scholarly journals A trade-off methodology for micro-launchers

2021 ◽  
Author(s):  
G. Governale ◽  
J. Rimani ◽  
N. Viola ◽  
V. Fernandez Villace
Keyword(s):  
Software Tool ◽  
Cost Effective ◽  
Automatic Generation ◽  
Low Earth Orbit ◽  
Performance Estimation ◽  
Small Satellite ◽  
Vehicle Engineering ◽  
Trade Off ◽  
Maximum Payload ◽  
Competitive Prices

AbstractThe trend of cost-effective access to space and satellite technologies’ evolution is increasing the small satellite market. However, small payloads usually ride as piggyback, being a secondary passenger of a space vector, with very low flexibility in target orbit and launch schedule. The micro-launchers are designed to answer the needs of the small satellite missions, with a payload capacity up to 350 kg to Low Earth Orbit, aiming to low turn-over time and competitive prices. This paper explains the work performed by Politecnico di Torino in support of the ESA–ESTEC activities on micro-launchers. The aim is to provide preliminary guidelines for choosing and evaluating new innovative micro-launcher flight vehicle engineering processes. A trade-off methodology is proposed and defined based on the Analytically Hierarchical Process (AHP). This methodology considers, among other features, the flight profile, maximum payload, and physical characteristics. To support the trade-off analysis, a software tool is built for the automatic generation of the aerodynamics and propulsion parameters needed for the completion of the preliminary designs, enabling the performance estimation. The launcher’s performance models, with an analysis of the take-off sites and target orbits, are also produced. This allows the definition of performance maps where the maximum payload is graphed as a function of the orbit altitude and inclination. A set of innovative micro-launchers exploiting different technologies is also assessed as a case study.

The Formability and Elongation of Aluminum Alloys AA5083 and AA3003 for Micro-Truss Sandwiches Manufacturing

2020 ◽  
Vol 38 (9A) ◽  
pp. 1396-1405
Author(s):  
Arwa F. Tawfeeq ◽  
Matthew R. Barnett
Keyword(s):  
Aluminum Alloy ◽  
Strain Rate ◽  
Cost Effective ◽  
Tensile Tests ◽  
Truss Structures ◽  
High Quality ◽  
Trade Off ◽  
Clad Layer ◽  
Higher Temperature ◽  
Different Shapes

The development in the manufacturing of micro-truss structures has demonstrated the effectiveness of brazing for assembling these sandwiches, which opens new opportunities for cost-effective and high-quality truss manufacturing. An evolving idea in micro-truss manufacturing is the possibility of forming these structures in different shapes with the aid of elevated temperature. This work investigates the formability and elongation of aluminum alloy sheets typically used for micro-truss manufacturing, namely AA5083 and AA3003. Tensile tests were performed at a temperature in the range of 25-500 ○C and strain rate in the range of 2x10-4 -10-2 s-1. The results showed that the clad layer in AA3003 exhibited an insignificant effect on the formability and elongation of AA3003. The formability of the two alloys was improved significantly with values of m as high as 0.4 and 0.13 for AA5083 and AA3003 at 500 °C. While the elongation of both AA5083 and AA3003 was improved at a higher temperature, the elongation of AA5083 was inversely related to strain rate. It was concluded that the higher the temperature is the better the formability and elongation of the two alloys but at the expense of work hardening. This suggests a trade-off situation between formability and strength. 

scholarly journals Approximator: A Software Tool for Automatic Generation of Approximate Arithmetic Circuits

Computers ◽  
2022 ◽  
Vol 11 (1) ◽  
pp. 11
Author(s):  
Padmanabhan Balasubramanian ◽  
Raunaq Nayar ◽  
Okkar Min ◽  
Douglas L. Maskell
Keyword(s):  
Software Tool ◽  
Digital Signal ◽  
Automatic Generation ◽  
Arithmetic Circuits ◽  
Design Flow ◽  
Attractive Alternative ◽  
Design Environment ◽  
Verilog Hdl ◽  
Arithmetic Circuit ◽  
Practical Applications

Approximate arithmetic circuits are an attractive alternative to accurate arithmetic circuits because they have significantly reduced delay, area, and power, albeit at the cost of some loss in accuracy. By keeping errors due to approximate computation within acceptable limits, approximate arithmetic circuits can be used for various practical applications such as digital signal processing, digital filtering, low power graphics processing, neuromorphic computing, hardware realization of neural networks for artificial intelligence and machine learning etc. The degree of approximation that can be incorporated into an approximate arithmetic circuit tends to vary depending on the error resiliency of the target application. Given this, the manual coding of approximate arithmetic circuits corresponding to different degrees of approximation in a hardware description language (HDL) may be a cumbersome and a time-consuming process—more so when the circuit is big. Therefore, a software tool that can automatically generate approximate arithmetic circuits of any size corresponding to a desired accuracy would not only aid the design flow but also help to improve a designer’s productivity by speeding up the circuit/system development. In this context, this paper presents ‘Approximator’, which is a software tool developed to automatically generate approximate arithmetic circuits based on a user’s specification. Approximator can automatically generate Verilog HDL codes of approximate adders and multipliers of any size based on the novel approximate arithmetic circuit architectures proposed by us. The Verilog HDL codes output by Approximator can be used for synthesis in an FPGA or ASIC (standard cell based) design environment. Additionally, the tool can perform error and accuracy analyses of approximate arithmetic circuits. The salient features of the tool are illustrated through some example screenshots captured during different stages of the tool use. Approximator has been made open-access on GitHub for the benefit of the research community, and the tool documentation is provided for the user’s reference.

scholarly journals Web-Based Simulation Environment for Vehicular Electrical Networks

Energies ◽  
2021 ◽  
Vol 14 (19) ◽  
pp. 6087
Author(s):  
Xavier Dominguez ◽  
Paola Mantilla-Pérez ◽  
Nuria Gimenez ◽  
Islam El-Sayed ◽  
Manuel Alberto Díaz Díaz Millán ◽  
...  
Keyword(s):  
Visual Analytics ◽  
Distribution Systems ◽  
Software Tool ◽  
Automatic Generation ◽  
Electrical Networks ◽  
Web Based ◽  
Electrical Distribution Systems ◽  
Technical Requirements ◽  
Information Interaction

For the validation of vehicular Electrical Distribution Systems (EDS), engineers are currently required to analyze disperse information regarding technical requirements, standards and datasheets. Moreover, an enormous effort takes place to elaborate testing plans that are representative for most EDS possible configurations. These experiments are followed by laborious data analysis. To diminish this workload and the need for physical resources, this work reports a simulation platform that centralizes the tasks for testing different EDS configurations and assists the early detection of inadequacies in the design process. A specific procedure is provided to develop a software tool intended for this aim. Moreover, the described functionalities are exemplified considering as a case study the main wire harness from a commercial vehicle. A web-based architecture has been employed in alignment with the ongoing software development revolution and thus provides flexibility for both, developers and users. Due to its scalability, the proposed software scheme can be extended to other web-based simulation applications. Furthermore, the automatic generation of electrical layouts for EDS is addressed to favor an intuitive understanding of the network. To favor human–information interaction, utilized visual analytics strategies are also discussed. Finally, full simulation workflows are exposed to provide further insights on the deployment of this type of computer platforms.

scholarly journals In Situ Measurement of Carbon Fibre/Polyether Ether Ketone Thermal Expansion in Low Earth Orbit

Aerospace ◽  
2020 ◽  
Vol 7 (4) ◽  
pp. 35 ◽  
Author(s):  
Farhan Abdullah ◽  
Kei-ichi Okuyama ◽  
Isai Fajardo ◽  
Naoya Urakami
Keyword(s):  
Thermal Expansion ◽  
Carbon Fibre ◽  
Material Science ◽  
Low Earth Orbit ◽  
Earth Orbit ◽  
Small Satellite ◽  
Polyether Ether Ketone ◽  
Ether Ketone ◽  
Orbit Data

The low Earth orbit (LEO) environment exposes spacecraft to factors that can degrade the dimensional stability of the structure. Carbon Fibre/Polyether Ether Ketone (CF/PEEK) can limit such degradations. However, there are limited in-orbit data on the performance of CF/PEEK. Usage of small satellite as material science research platform can address such limitations. This paper discusses the design of a material science experiment termed material mission (MM) onboard Ten-Koh satellite, which allows in situ measurements of coefficient of thermal expansion (CTE) for CF/PEEK samples in LEO. Results from ground tests before launch demonstrated the feasibility of the MM design. Analysis of in-orbit data indicated that the CTE values exhibit a non-linear temperature dependence, and there was no shift in CTE values after four months. The acquired in-orbit data was consistent with previous ground tests and in-orbit data. The MM experiment provides data to verify the ground test of CF/PEEK performance in LEO. MM also proved the potential of small satellite as a platform for conducting meaningful material science experiments.

scholarly journals Advanced Ultraviolet Radiation and Ozone Retrieval for Applications—Surface Ultraviolet Radiation Products

Atmosphere ◽  
2020 ◽  
Vol 11 (4) ◽  
pp. 324
Author(s):  
Antti Lipponen ◽  
Simone Ceccherini ◽  
Ugo Cortesi ◽  
Marco Gai ◽  
Arno Keppens ◽  
...  
Keyword(s):  
Ultraviolet Radiation ◽  
Synthetic Data ◽  
Software Tool ◽  
Ground Truth ◽  
Low Earth Orbit ◽  
Surface Radiation ◽  
Lower Atmosphere ◽  
The European Union ◽  
Operational Environment ◽  
Uv Index

AURORA (Advanced Ultraviolet Radiation and Ozone Retrieval for Applications) is a three-year project supported by the European Union in the frame of its H2020 Call (EO-2-2015) for “Stimulating wider research use of Copernicus Sentinel Data”. The project addresses key scientific issues relevant for synergistic exploitation of data acquired in different spectral ranges by different instruments on board the atmospheric Sentinels. A novel approach, based on the assimilation of geosynchronous equatorial orbit (GEO) and low Earth orbit (LEO) fused products by application of an innovative algorithm to Sentinel-4 (S-4) and Sentinel-5 (S-5) synthetic data, is adopted to assess the quality of the unique ozone vertical profile obtained in a context simulating the operational environment. The first priority is then attributed to the lower atmosphere with calculation of tropospheric columns and ultraviolet (UV) surface radiation from the resulting ozone vertical distribution. Here we provide details on the surface UV algorithm of AURORA. Both UV index (UVI) and UV-A irradiance are provided from synthetic satellite measurements, which in turn are based on atmospheric scenarios from MERRA-2 (Modern-Era Retrospective analysis for Research and Applications, Version 2) re-analysis. The UV algorithm is implemented in a software tool integrated in the technological infrastructure developed in the context of AURORA for the management of the synthetic data and for supporting the data processing. This was closely linked to the application-oriented activities of the project, aimed to improve the performance and functionality of a downstream application for personal UV dosimetry based on satellite data. The use of synthetic measurements from MERRA-2 gives us also a “ground truth”, against which to evaluate the performance of our UV model with varying inputs. In this study we both describe the UV algorithm itself and assess the influence that changes in ozone profiles, due to the fusion and assimilation, can cause in surface UV levels.

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