fruto. Las semillas son cónicas con base ancha, carunculadas y de color marrón oscuro. El embrión es espatulado, con un eje hipocótilo-radícula bien definido y cotiledones en forma de espátula. El contenido de humedad al momento de la cosecha fue de 9,846 %, la viabilidad fue de 75,83 % y el porcentaje de germinación del 55 % en presencia de luz. Los frutos, semillas y embriones de E. heterophylla tienen características representativas del género Euphorbia. Nuestros resultados sugieren que las semillas germinan en un mayor porcentaje en precencia de luz, sin que se observe dormancia. Este estudio es un punto de partida para trazar futuras estrategias en relación con la domesticación de esta especie, dada la importancia agropecuaria y farmacéutica de la planta

Salle de l'Expansion Basque. Musée Basque de Bayonne

Manuel de Ynchausti, "mecenas inspirado" que fue consejero del Museo Vasco de Bayona y amigo de su conservador, el comandante Willian Boissel, hace presentación de la Sala de la Diáspora Vasca, concebida, realizada y financiada por él mismo.Manuel de Ynchausti, "mezenas inspiratu", Baionako Euskal Museoko kontseilari eta haren kontserbadore Willian Boissel komandantearen laguna izan zenak, berak asmatu, eratu eta finantzaturiko Euskal Diasporaren Aretoa aurkezten digu.Manuel de Ynchausti, ce "mécène inspiré" fut conseiller du Musée Basque de Bayonne et ami de son conservateur, le commandant Willian Boissel. Il présente ici la Salle de l'Expansion Basque dans le monde, une salle qui'il a entièrement conçue, réalisée et financée lui-même.Manuel of Ynchausti, "inspirational patron", who was counsellor at the Basque Museum of Bayonne andfriend of its curator, commander Willian Boissel, presents the Hall on Basque Emigration, conceived, accomplished and financed by himself

Exploring Depth Adjustable Embedded Membrane Joints

This work presents methods for using membrane joints in origami-inspired mechanisms. Our method takes the previously presented hinge ideas of the Regionally Compliant Sheets (ReCS) method and the Compliant Rolling Contact Element (CORE) joint, and builds upon them to provide a hinge that has the benefits of being adhered between sheets using clamping with no adhesive needed, preserving panel volume that can be used as hard stops, and keeping the stress in the bending membrane below the yield stress, while reducing the parasitic motion of previous membrane joints. Two different configurations are presented: The Contacting Circles Embedded Membrane and the Enhanced ReCS. These two configurations are described for a planar, single-folding mechanism. A comparison between methods is presented, focusing on the axial parasitic motion of each configuration. Each configuration was also applied to a degree-4 origami vertex with a discussion of the benefits of each

Preliminary Exploration of Approaches to Increase the Stability of Flat-Foldable Origami-Adapted Designs in the Open, Flat State

Deployable spacecraft-based systems are benefitted from origami-adapted systems because they can be folded compactly and then deployed to larger areas. This unfolding motion must be stopped and held in specific configurations. In the case of reflectarrays, the panels need to deployed to flat and be kept there. Strain energy can be utilized to stabilize these systems. This works shows three ways, based on three different thickness accommodation techniques, that strain energy may be used to stabilize the systems in their deployed, flat positions. Additionally, each technique shown creates co-planar top surfaces to benefit reflectarray antenna design cases

Principles for Designing Origami-Inspired Composite Space Structures with High-Strain Compliant Laminate Joints

In space missions, many methods and techniques are used to enable large deployable structures—such as solar arrays, antennas, and radiators—for power, communication, and heat regulation. With origami as inspiration, a new class of self-deployable, self-stiffening, and retractable (SDSR) array has been developed and is reviewed. SDSR arrays are a scalable deployable architecture based on origami flasher patterns. They do not require the aid of external support and actuation structures common in space applications, instead replacing them with strained compliant joints and reeling cables. Aluminum construction has previously been successfully modeled and demonstrated, however, SDSR technology can be greatly improved with more advanced, lighter weight materials. This work presents the redesign of the SDSR array for construction from CFRP composite laminates, including principles developed for the design of high-strain composite flexural joints and their integration into composite panels that can be applied broadly in other sheetlike folding composite structures. The flexural joint used is an array of lamina emergent torsional (LET) joints, and is an innovative solution to attain large deflections needed for hinge-like motion in large foldable arrays. The research that has been done in LET joints assumes an isotropic material, whereas LET joints in anisotropic materials such as CFRPs have yet to be addressed in the literature. Panel flatness is an area of interest so deflections are analysed assuming a rectangular panel and basic panel deflection techniques. The culmination of the design and modeling is the demonstration of two prototype composite arrays, the second array overcoming weaknesses in the initial design