PRESSURE MEASUREMENT OF INDUCED EXTERNAL ATMOSPHERE ON THE RUSSIAN SEGMENT OF THE INTERNATIONAL SPACE STATION IN EXPERIMENT «CONTROL»

The goals and objectives of space experiment Control to study parameters of the induced external atmosphere of the Russian Segment of the International Space Station are presented. The processing and analysis procedure for telemetry data obtained using scientific equipment Indicator - ISS is described. Numerical calculations were performed by direct statistical modeling of the flow around the pressure sensor by incoming flotation the Earth's outer atmosphere in the background measurement conditions, as well as in disturbed conditions with two vernier engines of the Zvezda module being operated. A correction function of the pressure sensor is obtained depending on the orientation, temperature factor and selected model of interaction of incident flow molecules with the internal and external device surfaces. The results of numerical modeling of the jet discharges of the the Zvezda vernier engine were compared with the data obtained in full-scale pressure measurements in experiment Control. Key words: pressure sensor, orbital station, induced external atmosphere, direct statistical modeling method.

MOSCOW INTERNATIONAL SYMPOSIA ON SOLAR SYSTEM RESEARCH (10M-S3 AND 11M-S3) REPORTS REVIEW. Part 1. Mars exploration

A review of the reports of the last two Moscow International Symposia on Solar System Research has been completed. In the first part of the review, 43 reports of the main session of the "Mars" section are considered. The works of leading experts in the field of planetary science cover a wide range of scientific and applied problems - from the study of the geological history and climate of Mars, the search for traces of life and subsurface water reserves, to new technologies in planetary research, mission planning, as well as monitoring solar activity and radiation conditions in the interplanetary space, orbit and the surface of Mars. The data obtained in the last two decades has made it possible to significantly advance in understanding the nature of Mars, but many unresolved questions remain regarding the climate in the early era, the existence of the Martian oceans in the past, biological and geological activity. The scientific results obtained by unmanned spacecraft should be fully taken into account in the development of manned deep space exploration programs. Key words: Solar system, planetology, international symposium, deep space, automatic interplanetary stations, Mars, Moon, reports review

OPTICAL SYSTEM DESIGN OF THE DETECTOR FOR SOLAR TERAHERTZ EMISSION MEASUREMENTS

The objectives and scientific tasks of the planned space experiment “Solntse-Terahertz” to be performed onboard the ISS Russian Segment are briefly described in the paper. In particular, the aim of the experiment is to study uninvestigated solar electromagnetic emission in the terahertz domain, in ~ 1012 – 1013 Hz (300-30 µm) frequency range. It is expected to obtain new data on solar active region emission including solar flare emission. These data are necessary to clarify the nature of solar activity and construct physical model of charged particle acceleration in active regions during solar flares and other astrophysical objects. We focus on the telescope optical system design and evaluation of main characteristics of this system. Results of simulations and comparison with the experimental verification of obtained characteristics are presented. A close correlation of the estimations and experimental results was obtained. As a result, main parameters of the telescope optical system of experimental hardware “Solntse-Terahertz” were determined. Key words: Sun, solar flares, terahertz emission, optical system.

CRYOGENIC GREASE LUBRICANTS FOR ROCKET AND SPACE TECHNOLOGY

The paper represents requirements for cryogenic grease lubricants used in the rocket and space technology. Data on lubricants based on perfluoropolyether liquid FEN is provided. New lubricant testing methods enabling to analyze their chemical composition and low-temperature characteristics are proposed. Quoted are investigation results for the equivalents of previously used cryogenic lubricants NIKA, NIRA and «Ametist». A practical relevance of the paper has been proven by introduction of low-temperature lubricants «Sever» currently being used in rocket and space items, as well аs successful application of the developed lubricant incoming inspection procedures at RSC Energia. Key words: low-temperature lubricant, perfluoropolyether liquid FEN, viscosity, solidification temperature, IR spectrum, potential evaporation.

MEASUREMENT OF LEAKAGE CURRENTS AND QUASI-STATIONARY ELECTRIC FIELD IN THE SURFACE AREA OF THE ISS RS IN THE EARTH'S IONOSPHERE

The paper presents the results of analysis of electrical measurements performed in the space experiment "Impulse (stage 1)" on the Service module of the ISS RS. This experiment investigated the effects of the interaction of the charged component of the ionosphere to the surface of large KA, which is the ISS. This paper analyses the measurement of quasi-stationary electric field and current leakage, was, respectively, sensors of the vibration type and flat probes from the Complex control electrophysical parameters (CCEP), developed by SPJ MT. To study the dependence of measurements from the ionosphere flow direction to the surface of the ISS RS was installed two sets of sensors with the direction of the angle of "visibility" in the Nadir (towards the Earth) and to "satellite footprint " (against the velocity vector of the ISS). Carried out analysis of common regularities measurements depending on the sun-shadow environment on orbit ISS motions and depending on current geophysical dynamics of the ionosphere. Massive the measurements including more than 170 telemetric sessions were analyzed. More than 11000 hours of measurements current of leakage (or runoff current) and measurements of quasi-stationary electric field with discretization 1s and UT binding to each point were analysed. The data measurements, geophysical and orbital data were collected in an electronic album. It is shown that experimental data correlate with the crossing time of the ISS boundaries known geophysical structures: the noon Meridian, the Main ionospheric failure (MIF), the boundaries diffuse intrusion (BDI), the Equatorial Geomagnetic anomaly (EA). In this regard, despite the specificity of the ISS (the spacecraft super big sizes, the most complex spatial configuration) similar measurements, nevertheless, are quite suitable for monitoring researches of some features of an ionosphere at the level of F2 layer with a temporary scale from 1s and can be used for more detailed study of the geophysical structures and related effects in the ionosphere. In addition, the results obtained can be used for the analysis of disturbances of electromagnetic conditions near the surface of the ISS RS, for monitoring potential and currents of leakage on the surface of the ISS. Keywords: electrophysical measurements, sensors of the vibration type, flat probes, electric field, current leakage, geophysical structure, ionosphere

USE OF METHANE IN CLOSED-LOOP LIFE SUPPORT SYSTEMS FOR SPACE MISSIONS

The paper discusses the use of methane (generated in the process of oxygen recovery from carbon dioxide released by the crew during its hydrogenation in the Sabatier reaction, with subsequent extraction of 61% of oxygen through electrolysis of the resultant water) in a regenerative life support system for crews on space missions. It demonstrates that the methane resulting from Sabatier reaction can be used both for pyrolysis in order to return the resulting hydrogen into this reaction so as to extract 100% of oxygen from carbon dioxide, and for producing food protein for life support in space. The use of methane pyrolysis was enabled by new technologies which allowed lowering the process temperature down to 500–700°C and obtaining the easy-to-remove carbon. It provides recommendations for designing space systems for methane pyrolysis. The paper makes the case for use of the existing processes for industrial production of protein from methane using methanotrophic bacteria in the production of food protein for space food rations, determines the balance of a closed-loop methanotrophic reaction, provides calculation basis and recommendations for designing space systems for methanotrophic production of food protein. Development of a system for food protein production from methane will enable its use as one of the systems for providing food on the Moon and Mars, as well as a backup system in space transportation missions. Key words: space missions, crew life support, СО2 hydration, methane pyrolysis, methanotrophic bacteria, food protein.

COMPUTER PROCEDURE FOR SELECTING PARAMETERS OF THE PERIPHERAL DOCKING ASSEMBLY LATCH MECHANISM

When developing the country’s made peripheral docking assembly consistent with the International Docking System Standard a task arose concerning reduction of dimensions of the latch mechanisms that ensure the capture. The article describes the mode of operation of these mechanisms. Proposed is a procedure which makes it possible to choose such a layout of their joints in which the links are inside a given area during operation. A uniform LPτ-sequence is used to form various options of the joints layout. A criterion of maximum loads acting on the links is described. It is shown that the dimensions of the existing latch mechanism can be decreased only with an increase of the load-carrying capability of the links. The proposed procedure is part of a software tool computerizing the design of a new latch mechanism. Key words: spacecraft docking, peripheral docking assembly, latch mechanism, capture, LPτ-sequence.

DIFFUSION-VACUUM TECHNOLOGY OF MANUFACTURING LARGE AXISYMMETRIC ASSEMBLIES OF METAL MESH MATERIALS FOR HEAT EXCHANGE PATHS

Requirements for improving the reliability, service life, and increasing a specific pulse of liquid-propellant rocket engines justify a need for transfer to new designs and manufacturing technologies of regenerative engine cooling system. The paper describes a advanced diffusion-vacuum technology of manufacturing a regenerative cooling circuit for liquid-propellant rocket engine based on the concept of inter-channel coolant transpiration through a porous metal mesh material. The method of diffusion welding of metal wire mesh in vacuum makes it possible to obtain large axisymmetric blanks of metal mesh materials necessary to manufacture the regenerative cooling path of the liquid-propellant rocket engine and recuperative heat exchanger (RHE). The possibility of developing a high-efficient low-gradient porous heat exchange path obtained using a metal mesh material (MMM) has been experimentally confirmed. It is recommended to use metal woven cloth and twill filter screens of standard size П24–П60, С120 as a basic material for manufacturing MMM. Key words: diffusion-vacuum technology, porous mesh material, regenerative cooling system, inter-channel coolant transpiration.

MATH MODEL OF A DIRECT CURRENT MOTOR FOR STEERING ACTUATOR OF A LIQUID-PROPELLANT ENGINE

The paper presents the results of development of a math model for a direct current motor of a liquid-propellant engine steering actuator In accordance with the electrical machine theory, the math model of the motor uses a single electromagnetic coefficient. It is shown that the motor math model accuracy can be improved through the use, instead of a single electromagnetic coefficient, of two different coefficients of the math model: Electromechanical velocity coupling coefficient and torque curve coefficient. Elaborated and proposed are methods for identifying parameters of a math model of a dc motor that has natural and artificial static characteristics, which include determining its experimental static characteristics, calculating the values of static characteristics parameters using the linear regression method and calculating the values of the electric motor math model parameters using the proposed formulas. Key words: direct current electric motor, math model, parameter identification method.

SPACECRAFT RELIABILITY CALCULATIONS USING STATISTICAL REGULARITIES IN OCCURRENCES OF FAILURES IN DEVICES, UNITS AND ASSEMBLIES DURING THEIR OPERATION

The paper addresses reliability analysis of manned spacecraft with the use of statistical regularities in in-flight failures of their devices, units and assemblies. It formulates validity criteria for using a device failure in reliability analysis, proposes a method for analyzing and classifying failures which enables factoring in different types of failures in reliability analyses. It considers a hypothesis of the absence of statistically significant differences in probabilities of individual valid failures and demonstrates the feasibility of its adoption with the use of dispersion analysis. A method is developed for evaluating product reliability using a functional relationship between reliability and the number of failures occurring in flight which makes it possible to significantly simplify reliability analysis for complex products, to establish the number of in-flight failures that is acceptable from the standpoint of the product reliability requirements, to study various product architectures from the standpoint of reliability criteria. It proposes a method for evaluating the lower boundary for the probability of manned spacecraft completing their missions based on the failure modes, effects and criticality analysis, and demonstrates the feasibility of optimizing the product redundancy scheme based on the fault tolerance requirements. Key words: manned spacecraft, flight, failure, fault tolerance, classification of failures, reliability, probability of failure-free operation, statistical analysis, dispersion analysis.