Space Engineering and Technology magazine
¹3 (6), 2014
STRATEGY AND PROSPECT FOR SPACE ENGINEERING
AND TECHNOLOGY DEVELOPMENT
Space weather and risks of space activity
The paper provides an overview of space weather factors and their effects on near-Earth space and space activities. Solar activity and its manifestations in the form of increased flux of high-energy electromagnetic and particle radiation are considered as the main source of space weather presenting danger to cosmonauts, spacecraft (SC) and the International Space Station. It provides a qualitative assessment of direct or indirect impact of space weather factors (galactic cosmic rays (GCR), radiation belts, solar cosmic rays (SCR), electromagnetic emissions) and geomagnetic storms and substorms on radiation hazard for cosmonauts, surface and volume electrization of SC, deterioration of SC solar arrays and materials, soft errors in avionics, anomalous SC deceleration and orbital decay, disruption in radio communications and operation of space radio systems. During strong geomagnetic perturbations and geomagnetic storms there is an increase in the overall danger level resulting from growth in particle radiation level, occurrences of ionospheric disturbances and ionospheric irregularities, swelling of the atmosphere, generation of geomagnetically induced currents, and it becomes easier for high-energy GCR and SCR particles to penetrate into magnetosphere. The paper provides examples of effects of various space weather factors, including extreme cases, on space hardware and technologies.
Key words: space weather, galactic cosmic rays, radiation belts, solar cosmic rays, electromagnetic radiation, geomagnetic storms, danger for cosmonauts, space equipment malfunction.
BALLISTICS, AERODYNAMICS, FLIGHT DYNAMICS,
STRENGTH, SPACE EXPLORATION
Alabova N.P., Bryukhanov N.A., Dyadkin A.A., Krylov A.N., Simakova T.V.
Role of computer simulation and physical experiment in investigations of space rocket system aerogasdynamics throughout the designing
The paper analyses the RSC Energia experience in using computer simulations to predict aerogasdynamic characteristics when designing rocket and space hardware. It outlines the problems in studying aerodynamic properties by analysis and by experiment. It shows how the ratio between characteristics determined by analytical and experimental methods changes over time, as well as the role of physical experiment in studying the aerodynamics of the hardware. It discusses the advantages and the drawbacks of the two mutually complementary methods of research. It provides a brief account of the technology of using computer simulations in industrial practice in order to determine aerodynamic properties of a product. It lays down conditions for successful introduction of analytical methods into design process. It presents some results of comparing analytical and experimental data for a reentry vehicle that has a cone segment shape which is now being designed by RSC Energia.
Key words:computer (mathematical) simulation, experiment, space rocket technology.
DEVELOPMENT, UTILIZATION AND OPERATION OF MANNED SPACECRAFT AND COMPLEXES
Belyaev M.Yu., Legostaev V.P., Matveeva T.V., Monakhov M.I., Rulev D.N., Sazonov V.V.
Development of methods of conducting microgravity experiments in free flight of Progress M-20M logistics vehicle
The paper discusses experiments designed to select uncontrollable rotation modes of Progress spacecraft for conducting microgravity studies. It provides results of determining uncontrollable rotation of Progress M-20M logistics vehicle in the mode of gravity orientation of the rotating spacecraft, which provides a fairly low level of residual microaccelerations. The studies were conducted for three variants of satellite rotational motion in the given mode of one-axis gravitational orientation: with angular rate w = 0,1 °/s about the longitudinal axis of the logistic vehicle, with angular rate w = 0,15°/s about the longitudinal axis of the logistic vehicle, and angular rate w = 0,2°/s about the longitudinal axis of the logistic vehicle. As a result of processing telemetry data on angular rates and solar array currents, initial motion conditions and parameters of the math model that was used were evaluated. It was shown that the implemented variants of the gravitation orientation mode provide stable angular motion of the logistics vehicle, sufficient electrical energy input and residual microaccelerations, that are acceptable for conducting microgravity studies. Development of gravitation orientation modes was carried out within the framework of preparations for conducting experiments with convection sensor DAKON onboard Progress spacecraft.
Key words: microgravity, gravitation orientation, residual microaccelerations, dynamic Euler equations, kinematic Poisson equations.
DEVELOPMENT AND OPERATION OF UNMANNED SPACECRAFT, COMPLEXES AND SYSTEMS
The paper discusses attitude control of a spacecraft (SC) designed for imaging specified areas on the Earth surface at high spatial resolution (of 1,0 m when pictures are taken in nadir direction), operating in a circular orbit with altitude of 720 km and inclination 51,6 °. During one observation session (lasting 20 minutes), the Guidance, Navigation and Control System (GN&CS) must provide support for imaging of up to 12 individual targets, or take 6 stereoscopic images. GN&CS includes: three star trackers, an angular rate sensor, satellite navigation equipment, a system of inertial end-effectors consisting of eight fly wheels, electromagnetic end-effectors for cancelling the angular momentum accumulated in the fly wheels. When the SC turns prior to the imaging session, the angular rate exceeds the measuring range of the angular rate sensor. The accuracy characteristics of the angular rate sensor immediately after entry into the measuring rate are not guaranteed by the developers of the instrument. That is why star trackers are used to determine the SC angular rate during the turn and the imaging session. A study was done on the feasibility of meeting the requirements for the SC stabilization accuracy and the number of observations in a session without using measurements from the angular rate sensors. Parameters were selected for the observer and regulator of the dynamic control loop for the SC attitude control. The paper provides SC dynamic mode simulation results.
Key words: flywheels, attitude rate, angular momentum, covariance matrix.
Zubov N.E., Savchuk D.V., Starovoytov E.I.
Optimization of the mass and power consumption of laser ranging systems to control the rendezvous and docking spacecraft
The authors solved the problem of optimization of power consumption and the mass of the onboard laser ranging systems (LRS) to control the rendezvous and docking spacecraft beyond Earth orbit, on the criteria of the mass the receiver objective and the power consumed by laser sources, as they were considered as solid-state diode-pumped lasers and optical parametric oscillator on the basis of a neodymium laser with diode pumping, which allowed to determine of total power consumption and weight of the LRS. As a result, with using of Pareto sets, found the values of weight and power consumption, which meet the requirements to the analogue of LRS, specified in literature.
Key words: laser ranging system, space vehicles, rendezvous and docking, Pareto optimization, solid-state laser.
LAUNCHERS, SPACE TRANSPORT SYSTEMS, ENGINES, PROPULSION AND POWER SYSTEMS
The paper presents basic provisions of the procedure for verifying quantitative requirements for the reliability of the block DM-type upper stages based on flight test results taking into account lessons learned from the operation of prototypes. The procedure is based on combining statistical data in the form of binomial statistics on the results of flight tests of the newly developed modification of the upper stage with the results of the prototype operation. The math model used to combine statistical data takes as its basis the achievable significance level of the testing criterion for the hypothesis that binomial samplings belong to one entire assembly. The paper discusses the use of a truncated sequential testing plan for statistical monitoring of the product quality in order to make a decision on the completion of the upper stage flight tests taking into account the results of the prototype operation. The use of this plan allows to reduce the number of launches needed within the framework of flight tests in order to confirm the specified requirement for the probability of faultless operation of the upper stage in flight.
Key words: upper stage of the block-DM type, quantitative reliability estimate based on test results, apriori information.
ONBOARD AND GROUND CONTROL
COMPLEXES AND SYSTEMS
The paper discusses the development and study the efficiency of a new polyharmonic autointegration method with full averaging of Fourier coefficient for calculating amplitude-phase-frequency characteristics of non-linear dynamic objects and control systems within a specified computational error and a minimum amount of time. The proposed version of the polyharmonic autointegration method is based on numerical integration of systems of non-linear differential equations of the math models of the objects and control systems with monoharmonic inputs at fixed frequencies and analysis of periodic responses to these inputs using Fourier method. According to the proposed method the process of integrating differential equations of the math model at each of the fixed frequencies continues until the average values of Fourier coefficients of the harmonic under study and the additional harmonics of the output periodic response of a dynamic object or a control system to a monoharmonic input over the elapsed number of periods of the input signal become sufficiently constant.
Key words: frequency response characteristics, dynamic objects, control systems.
Kovtun V.S., Strochenkin A.V., Frolov V.N.
Choosing optimal survey routes for Earth remote sensing space system
Earth Remote Sensing Space Systems (ERS SS) are the systems with the fastest development dynamics and the program of work on them is considerably expanding. Therefore, much attention is always focused on such subjects as selection of ERS SS configuration and parameters, efficient control of their operation under engineering and technological constraints, expanding their capabilities under the said constraints. There exists a broad spectrum of various ERS system types, each to address a specific application and social or economic objective, and each having a different set of features. Developing methods for systems analysis of specific system modifications is an important scientific and engineering problem. This paper discusses the management system of the E-Star ERS SS. It addresses the key task of the system operational management using the hierarchy analysis and decomposition of the complex process of simulating initial conditions of the Earth surface imaging. This method allows minimizing the time spent on preparations for and planning of imaging from space, as well as to evaluate the feasibility of an observational program and its efficiency from the standpoint of the use of ERS SS resources.
Key words: space system, Earth remote sensing, management system, hierarchic structure, structure decomposition, matrix method for hierarchy analysis.
THERMAL CONTROL AND LIFE SUPPORT SYSTEMS. VITAL FUNCTIONS OF COSMONAUTS
Basov A.A., Klochkova M.A., Makhin I.D.
On the feasibility of using «cold» gas dynamic spraying of a heat-conducting powder to provide thermal contact between structural elements
The paper discusses the problem of providing thermal contact between structural elements using the heat pipes in the node module of the Russian Segment of the International Space Station as an example. It describes the process for gas dynamic spraying of a heat-conducting powder between the pipe and the primary structure. Illustrated by five experimental samples are various layouts for heat-conducting joints. It describes the procedure for experimental study of the samples. It provides the results of the experimental study. Powder layer durability with the use of different layouts was analyzed. It compares an integral characteristic of heat transfer for the power layer with a similar value obtained for a heat conductive adhesive – adhesive sealant Elasil. It demonstrates the feasibility of using gas dynamic spraying of a heat-conducting powder to provide thermal contact between structural elements.
Key words: thermal contact, gas dynamic spraying, powder material.
MATERIALS, MANUFACTURING AND PROCESSES FOR ROCKET AND SPACE PRODUCTS
Bezmozgiy I.M., Sofinskiy A.N., Chernyagin A.G.
The simulation in problems of vibration strength of rocket and space hardware
The concept of the current system ensuring strength of the rocket and space hardware under the vibration loading is described. The role of the finite-element dynamic model of the design at each stage of product development is shown. The use of a model in calculation, theoretical and experimental works is demonstrated. The principles of the model construction are stated. These principles are formulated for most convenient model application in an iterative process of the structure design and calculation. Complexity and special feature of the specific constructions simulation, the methods of refining the model parameters, model tuning and its verification are shown. Every issue is posed in the perspective of vibration strength problems. The possibilities of modern computer technology and universal software systems for solving the problem of dynamic effects on the structure are presented. The special features of the dynamic simulation of loading processes of experimental product (prototype) during the tests are presented. For the tests simulation the development of the specific models of prototype and equipment is required. Examples of the dynamic simulation of the automatic spacecraft for Earth remote sensing and space station module are given. The types of finite elements used in the model are described. The results of calculations and measurements during the experimental testing are given. Refinement and adjustment models based on experimental data are shown.
Key words:structure, vibration strength, finite-element model, modal analysis, harmonic response analysis, developmental testing.
SPACE BUSINESS, ECONOMICS AND MANAGEMENT, PROJECT AND PERSONNEL MANAGEMENT, INFORMATION TECHNOLOGIES, INTERNATIONAL ACTIVITIES
Velikoivanenko V.I., Gusakov N.V., Pantenkov D.G., Sokolov V.M.
A simplified algorithm to construct a probabilistic model to evaluate the level of risks involved in innovation projects
The paper presents an advanced scientific procedural apparatus for constructing a probabilistic model for evaluating the level of risks and practicability of implementing innovation projects to develop high-technology products that is based on fuzzy sets theory; also presented are results of numerical simulations and an algorithm for the software implementation of the proposed method. This paper presents a model for evaluating the level of risks by one criterion, which is then extended to cover the cases where risk levels are evaluated by two or more criteria. By innovation projects this paper means such projects which require scientific engineering and methodological support for their implementation, the use of new types of technology platforms and materials, and of critical technologies, as well as have long development periods and high risks of payback time.
Key words: new method, probabilistic evaluation model, criterion, fuzzy sets, innovation project, numerical estimates.
¹ 3 (6) july — september 2014