Satellite Launch Research Articles

Space flight mechanics theoretist and practitioner. On the 100th anniversary of the birth of academician T.M. Eneev

The article presents materials about Academician Timur Magometovich Eneev, an outstanding scientist in the field of space flight mechanics, one of the founders of modern space flight dynamics. His works have made a significant contribution to the achievements of world science. Namely, his contribution to the launch of the first artificial satellite of the Earth, the flight of Yuri Gagarin, to the implementation of flights to the Moon, planets of the Solar system, to the study of small bodies of the Solar system, to the theory of cosmogony, solving problems of genetics is great. The new mathematical methods proposed by T.M. Eneev to solve the problems of space exploration constitute the golden fund of Russian astrodynamics and are successfully used for the implementation of Russian space exploration projects. T.M. Eneev is not only an outstanding scientist, but also a citizen of our Fatherland, who responded to the problems of the formation of science, cosmonautics, cosmogony, biology and other issues of concern to modern society.

Research on Distributed Autonomous Timekeeping Algorithm for Low-Earth-Orbit Constellation

The time of a satellite navigation system is primarily generated by the main control station of the ground system. Consequently, when ground stations fail, there is a risk to the continuous provision of time services to the equipment and users. Furthermore, the anticipated launch of additional satellites will further strain the satellite–ground link. Next-generation satellite navigation systems will rely on time deviation measurements from inter-satellite links to independently establish and maintain a space-based time reference, enhancing the system’s reliability and robustness. The increasing number of low-Earth-orbit satellite navigation constellations provides ample resources for establishing a space-based time reference. However, this also introduces challenges, including extensive time scale computations, increased link noise, and low clock resource utilization. To address these issues, this paper proposes a Distributed Kalman Plus Weight (D-KPW) algorithm, which combines the benefits of Kalman filtering and the weighted average algorithm, balancing the performance with computational resources. Furthermore, an adaptive clock control algorithm, D-KPW (Control), is developed to account for both the short-term and long-term frequency stability of the time reference. The experimental results demonstrate that the frequency stability of the time reference established by the D-KPW (Control) algorithm reaches 7.40×10−15 and 2.30×10−15 for sampling intervals of 1000 s and 1,000,000 s, respectively, outperforming traditional algorithms such as ALGOS. The 20-day prediction error of the time reference is 1.55 ns. Compared to traditional algorithms such as AT1, ALGOS, Kalman, and D-KPW, the accuracy improves by 65%, 65%, 66%, and 67%, respectively.

Studies on multiple weld repairs of M250 maraging steel for solid motor casing used in satellite launch vehicle application

Studies on multiple weld repairs of M250 maraging steel for solid motor casing used in satellite launch vehicle application

Fuel Ignition in HTP Hybrid Rockets at Very Low Mass Fluxes: Challenges and Pulsed Preheating Techniques Using Palladium-Coated Catalysts

In a worldwide scenario which sees an increasing number of small satellite launches, novel mission concepts may be unlocked providing the spacecrafts with the very precise and rapid maneuvering capability that electric thrusters cannot guarantee. In this context, chemical thrusters appear to be a possible solution. This work aimed to experimentally study and solve the problem of ignition for 10 N hybrid rockets based on hydrogen peroxide. Firstly, the study analyzed the performance of a monopropellant engine capable of functioning as a hybrid injection system. In particular, the effects of the liquid mass injected, the initial temperature, and the supply pressure on the pulsed engine performance were experimentally investigated. The injected mass showed a greater impact on the performance with respect to the starting chamber temperature and injection pressure. This thruster also showed a good potential for space applications. In the second part of the work, the objective was to find an ignition procedure that reduced propellant consumption and eliminated the need for a glow plug. This is important because the electrical power consumption in real applications significantly affects other subsystems and is undesirable for chemical engines. Different ignition procedures were tested to emphasize their respective advantages and disadvantages, and the findings indicated that the concept of pulsed preheating is feasible with only a small amount of propellant consumption, while substantially decreasing the ignition duration from approximately 45 min to a maximum of just 3 min. Finally, similar ignition procedures were adopted using different fuels. The results showed that PVC and ABS, under the same operating conditions, ignite more easily than HDPE, which requires an oxidizer consumption approximately double that of the other two fuels. Considerations about the effect of chamber pressure and oxidizer mass flow rate on engine ignition were also included.

Precision Manufacturing in China of Replication Mandrels for Ni-Based Monolithic Wolter-I X-ray Mirror Mandrels

The X-ray satellite “Einstein Probe” of the Chinese Academy of Sciences (CAS) was successfully launched on 9 January 2024 at 15:03 Beijing Time from the Xichang Satellite Launch Center in China with a “Long March-2C” rocket. The Einstein Probe is equipped with two scientific X-ray telescopes. One is the Wide-field X-ray Telescope (WXT), which uses lobster-eye optics. The other is the Follow-up X-ray Telescope (FXT), a Wolter-I type telescope. These telescopes are designed to study the universe for high-energy X-rays associated with transient high-energy phenomena. The FXT consists of two modules based on 54 thin X-ray Wolter-I grazing incidence Ni-replicated mirrors produced by the Italian Media Lario company, as contributions from the European Space Agency and the Max Planck Institute for Extraterrestrial Physics (MPE), which also provided the focal-plane detectors. Meanwhile, the Institute of High Energy Physics (IHEP), together with the Harbin Institute of Technology and Xi’an Institute of Optics and Precision Mechanics, has also completed the development and production of the structural and thermal model (STM), qualification model (QM) and flight model (FM) of FXT mirrors for the Einstein Probe (EP) satellites for demonstration purposes. This paper introduces the precision manufacturing adopted in China of Wolter-I X-ray mirror mandrels similar to those used for the EP-FXT payload. Moreover, the adopted electroformed nickel replication process, based on a chemical nickel–phosphorus alloy, is reported. The final results show that the surface of the produced mandrels after demolding and the internal surface of the mirrors have been super polished to the roughness level better than 0.3 nm RMS and the surface accuracy is better than 0.2 μm, and the mirror angular resolution for single mirror shells may be as good as 17.3 arcsec HPD (Half Power Diameter), 198 arcsec W90 (90% Energy Width) @1.49 keV (Al-K line). These results demonstrate the reliability and advancement of the process. As the first efficient X-ray-focusing optics manufacturing chain established in China, we successfully developed the first focusing mirror prototype that could be used for future X-ray satellite payloads.

Reconstructing a Fine Resolution Landscape of Annual Gross Primary Product (1895–2013) with Tree-Ring Indices

Low carbon management and policies should refer to local long-term inter-annual carbon uptake. However, most previous research has only focused on the quantity and spatial distribution of gross primary product (GPP) for the past 50 years because most satellite launches, the main GPP data source, were no earlier than 1980. We identified a close relationship between the tree-ring index (TRI) and vegetation carbon dioxide uptake (as measured by GPP) and then developed a nested TRI-GPP model to reconstruct spatially explicit GPP values since 1895 from seven tree-ring chronologies. The model performance in both phases was acceptable: We chose general regression neural network regression and random forest regression in Phase 1 (1895–1937) and Phase 2 (1938–1985). With the simulated and real GPP maps, we observed that the GPP for grassland and overall GPP were increasing. The GPP landscape patterns were stable, but in recent years, the GPP’s increasing rate surpassed any other period in the past 130 years. The main local climate driver was the Palmer Drought Severity Index (PDSI), and GPP had a significant positive correlation with PDSI in the growing season (June, July, and August). With the GPP maps derived from the nested TRI-GPP model, we can create fine-scale GPP maps to understand vegetation change and carbon uptake over the past century.

Microstructure characterization and formability assessment of electron beam welded Nb-10Hf-1Ti (wt.%) refractory alloy sheets

Formability study on welded blanks of Nb-based refractory alloy C-103 (Nb-10Hf-1Ti (wt.%)) has tremendous potential for utilizing smaller sheets for realization of large-size divergent portions of upper-stage liquid engine nozzle of satellite launch vehicles and thrusters of attitude orbital control systems. In this work, vacuum-annealed monolithic C-103 sheets were electron beam welded successfully to obtain defect-free welds and detailed microstructural and mechanical characterizations were investigated. Columnar epitaxial grains were found in fusion zone (FZ) instead of equiaxed grains in base metal (BM). Detailed SEM and HRTEM analyses revealed spherical shape of nano-sized HfO2 precipitates with monoclinic crystal structure in the C-103 sheet. Further, microhardness across the weld cross-section indicated that the FZ had a uniform and maximum hardness of ∼195 HV0.5 due to formation of finer nano-sized HfO2 precipitates with higher number density, followed by a lowering of hardness in a narrow heat-affected zone. A marginal reduction in tensile strength of ∼6% with a considerable decrease in ductility of ∼29% was noticed for the welded sample. However, fracture occurred in the BM region, indicating good weld integrity. Furthermore, formability of the welded blanks was evaluated in terms of limiting dome height (LDH), forming limit diagram, and deep drawn cup depth. The effect of the presence of WZ on the formability of the C-103 sheet was estimated under uniaxial, plane strain, and biaxial tensile strain paths for the first time, and the results were compared with the monolithic sample. It was noted that the failure limit of the welded specimens decreased compared to that of the monolithic sample, resulting in a lower LDH of approximately 69% and 62% when deformed along plane strain and biaxial tensile strain paths, respectively. However, a marginal variation in LDH was observed for the uniaxial strain path. Also, the welded blank had more resistance to material flow into the die cavity due to the harder weld region, resulting in a reduction of deep drawn cup depth by 52% than that of the monolithic blank. The overall results concluded that the presence of the WZ significantly affected the formability of the C-103 sheet, especially in plane strain and biaxial strain paths. However, the fracture was never found to be propagating along the weld line, indicating the ability of the weld to sustain large plastic strains. This study provides insightful information on the formability of electron beam welded C-103 sheets for the successful fabrication of space components.

On-orbit spectral characteristics analysis of the greenhouse gases monitoring instrument: Spectral wavelength stability and instrumental line shape stability

The Greenhouse Gases Monitoring Instrument (GMI) is a carbon satellite payload developed based on the principle of spatial heterodyne spectroscopy technology, which is specifically designed for the global analysis of greenhouse gases (CO2 and CH4) “sources” and “sinks”. Due to the low concentration and minimal gradient variations of CO2 and CH4 in the atmosphere, higher precision is required for their retrieval. Vibrations during satellite launch and harsh space environments during on-orbit operation may cause changes in the performance of various payload components, resulting in decreased quality of spectrum products and retrieval precision. This paper proposes a set of on-orbit spectral characteristic evaluation methods tailored for the GMI to monitor the quality of its spectrum. It also develops an adaptive blind pixel detection and correction algorithm specifically for the GMI and optimizes the interferogram processing flow algorithm. On-orbit spectral calibration is performed, and methods to evaluate spectral characteristic parameters have been established. The analysis focuses on the variations of the spectral characteristics in the CO2-1 bands (1.575 μm) of the GMI during one-year of on-orbit calibration spectrum. The initial spectral wavenumber offset is 0.133 cm−1 after entering orbit, and the average spectral wavenumber offset is 0.0313 cm−1 during stable operation. During the one-year period, the maximum variation in the instrumental line shape function of the GMI is 0.006 cm−1. The observed spectrum obtained in nadir observation mode, underwent to accuracy verification. The results demonstrate consistency between the spectral peak wavenumbers and the relative trend changes of the observed and theoretical spectrum, with an average relative residual of 0.987%.

Effect of aging temperature on the redrawn cup wall of a novel Cu-0.5Cr-0.05Zr-0.05Ti (wt.%) alloy sheet: Analyses on microstructure evolution, mechanical properties and strengthening mechanism

A solution-treated Cu-0.5Cr-0.05Zr-0.05Ti (wt.%) alloy was drawn into a large-depth cup implementing a two-stage deformation process in the present study, firstly using a ∅50 mm cylindrical punch and subsequently redrawn by a ∅34 mm punch. The redrawn cup wall was subjected to aging heat treatment up to 400 °C, 500 °C, and 600 °C for 2 h followed by water quenching to understand the microstructural evolution and its correlation with mechanical properties. These aging temperatures were adopted to simulate a similar environmental condition in which the inner liner of the thrust chamber of cryogenic and semi-cryogenic engines was exposed during satellite launching. It was identified that the above aging temperatures influenced the grain characteristics, recrystallization, and annealing twin formation significantly. The redrawn cup wall possessed semi-coherent bcc spherical Cr-rich precipitates with an average size of 1.8 ± 0.1 nm, which progressively increased to 5.5 ± 0.3 nm at 600 °C, while the precipitate volume fraction increased to a maximum of 1.2% at 500 °C. The precipitation mostly influenced the strength, while the recrystallization and twin formation governed the ductility during the aging. After an initial decrement at 400 °C, the yield strength of the aged specimen was increased to a maximum of 193 MPa with a concurrent increase in ductility to 24% upon the optimal aging at 500 °C. However, a higher increment in the strength than the ductility indicated the dominance of the precipitation. Further increase in the temperature to 600 °C reduced the strength while considerably enhancing the ductility. This was attributed to the highest recrystallization and twin fraction, as well as precipitate coarsening with reduced volume fraction. Moreover, precipitation strengthening prevailed in the aged specimens, unlike dislocation strengthening in the redrawn condition. The contribution from the former was maximum at 500 °C with a 52% share of the total estimated strength, whereas it was only 31% in the redrawn specimen.

First observation results of Macao Science Satellite 1 on lightning-induced electron precipitation

AbstractThe mid-energy electron detector (MEED) is a space-borne instrument onboard Macao Science Satellite 1 (MSS-1) dedicated to monitoring the typical charged particle radiation characteristics in the satellite orbit and the process of their occurrence and development, including short bursts of lightning-induced electron precipitation (LEP). This paper presents the first results of the LEP measurements by the MSS-1. 47 LEP events are identified with the routine operation for 3 months since satellite launch, all within the range of 1.5<L<3.0 (where L represents the McIlwain L-parameter), and the causative lightning discharges are definitively geo-located for these LEP events. The LEP events occur within <1 s of the causative lightning and consist of 40–300 keV electrons. A preliminary observation result indicates that, with medium-energy electron detectors, MSS-1 can present in-situ observations of large regions of enhanced background precipitation and reveal their fine spatiotemporal characteristics and spectral signatures. The collaborative VLF ground-based measurements at the Great Wall Station, Antarctica also have a good correspondence with LEP measurements of MSS-1. The observations also imply that lightning activity has a modulation effect on the energetic electron energy-spatial structure.

Verification of the accuracy of Sentinel-1 for DEM extraction error analysis under complex terrain conditions

The successful launch of the Sentinel-1 satellite in 2014 brought a large amount of free SAR images to researchers and scholars, and its application in the fields of ocean monitoring, land use change, natural disaster monitoring and emergency response is becoming increasingly mature and precise. The main applications of InSAR can be categorized into surface deformation monitoring and DEM generation. Sentinel-1 was initially designed for surface deformation monitoring; thus, there are fewer relevant studies on the use of Sentinel-1 data for DEM extraction. However, as the only SAR satellite whose data are currently free and openly available and whose data are constantly updated, it is highly important to study its sources of error in the DEM generation process and the accuracy of its products. In addition, the SAR data provided by the Sentinel-1 satellite has the advantages of high resolution, all-day, all-weather, providing a large data source for DEM production. Taking the Ankang area as an example, this paper analyzes the influence of the InSAR spatiotemporal baseline, ground cover, terrain factors, SAR imaging and other factors on the accuracy of the Sentinel-1-extracted DEM using multisource ground observation data to validate its feasibility for terrain mapping in complex terrain. Finally, we look forward to how to effectively improve the quality of Sentinel-1 DEM products to provide guidance and a reference for subsequent research on DEM extraction using Sentinel-1 SAR images and designation of Sentinel-1 C satellite’s parameters.

A Review on Drag Reduction and Stability Optimization Techniques for Small Satellite Launch Vehicles

A Review on Drag Reduction and Stability Optimization Techniques for Small Satellite Launch Vehicles

Motion interval prediction of a sea satellite launch platform based on VMD-QR-GRU

Accurately forecasting the motion of a sea satellite launch platform is crucial for decision support in selecting the optimal launch window and ensuring safety during sea launches. Hence, this paper proposes a novel hybrid prediction model that integrates gated recurrent units (GRU), variational mode decomposition (VMD), and quantile regression (QR) to predict the motion interval of the launch platform. The VMD algorithm effectively captures the multi-scale features of the data, while the QR-GRU model excels in handling nonlinear time series and providing enriched information. Combining the VMD, QR, and GRU leverages their respective strengths, resulting in enhanced prediction accuracy and stability. The experimental data were derived from field measurements of a satellite launch platform during its sea voyage and launch process. By comparing the VMD-QR-GRU model with other models, it was found that the comprehensive metrics for interval prediction of roll and pitch reduced by over 1.4% and 15.7%, respectively. Additional analysis was conducted to evaluate the robustness and transferability of the model, considering various scenarios such as different training data volumes, varying prediction durations, and different states of platform. The VMD-QR-GRU model consistently yielded satisfactory results, underscoring its effectiveness and reliability in predicting sea satellite launch platforms motion.

Reindeer, rockets and space infrastructures: Enacting oligoptic-satellitarian environments in Northern Sweden

This article focuses on a series of connections between space infrastructures and environments in northern Sweden. Swedish space professionals often highlight the centrality of outer space for contemporary imaginaries about the planet as an interconnected whole. At the same time, the country's sounding rocket range outside the city of Kiruna relies on deep-seated constructions of the subarctic environment as empty wilderness. With the ongoing development of small satellite launch capability, the surrounding landscape needs to be sustained as an impact area, with the consequence that Sámi land practices are increasingly pushed to the sidelines. By turning to reindeer herders’ own uses of satellite technology, I delineate an oligoptic-satellitarian environment that runs athwart panopticonic understandings of satellite vision. Rather than trying to see everything from nowhere, the herders bring into view a limited set of more-than-human relations in order to challenge conceptions of the landscape as empty and exploitable. While showing that space activities in Sweden fold into and reproduce colonial histories, the article also argues that space infrastructures contain the potential for their own reconfiguration by eliciting the other worlds that are already being performed from within dominant socio-technical regimes.

High-Accuracy Phase Frequency Detection Technology Based on BDS Time and Frequency Signals.

For the time and frequency signals of Beidou satellites, a high-accuracy phase frequency detection technology based on phase group synchronization is proposed. Using the Beidou receiver and satellite signals as the frequency standard and the measured signals, respectively. The Beidou receiver and the satellite signals are sent to the phase coincidence detector of the different frequencies to generate a phase coincidence point pulse, which is sent to the different frequency phase detector as a control signal to generate the phase differences between the Beidou receiver and satellite signals, and then complete the high-accuracy phase synchronization between the Beidou receiver and satellite signals. Experimental results show that when the delay resolution reaches ps level, the phase synchronization accuracy of the system can reach 10 ps, which has the characteristics of small phase noise, low development cost, simple circuit structure, and high synchronization accuracy compared with the traditional phase synchronization technologies. Therefore, it would be widely used in satellite positioning, astrometry, precision navigation, aerospace, satellite launch, power transmission, communications, radar, and other high-tech fields.

Metallurgical Investigation of Non-separation in SS304L NC Pyrovalve of Satellite Launch Vehicle During Functional Test

Metallurgical Investigation of Non-separation in SS304L NC Pyrovalve of Satellite Launch Vehicle During Functional Test

Iterative design of satellite structures and topology optimisation methods

Abstract Satellite launches are critical amid increasing demands for advanced services. Rising costs urge innovation in engineering. Enhancing satellite structural integrity during launches is crucial due to intense vibrations. Topology optimisation and additive manufacturing converge as promising solutions. Topology optimisation uses mathematical techniques to iteratively improve structures by reducing mass while enhancing attributes like load capacity. This field, active for about three decades, employs continuum and discrete algorithms to optimise structures. Recent trends show optimised structures through topology optimisation and additive manufacturing promise cost-effective and high-performance solutions. This study aims to extensively review topology optimisation methods, specifically focusing on satellite structures, to shape future developments within the years to come.

The Influence of Space Traffic on AIM/CIPS PMC Frequencies at 80°N

AbstractWe explore the effects of lower thermospheric water vapor deposited by launch vehicle plumes on polar mesospheric cloud (PMC) frequencies at 80°N. We use July‐averaged PMC frequencies from 2007 to 2022 from the Cloud Imaging and Particle Size (CIPS) instrument on NASA's Aeronomy of Ice in the Mesosphere (AIM) satellite. Launch sites worldwide are typically located near northern mid‐latitudes. Using the orbital launch record for the same time period, we find that the number of launches correlates with PMC frequencies with a coefficient of r = 0.60, which increases to r = 0.75 when only selecting launches from 2.5 to 21.5 local time (LT), indicating a weak LT dependence on global‐scale transport to 80°N. To support our findings, we use meridional winds from the Michelson Interferometer for Global High‐resolution Imaging experiment on NASA's Ionospheric Connection Explorer satellite and winds from the Horizontal Wind Model climatology to interpret the northward motion of air parcels at 105 km. We find the launch LT window that maximizes the correlation coefficient to be consistent with the expected maximum northward motion from the diurnal variation of mid‐latitude meridional winds. Comparisons with Microwave Limb Sounder satellite observations of upper mesospheric temperature and water vapor reveal a strong dependence of cloud frequency on water vapor (r = 0.86) but not on temperature (r = −0.26), indicating that water vapor is the primary source of PMC variability for the bright PMCs at 80°N. We therefore find that launch vehicle plumes originating primarily from northern mid‐latitudes modulate PMC frequency at 80°N in July.

Reconsidering the Overlooked Threat of North Korea's Outer Space Activities: Focusing on the Menace of Militarization and Weaponization of Outer Space

What security implications do North Korea's purported peaceful space activities have? North Korea's recent launch of a reconnaissance satellite not only raises concerns about its nuclear weapons program but also has broader implications for international security. The nuclear threat posed by North Korea is certainly growing. However, there seems to be an overlooked security threat in North Korea's space initiative: the threat of militarization and weaponization of outer space. Therefore, the security policy toward North Korea must be changed comprehensively to address the militarization and weaponization of space, as North Korea's threats can be transformed by the use of space. North Korea's destructive weapons and strategies, such as EMP attacks and space hybrid operations, are not prohibited, even when they appear to be aligned with the outer space legal regime. Hence, rather than concentrating only on nuclear weapons, this study proposes that a fundamental shift in policy is required.

Influence of ideas of Russian cosmism on formation and development of scientific and technical elite of rocket engineering and cosmonautics

The article is devoted to the influence of philosophical and theoretical ideas of the scientific direction of Russian cosmism on their transformation into a scientific and practical plane – the creation of the rocket and space industry, the launch of satellites, rockets, and humans into space. The relevance of the problem considered in the article lies in the fact that space, while remaining the sphere of interests of the leading world powers competing with each other in political, economic, cultural, and military terms, remains a platform for international cooperation, on which factors of national and global security largely depend. In this work, space exploration is considered in the development from philosophical and scientific research of the late 19th – early 20th century to projects of private corporations investing in the exploration of the Moon, colonization of Mars, development of a fleet of interstellar ships for travel to the Alpha Centauri system in our days. Scientific novelty is determined by a comprehensive consideration of the dialectics of the intellectual, creative and pragmatic in matters of space exploration. In a short period of time, under the influence of the philosophical ideas of the scientific direction of cosmism, and their logical continuation in the form of the development of the theory of cosmonautics and rocket science, there was the emergence of a new stratum of society – scientific and technical elite, which brought the country to a new level of technical development, which allows it to remain the world's leading space power to this day.