Spacecraft Communications Research Articles

The metamaterial with high thermal-mechanical stability and the practical application as the microwave antenna: Mechanical designs, theoretical predictions, and experimental demonstrations

To address the demand of maintaining the structural configuration upon extreme temperature changes, metamaterials with high thermal-mechanical stability have attracted wide attention recently. However, there are still some challenges for previous studies regarding mechanical design and practical application exploration. This manuscript proposes the design strategy for the lattice sandwich metamaterial with excellent zero thermal-induced warping, along with the metamaterial-based antenna with a high stability of electromagnetic signal transmission. Through the design strategy of discrete lattice units of the metamaterial, the ultra-low thermal warping of the metamaterial is realized upon the non-uniform temperature field. Here, the theoretical model is established to predict both heat transfer and thermal-induced deformation behavior upon complex mechanical-thermal loading conditions. The combination of theoretical predictions, finite element analysis, and experiments verifies the thermal dimensional stability of the metamaterial proposed here. Compared with the heterogeneous bilayer plate, experimental thermal warping of the metamaterial specimen is reduced by 99.7%. Additionally, compared with the bilayer-based specimen, gain attenuation, the main lobe's offset angle, and the voltage standing wave ratio offset of the metamaterial-based antenna specimen are experimentally reduced by 99.5%, 99.9% and 74.2%, revealing the huge application potential of this metamaterial in the field of spacecraft communication.

Deep-Coupled Sliding Mode Disturbance Observer-Based Composite Attitude Control for Flexible Communication Spacecrafts

Deep-Coupled Sliding Mode Disturbance Observer-Based Composite Attitude Control for Flexible Communication Spacecrafts

Ensuring the thermal regime of spacecraft structures

The main requirement for the smooth operation of the spacecraft is its stable thermal regime. A particularly difficult task is to ensure a stable temperature control system of the device, taking into account strict restrictions on energy and mass costs for temperature control devices. These tasks need to be solved at every stage of the creation of satellites. At each stage, thermal calculations are carried out with the choice of optimal thermophysical parameters. This amount of work is about a tenth of all work with the satellite. The need for theoretical and experimental refinement of calculation methods is an urgent task that will significantly reduce the material and time costs of designing, testing and fine-tuning the device. Therefore, the calculation and analysis of the thermal regimes of spacecraft is an important stage in the design of satellites. Ground thermal vacuum tests are very costly, both in time and financially. The essence of the concept is to conduct only stationary thermal modes under conditions of maximum and minimum thermal loads on the satellite as a whole and its individual external elements, followed by ensuring convergence of test results with calculated results. And the confirmation of intermediate requirements to ensure the specified thermal conditions is carried out by calculation. The article considers the tasks of ensuring the thermal regime of spacecraft structures. Classification of devices used to ensure the thermal regime. Ground-based testing of the thermal regime of communication satellites during thermal vacuum tests. Ensuring the thermal regime of the communication spacecraft during ground-based electrical tests. Thermal regime of spacecraft structures during transportation from the manufacturer to the technical position.

Mathematical modeling of cross-corrugated waveguide shell formation

Flexible cross-corrugated shells are used to create flexible waveguides that connect rigid waveguides. They compensate for mounting stresses during assembly, provide temperature compensation and vibration damping. These waveguides are widely used in spacecraft communication systems, they are required – flexibility, mechanical strength, geometric accuracy and minimal energy loss when connected to the transmission line. In this paper, the process of corrugating rectangular profile pipes made of BrB 2 bronze to create transversely corrugated shells is investigated. Objectives of the work: 1) analysis of technological processes of corrugation of waveguide pipes to select the most accurate method; 2) conducting a numerical experiment to determine technological parameters. Based on the analysis of the methods of transverse corrugation, the most rational method of corrugation with a liquid punch on a solid matrix has been incorporated. The scientific novelty lies in the creation of a mathematical model based on the theory of bending moments and beam stretching. With its help, a mathematical experiment was carried out, which has an applied benefit for the calculations of technological operations, for the corrugation of a waveguide. The pressures necessary for corrugation for different corrugation geometries are found and patterns are revealed. The mathematical model has an applied use for preliminary calculations of technological operations of corrugation of rectangular pipes. The calculation allows you to choose the most optimal mode of the technological process: fluid pressure, deformation, change in yield strength, allowing you to produce a flexible waveguide qualitatively. The result of the calculations is useful in preliminary design to determine the size of the corrugating equipment and the effort required to implement the technological process of forming the corrugations of rectangular pipes.

Indian Interplanetary Missions - A Technology Perspective

The successful insertion of the Indian Mars Orbiter Mission in September 2014 in its maiden attempt along with the preceding Chandrayaan-1 mission has provided a huge boost to the global perception of Indias technological prowess. This technological achievement is built upon the decades of ISRO’s experience in mission design, launch and operation of earth observation and communication spacecraft. The main driving factors for the Indian efforts in the direction of lunar and interplanetary missions were the optimal utilization of an existing launch system (PSLV) to achieve minimum energy orbit placement around the Moon and Mars with an innovative, highly elliptic orbit. An exposition of the mission planning, payload design, strategy and the technological features along with the differences with respect to the earth-or-biting missions is presented.

A novel antenna steering mechanism with self hold-down feature for communication spacecrafts

A novel antenna steering mechanism with self hold-down feature for communication spacecrafts

Navigating Challenges and Opportunities in Space Exploration: Insights from Perseverance Rover, Spacecraft Communication, and the Commercial Space Industry

Navigating Challenges and Opportunities in Space Exploration: Insights from Perseverance Rover, Spacecraft Communication, and the Commercial Space Industry

Research on Mono-Pulse Beam Angle Tracking Algorithm of Phased Array Antenna Based on CKF

Phased array antenna beam tracking and communication system based on mono-pulse system is an alternative satellite-to-earth communication technology solution for future planetary spacecraft, which meets the mission requirements of agile scanning, multimode, wide field of view, and small size. This paper firstly outlines the technical scheme of mono-pulse angle tracking based on the planar phased array antenna. A simplified mathematical model of angle measurement is summarized. Secondly, the beam pointing of the spacecraft communication antenna is frequently affected by the attitude and presents a nonlinear dynamic change. A robust two-dimensional angular tracking filtering algorithm based on cubature Kalman filter (CKF) is proposed, in order to solve this complex high-order nonlinear dynamic estimation problem. Finally, the comprehensive performance of the proposed algorithm is simulated and analyzed under two conditions of stable flight and high dynamic flight of the spacecraft. When the angular velocity is within 4°/s, the tracking accuracy can be better than 0.65°, and the tracking accuracy will be better than 1° when the angular velocity is within 8°/s. Compared with the basic CKF algorithm, the robust CKF tracking accuracy is significantly improved, while the resource consumption is slightly reduced. The research results can provide reference for the engineering implementation of related fields in the future.

Transporting MIL-STD-1553 Signals by Means of Optical Wireless Interfaces

Today, the on-board Spacecraft (SC) communication requires an impressive network of massive wires, both in flight and in the Assembly Integration and Test (AIT) phase. Here, we present the design and the experimental characterization of novel Optical Wireless Communication (OWC) transceivers compatible with MIL-STD-1553B, which is the shared bus predominantly deployed in SCs. Each transceiver works as an interface that transports the bipolar Manchester-coded signal by converting it to/from the optical domain. These OWC interfaces can effectively reduce the overall weight and cost of the SC and can also largely decrease the AIT time. Since they are fully analog and do not need any microprocessors or Digital Signal Processing, they have a small footprint and a very low power consumption. We initially characterize the transceivers using a non-return-to-zero (NRZ) signal, then we used them to replace a cable and connect a pair of test units, transmitting MIL-STD-1553B signals: the measurements show that our solution has a good power budget (+65dB), which will allow the interoperability with MIL-STD-1553B boards in a wide range of scenarios. Furthermore, it is realized by means of commercially available components; it could also be implemented by using proven space-graded devices.

Математическая модель системы функционирования космических аппаратов связи

The paper discusses a mathematical model of the functioning of communication spacecraft, using systems of differential equations for translational and rotational motion, as well as the process of distributing problems in a constellation of three satellites. The model is implemented by means of the python 3.6 language and the computational method library numpy1.19. A series of computational experiments was carried out in order to estimate the energy costs for the operation of grouping with various orbital parameters and external impact models. The presented results of the experiments suggest the possibility of increasing the life of spacecraft by improving the operating system.

Effect of Plasma Sheath Covering Spacecraft-Borne Array Antenna on Direction-of-Arrival Estimation

During the reentry process of a spacecraft, a plasma sheath will attenuate and distort the amplitude and phase of the transmitting electromagnetic (EM) waves, influencing signal reception and measurement accuracy of the direction of wave arrival of the spacecraft-borne array antenna, by which the spacecraft communication and guidance system may be affected. To solve this problem, based on the space distribution characteristics of plasma sheath flow field, an EM simulation model of an array antenna under plasma sheath is established, and EM simulations related to field propagation across plasma sheath and radome are performed. Then, the array signal model is constructed by extracting the field strength data at the array element. Several spatial spectrum estimation methods are conducted to calculate the direction of arrival of an EM wave incident on the array antenna. By comparing the direction of the incoming wave in free space with the estimated direction after propagating through the plasma sheath, the direction-finding error of the spacecraft-borne array under the plasma sheath is obtained, and the cause of the error is analyzed. With compensation information, the results of the proposed method can enable higher target-tracking accuracy for the spacecraft guidance system.

Analysis of the functioning of the orientation device to the Earth of a telecommunications space satellite

This article presents the results of statistical observations of an operating communications spacecraft. The functioning of the orientation system to the Earth is considered. For ensure the reliability of communication between the satellite and ground stations, it is important to have a constant direction to the coverage area. For this, the spacecraft has an orientation system to the Earth. The orientation aims to create a reliable connection on the territory of the country of the spacecraft owner. The article examines the analysis of the operation of the satellite guidance system to the Earth using the example of a telecommunications communication satellite of the Republic of Kazakhstan. At the same time, the satellite orientation system to the Sun works in parallel to organize a stable and stable connection. The statistics of the operation of the orientation system to the Earth are presented. For this, the satellite has devices responsible for positioning – the orientation devices to the Earth. There are two given devices, namely, POZ-1 and POZ-2. The analysis of real statistics is given. The forecast of the system operation for the next nine years has been made.

The Experience of Digital Transformation of Business Processes of Applied Experimental Research by Using the Multitenancy of the Resources

As part of the digital transformation of various areas of human activity, the urgent task is to transform existing business processes (BP) in order to increase their variability according to the needs of the customer, to increase productivity, quality and competitiveness of products. The introduction of end-to-end digital technologies allows for this. The article examines the experience of transforming the BP of experimental research in solving a number of applied tasks in the field of electronic instrumentation, which is obtained as a result of the introduction of operation technology for test, research and laboratory equipment based on the concept of multitenancy. Developed on the basis of the experience of the authors, a number of industrial samples and prototype multiuser distributed measurement-control systems implementing this concept have allowed to transform the following processes: end-to-end BP of tests on-board electronic equipment of spacecraft (communications, relay, navigation, geodesy, remote sensing, etc.); BP of forming the operational load of the spacecraft's on-board relay complex; BP of conducting experimental laboratory research in the industry training system. The effectiveness of modernized BP was evaluated on the basis of their formalized models and a set of qualitative indicators. The key resulting effects of transformation: improving the quality of BP by improving the informativeness of individual business functions and the efficiency of the use of high-tech experimental equipment; reducing the number of gaps in BP by reducing the number of business roles involved in their implementation; reducing the duration of BP by significantly reducing material and time costs and improving the productivity of individual business functions; transition to a service model "Laboratory As Service" for access to high-tech equipment while performing experimental laboratory studies based on digital educational environments.

Improving Small Satellite Communications and Tracking in Deep Space—A Review of the Existing Systems and Technologies With Recommendations for Improvement. Part II: Small Satellite Navigation, Proximity Links, and Communications Link Science

This article is the second of a three-part series in which we present the results of a study exploring concepts for improving communications and tracking capabilities of deep space SmallSats. In Part I, we discussed SmallSat direct-to-earth links and SmallSat communications equipment, and provided recommendations for future work. In Part II, we focus on SmallSat navigation options, Disruption Tolerant Networking (DTN), proximity links, and the use of the communication link for science observations, and we provide recommendations for future work. We have examined both radio and optical navigation options, and considered autonomous and semiautonomous navigation to reduce operational costs for planetary SmallSats. We note that communication link resilience to delay and disruption enhances spacecraft autonomy; therefore, we have provided a discussion of DTN to indicate that using DTN allows for automated data transmission and recovery, therefore, reducing manual operations. SmallSats in deep space may utilize a relay spacecraft for communications with earth or function as a relay for landed and in-orbit assets. We present a detailed examination of relay proximity links and networks where we address both proximity hardware and networking scenarios. The proximity link features that we examine include the network architecture and its relationship to DTN, proximity radios and antennas, communications link performance, and proximity navigation. The use of the communication link for science has been practiced by primary missions in deep space scenarios. (Two examples of past planetary radio science experiments can be found in the following: https://solarsystem.nasa.gov/missions/cassini/mission/spacecraft/cassini-orbiter/radio-science-subsystem/ and https://www.boulder.swri.edu/pkb/ssr/ssr-rex.pdf) Likewise, SmallSats can offer their radio links for radio science investigations. This article provides a brief introduction to radio science and presents the prerequisite features necessary for radio science observations by SmallSats. We conclude with nine recommendations based on the findings of the study. These recommendations are guidelines on the design, implementation, and operation of deep space SmallSat communication links. The adoption of some or all of the guidelines should result in an enhanced communication and tracking capability for the deep space SmallSat missions.

The electromagnetic problems of interplanetary spacecraft communication

The results of the radio frequency emission measurements from the ground-based experiments using electric propulsion engine applied to electromagnetic compatibility evaluation of spacecraft radio communication. The report presents the way of looking at the electromagnetic compatibility problem based on experimental and theoretical investigations of the physical foundation of the electromagnetic field generation by the electric propulsion engines. The approach under review allows evaluating the electromagnetic performance characteristics depending on thruster construction and engine operating modes.

ІННОВАЦІЙНЕ РІШЕННЯ ДЛЯ LEO-СИСТЕМИ З АРХІТЕКТУРОЮ «РОЗПОДІЛЕНОГО СУПУТНИКА»

An innovative solution for practical implementation in a LEO system with a "distributed satellite" architecture that can be used to provide low-orbital spacecraft communications with ground stations and users of 5G / IoT satellite services is proposed. The essence of the proposed development in the system of low-orbital satellite communication with FC-architecture is that to reduce the delay in signaling to consumers and the probability of overloading the network into a prospective system of low-orbital satellite communication, which contains artificial Earth satellites, each of which functions in Earth orbit and equipped with onboard repeaters, inter-satellite communications, a network of ground-based communication and control systems for artificial satellites of the Earth, a grouping of low-orbiting space their devices (LEO-system), which includes the grouping of root (leading) satellites and satellites-repeaters (slave), around each root satellite is formed micro-grouping of satellites-repeaters, and functions of the root satellite in the selected orbital phase of the orbital -or micro-satellites that are connected to the annular network by communication lines between satellites, and - functions of satellites-repeaters - kubsat, new is the introduction of a multilevel boundary cloud system, which is a heterogeneity well distributed computing cloud structure. At the same time, the boundary clouds of the multilevel system are connected by ultra-high-speed wireless terahertz radio lines and wireless optical communication systems. The technique of estimation of access time in the proposed structure of "fog computing" on the basis of the model of access in "fog computing" with the resolution of collisions of data sources implementing the survey mode is presented

Analysis of the Influence of Electromagnetic Emission from Stationary Plasma Thrusters on the Interference Immunity of the Earth–Spacecraft Communication Channel

A complete cycle of studies is considered, which are related to obtaining knowledge on spectral and time-response characteristics of emission from stationary plasma thrusters (SPTs), to the development of mathematical and simulation models of such emission, and assessment of its influence on the interference immunity of space communication systems. The reliability of data transmission via Earth–spacecraft digital communication channels is assessed based on the results of simulation modeling. The bit error rate is studied as a function of signal-to-noise and signal-to-SPT-interference ratios. Power loss of the communication channel in the presence of SPT emission relative to the standard system is considered as its interference immunity indicator. Calculations are made for the power budget of deep- and near-space radio links. Power loss is assessed for the Earth–Mars radio links and within the geostationary orbit. Recommendations on reducing the SPT emission effect are presented.

Multiobjective Reinforcement Learning for Cognitive Satellite Communications Using Deep Neural Network Ensembles

Future spacecraft communication subsystems will potentially benefit from software-defined radios controlled by artificial intelligence algorithms. In this paper, we propose a novel radio resource allocation algorithm leveraging multiobjective reinforcement learning and artificial neural network ensembles able to manage available resources and conflicting mission-based goals. The uncertainty in the performance of thousands of possible radio parameter combinations and the dynamic behavior of the radio channel over time producing a continuous multidimensional state–action space requires a fixed-size memory continuous state–action mapping instead of the traditional discrete mapping. In addition, actions need to be decoupled from states in order to allow for online learning, performance monitoring, and resource allocation prediction. The proposed approach leverages the authors’ previous research on constraining decisions predicted to have poor performance through ”virtual environment exploration.” The simulation results show the performance for different communication mission profiles, and accuracy benchmarks are provided for the future research reference. The proposed approach constitutes part of the core cognitive engine proof-of-concept delivered to the NASA John H. Glenn Research Center’s SCaN Testbed radios on-board the International Space Station.

Fully optical spacecraft communications: implementing an omnidirectional PV-cell receiver and 8 Mb/s LED visible light downlink with deep learning error correction

The large surface area of the photovoltaic (PV) cells on a spacecraft provides a significant sensor area, which can be used as an omnidirectional receiver on many solar panel layouts. Previous researchers have proposed the use of this unique asset as a backup communication system [1], realizing that a low-cost, low-power consumption uplink could be created by using the photovoltaics as a laser receiver. Such proposed systems have data rates of less than 10 Kb/s, allowing them to serve as effective emergency alternative- band communication systems, though not as an operational uplink.

Performance Analysis of Ranging Techniques for the KPLO Mission

In this study, the performance of ranging techniques for the Korea Pathfinder Lunar Orbiter (KPLO) space communication system is investigated. KPLO is the first lunar mission of Korea, and pseudo-noise (PN) ranging will be used to support the mission along with sequential ranging. We compared the performance of both ranging techniques using the criteria of accuracy, acquisition probability, and measurement time. First, we investigated the end-to-end accuracy error of a ranging technique incorporating all sources of errors such as from ground stations and the spacecraft communication system. This study demonstrates that increasing the clock frequency of the ranging system is not required when the dominant factor of accuracy error is independent of the thermal noise of the ranging technique being used in the system. Based on the understanding of ranging accuracy, the measurement time of PN and sequential ranging are further investigated and compared, while both techniques satisfied the accuracy and acquisition requirements. We demonstrated that PN ranging performed better than sequential ranging in the signal-to-noise ratio (SNR) regime where KPLO will be operating, and we found that the T2B (weighted-voting balanced Tausworthe, voting v = 2) code is the best choice among the PN codes available for the KPLO mission.