Satellite Launch Research Articles

Legal Framework for Space Exploration. Benefits and Threats for the Earth

Since the launch of the first artificial satellite – Sputnik 1 in 1957 – and humans first setting foot on the Moon in 1969, astronauts and other spaceflight participants have travelled to the International Space Station and man-made probes and rovers have landed on planets, comets and asteroids, exploring new uncharted corners of our solar system. States and private entities are developing new types of space activities such as space mining and human settlements on celestial bodies. Since the 1980s, human activity in space is moving away from the convention of highly specialized space missions by trained cosmonauts in favor of space travel for all. But this heightened cosmic activity brings to light various issues such as those related to space debris and the environment, as well as a lack of appropriate legal regulations. In this article, its authors analyze the legal framework of space law in order to determine the conditions for space exploitation and its legal consequences particularly to environmental aspects of sub-orbital, orbital and space flights are presented.

Содружество ленинградских ученых и производственников в обеспечении работ по изучению космоса и созданию аппаратуры для этих целей (вторая половина 50-х – 70-е годы XX века)

The article considers a set of works on the development of systems used for the study of outer space and the development of cosmonautics in the early years of the space age. The development of the unified time system, the system of the onboard standard of time and frequency "Liana", as well as equipment for studying long-wave X-ray radiation of the Sun, which was installed on the second artificial Earth satellite (AES), is being investigated. Attempts have been made to analyze the creation of equipment for recording the physiological parameters of living beings in space flight, the development of secondary electronic and photo-multipliers used in the creation of the first AES equipment, the development and manufacture of a complex of peripheral digital machines that allowed real-time processing and transmission of trajectory measurement data to the coordination and computing center. The issues of developing and manufacturing an automatic detonation system for unmanned vehicles are being studied. The data on the observation of the flight of the first satellites, on the improvements that made it possible to photograph with great accuracy, on the creation of a theory that allows calculating the orbit of the satellite, as well as to assess the influence of various factors on it: changes in atmospheric density, light pressure, the influence of harmonics of the gravitational field of the Earth. It tells about the first Soviet-American space experiment with a passive communication satellite "Echo-2". All this clearly illustrates the notable contribution of scientists and engineers from Leningrad (now Saint Petersburg) to space research at the dawn of the space age. The article pays special attention to the history of events that unfolded both inside the country and abroad regarding the creation and launch of the first artificial Earth satellite. And first of all, the reaction to this epoch-making event in the international scientific community, as well as the reaction to this event from some politicians in Western Europe. The analysis of some of the first joint experiments of Soviet and American scientists in the field of space exploration at the beginning of the space age of mankind is also of interest to readers.

An Overview of the Situation of Small Satellites According to the United Nations Space Treaties

The growing number of small satellite systems and launches is considered to play an essential role in conducting space activities. The development of these space activities has opened up new opportunities for novel and creative uses of space systems, especially among new entrants and users from emerging economies. Small satellites have generally been launched into low Earth orbit, with the associated missions expanding access to space while requiring less time and money than traditional satellite missions. This paper is documentary research that analyzes the situation of small satellites according to the United Nations space treaties. This body of law consists of five treaties, three of which are highly relevant to small satellites, namely the Outer Space Treaty, the Liability Convention, and the Registration Convention. Even though small satellites fundamentally differ from traditional satellites, it is evident that the current space law regime applies to small satellites as “space objects” in the same way as it does to traditional satellites. Thus, as the current legal regime does not distinguish between space objects based on their dimensions, small satellite operations are not regulated differently to other space activities.

Conflict Analysis of Iranian Military-Communications Satellite Launches

Conflict Analysis of Iranian Military-Communications Satellite Launches

Management of Celestial Systems under Spatial Grasp Model

Many governmental agencies and private companies of different countries are now rushing into space around Earth in hope to provide smart communication, industrial, security, and defense solutions. This often involves massive launches of cheap small satellites which are also contributing to the growth of space debris. The current paper discusses how the developed high-level system philosophy and model can effectively organize distributed space-based systems on different stages of their development and growth. The briefed Spatial Grasp Technology, based on parallel pattern-matching of distributed environments with high-level recursive mobile code, can effectively provide any networking protocols and important applications of large satellite constellations, especially those on Low Earth Orbits. The paper contains examples of technology-based solutions for establishing basic communications between satellites, starting from their initial, often chaotic, launches and distributing and collecting data in the growing constellations with even unstable and rapidly changing connections between satellites. It describes how to organize and register networking topologies in case of predictable distances between satellites, and how the fixed networking structures can help in solving complex problems. The latter including those related to the new Space Development Agency multiple-satellite defense-oriented architecture and allowing for effective integration of its continuous earth custody observation and cooperative missile tracking and elimination layers, based on self-spreading mobile intelligence. Earlier versions of the technology, described in many papers, six books including, were prototyped and used in different countries, with the current one quickly implementable too, even in university-based environments.

Very High-Resolution Satellite-Derived Bathymetry and Habitat Mapping Using Pleiades-1 and ICESat-2

Accurate and reliable bathymetric data are needed for a wide diversity of marine research and management applications. Satellite-derived bathymetry represents a time saving method to map large shallow waters of remote regions compared to the current costly in situ measurement techniques. This study aims to create very high-resolution (VHR) bathymetry and habitat mapping in Mayotte island waters (Indian Ocean) by fusing 0.5 m Pleiades-1 passive multispectral imagery and active ICESat-2 LiDAR bathymetry. ICESat-2 georeferenced photons were filtered to remove noise and corrected for water column refraction. The bathymetric point clouds were validated using the French naval hydrographic and oceanographic service Litto3D® dataset and then used to calibrate the multispectral image to produce a digital depth model (DDM). The latter enabled the creation of a digital albedo model used to classify benthic habitats. ICESat-2 provided bathymetry down to 15 m depth with a vertical accuracy of bathymetry estimates reaching 0.89 m. The benthic habitats map produced using the maximum likelihood supervised classification provided an overall accuracy of 96.62%. This study successfully produced a VHR DDM solely from satellite data. Digital models of higher accuracy were further discussed in the light of the recent and near-future launch of higher spectral and spatial resolution satellites.

Flight Experiment Validation of Altitude Measurement Performance of MOSIR on Tianwen-1 Orbiter

The MOSIR (Mars Orbiter Subsurface Investigation Radar) is one of the scientific payloads carried by the Tianwen-1 orbiter. MOSIR conducted a ground experiment in the desert near Dengkou County, northern China, before the launch of the Tianwen-1 satellite. The MOSIR prototype was suspended from a hot air balloon and flew over a flat region at an altitude of 2500–3300 m. This experiment aimed to verify the system performance and data processing. The data collected in subsurface sounding mode is performed range compression, and the altitude measurement data removes invalid data. After processing, the altitude measurement results of two operating modes are analyzed and compared with that of the Global Position System (GPS), which verifies the accuracy of the altitude measurement.

History and activities of the Kourovka astronomical observatory of the Ural university

The history of origin and scientific activities of the suburban Astronomical Observatory of the Ural University are associated with K.A. Barkhatova’s life and work, among her achievements were restoration of the Department of Astronomy and Geodesy in 1960, and the resumption of the training of specialists in astronomy and geodesy. The First satellite launch on October 4, 1957 was great stimulus for the opening of department. A station for optical observations of satellites was organized in Sverdlovsk. Successful scientific and academic work of the department required a modern, properly equipped suburban observatory. Yu.A. Gagarin flight around the Earth on April 12, 1961 aroused unprecedented interest in astronomy and space among people and accelerated the resolution of the issue of an observatory construction. K.A. Barkhatova, with the support of colleagues from the Astronomical Council of the USSR Academy of Sciences, other observatories of the country, rector of the Ural University, and the public took up the construction. In 1963 the observatory near Kourovka station was founded. January 12, 1965 is considered to be the birthday of the new observatory. K.A. Barkhatova was it’s scientific adviser; at present, the observatory is named after her. The observatory performs observations on modern equipment, conducts excursions for students, teachers and public. Each year, the observatory hosts a student scientific conference "Physics of Space" – a unique astronomical school for young students and graduate students.

Certain analysis of a solid rocket motor (SRM) with modified pentagonal grain configuration

Solid propellant rocket motors (SRMs) have wide range of usage in satellite launchers. SRM uses solid propellant grains with different types of perforations. Usage of perforations with cornered shapes (i.e., square, rectangle, pentagon etc.) results in higher burning rate which results in sudden decrease of chamber pressure (or thrust). Since change of state of burning is not desirable, these kinds of perforations cannot be used for SRMs. Better reduction in burning rate can be achieved by changing the geometrical configuration of these shapes which enables the usage of cornered shapes as grain perforations in SRMs. Design and analysis of grain configurations with number of web steps can be used as tool for predicting the performance of rocket motors. Burn back steps of the grain can be predicted for required intervals of time by 2D design using CATIA. In this study, burn back steps of 3D grains with different types of pentagonal configuration perforations was investigated. For each web step, a 3D model was prepared and a required performance characteristic was obtained using analytical calculations. CFD simulation of the 3D grain was done in ANSYS (FLUENT) to assure the validity of the grain geometry of SRM. Various types of CFD models were used for CFD simulation in the field of SRM in this study, standard k-ɛ model is used for simulation purpose.

Modeling and assessment of multi-frequency GPS/BDS-2/BDS-3 kinematic precise point positioning based on vehicle-borne data

BeiDou Navigation Satellite System (BDS) has got the global service capability after the launch of the 55th BDS-3 satellite on June 23, 2020. Currently, BDS is operated based on both the second generation BDS (BDS-2, with 15 satellites transmitting triple frequency signals) and the third generation BDS (BDS-3, with 30 satellites providing services from five frequency signals). To make full use of BDS-2 + BDS-3 signals (B1I, B2I, B3I, B1C, and B2a), this paper introduces an undifferenced and uncombined Precise Point Positioning (PPP) model by using single/dual/triple frequencies BDS-2/BDS-3 data. Results illustrate that the Root Mean Square (RMS) values of BDS-3 PPP based on new signals are better than BDS-2 (B1I + B3I), but worse than BDS-3 (B1I + B3I). Generally, triple-frequency PPP is close to that of dual-frequency PPP, but it is improved significantly in the north, east and vertical components comparing with single-frequency PPP. Compared to the positioning accuracy of GPS + BDS-2 PPP, those of GPS + BDS-3 PPP are improved obviously, especially in the horizontal components. While using BDS-2 and BDS-3 together, the positioning performance of GPS + BDS-2 + BDS-3 is upgraded significantly in both horizontal and vertical directions. Moreover, the convergence time of BDS-3 (especially B1C + B2a) and BDS-2 + BDS-3 PPP are accelerated visibly comparing with that of BDS-2 PPP.

National-Scale Cropland Mapping Based on Phenological Metrics, Environmental Covariates, and Machine Learning on Google Earth Engine

Many challenges prevail in cropland mapping over large areas, including dealing with massive volumes of datasets and computing capabilities. Accordingly, new opportunities have been opened at a breakneck pace with the launch of new satellites, the continuous improvements in data retrieval technology, and the upsurge of cloud computing solutions such as Google Earth Engine (GEE). Therefore, the present work is an attempt to automate the extraction of multi-year (2016–2020) cropland phenological metrics on GEE and use them as inputs with environmental covariates in a trained machine-learning model to generate high-resolution cropland and crop field-probabilities maps in Morocco. The comparison of our phenological retrievals against the MODIS phenology product shows very close agreement, implying that the suggested approach accurately captures crop phenology dynamics, which allows better cropland classification. The entire country is mapped using a large volume of reference samples collected and labelled with a visual interpretation of high-resolution imagery on Collect-Earth-Online, an online platform for systematically collecting geospatial data. The cropland classification product for the nominal year 2019–2020 showed an overall accuracy of 97.86% with a Kappa of 0.95. When compared to Morocco’s utilized agricultural land (SAU) areas, the cropland probabilities maps demonstrated the ability to accurately estimate sub-national SAU areas with an R-value of 0.9. Furthermore, analyzing cropland dynamics reveals a dramatic decrease in the 2019–2020 season by 2% since the 2018–2019 season and by 5% between 2016 and 2020, which is partly driven by climate conditions, but even more so by the novel coronavirus disease 2019 (COVID-19) that impacted the planting and managing of crops due to government measures taken at the national level, like complete lockdown. Such a result proves how much these methods and associated maps are critical for scientific studies and decision-making related to food security and agriculture.

The Current State and Future Directions of Modeling Thermosphere Density Enhancements During Extreme Magnetic Storms

Satellites, crewed spacecraft and stations in low-Earth orbit (LEO) are very sensitive to atmospheric drag. A satellite’s lifetime and orbital tracking become increasingly inaccurate or uncertain during magnetic storms. Given the planned increase of government and private satellite presence in LEO, the need for accurate density predictions for collision avoidance and lifetime optimization, particularly during extreme events, has become an urgent matter and requires comprehensive international collaboration. Additionally, long-term solar activity models and historical data suggest that solar activity will significantly increase in the following years and decades. In this article, we briefly summarize the main achievements in the research of thermosphere response to extreme magnetic storms occurring particularly after the launching of many satellites with state-of-the-art accelerometers from which high-accuracy density can be determined. We find that the performance of an empirical model with data assimilation is higher than its performance without data assimilation during all extreme storm phases. We discuss how forecasting models can be improved by looking into two directions: first, to the past, by adapting historical extreme storm datasets for density predictions, and second, to the future, by facilitating the assimilation of large-scale thermosphere data sets that will be collected in future events. Therefore, this topic is relevant to the scientific community, government agencies that operate satellites, and the private sector with assets operating in LEO.

Three-dimensional and long-term landslide displacement estimation by fusing C- and L-band SAR observations: A case study in Gongjue County, Tibet, China

Recently, a large number of synthetic aperture radar (SAR) images has been introduced into landslide investigations with the growing launch of new SAR satellites, such as ALOS/PALSAR-2 and Sentinel-1. Therefore, it is appropriate to develop new approaches to retrieve three-dimensional (3D) displacements and long-term (> 10 years) displacement time series to investigate the spatio-temporal evolution and creep behavior of landslides. In this study, a new approach for the estimation of 3D and long-term displacement time series of landslides, based on the fusion of C- and L-band SAR observations, is presented. This method is applied to map 3D and long-term displacements (nearly 12 years) of the landslides in Gongjue County, Tibet in China; four sets of SAR images from different platforms (i.e., L-band ascending ALOS/PALSAR-1, C-band descending ENVISAT, and C-band ascending and descending Sentinel-1 SAR datasets) covering the period of January 2007 to November 2018 were collected and exploited. First, the assumption that the landslide moves parallel to its ground surface is used to produce 3D displacement rates and time series by fusing ascending and descending Sentinel-1 SAR images, from which the optimal sliding direction for each pixel of the slope is well estimated. Then, the long-term displacement time-series of the landslide between January 2007 and October 2018 in the estimated sliding direction is recovered by fusing L-band ALOS/PALSAR-1 and C-band Sentinel-1 SAR images. In order to fill the time gap of nearly four years between ALOS/PALSAR-1 and Sentinel-1 SAR images, the Tikhonov regularization (TR) method is developed to establish the observational equation. Moreover, to solve the problem arising from ALOS/PALSAR-1 and Sentinel-1 images with different wavelengths, incidence angles and flight directions, the measurements from ALOS/PALSAR-1 and Sentinel-1 images are both projected to the estimated optimal sliding direction to achieve a unified displacement datum. Our results from ascending and descending Sentinel-1 images suggest that the maximum displacement rates of the study area in the vertical and east-west directions from December 2016 to October 2018 were greater than 70 and 80 mm/year, respectively, and 2D displacement results reveal that the displacement patterns and movement characteristics of all the detected landslides are not identical in the study area. Specifically, the 3D displacement results successfully revealed the spatiotemporal displacement patterns and movement direction of each block of the Shadong landslide, and long-term displacement time series showed for the first time that the maximum cumulative displacement exceeds 1.3 m from January 2007 to October 2018. Moreover, the kinematic evolution and possible driving factors of landslides were investigated using 2D and 3D and long-term displacement results, coupled with hydrological factors and unidimensional constitutive models of the rocks.

Similarity based telemetry data recovery for enhancing operating reliability of satellite

Recently, the satellite launching grows rapidly, especially in the commercial aerospace, which produces thousands of in-orbit spacecrafts. The operation and ground management of these satellites is a hotspot issue to ensure the satellites' in-orbit operation reliability. The telemetry data transmission may be delayed by the unstable telemetry link, insufficient ground station sources, interface failures and so on, which exerts a negative influence on the ground management capability and increases the failure risk. Meanwhile, the deep space spacecrafts, space station and Mars exploration expand this transmission delay. Thus, management and intelligent analysis of the telemetry data from Telemetry Ground Station (TGS) gradually become critical for in-orbit satellite operation. To solve above issues, a similarity-based deep learning time series prediction method is proposed to achieve telemetry data recovery. Considering the pseudo-periodic characteristics in telemetry data, this approach extracts similar segments to construct training samples instead of feeding all the observation samples to train the prediction model. As the predicted data is obtained ahead of the actual time-delayed telemetry data, which can provide sufficient analysis time for ground operator to optimize the maintenance strategy. Furthermore, the telemetry prediction data can also guarantee high-complexity digital twin modelling, virtual maintenance and so on. Experimental results with actual satellite telemetry data verify the effectiveness of the proposed method.

Take Your Time? How Activity Timing Affects Organizational Learning and Performance Outcomes

Organizational learning theory has long examined how organizations learn to perform better as they accumulate experience. Although experience accumulation is inherently related to the timing of the repeated activities carried out by an organization, the direct relationship between activity timing and organizational learning has not been examined explicitly in the literature and remains an open question. Organizational learning theory contains two competing perspectives on how timing should impact learning—one suggesting that iterating faster is better for learning and one suggesting that taking more time between iterations is more helpful. Here, we reconcile these perspectives and develop a theory about the boundary conditions between them, arguing that, in general, iterating more rapidly enhances learning but that iterations of novel or complex activities, or ones following recent failure, benefit from a slower pace. We conduct tests of this theoretical perspective using data from the entire history of the orbital satellite launch industry from 1957–2017, and we find broad support for our theory and hypotheses.

A chlorophyll-a retrieval algorithm for the Coastal Zone Imager (CZI) onboard the HY-1C satellite in the Pearl River Estuary, China

ABSTRACT Accurate estimation of the near-surface chlorophyll-a (Chl-a) concentration in turbid estuaries via remote sensing is an ongoing challenge. Recently, with the successful launch of the third satellite of the China Ocean Colour Satellite Series, HY-1 C, equipped with the Coastal Zone Imager (CZI) with a 3-day revisit period and 50-m resolution in four bands, this study constructed a Chl-a inversion model via symbolic regression (SR) in the Pearl River Estuary (PRE) considering 60 in situ samples to explore the current ocean colour monitoring potential of the CZI. Compared to five state-of-the-art algorithms, the SR model attained a lower mean absolute percentage error (MAPE, 35.51%), mean absolute error (MAE, 1.56) and root-mean-square error (RMSE, 0.24). Additionally, the Chl-a spatial distributions determined with the SR model also better coincided with those determined with synchronous satellite products. The above results indicate that the SR model performed better than the five state-of-the-art models and could be effectively applied to turbid PRE waters. This research may provide a reference regarding the practicality and feasibility of the CZI in water environment monitoring in coastal and estuarial waters at a high temporal-spatial resolution.

Probability for cosmic masses of the main asteroid belt to approach the Earth

The problem of space flights safety arose with the beginning of the first launches of artificial Earth satellites. With expansion of the boundaries of space flights, the area of outer space that must be controlled to ensure flight safety is significantly increasing.In this study, we consider the possibility of capturing space objects into near-planetary space and further movement of these objects. Such statistical analysis is very important when planning the long-term flights.The objects of our research are both: the particles that came from deep space and the evolving asteroids of the Main asteroid belt. A special attention is paid to the evolution of the Griqua family of asteroids, which belong to the main asteroid belt, and move in orbital resonance with Jupiter.

Assessment of environmental risks of space activities as a determinant of global security

The paper investigates environmental risks of space activities in ensuring the concept of Clean Space as an integral component of global security. It has been proven that man-made debris in orbital space reached catastrophic proportions which calls upon immediate changes with the purpose of sustainable development of space activities. The work incorporates an elaborated classification of environmental risks that occur in the process of space activities, divided into four groups: by the source of risk, by type of orbit, by cause and effect and by the possibility of influence. It has been determined that countries to have generated the most space debris objects are Russia (the USSR), USA and China. Ukrainian national legislation in the sphere of space activities is currently at the stage of harmonization with international space agencies. Numerous issues remain insufficiently substantiated: improvement of the Technical Regulations for space activities, Procedures of liability insurance for damage inflicted to the space object, since the respective insurance contract must be one of the documents mandatory for fulfilling international obligations of the state with regard to its accountability for any type of national space activities. It has been established that apart from the Kessler effect there also exists a temporality effect – the effect of ”lengthened” time combined with the effect of its acceleration (singularity) – accelerated development of situational changes. This affects the catastrophic state of space debris cluttering in Earth’s orbit since the launch of the first artificial satellite. The paper examines a particular range of risks in accordance with two phases of the technological lifespan of space systems – ‘Operation’ & ‘Utilization’. It is stipulated by the fact that namely in these phases there exists the highest probability of occurrence of major risks of “influence”. Prospects of further research consist in the development of the system for assessment of risks of influence at all phases of the technological lifespan of space systems: ‘Mission analysis/needs definition’; ‘Feasibility’; ‘Preliminary design’; ‘Detailed design’; ‘Qualification & Production’; ‘Operation’; ‘Utilization’.

FY-3E: The First Operational Meteorological Satellite Mission in an Early Morning Orbit

Fengyun-3E (FY-3E), the world’s first early-morning-orbit meteorological satellite for civil use, was launched successfully at the Jiuquan Satellite Launch Center on 5 July 2021. The FY-3E satellite will fill the vacancy of the global early-morning-orbit satellite observation, working together with the FY-3C and FY-3D satellites to achieve the data coverage of early morning, morning, and afternoon orbits. The combination of these three satellites will provide global data coverage for numerical weather prediction (NWP) at 6-hour intervals, effectively improving the accuracy and time efficiency of global NWP, which is of great significance to perfect the global earth observing system. In this article, the background and meteorological requirements for the early-morning-orbit satellite are reviewed, and the specifications of the FY-3E satellite, as well as the characteristics of the onboard instrumentation for earth observations, are also introduced. In addition, the ground segment and the retrieved geophysical products are also presented. It is believed that the NWP communities will significantly benefit from an optimal temporal distribution of observations provided by the early morning, mid-morning, and afternoon satellite missions. Further benefits are expected in numerous applications such as the monitoring of severe weather/climate events, the development of improved sampling designs of the diurnal cycle for accurate climate data records, more efficient monitoring of air quality by thermal infrared remote sensing, and the quasi-continuous monitoring of the sun for space weather and climate.

Using Remote Sensing and an Unmanned Aerial System for Weed Management in Agricultural Crops: A Review

Weeds are unwanted plants that can reduce crop yields by competing for water, nutrients, light, space, and carbon dioxide, which need to be controlled to meet future food production requirements. The integration of drones, artificial intelligence, and various sensors, which include hyperspectral, multi-spectral, and RGB (red-green-blue), ensure the possibility of a better outcome in managing weed problems. Most of the major or minor challenges caused by weed infestation can be faced by implementing remote sensing systems in various agricultural tasks. It is a multi-disciplinary science that includes spectroscopy, optics, computer, photography, satellite launching, electronics, communication, and several other fields. Future challenges, including food security, sustainability, supply and demand, climate change, and herbicide resistance, can also be overcome by those technologies based on machine learning approaches. This review provides an overview of the potential and practical use of unmanned aerial vehicle and remote sensing techniques in weed management practices and discusses how they overcome future challenges.