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Star stories : constellation tales from around the world
\"For thousands of years people have looked up to the night sky and told stories about the stars. These epic tales tell of vengeful gods and goddesses, of monsters and heroes. Others try to make sense of the natural world, or unravel the mysterious forces of the universe. This ... book brings together 23 of these legends from all over the world: from ancient Greece to North America, Egypt, China, India, and the South Pacific\"-- Publisher's description.
Book
Simulation of the space conjunction of a Chinese mega-constellation with other space objects
At present, there are 90 member satellites of a Chinese mega-constellation in space. More member satellites will be deployed in space in the future. It is quite crowded in near-Earth space since there are many low-Earth orbiters in this space. Authors have focused on simulations of space conjunctions of mega-constellations with other space objects. The main orbit elements are presented in form of graphics, which could show the general deployment situation of the mega-constellation; based on orbit data set, authors have simulated the possible conjunctions, which include NORAD catalog number for objects, object names, time of closest approach, minimum range and maximum probability, relative speed. These simulations will support the effective operation and smooth deployment of follow-up member satellites.
Journal Article
Constellations
An illustrated introduction to constellations that explains how constellations are useful, who discovered them, and related topics.
Book
Enhancing the Robustness of Global Navigation Satellite Systems for Connected and Autonomous Vehicles
This thesis presents an overview of GNSS vulnerabilities from a CAV perspect ive and surveys the immediate GNSS challenges and current (un)-intentional interference mitigating techniques. In this thesis, the effect of antenna place ment on the localisation accuracy is evaluated. The evaluation results show that it is recommended that the GNSS antenna is placed along the longitudinal mid-way section and approximately one-third from the front or back of a car's roof. Additionally, this research evaluates supervised learning techniques for GNSS pseudorange discrimination. A prediction accuracy of approximately 98 % can be obtained from a fine decision tree using the GNSS carrier-to-noise ratio and the rate of change of the epochs of the satellite vehicles in view. Moreover, this thesis proposes the design of a possible method with two layers of GNSS observation checks to exclude non-line-of-sight and multipath effects. Results will show that the exclusion of the inconsistent measurements can yield a 96 % increase in mean positioning accuracy of the estimated position in a high and medium multipath environment and a mean positioning error of 85 cm can be attained. Furthermore, this thesis evaluates the impact of GNSS pseudor anges and Doppler measurements effects as decision tree prediction features for multi-constellation GNSS signal classification. The analysis shows that both features could enhance the classification, with the pseudorange having higher predicting importance. A 13 % enhancement in the prediction accuracy is obtained compared to the signal strength and the elevation angle as standalone features. Also evaluated is the use of a GPS L1 signal prediction regression model on other GNSS constellations. Analysis of the investigated scenario shows that the current model is not adequate for non-GPS constellations. Moreover, open research areas and techniques are identified, which can be further investigated to enhance the robustness of GNSS for CAV applications.
Dissertation
Analyses of Qianfan constellation coverage with respect to the ground users as of May 23, 2025
The Qianfan constellation has been proposed by joint task teams in Shanghai, China, which has been under development. Its goal is to form a constellation of more than 10, 000 microsatellites, which is dedicated to providing space-based internet services. Based on an open data set of orbit information online, authors have made simulations of the Qianfan constellation, consisting temporarily of 90 microsatellites. Semi-major axis, inclination, and eccentricity data analyses are made, which have shown the status quo of 90 satellites in orbit. 10 deg *10 deg grids are assumed on the surface of the Earth; 90-satellite coverage has been simulated with respect to the assumed ground grids. These simulations and analyses will help technicians learn the current state of the Qianfan constellation, and further promote the effective development of the follow-up Qianfan satellites.
Journal Article
Potential Ozone Depletion From Satellite Demise During Atmospheric Reentry in the Era of Mega‐Constellations
Large constellations of small satellites will significantly increase the number of objects orbiting the Earth. Satellites burn up at the end of service life during reentry, generating aluminum oxides as the main byproduct. These are known catalysts for chlorine activation that depletes ozone in the stratosphere. We present the first atomic‐scale molecular dynamics simulation study to resolve the oxidation process of the satellite's aluminum structure during mesospheric reentry, and investigate the ozone depletion potential from aluminum oxides. We find that the demise of a typical 250‐kg satellite can generate around 30 kg of aluminum oxide nanoparticles, which may endure for decades in the atmosphere. Aluminum oxide compounds generated by the entire population of satellites reentering the atmosphere in 2022 are estimated at around 17 metric tons. Reentry scenarios involving mega‐constellations point to over 360 metric tons of aluminum oxide compounds per year, which can lead to significant ozone depletion. Plain Language Summary With ongoing plans for many constellations of small satellites, the number of objects orbiting the Earth is expected to continue increasing in the foreseeable future. At the end of service life, satellites are disposed into the atmosphere, burning up during the process and generating aluminum oxides, which are known to accelerate ozone depletion. The environmental impacts from the reentry of satellites are currently poorly understood. This paper investigates the oxidation process of the satellite's aluminum content during atmospheric reentry utilizing atomic‐scale molecular dynamics simulations. We find that the population of reentering satellites in 2022 caused a 29.5% increase of aluminum in the atmosphere above the natural level, resulting in around 17 metric tons of aluminum oxides injected into the mesosphere. The byproducts generated by the reentry of satellites in a future scenario where mega‐constellations come to fruition can reach over 360 metric tons per year. As aluminum oxide nanoparticles may remain in the atmosphere for decades, they can cause significant ozone depletion. Key Points We present the first atomic‐scale molecular dynamics simulation of high‐temperature aluminum ablation during reentry from low‐Earth orbit The amount of aluminum oxide nanoparticles generated is quantified and the accumulation in the atmosphere is estimated The long‐term accumulation of aluminum oxides from reentering satellites can cause significant ozone depletion
Journal Article
Goodnight, constellations
Provides an introduction to the major constellations, with illustrations of the stars in each one and descriptions of the figures they represent.
Book
The effects of satellite constellations on amateur astronomy
This paper presents some results from a survey carried out by the UK’s Federation of Astronomical Societies to determine the effect of satellite constellations on (principally) amateur astronomers’ observations, their mitigation methods and the effectiveness of those methods.
Journal Article