scholarly journals Tunable RF Filters Based on Liquid Crystal for Space Applications

Crystals ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 455 ◽  
Author(s):  
Tobias Kaesser ◽  
Carsten Fritzsch ◽  
Michael Franz
Keyword(s):  
Liquid Crystal ◽  
Communication Systems ◽  
Space Environment ◽  
Space Applications ◽  
Rf Filters ◽  
Liquid Crystal Material ◽  
Market Situation ◽  
Satellite Applications ◽  
Long Time ◽  
Long Lifetime

On board of communication satellites, there are numerous RF filters in the payload used for guiding wanted signals as desired and for rejecting unwanted signals such as not to interfere with wanted signals. At present, satellites have a long lifetime (15 years at least for a typical geostationary communication satellite) and there is also time elapsing between its design and the start of in-orbit service (2 years at least). On the other hand, conventional RF filters for satellite applications are fixed frequency. Therefore, there is a growing demand for in-orbit tunable filters to be able to cope with changes in the market situation during that long time. Also, there are communication systems evolving that rely on tunable devices used for adaptive filtering or steering. This article reports on in-orbit tunable bandpass filters employing liquid crystal material and operating at 20 GHz, and especially on design aspects dealing with the harsh space environment, on the operating principles for commanding the filters on board the satellite, and on a qualification campaign passed successfully. A demonstrator unit is in manufacturing for in-orbit verification.

Robust Test Method of TSOP PEMs for Space Application

2019 ◽  
Author(s):  
Yasunobu Iwai ◽  
Koichi Shinozaki ◽  
Daiki Tanaka
Keyword(s):  
Evaluation Method ◽  
Low Cost ◽  
Reliability Evaluation ◽  
Test Method ◽  
Thermal Shock Test ◽  
Space Application ◽  
Space Applications ◽  
Limit Test ◽  
Long Time ◽  
Short Time

Abstract Compared with space parts, consumer parts are highly functional, low cost, compact and lightweight. Therefore, their increased usage in space applications is expected. Prior testing and evaluation on space applicability are necessary because consumer parts do not have quality guarantees for space application [1]. However, in the conventional reliability evaluation method, the test takes a long time, and the problem is that the robustness of the target sample can’t be evaluated in a short time. In this report, we apply to the latest TSOP PEM (Thin Small Outline Package Plastic Encapsulated Microcircuit) an evaluation method that combines preconditioning and HALT (Highly Accelerated Limit Test), which is a test method that causes failures in a short time under very severe environmental conditions. We show that this method can evaluate the robustness of TSOP PEMs including solder connections in a short time. In addition, the validity of this evaluation method for TSOP PEM is shown by comparing with the evaluation results of thermal shock test and life test, which are conventional reliability evaluation methods.

scholarly journals Self-healing materials for space applications: overview of present development and major limitations

2021 ◽  
Author(s):  
Laura Pernigoni ◽  
Ugo Lafont ◽  
Antonio Mattia Grande
Keyword(s):  
Orbital Debris ◽  
Space Environment ◽  
Technological Evolution ◽  
Self Healing ◽  
Space Systems ◽  
Space Applications ◽  
Structural Fatigue ◽  
Operational Life ◽  
Technological Limitations ◽  
Human Exploration

AbstractIn the last decade, self-healing materials have become extremely appealing for the field of space applications, due to their technological evolution and the consequent possibility of designing space systems and structures able to repair autonomously after damage arising from impacts with micrometeoroids and orbital debris, from accidental contact with sharp objects, from structural fatigue or simply due to material aging. The integration of these novel materials in the design of spacecraft structures would result in increased reliability and safety leading to longer operational life and missions. Such concepts will bring a decisive boost enabling new mission scenario for the establishment of new orbital stations, settlement on the Moon and human exploration of Mars.The proposed review aims at presenting the newest and most promising self-healing materials and associated technologies for space application, along with the issues related to their current technological limitations in combination with the effect of the space environment. An introductory part about the outlooks and challenges of space exploration and the self-healing concept is followed by a brief description of the space environment and its possible effects on the performance of materials. Self-healing materials are then analysed in detail, moving from the general intrinsic and extrinsic categories down to the specific mechanisms.

Electro-thermal tuning in a negative dielectric cholesteric liquid crystal material

2008 ◽  
Vol 103 (9) ◽  
pp. 093107 ◽  
Author(s):  
Lalgudi V. Natarajan ◽  
Jeremy M. Wofford ◽  
Vincent P. Tondiglia ◽  
Richard L. Sutherland ◽  
Hilmar Koerner ◽  
...  
Keyword(s):  
Liquid Crystal ◽  
Cholesteric Liquid Crystal ◽  
Crystal Material ◽  
Liquid Crystal Material ◽  
Thermal Tuning

scholarly journals Analysis of the Cosmic Ray Effects on Sentinel-1 SAR Satellite Data

Aerospace ◽  
2021 ◽  
Vol 8 (3) ◽  
pp. 62
Author(s):  
Hakan Köksal ◽  
Nusret Demir ◽  
Ali Kilcik
Keyword(s):  
Count Data ◽  
Communication Systems ◽  
Pearson Correlation ◽  
Cosmic Ray ◽  
Electronic System ◽  
Google Earth ◽  
Space Environment ◽  
Cosmic Ray Intensity ◽  
Radiation Sources ◽  
Ray Effects

Ionizing radiation sources such as Solar Energetic Particles and Galactic Cosmic Radiation may cause unexpected errors in imaging and communication systems of satellites in the Space environment, as reported in the previous literature. In this study, the temporal variation of the speckle values on Sentinel 1 satellite images were compared with the cosmic ray intensity/count data, to analyze the effects which may occur in the electromagnetic wave signals or electronic system. Sentinel 1 Synthetic Aperture Radar (SAR) images nearby to the cosmic ray stations and acquired between January 2015 and December 2019 were processed. The median values of the differences between speckle filtered and original image were calculated on Google Earth Engine Platform per month. The monthly median “noise” values were compared with the cosmic ray intensity/count data acquired from the stations. Eight selected stations’ data show that there are significant correlations between cosmic ray intensities and the speckle amounts. The Pearson correlation values vary between 0.62 and 0.78 for the relevant stations.

EFFECT OF CELL THICKNESS ON THE DIELECTRIC RELAXATION PROCESSES IN FERROELECTRIC LIQUID CRYSTALS

2008 ◽  
Vol 22 (14) ◽  
pp. 2263-2273 ◽  
Author(s):  
RAJBIR SINGH ◽  
K. K. RAINA
Keyword(s):  
Liquid Crystal ◽  
Dielectric Relaxation ◽  
Dielectric Strength ◽  
Relaxation Processes ◽  
Goldstone Mode ◽  
Ferroelectric Liquid Crystal ◽  
Dielectric Relaxation Spectroscopy ◽  
Dielectric Parameters ◽  
Liquid Crystal Material ◽  
Cell Thickness

Dielectric relaxation spectroscopy in the frequency range 50 Hz to 1 MHz has been carried out in a room temperature ferroelectric liquid crystal mixture in the SmC*, SmA and N* phases in cells of different thickness. The relaxation frequency fr, distribution parameter α and dielectric strength δ∊ have been evaluated. Goldstone mode, domain mode and soft mode have been observed. It is found that the cell thickness has a significant effect on the dielectric parameters of the ferroelectric liquid crystal material. The results have been discussed.

Chemical potential variation effect of new design of graphene antenna for satellite applications

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Mohammed Amin Rabah ◽  
Bekhti Mohammed
Keyword(s):  
Patch Antenna ◽  
Chemical Potential ◽  
Space Environment ◽  
Antenna Element ◽  
Space Technology ◽  
Content Type ◽  
Antenna Performance ◽  
Technology Applications ◽  
Satellite Applications ◽  
Cst Microwave Studio

Purpose The present work aims to analyze the performance of a newly designed graphene-based patch antenna by varying the chemical potential in graphene sheet, using the CST Microwave Studio ® software. This study mainly seeks to discuss and assess the advantage of using graphene, instead of copper, as the radiating patch. It should be noted that graphene is a new material that possesses unique properties. Its parameters are optimized for the purpose of introducing it in satellite technology. Design/methodology/approach The use of graphene as a radiating patch of space technology applications, where a polygonal graphene patch antenna element is designed by the CST Microwave Studio ® software with Taconic RF-41 substrate to resonate in the satellite bands. Findings Analysis of a graphene patch sheet by a variation in the chemical potential to ensure operation in a space environment. Originality/value The increase in the chemical potential for a graphene patch antenna has shown a prominent increase in the values of the gain. A new contribution, by the combination of the antenna performance improvement techniques and the use of graphene as a radiating patch of space technology applications.

Thermoelectric Applications as Related to Biomedical Engineering for Nasa Johnson Space Center

1997 ◽  
Vol 478 ◽  
Author(s):  
C. D. Kramer ◽  
P.E.
Keyword(s):  
International Space Station ◽  
Space Station ◽  
Space Environment ◽  
Space Applications ◽  
International Space ◽  
Future Technology ◽  
Technological Developments ◽  
Environment Noise ◽  
Scientific Value

AbstractThis paper presents current NASA biomedical developments and applications using thermoelectrics. Discussion will include future technology enhancements that would be most beneficial to the application of thermoelectric technology.A great deal of thermoelectric applications have focused on electronic cooling. As with all technological developments within NASA, if the application cannot be related to the average consumer, the technology will not be mass-produced and widely available to the public (a key to research and development expenditures and thermoelectric companies). Included are discussions of thermoelectric applications to cool astronauts during launch and reentry. The earth-based applications, or spin-offs, include such innovations as tank and race car driver cooling, to cooling infants with high temperatures, as well as, the prevention of hair loss during chemotherapy. In order to preserve the scientific value of metabolic samples during long-term space missions, cooling is required to enable scientific studies. Results of one such study should provide a better understanding of osteoporosis and may lead to a possible cure for the disease.In the space environment, noise has to be kept to a minimum. In long-term space applications such as the International Space Station, thermoelectric technology provides the acoustic relief and the reliability for food, as well as, scientific refrigeration/freezers. Applications and future needs are discussed as NASA moves closer to a continued space presence in Mir, International Space Station, and Lunar-Mars Exploration.

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