138 Propulsion Units Launched in 4 Years: A Review and Lessons Learned

After the first launch of an ENPULSION NANO thruster in 2019 together with FOTEC1,2,3, which verified for the first time the operation of a propulsion system based on liquid metal Field Emission Electric Propulsion (FEEP) in space, ENPULSION has delivered hundreds of flight systems to 36 different commercial customers. To date, 135 additional ENPULSION NANO systems have been launched on a variety of spacecraft across different platforms and customers. In addition, the ENPULSION MICRO R3 , an increased power and thrust unit, has been developed, which was successfully demonstrated in orbit in 2021. Recently, the first new generation ENPULSION NANO AR3 propulsion system was launched to debut on orbit. To date, hundreds of flight models have been manufactured, acceptance tested and delivered to customers. Based on lessons learnt during manufacturing, AIT and in-space operation of the ENPULSION NANO, a new generation of propulsion systems with increased resilience has been developed, denoted R3 . In this paper we provide an overview of the onorbit statistics of the ENPULSION propulsion systems. This includes the evolution of launch history of the ENPULSION NANO over time, the accumulated orbit life for all operational propulsion systems that ENPULSION has visibility on confirmed thrust generation, as well as the accumulated orbit life for operational thrusters between launch and last telemetry of thrust maneuver made available to ENPULSION. We then present efforts undertaken in AIT, onorbit operation support and ground testing campaigns conducted in different independent facilities. Based on this, we derive lessons learnt, best practices and limitation over a large number of customers of the smallsat community, over different systems and different implementations for a standardized electric propulsion system based on the ENPULSION NANO

Preliminary Assessment of Performance and Cost of a Cubesat Component of the Earth Science Decadal Survey

In 2007, The National Research Council released a report known as the Earth Science Decadal Survey. This report lays out an architecture for a holistic Earth Observation Program consisting of 17 missions to be flown in a decade for a total cost of about $7B. Six years after, mission cost estimates have grown by 70% on average, and at the current levels of funding for NASA Earth Science, it would take about 40 years to fly these missions. Furthermore, missions that played central roles in satisfying the needs of the Earth science community have not materialized, due to launch failures, mission cancellations, severe delays or descoping processes. The Earth Science community is in desperate need of novel architectures for Earth observation missions that can satisfy at least part of the scientific requirements at a fraction of the cost of the Decadal Survey missions. Cubesats have the potential to become an important component of such novel architectures by providing low-cost opportunities to fly advanced miniature instruments such as GNSS receivers in radio occultation and reflectometry modes, visible and near-infrared imagers, short-wave infrared spectrometers, millimeter-wave radiometers, microbolometers, and so forth. While Cubesats have hitherto mostly been used for technological demonstration and educational purposes, there has been some emphasis lately in developing Cubesats capable of satisfying demanding scientific requirements. In a recent paper, a survey and assessment of the capabilities of Cubesats as a platform for Earth observation instruments of high scientific value, was presented. This paper takes that work a step further by analyzing, in terms of both performance and cost, several constellations of Cubesats carrying such instruments. The performance of an architecture (i.e., a certain mix of constellations of Cubesats) is computed by assessing its potential to satisfy the Decadal Survey scientific requirements. This is done leveraging prior work on the development of a rule-based expert system for assessing the relative merit of Earth observing system architectures. Different constellation designs carrying different mixes of payloads are analyzed using performance and cost models. Non-dominated architectures in the Pareto sense are identified, and one preferred architecture is analyzed in more detail. A preliminary mission analysis is conducted for this preferred architecture, and its cost-effectiveness is compared to that of the original Decadal Survey architecture. The paper shows how, while Cubesats still suffer from serious limitations in terms of their performance and capabilities for Earth science, they are a very cost-effective way of satisfying a relatively large portion of the Decadal Survey requirements

IFM Nano Thruster Electric Space Propulsion: From First Cubesat Demonstration to the First 100 Thrusters Produced

Following the successful In-Orbit-Demonstration of the first IFM Nano Thruster, a high rate production facility has been established at ENPULSION, which has delivered 2 thruster per week since opening in 2018. This paper gives a brief overview on the passively fed, metal propellant based technology which enables simple integration and manufacturing procedures. The thrusters IFM Nano Thruster and the IFM Micro Thruster are described, before a discussion of the underlying high rate production philosophy is given. The paper further details the specific implementation of the high rate approach by discussing the ENPULSION manufacturing flow

Sprachliche Dynamik im politischen Diskurs

Die Natur des politischen Wettstreits um die Gunst der Wähler nimmt einen zentralen Platz in der Wahlforschung ein. Die Konfrontationstheorie und die Salienztheorie kommen bei der Natur der Konfrontation im politischen Raum zu unterschiedlichen Voraussagen. Auf welche Art kämpfen politische Parteien um die Aufmerksamkeit und Zustimmung der Wähler? In der vorliegenden Arbeit wird ein Schwerpunkt auf den Umgang mit etablierten Frames und deren Verwendung durch politische Mitbewerber gelegt. Nach Beschreibung der zu untersuchenden Theorien wird der Framing Ansatz vorgestellt und die Reduktion auf Schlüsselwörter als Untersuchungsgegenstand argumentiert. Eine auf den Untersuchungsgegenstand abgestimmte automatisierte Analyse auf Wortebene wird erarbeitet, die es erlaubt, einen Datensatz aller parlamentarischen Debatten über mehrere Jahre hinweg zu analysieren. Dies ermöglicht die Erstellung von Zeitreihen zur Untersuchung der zeitabhängigen Verwendung von Schlüsselwörtern nach Parteien. So kann das Reaktionsverhaltens konkurrierender Parteien in Bezug auf die Schlüsselwörter eines Frames untersucht werden, und damit Rückschlüsse auf die Natur des politischen Diskurses getroffen werden. Mithilfe induktiv gefundener Kriterien zur Auswahl von Schlüsselbegriffen ist es möglich, die Verwendungscharakteristika von 160 Begriffen über drei Legislaturperioden zu analysieren und den untersuchten Theorien zuzuordnen. Dabei wurde eine klare Dominanz der direkten Konfrontation gefunden und anhand ausgewählter Beispiele diskutiert. Überdies konnte anhand ausgewählter Beispiele eine aktive Übernahme einzelner Begriffe durch politische Gegner gezeigt werden. Dieses bewusste Aufgreifen und Besetzen gegnerischer Begriffe führt zu einer ausgeprägten zeitlichen Fluktuation der Wortverwendung durch die Parteien und weist auf die zeitliche Problematik hin, politische Akteure aufgrund ihres Sprachgebrauchs zu klassifizieren.The nature of political dispute is a central issue in the field of electoral studies. Two theories, the confrontation theory and the salience theory, differ in their predictions of the nature of political dispute. In this work, focus is laid on the utilization of frames in the political discourse and the way political parties handle frames owned by their opponents. After depiction of the investigated theories, the concept of framing is introduced and a reduction on value words as an object of study is argued. Based on this, a dedicated computer based analysis routine is elaborated, allowing the investigation of a record of parliamentary debates over a period of various years. This allows the generation of time series of word frequencies as a function of party membership. Based on this data, the manner of reaction of political actors on value words of dedicated frames is investigated and inferences on the nature of political dispute are drawn. With the inductively found criteria to identify value words, word utilization characteristics of 160 candidate value words have been examined over three legislative periods and matched to the theories investigated. This resulted in a clear dominance of value word using in the means of direct confrontation. In addition, it was possible to show takeovers of value words from opponents. These results show the difficulties of automated classification methods the field of political debates due to the highly confrontational nature of political discourse

Applications of responsive small satellites with MIT TILE electrospray propulsion

Responsive, manoeuvrable small satellites are an enabling technology for affordable, flexible and agile space missions with possible applications as wide-reaching as military reconnaissance, disaster response, and even wildlife tracking. This paper presents an analysis of some of these applications and is the outcome of a four month collaborative research visit at the Space Propulsion Laboratory of the Massachusetts Institute of Technology. This work builds upon the analytical satellite manoeuvring strategy previously developed by the author, and analyses the potential capabilities and applications of small satellites equipped with the MIT TILE electrospray thruster. This previously developed analytical method enables the rapid investigation of the manoeuvres of a constellation of small satellites, with the goal of targeting a particular region on the Earth. A full overview of the solution space can be rapidly generated, allowing for the mission designer or operator to trade off all possible manoeuvres and select the best solution for their specific purpose. The MIT TILE is a modular, miniaturised MEMS based propulsion system for nanosatellites capable of producing 350μN nominal thrust for up to 200hrs operation. A standard TILE system weighs <450g and is sized to fit in 0.5U of a CubeSat. Three case studies are presented which demonstrate the effectiveness of responsive satellites in disaster response missions. The first case study considers a rapid flyover of Los Angeles following an earthquake. The results show a reduction in flyover time of almost 9 days using 21m/s Δ퐕 when compared with a non-manoeuvring satellite. A second case study considers a fire detection constellation of 24 satellites, which can manoeuvre to provide targeted coverage of a given region as required. Selecting the Cairngorms National Park in Scotland, UK as the region of interest, the results show that by manoeuvring the constellation to directly target the region, an increase in coverage is achievable over the entire target area, with total coverage times of some areas more than doubled from 3.4 minutes coverage in a week to 8.4 minutes. The final case study considers providing communication services to helicopters at a range of locations from the UK to Svalbard, Norway. The manoeuvring capabilities of the satellites are used to follow the helicopters over an eight week period. Results show that a single satellite using <150m/s ΔV can achieve 50 flyovers of the helicopters during the journey, compared with 24 flyovers if a static satellite is used. These missions are all shown to be possible with existing technologies, and they exemplify the dramatic improvement in performance that can be achieved by using manoeuvrable satellites

The role of connexin40 in developing atrial conduction

AbstractConnexin40 (Cx40) is the main connexin expressed in the murine atria and ventricular conduction system. We assess here the developmental role of Cx40 in atrial conduction of the mouse. Cx40 deficiency significantly prolonged activation times in embryonic day 10.5, 12.5 and 14.5 atria during spontaneous activation; the severity decreased with increasing age. In a majority of Cx40 deficient mice the impulse originated from an ectopic focus in the right atrial appendage; in such a case the activation time was even longer due to prolonged activation. Cx40 has thus an important physiological role in the developing atria

3D visualization of bioerosion in archaeological bone

Palaeoradiology is increasingly being used in archaeological and forensic sciences as a minimally invasive alternative to traditional histological methods for investigating bone microanatomy and its destruction by diagenetic processes. To better understand ancient mortuary practices, taphonomic studies using microCT scanning methods are gaining an ever more important role. Recently it was demonstrated that 2D virtual sections obtained by microCT scanning of intact samples are comparable to physical sections for the rating and diagnosis of bioerosion in archaeological bone. Importantly, volume image data obtained from tomographic methods also allow the rendering and analysis of 3D models. Building on these methods we provide (1) detailed descriptions of bioerosion in 3D volume renderings, virtual sections, and traditional micrographs, and (2) accessible techniques for the visualization of bioerosion in skeletal samples. The dataset is based on twenty-eight cortical bone samples, including twenty femora (of which five are cremated), two ribs, two parietals, one mandibular ramus, one humerus, and two faunal long bones from five archaeological sites in Lower Austria dating from the Early Neolithic to the Late Iron Age. Notably, we reduce the need for time-consuming image segmentation by sequentially applying two noise-reducing, edge-preserving filters, and using an image-display transfer function that visualizes bioerosion, as well as Haversian and Volkmann canal structure and density in 3D. In doing so we are also able to visualize in 3D the invasion of canals by microbiota, which has previously only been reported in 2D sections. Unlike conventional thin sections, the 3D volume images shown here are easy to create and interpret, even for archaeologists inexperienced in histology, and readily facilitate the illustration and communication of microtaphonomic effects

Individual Particle Characteristics, Optical Properties and Evolution of an Extreme Long‐Range Transported Biomass Burning Event in the European Arctic (Ny‐Ålesund, Svalbard Islands)

This paper reports an exceptional biomass burning (BB) advection event from Alaska registered at Ny‐Ålesund from 10 to 17 July 2015 with particular interest on the influence of the airborne particle characteristics on the optical properties of the aerosol during the event. To this purpose we considered two DEKATI 12‐stage aerosol samples spanning the entire advection and analyzed them by scanning electron microscopy techniques. Aerosol chemical data and microphysical properties were also evaluated in order to correlate any change of individual particle characteristics with the bulk properties of the aerosol. The results of individual particle analysis depict a complex event characterized by a first phase (P1) of massive input of BB carbonaceous particles (i.e., tar balls, popcorn refractory particles, and organic particles), and by a second phase (P2) dominated by inorganic salts. The peculiar feature of this BB event is the exceptionally large grain size of the subspherical organic particles at the beginning of the event with respect to the background. At these conditions a significant increase of the scattering efficiency may occur even for a small increase of the size parameter. Results of the simulation of the complex refractive indices (n‐ik) confirm this evaluation. Aerosol evolution during the event resulted from the combination of three distinct occurrences: (a) progressive rotation of air mass circulation toward non‐BB source areas, (b) development of a thick fog layer in the planetary boundary layer, and (c) sea salt spray direct advection of local/regional provenance

Substantiating microCT for diagnosing bioerosion in archaeological bone using a new Virtual Histological Index (VHI)

Recent technological advances have broadened the application of palaeoradiology for non-destructive investigation of ancient remains. X-ray microtomography (microCT) in particular is increasingly used as an alternative to histological bone sections for interpreting pathological alterations, trauma, microstructure, and, more recently, bioerosion with direct or ancillary use of histological indices. However, no systematic attempt has been made to confirm the reliability of microCT for histotaphonomic analysis of archaeological bone. The objective of this study is therefore to compare thin sections of human femora rated with the Oxford Histological Index to microCT sections using the newly developed Virtual Histological Index in order to provide an accessible methodology for the evaluation of bioerosion in archaeological bone. We provide detailed descriptions of virtual sections and assess the efficacy of the method on cranial and postcranial elements, cremated long bones, and faunal samples. The traditional histological and virtual methods showed a strong correlation, providing the first systematic data substantiating lab-based microCT as a suitable alternative tool for reconstructing post-mortem history in the archaeological record, and for the reliable, non-destructive screening of samples for further analyses