Reliable, Fast, and Flexible: A Thermal Modeling Approach for Small Satellites

The ongoing revolution of space access by means of cost-effective and highly performant small satellites, in particular CubeSats, drives the development of a vast host of new and increasingly complex applications. However, the use of small satellites for ambitious missions brings its own challenges with thermal breakdown as one of the key contributors to component failure. We have therefore developed a lightweight approach specifically tailored to the thermal modeling of small satellites to localize and mitigate the associated thermal risks while maintaining the flexibility and low resource footprint necessary to be applicable in the framework of small satellite mission design. At the core of the methodology, we implemented an experimental database of physical parameters as well as highly parallelized numerical analysis methods. In particular, we introduce an efficient way to determine view factors for insolation and internal radiative energy transport based on a hemicube radiosity algorithm. The results agree within 1 K with commercially available modeling software and allow us to perform highly reliable temperature predictions while conserving the flexible and cost-efficient spirit of small satellite missions

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

Demonstration of a Heterogeneous Satellite Architecture During RIMPAC 2018

The Micro-Satellite Military Utility (MSMU) Project Arrangement (PA) is an agreement under the Responsive Space Capabilities (RSC) Memorandum of Understanding (MOU) involving the Departments and Ministries of Defence of Australia, Canada, Germany, Italy, Netherlands, New Zealand, Norway, United Kingdom and United States. MSMU’s charter is to inform a space enterprise that provides military users with reliable access to a broad spectrum of information in an opportunistic environment. The MSMU community participated on a non-interference basis in the biennial Rim of the Pacific (RIMPAC) exercise from 26 June to 2 August 2018. This provided an opportunity to explore the military utility of a heterogeneous space architecture of satellites including traditional government and commercial satellites, as well as micro-satellites and nanosatellites associated with the “new space” paradigm. The objective was to test the hypothesis that a heterogeneous space architecture, mostly composed of small satellites, can bring significant value to the operational theatre. This paper describes the results from the MSMU experiment, outlines the lessons learned in terms of the infrastructure required to support such an experiment, and offers insights into the military utility of the heterogeneous space architecture. It concludes that a cooperative heterogeneous space architecture does have advantages and value, and that micro-satellites and nanosatellites contribute significant capability

In-Situ-Detektion von Partikeleinschlägen auf Satelliten mittels Antennen

Der Hypervelocity-Impakt von Partikeln der Orbitumgebung erzeugt eine transiente Plasmawolke auf Raumfahrtsystemen, die zur In-Situ-Detektion von Impaktereignissen genutzt werden kann. In numerischen Simulationen mit einem eigens entwickelten Modell wurde ein einfaches Detektionskonzept untersucht, das auf der Wechselwirkung des Impaktplasmas mit Antennen beruht. Es konnte gezeigt werden, dass ein Array von wenigen, zentimetergroßen Antennen auf der Außenseite eines Raumfahrzeugs ausreichend ist, um die Bedingungen des Impakts aus den induzierten Spannungssignalen abzuleiten

Fast and flexible space debris risk assessment for satellites

The rapid increase in uncontrolled high velocity objects orbiting earth poses a continuously growing failure potential for ongoing and future space missions. Despite increasing efforts to mitigate collisional risks, e.g. via active debris removal, potential solutions are currently only emerging at the horizon, emphasizing the importance of space debris related risk assessment. However, traditional impact shielding requirements for manned mission cannot directly be transferred to unmanned missions. Instead of restricting the analysis to the outer hull, it is necessary to directly assess the failure risk on the level of individual, internal components. Here, we outline a newly developed deterministic methodology to enable the evaluation of system level effects on the spacecraft. In particular, we employ a computational model based on available probabilistic debris models and component-specific ballistic limit equations. The methodology has been implemented into the easily accessible software tool PIRAT (Particle Impact Risk and Vulnerability Assessment Tool)

Stereoscopic imaging determines space debris impact crater distribution and morphology

A two-step methodology based on imaging a spacecraft target surface in orbit is analyzed, which is capable of counting impact craters and determining their morphology. The methodology can be used to measure impact flux data and subsequently improve near-Earth particle environment models like MASTER and ORDEM. Craters are detected by a surface scan in a first step, and the morphology of selected craters is determined using stereoscopic images in a second step. To analyze the methodology, impact craters were modeled using Blender, visualized through MonoGame and the generated images analyzed with MATLAB using generic camera parameters. Optimum camera settings were derived for the particular scenario. For identification of the craters, the camera should be placed within 1.2 m of the surface. To determine the full, three-dimensional crater morphology, the camera needs to be placed much closer to the target surface. Both a rotation and a translation movement of the camera were investigated for recording the stereoscopic images. However, in view of the applicability of the method to map spacecraft surfaces, the translational movement is found to be more feasible to implement and less sensitive to inaccuracy during the positioning of the camera. In particular, a translation of the camera by about 0.4 times the target crater radius minimizes the sensitivity to misalignment of the camera. Improved particle environment models allow for more precise risk estimation for any future space mission, helping to save the lives of astronauts as well as preserving investments in space infrastructure