scholarly journals LEO Object’s Light-Curve Acquisition System and Their Inversion for Attitude Reconstruction

Aerospace ◽  
2020 ◽  
Vol 8 (1) ◽  
pp. 4
Author(s):  
Fabrizio Piergentili ◽  
Gaetano Zarcone ◽  
Leonardo Parisi ◽  
Lorenzo Mariani ◽  
Shariar Hadji Hossein ◽  
...  
Keyword(s):  
Genetic Algorithm ◽  
Space Debris ◽  
Attitude Determination ◽  
Light Curves ◽  
Optical Systems ◽  
Optical Data ◽  
Impact Point ◽  
Space System ◽  
The Impact ◽  
Space Activities

In recent years, the increase in space activities has brought the space debris issue to the top of the list of all space agencies. The fact of there being uncontrolled objects is a problem both for the operational satellites in orbit (avoiding collisions) and for the safety of people on the ground (re-entry objects). Optical systems provide valuable assistance in identifying and monitoring such objects. The Sapienza Space System and Space Surveillance (S5Lab) has been working in this field for years, being able to take advantage of a network of telescopes spread over different continents. This article is focused on the re-entry phase of the object; indeed, the knowledge of the state of the object, in terms of position, velocity, and attitude during the descent, is crucial in order to predict as accurately as possible the impact point on the ground. A procedure to retrieve the light curves of orbiting objects by means of optical data will be shown and a method to obtain the attitude determination from their inversion based on a stochastic optimization (genetic algorithm) will be proposed.

scholarly journals Classification of multiwavelength transients with Machine Learning

2020 ◽  
Author(s):  
K Sooknunan ◽  
M Lochner ◽  
Bruce A Bassett ◽  
H V Peiris ◽  
R Fender ◽  
...  
Keyword(s):  
Machine Learning ◽  
Small Sample ◽  
Light Curves ◽  
Machine Learning Techniques ◽  
Optical Data ◽  
Test Time ◽  
Test Accuracy ◽  
Training Set ◽  
The Impact

Abstract With the advent of powerful telescopes such as the Square Kilometer Array and the Vera C. Rubin Observatory, we are entering an era of multiwavelength transient astronomy that will lead to a dramatic increase in data volume. Machine learning techniques are well suited to address this data challenge and rapidly classify newly detected transients. We present a multiwavelength classification algorithm consisting of three steps: (1) interpolation and augmentation of the data using Gaussian processes; (2) feature extraction using wavelets; (3) classification with random forests. Augmentation provides improved performance at test time by balancing the classes and adding diversity into the training set. In the first application of machine learning to the classification of real radio transient data, we apply our technique to the Green Bank Interferometer and other radio light curves. We find we are able to accurately classify most of the eleven classes of radio variables and transients after just eight hours of observations, achieving an overall test accuracy of 78%. We fully investigate the impact of the small sample size of 82 publicly available light curves and use data augmentation techniques to mitigate the effect. We also show that on a significantly larger simulated representative training set that the algorithm achieves an overall accuracy of 97%, illustrating that the method is likely to provide excellent performance on future surveys. Finally, we demonstrate the effectiveness of simultaneous multiwavelength observations by showing how incorporating just one optical data point into the analysis improves the accuracy of the worst performing class by 19%.

scholarly journals The Impact of Rendezvous Proximity Operation Mission on Space Debris Toward Sustainable Space Activities

2021 ◽  
Vol 7 (3) ◽  
pp. 17-32
Author(s):  
D. Susanti
Keyword(s):  
Space Debris ◽  
Difficulty Level ◽  
Risk Of Falling ◽  
Proximity Operations ◽  
Space Objects ◽  
The Impact ◽  
Space Activities

Abstract. In the last thirty years, the encounter and approach of Rendezvous Proximity Operations (RPO) of human made space objects have developed. This development indicated by the developments in field of technology. The focus of this study is regarding RPO as a mission that has potential to increase the amount of space debris. This study aims to analyze the RPO activity as a potential hazardous mission in increasing the space debris population. Moreover, this research aims to analyze RPO activity as a potentially vulnerable mission to increase the space debris population. In this study, the method was carried out descriptively, by exploring data and information about RPO. The results of this study indicated that RPO activity still limited to LEO due to the high difficulty level for the GEO orbit. The results of this study indicate that RPO activity is still limited to LEO due to the high difficulty level for the GEO orbit. This is actually because in LEO orbit have more space debris (75%) than GEO orbit and it has a higher risk of falling to Earth. Based on the results obtained, it can be concluded that RPO activities are double-edged and therefore greater supervision needs to be carried out especially to safeguard Indonesia’s interests in space.

The role of science in the study of and response to space threats

2019 ◽  
Vol 89 (8) ◽  
pp. 777-799
Author(s):  
B. M. Shustov
Keyword(s):  
Comparative Analysis ◽  
20Th Century ◽  
21St Century ◽  
Space Debris ◽  
The Sun ◽  
National Program ◽  
Biological Hazard ◽  
Academy Of Sciences ◽  
Space Activities

During the second half of the 20th century and the beginning of the 21st century, space hazards multiplied, the most urgent of which is space debris. Professionals working in space are exposed to this hazard daily and are aware of it as a problem. Furthermore, increasing attention is being paid to the unpredictable behavior of the Sun, which produces the so-called space weather. The asteroid-comet hazard is considered as potentially having the most catastrophic consequences. No manifestations of biological hazard have yet been observed, although as space activities develop, it is becoming increasingly important. The appropriate time scale for astrophysical hazards is many millions of years, so from a practical perspective, they have no importance. This article briefly describes the main types of space hazards. The author analyzes the results of research and practical work in the field, both worldwide and specifically in Russia. Comparative analysis leads to the clear conclusion that a national program must be developed for the study of space hazards and to respond to space threats. This article is based on a report made by the author at the meeting of the Presidium of the Russian Academy of Sciences (RAS) on January 15, 2019.

scholarly journals Optimized Strategic Planning of Future Norwegian Low-Voltage Networks with a Genetic Algorithm Applying Empirical Electric Vehicle Charging Data

Electricity ◽  
2021 ◽  
Vol 2 (1) ◽  
pp. 91-109
Author(s):  
Julian Wruk ◽  
Kevin Cibis ◽  
Matthias Resch ◽  
Hanne Sæle ◽  
Markus Zdrallek
Keyword(s):  
Genetic Algorithm ◽  
Electric Vehicle ◽  
Electric Vehicles ◽  
Low Voltage ◽  
Network Planning ◽  
Voltage Regulation ◽  
Electric Vehicle Charging ◽  
Vehicle Charging ◽  
The Impact

This article outlines methods to facilitate the assessment of the impact of electric vehicle charging on distribution networks at planning stage and applies them to a case study. As network planning is becoming a more complex task, an approach to automated network planning that yields the optimal reinforcement strategy is outlined. Different reinforcement measures are weighted against each other in terms of technical feasibility and costs by applying a genetic algorithm. Traditional reinforcements as well as novel solutions including voltage regulation are considered. To account for electric vehicle charging, a method to determine the uptake in equivalent load is presented. For this, measured data of households and statistical data of electric vehicles are combined in a stochastic analysis to determine the simultaneity factors of household load including electric vehicle charging. The developed methods are applied to an exemplary case study with Norwegian low-voltage networks. Different penetration rates of electric vehicles on a development path until 2040 are considered.

Space Debris Mitigation as an International Law Obligation

2015 ◽  
Vol 17 (3) ◽  
pp. 297-335
Author(s):  
Lawrence Li
Keyword(s):  
International Law ◽  
Space Debris ◽  
Outer Space ◽  
Legal Framework ◽  
International Responsibility ◽  
International Liability ◽  
International Instruments ◽  
Space Activities ◽  
Proper Interpretation ◽  
Debris Mitigation

Human space activities have grown rapidly in recent decades, but the international legal framework, comprising of the five space treaties, has largely remained unchanged since the 1980s. One of the consequences is that international responsibility and liability for space debris, which is a major hazard to space activities, have also remained uncertain for years. Nonetheless, States have responded to these problems by implementing national voluntary measures. More importantly, two major non-binding international instruments have been laid down by the Inter-Agency Space Debris Coordination Committee and the United Nations Committee on the Peaceful Uses of Outer Space, respectively. This article argues that, in light of recent States practice established under these international instruments, and a proper interpretation of the space treaties, it has been recognised by the international community that States are obliged to mitigate the generation of space debris, a failure of which will lead to international liability.

Debris/Micrometeoroid Impacts and Synergistic Effects on Spacecraft Materials

MRS Bulletin ◽  
2010 ◽  
Vol 35 (1) ◽  
pp. 41-47 ◽  
Author(s):  
E. Grossman ◽  
I. Gouzman ◽  
R. Verker
Keyword(s):  
Space Debris ◽  
Synergistic Effects ◽  
Degradation Mechanism ◽  
Space Environment ◽  
Materials Properties ◽  
Gas Gun ◽  
Naturally Occurring ◽  
Space Activity ◽  
The Impact ◽  
Debris Impact

AbstractIn the last 40 years, the increased space activity created a new form of space environment of hypervelocity objects—space debris—that have no functional use. The space debris, together with naturally occurring ultrahigh velocity meteoroids, presents a significant hazard to spacecraft. Collision with space debris or meteoroids might result in disfunction of external units such as solar cells, affecting materials properties, contaminating optical devices, or destroying satellites. The collision normally results in the formation of additional debris, increasing the hazard for future missions. The hypervelocity debris effect is studied by retrieving materials from space or by using ground simulation facilities. Simulation facilities, which include the light gas gun and Laser Driven Flyer methods, are used for studying the materials degradation due to debris impact. The impact effect could be accelerated when occurring simultaneously with other space environment components, such as atomic oxygen, ultraviolet, or x-ray radiation. Understanding the degradation mechanism might help in developing materials that will withstand the increasing hazard from the space debris, allowing for longer space missions. The large increase in space debris population and the associated risk to space activity requires significant measures to mitigate this hazard. Most current efforts are being devoted to prevention of collisions by keeping track of the larger debris and avoiding formation of new debris.

Diamond-Like Carbon Coating—It'S Application for Polymeric Substrates

1991 ◽  
Vol 239 ◽  
Author(s):  
Fred M. Kimock ◽  
Alex J. Hsieh ◽  
Peter G. Dehmer ◽  
Pearl W. Yip
Keyword(s):  
High Speed ◽  
Protective Coatings ◽  
Ion Beam ◽  
Chemical Exposure ◽  
Optical Systems ◽  
Impact Behavior ◽  
Organic Liquids ◽  
Diamond Like Carbon ◽  
Dlc Coating ◽  
The Impact

ABSTRACTWe report on a recently commercialized Diamond-Like Carbon (DLC) coating that has been deposited on polycarbonate at near room temperature, via a unique ion beam system. Aspects of high speed impact behavior, chemical resistance, abrasion resistance, and thermal stability of the coating are examined. Results of scanning electron microscopy studies indicate that adhesion of the DLC coating is very good; no delamination of the coating was found on ballistically tested specimens. The well-bonded DLC coating did not cause the impact performance of polycarbonate to become brittle. Chemical exposure test results show that the DLC coating is capable of protecting polycarbonate from chemical attack by aggressive organic liquids. These ion beam deposited DLC coatings have considerable potential as protective coatings for optical systems.

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