The Space Engineering and Technology magazine
¹ 4 (23), 2018
FLYING VEHICLES AERODYNAMICS AND HEAT EXCHANGE PROCESSES
Kotlyarov E.Yu., Luzhenkov V.V., Tulin D.V., Basov A.À.
Thermal control system of the unpressurized instrument compartment for Intergeliozond spacecraft intended for Solar research at close distances
Consideration is given to specifics of thermal control of the unpressurized instrument compartment of the Intergeliozond spacecraft developed by Lavochkin Association by the order of Roscosmos State Corporation. Brief description of the spacecraft and relevant bibliographic references are given. Two identical spacecraft will be developed under the Intergeliozond program, which will perform physical research of the Sun at close distances operating in heliocentric non-ecliptic orbits. Taking into account the conditions of the spacecraft operation characterized by a significant change of the incoming solar radiation density, a pumped fluid loop-based segment is proposed to be introduced in addition to the existing basic TCS based on heat pipes and honeycomb panels. The pumped fluid loop fulfills the function of a general-purpose system, which ensures temperature conditions in the ground developmental test phases, and during the flight operation, and is capable of ensuring a heat supply or additional cooling of the instrument compartment. A multiple-option process characterized by a level of complexity of the fluid loop integration into TCS of the instrument compartment of the spacecraft is presented.
Key words: pumped fluid loop, thermal control system, spacecraft, heat pipes, ground developmental test, general-purpose system, thermal cluster.
FLYING VEHICLES ENGINEERING, DESIGN AND MANUFACTURING
Markov A.V., Konoshenko V.P., Beglov R.I., Sokolov V.G., Gorbenko A.V.
Main areas and results of work to protect the ISS Russian Segment from meteoroids and space debris
The task of ensuring the space station safe operation in conditions of growing pollution of the near earth space by so called space debris has become especially crucial in development of the International Space Station (ISS). In the initial ISS assembly phase a difference in the approaches of the main Project Partners (NASA and RSC Energia) to safety assurance associated with the impact of space debris was identified. Due to fruitful cooperation between the project managers and specialists general safety requirements for protection against meteoroids and space debris were formulated, and the main technical solutions meeting these requirements were found.
This article provides a review of the main issues encountered while designing the Russian module shields, as well as resolutions and results. The evaluated options of on-orbit hardening of the Service Module shielding, and a stepwise implementation of the selected option are described. Presented are design concepts of other RS modules and transport vehicles shielding structures, and calculation results of major safety indicators when exposed to meteoroids and space debris obtained as a results of implementation of the developed shielding means.
Key words: the International Space Station, ISS Russian Segment, meteoroid, space debris, shielding design.
Salnikov N.A., Bobe L.S., Kochetkov A.A., Zheleznyakov A.G., Andreychuk P.O., Shamshina N.A.
Use of membrane equipment for hygiene water processing aboard the space station
The sanitary and hygienic facilities and hygiene water processing system are supposed to be integrated into the complex of space station life support systems. The Russian concept is to establish a closed hygiene water supply loop. For increasing the crew comfort while staying onboard the space station the following sanitary and hygienic facilities are supposed to be added: hand and face wash hardware (washstand); body wash equipment; sauna; washing machine. This hardware and equipment is supposed to be used with the hygiene water processing system. When taking water procedures, the crew will use the common liquid detergents that minimize air pollution. The paper experimentally confirms the efficiency of the reverse osmosis method as applied to the hygiene water purification. The prototype of the hygiene water processing system ensured a required quality of the product water, made it possible to assess the purification performance and life characteristics of the system being developed. Based on the mockup models and flight equipment characteristics the mass expenditures were estimated when putting various sanitary and hygienic facilities on board the ISS together with the hygiene water processing system.
Key words: life support system, hygiene water, water processing, reverse osmosis, space station.
FLYING VEHICLES STRENGTH AND THERMAL ENVIRONMENTS
Lunar exploration is one of the major future development paths for spaceflight. Also, besides that, one of the most important tasks is to reduce the cost of transporting payloads from low orbits to higher orbits. A reusable orbital transfer vehicle with electrical rocket propulsion system can be an effective solution for achieving both of these objectives.
The reusable orbital transfer vehicle structure is a multi-section large truss. Such structures have several variable parameters such as: diameter of the rods, rod wall thickness, number of sections, the radius of the base of the structure. When designing large space frame structures, it is necessary to determine the design with the maximum dynamic properties and the minimal mass. This work uses optimization methods to solve the problem of finding the design of the frame structure that is optimal from the standpoint of mass minimization while meeting the requirement to minimize the first natural frequency.
It also solves the problem of transient dynamic loads on the structure of the electrical thruster mount during thruster firing. The time dependence of the maximum equivalent stresses is determined.
Key words: truss structures, reusable orbital transfer vehicle, dynamic characteristics, optimal design.
FLYING VEHICLES THERMAL, ELECTRIC PROPULSION ENGINES AND POWER GENERATING SYSTEMS
On the basis of the modern software package COMSOL Multiphysics the authors developed a basic version of the program method, named COMSOL–TFE, for performing three-dimensional calculations of the thermionic fuel elements (TFE) thermal and electrical characteristics as part of the nuclear reactors for space and ground applications. The main functional capabilities of the developed COMSOL–TFE optimized for the TFE calculation of any construction are described in this work. Expansion of functionality of the TFE mathematical model in COMSOL–TFE is carried out by adding new program modules (physical partitions) to the basic mathematical model of electrothermophysical processes in TFE. The description of the developed program module that allows to calculate the effect of the TFE own magnetic field (OMF) on its characteristics is provided in the paper. Several test calculations for a single- and multi-cell TFE were performed for processing test the created mathematical model of the influence of the TFE OMF.
Key words: thermionic fuel element, nuclear reactors for space and ground applications, TFE mathematic model, software package COMSOL.
Akhmedov M.R., Bideev A.G., Sazonov V.V., Khamits I.I.
Experimental research of the temperature effect on the solar arrays output power using telemetry of Progress MS spacecraft
The paper presents a study of the effects of temperature on the power output of solar arrays conducted by means of analyzing the current-voltage curves of photovoltaic cells and experimentally validated through telemetry measurements on a logistics spacecraft Progress MS. Based on the relationships between electrical parameters of the cells and temperature current-versus-voltage curves were plotted, which were used to find out how heating affects current, voltage and power output of solar arrays. It was found that the effect depends on the method of matching the solar arrays to current loads. In spacecraft the matching is usually provided through solar array voltage regulation or optimizing control. The analysis results for the case of voltage regulation were experimentally validated through telemetry measurements of current and temperature in solar arrays on free-flying Progress MS-07 spacecraft with solar arrays pointing at the Sun. The results of the study are of interest to developers of solar arrays and spacecraft power supply systems.
Key words: solar array power output vs. temperature, solar array simulation, photovoltaic cell current vs. voltage curve.
GROUND FACILITIES, LAUNCHING EQUIPMENT, OPERATION OF FLYING VEHICLES
Belyaev B.I., Belyaev Ì.Yu., Borovikhin P.A., Golubev Yu.V., Lamaka A.À., Ryazantsev V.V., Sarmin E.E., Sosenko V.À.
Automatic positioning system for science hardware in Uragan experiment on the ISS
When studying ground and astronomical objects using the Salyut and Mir orbital stations a required station attitude was established to the objects under observation. For the ISS having large dimensions and mass the gyrodynes installed on the US On-orbit Segment have no available kinematic momentum sufficient to point the station to the objects under observation. It is evident that in such ISS attitude it is impossible to position rigidly fixed instruments to objects under observation. Therefore, when conducting scientific experiments on the ISS mobile pointing platforms (PP) shall be used. Using several PP also allows for simultaneous observation of different objects. Since the beginning of the ISS flight hand-held observation devices have been used in the Earth exploration experiment «Uragan», and the crew points the photographic, photo- and video-spectrometers to the objects under observation through the windows. However, strong constraints are placed on the planning of such experiments, primarily related to a need for accounting for the crew schedule and availability of the time allocated for scientific experiments. In order to expand the capabilities for studying ground objects, new PP are planned to be sent to the ISS. Two-axial PP on which the science hardware shall be placed is intended for installation inside the ISS on the windows of the Service Module and the Multipurpose Laboratory Module. At the same time the following conditions shall be provided: automatic pointing of science hardware and imagery under a given program with or without involvement of an operator, as well as compensation for the «blurred image» of the object during the exposure. The pointing platform will make it possible to perform imagery and spectrometry of objects under observation along the flight track including those located far from nadir direction, in the area of the underlying surface at viewing angles of –30...+30 ° from nadir (the angles are primarily determined by the sizes of windows). Although the pointing capabilities for such «internal» platforms on the Russian Segment of the ISS are generally limited as compared to the potential capabilities of «external» PP, they have significant advantages, first of all, low price, and serviceability, maintainability and reliability. The pointing platforms described in the article will help continuously monitor specified objects on the Earth's surface using research hardware.
Key words: pointing to the object under observation, International Space Station, mobile pointing platforms, space experiments.
CHECKING AND TESTING FLYING VEHICLES
Guzenberg A.S., Zheleznyakov A.G., Telegin A.A., Yurgin A.V.
A study of purification of the ISS Russian segment atmosphere in case of a containment failure in the hardware containing a toxic component
A study has been conducted on purification of the atmosphere in the Russian Segment of the International Space Station (ISS) using the newly developed Russian AFOT-M assembly and FTD-A ammonia filter in case of a containment failure in the external heat exchanger connecting the inner and outer loops of the Thermal Control System (TCS) on the US Orbital Segment of the ISS. Since the pressure in the outer loop is significantly higher than in the inner loop, an entry of ammonia into the inner TCS loop will result in the loop containment failure with ammonia entering the US Orbital Segment atmosphere and, subsequently, into the ISS Russian Segment atmosphere.
Experimental data was obtained on ammonia absorption by the Russian-made ammonia filter FTD-A. A procedure was developed for calculating the removal of ammonia from the ISS Russian Segment atmosphere and experimental data was processed resulting in time values for Soyuz and ISS Russian Segment atmosphere purification that confirmed the effectiveness of the scrubbing. A parallel filter operation method is recommended for scrubbing the module atmosphere in order to achieve efficient use of the absorbers.
Key words: Space Station, ISS, Russian Segment, US Orbital Segment, ammonia, ammonia filter, containment failure, TCS, air purification, calculation procedure, experimental data processing, parallel filter operation.
FLYING VEHICLES DYNAMICS, TRAJECTORY AND MOTION CONTROL
Mikrin E.A., Belyaev M.Yu., Borovikhin P.A., Karavaev D.Yu.
Determining orbit from Earth and Moon surface pictures taken by cosmonauts
Lunar exploration is one of the major tasks of the next few decades for the leading spacefaring nations. Some of the tasks of the planned lunar program can be practiced within the framework of the ISS project. One of them, dealing with the developmental testing of techniques for determining a SC orbit from pictures of the planetary surface, is discussed in this paper. The paper describes procedural aspects involved in solving this problem and provides examples of developmental testing of the proposed autonomous navigation technique using pictures of Earth taken from onboard the ISS Russian Segment Using pictures taken by US astronauts through the window of the lunar orbital module, it also demonstrates the viability of using the proposed technique for determining orbit from pictures of the lunar surface.
Key words: Lunar program, determination of orbit, space pictures, orthotransformation of pictures.
SYSTEMS ANALYSIS, CONTROL AND DATA PROCESSING
The paper discusses a new approach to development of multichip systems based on Field-Programmable Gate Arrays (FPGA) implementing volume algorithms for spacecraft control. This approach takes into account requirements for resistance to special factors and specifics of the implemented algorithms. It describes the principle of dividing a single algorithm into functional units and principles of their interfacing. A technique is proposed for protecting chip-to-chip interconnections using error correcting codes taking into account the probability of errors occurring in the encoder. It summarizes the results of testing the math model of a radiation-resistant encoding method based on convolutional code, as well as tests of the implementation of the developed circuit in FPGA chips. It draws conclusions about future prospects for application of this technique taking into account the expanding range of available Russian-made FPGAs.
Key words: convolution code, onboard control system, chip interconnection, field-programmable gate array, development, testing.
¹ 3 (22) july - september 2018