Small and Large Satellites: Joint Operations in Earth Observation

While projects for the exploration of space remain ambitious and financially as well as technologically demanding projects, their benefit in understanding our planet is unrivaled [1]. On top of enabling technologies that keep drastically altering the way we communicate, navigate, or build our cities, they currently present the only means of assessing key environmental variables on a global scale [2]–[5]. Today, we witness the New Space era with promises of ever easier, faster, and cheaper space access as a major driving force for the future development to four space capabilities, specifically in Earth Observation (EO), but also in communication (COM) and navigation (NAV) applications. Since from an economic point of view, only now it became possible to achieve resolution and coverage matching the needs of many applications outside the scientific community by means of small satellite constellations[6]–[9]

Additive Manufactured Structures for the 12U Nanosatellite ERNST

One of the emerging technologies in recent years is additive manufacturing. It promises unprecedented design freedom in both modeling and rapid manufacturing. We are reaping the benefits of additive manufacturing for our 12U nanosatellite ERNST by printing the optical bench that supports the spacecraft payloads. We design the structures by using a finite-element numerical approach for optimizing the topology with respect to 1) available design space, 2) payload interfaces, 3) mechanical launch loads, and 4) thermal loads generated by the cryocooler of the MWIR main payload. We cope with the latter by integrating a pyramidal structured radiator surface in the optical bench as a functional element. Making use of the selective laser melting technique, we manufactured the first version of the optical bench for the engineering model of the ERNST spacecraft from AlSi10Mg alloy. Vibrational testing proved the suitability of our multidisciplinary design approach and the production quality. We are currently implementing the next version of the ERNST optical bench including spacecraft design changes and using Scalmalloy®, a material developed for additive manufacturing that provides high tensile strength and low thermal expansion. This marks a next step on the way to the application of additive manufactured components in space

Towards flight qualification of an additively manufactured nanosatellite component: Paper presented at 69th International Astronautical Congress, Bremen, Germany, October 1-5, 2018

Fraunhofer EMI is currently designing a 12U nanosatellite. The mission is called ERNST (Experimental Spacecraft based on Nanosatellite Technology) and its main goal is to evaluate the utility of a nanosatellite mission for scientific and military purposes. As spacecraft developments demand the adaption of different subsystems for every mission, Fraunhofer EMI decided to use Additive Manufacturing (AM) in the construction of secondary satellite structures in order to achieve a highly adjusted structure which serves the exact required purpose of each individual mission. The significant advantage of using AM lies in the design freedom as it has almost no design restrictions as compared to conventional manufacturing methods. Given this, the design freedom can be used to implement a numerical optimization process, using topology optimization algorithms. During the optimization process, material is only placed at necessary areas. A Multidisciplinary Design Optimization for the optical mounting structure (optical bench) of the satellite was established, considering vibrational boundary conditions during the launch period and thermal boundary conditions during the operational phase. This paper presents the latest updates towards flight qualification of the optical bench in terms of design, optimization model and post-process concepts

Micro- and macrostructural investigations of AlSiMg produced by laser beam melting

In Laser Beam Melting (LBM), alloys like AlSi10Mg are locally melted by an intense laser beam. Specifically Designed Materials can be realized by locally varying the exposure parameters and applying diverse exposure strategies. By this approach, different micro- and macrostructures can be obtained that lead to individual mechanical properties within one part. A well-established understanding of the correlation between manufacturing parameters, generated micro- and macrostructure and resulting material properties enables the creation of complex microstructural material compositions meaning specifically Designed Materials. The interdependency of manufacturing parameters on the micro- and macrostructure was studied for different exposure strategies in LBM processing of AlSi10Mg using a 1 kW laser source and building layers of 90 μm. The investigations focus on the analysis of data obtained by imaging techniques like light and scanning electron microscopy. In particular, melt pool boundaries and crystal grains are examined

Data, Calibration and Processing of Thermal Infrared Data from the LisR ISS Mission

Longwave Infrared Sensing demonstratoR (LisR) mission is a longwave infrared camera which is flying on board the International Space Station (ISS), launched in February 2022 with first light in early March 2022. This demonstrator, developed by the founders of ConstellR at Fraunhofer Institute of High Speed Dynamics in Freiburg/ Germany, is a platform to demonstrate the capabilities of cryo-cooled long wave infrared detectors from space. The goal of this mission is to derive high-accuracy Land Surface Temperature (LST) information used for better planning and efficiency in the agricultural sector. This information is critical in order to ensure the sustainability of global food supplies. LisR is the precursor of a full satellite constellation called HiVE which is planned to deliver high temporal, spatial and spectral resolution thermal and VisNir information from space from the end of 2023 onwards. The demonstrator mainly consists of a cryo-cooled thermal infrared frame camera, a free form optical assembly and an on board data processing unit. It images the earth’s surface in two longwave infrared bands which allows the derivation of highly accurate Land Surface Temperature information with high spatial resolution. The main industries benefitting of such data are, but not only, the global agricultural sector, food supply chains, sustainable finance and insurance industries which can monitor and optimize the water cycle of global food production with this information. Besides a brief description of the instrument itself the envisaged presentation will detail: • the pre-launch laboratory characterization of the instrument for spectral resolution, spatial resolution and the MTF characterization, • the laboratory absolute radiometric measurements, • the available data products, • the operational radiometric and geometric correction and processing algorithms and pipeline, • the algorithm used to derive Land Surface temperature from absolute calibrated and orthorectified radiance data, • the initial image quality and accuracy assessments, • the initial in-flight absolute radiometric characterization and calibration and finally, • an insight into the planned constellation of multispectral vis/nir/tir satellites

Nachhaltigkeit der Additiven Fertigung: Vergleichende ökonomische und ökologische Bewertung von additiven und konventionellen Fertigungstechnologien

Additive Fertigungsverfahren (Additive Manufacturing, AM) bieten aufgrund der schichtweisen Generierung von Strukturen eine einzigartige Designfreiheit. Auch die Flexibilität, die Möglichkeit der Funktionsintegration, die Individualisierungsmöglichkeit sowie beschleunigte Innovationszeiten machen die AM zu einer Schlüsseltechnologie der Industrie 4.0. In der vorgestellten Studie geht es um die künftige Anwendung von AM, insbesondere hinsichtlich der Energie- und Ressourceneffizienz sowie der Wirtschaftlichkeit dieser Technologie

Resource analysis model and validation for selective laser melting, constituting the potential of lightweight design for material efficiency

Selective Laser Melting (SLM) offers significant potential for a sustainable way of production. Raw material in form of metallic powder can directly be reused and the selective nature of the process offers new potential for resource economization. We introduce a mathematical model, which allows conclusions about the influence of parameters like part volume (influenced by lightweight design) and exposure parameters onto the resource consumption in an SLM process. For this purpose, time and energy consumption are classified in process shares as a function of volume and process parameters. The introduced approach is validated by experimental methods under the consideration of part volume, exposure parameters and batch size. While the approach shall be independent of the manufactured material, the experiments are executed for the aluminum alloy AlSi10Mg. The measurements quantify the impact of the part volume and process parameters on the resource consumption and provide recommendations for improvements regarding an increased material efficiency. Additionally, the established model can be used to analyze manufacturing costs for single parts or series productions. The results illustrate the importance of lightweight design methods for an efficient and sustainable production by powder bed fusion methods like SLM

A Series of Workshops and presentations provided by the Fraunhofer Additive Manufacturing Alliance: Presentation held at Additive Manufacturing for Aerospace & Space, 21st - 22nd February 2018, München

Facilitated by the Fraunhofer Alliance for Additive Manufacturing, which is the largest consortium for applied research in the field of Additive Manufacturing in Europe – the workshop provides the opportunity to learn about the newest research in this field and the possible implementation of state of the art processes for your products. An overview will be given on how to design complex products for AM with a focus on metals and polymers and with respect to different applications related to Aerospace and Space. It will be discussed how AM can be integrated in the product development with other manufacturing technologies. A significant factor for the quality of AM products is the processing and quality of the raw material, which is metal or polymer powder for most AM processes. You will learn about influencing factors for powder quality and the implementation of an efficient powder process for AM. The information given will enable participants to evaluate potentials for their own AM processes and products and it is hoped to enable them to find approaches for the implementation of new or enhanced methods, tools and processes for their companies and organizations. What you will learn:• Overview of research state in design methods for AM and how to design complex geometries(e.g. bionic design, lattices) with already available design tools• How to implement design guidelines and additional functionality (e.g. electronics) in AM for metals and polymers in CAE product development and AM processes• Understanding of the importance of powder quality and processing and how to implement an efficient powder process for AM• New potentials in using surface-treated polymers for space applications About the Fraunhofer Additive Manufacturing Alliance:Fraunhofer is Europe’s largest application-oriented research organization. Its research activities are conducted by 69 institutes and research units at locations throughout Germany. The Fraunhofer Gesellschaft employs a staff of 24,500, who work with an annual research budget totaling 2.1 billion euros. Of this sum, 1.9 billion euros is generated through contract research. More than 70 percent of the Fraunhofer-Gesellschaft’s contract research revenue is derived from contracts with industry and from publicly financed research projects. International collaborations with excellent research partners and innovative companies around the world ensure direct access to regions of the greatest importance to present and future scientific progress and economic development. The Fraunhofer Additive Manufacturing Alliance integrates seventeen Fraunhofer institutes across Germany, which depending on their main focus, deal with subjects concerning additive manufacturing and represent the entire process chain. This includes the development, application and implementation of additive production processes as well as associated materials

A parametric mesostructural approach for robust design of additive manufacturing parts

Additive Manufacturing (AM) allows for production of potentially complex design solutions and motivates the use of Structural Optimization tools in product development to chase the structural limit of a design problem and its solution concept. Scratching on the limits of the material strength, design solutions can lack robustness concerning simplifications in model assumptions and uncertainties. However, the design freedom with AM can also actively be used to enhance robustness and reliability of solutions. To this end, an approach is presented that introduces Parametric Mesostructures into selective areas of the Additive Design. Structural members and coherent mechanical characteristics of these mesostructures can significantly reduce local stress peaks and can account for uncertainties, e.g. direction of load application. Their design is motivated by Structural Optimization and analysis results. Implementation of the approach is demonstrated and discussed on the example of a structural aircraft component