Space Platforms Research Articles

Revival of Anhydrobiotic Cyanobacterium Biofilms Exposed to Space Vacuum and Prolonged Dryness: Implications for Future Missions beyond Low Earth Orbit.

Dried biofilms of Chroococcidiopsis sp. CCMEE 029 were revived after a 672-day exposure to space vacuum outside the International Space Station during the EXPOSE-R2 space mission. After retrieval, they were air-dried stored for 3.5 years. Space vacuum reduced cell viability and increased DNA damage compared to air-dried storage for 6 years under laboratory conditions. Long exposure times to space vacuum and extreme dryness decrease the changes of survival that ultimately depend on DNA damage repair upon rehydration, and hence, an in silico analysis of Chroococcidiopsis sp. CCMEE 029's genome was performed with a focus on DNA repair pathways. The analysis identified a high number of genes that encode proteins of the homologous recombination RecF pathway and base excision repair that were over-expressed during 1 and 6 h rehydration of space-vacuum exposed biofilms. This suggests that Chroococcidiopsis developed a survival strategy against desiccation, with DNA repair playing a key role, which allowed the revival of biofilms exposed to space vacuum. Unravelling how long anhydrobiotic cyanobacteria can persist under space vacuum followed by prolonged air-dried storage is relevant to future astrobiological experiments that use space platforms and might require prolonged air-dried storage of the exposed samples before retrieval to Earth.

Advances in Underwater Oil Plume Detection Capabilities

Historically, visual observation is an emergency responder's first ‘tool’ in identifying spilled oil. Optical detection has since expanded to include a myriad of signals from space, aircraft, drone, vessel and submersible platforms that can provide critical information for decision-making during spill response efforts. Spill monitoring efforts below the air-water interface have been vastly improved by advances with in situ optical sensors and vehicle platform technology. Optical techniques using fluorescence, scattering, and holography offer a means to determine dissolved versus droplet fractions, provide oil concentration estimates and serve as proxies for dispersion efficiency. For subsurface spills over large space and time scales, Autonomous Underwater Vehicles (AUVs) can be used to provide subsurface plume footprints and estimate oil concentrations. For smaller, more frequent spills, tethered compact Remotely Operated Vehicles (ROVs) may be more appropriate as they are easy to deploy for rapid detection. Two underwater oil detection technologies have been developed: (1) A Remote Environmental Monitoring UnitS (REMUS-600) AUV equipped with fluorescence and backscatter SeaOWL UV-A (Oil-in-Water Locator; Sea-Bird Scientific WET Labs Inc.), holographic imager (HoloCam; SeaScan, Inc), hydrographic information, video camera, CTD and a water/oil sampler. (2) A tethered ROV system (DTG2, Deep Trekker Inc.) equipped with video camera, UviLux (Chelsea Technologies Group, Inc) fluorometer, a CTD and water/oil sampler. Calibration and validation tests of the sensor suite were conducted at the Coastal Response Research Center flume tank (NH, USA). Oil concentration estimates were verified by chemical analysis of hydrocarbons and particle size analysis (LISST 200X, Sequoia, Inc). Operational performance of the ROV platform and sensors was evaluated at the Ohmsett wave tank (NJ, USA). Field performance of the REMUS and sensor suite was evaluated at natural seeps near Santa Barbara, CA. This research demonstrates the forensic value of in situ optical data for improved understanding of the behavior and transport of spilled oil below the air-sea interface.

Geocorrection of Airborne Mid-Wave Infrared Imagery for Mapping Wildfires without GPS or IMU.

The increase in annual wildfires in many areas of the world has triggered international efforts to deploy sensors on airborne and space platforms to map these events and understand their behaviour. During the summer of 2017, an airborne flight campaign acquired mid-wave infrared imagery over active wildfires in Northern Ontario, Canada. However, it suffered multiple position-based equipment issues, thus requiring a non-standard geocorrection methodology. This study presents the approach, which utilizes a two-step semi-automatic geocorrection process that outputs image mosaics from airborne infrared video input. The first step extracts individual video frames that are combined into orthoimages using an automatic image registration method. The second step involves the georeferencing of the imagery using pseudo-ground control points to a fixed coordinate systems. The output geocorrected datasets in units of radiance can then be used to derive fire products such as fire radiative power density (FRPD). Prior to the georeferencing process, the Root Mean Square Error (RMSE) associated with the imagery was greater than 200 m. After the georeferencing process was applied, an RMSE below 30 m was reported, and the computed FRPD estimations are within expected values across the literature. As such, this alternative geocorrection methodology successfully salvages an otherwise unusable dataset and can be adapted by other researchers that do not have access to accurate positional information for airborne infrared flight campaigns over wildfires.

Clay content prediction using spectra data collected from the ground to space platforms in a smallholder tropical area

Proximal and remote sensors are emerging as powerful sources of soil spectral information at an array of temporal and spatial resolutions. This study investigated clay content prediction at three spectral acquisition levels: laboratory, airborne, and spaceborne. Two approaches were tested, the use of prediction models developed with local and regional spectral libraries (52 samples for local scale and 950, 200 e 224 samples for regional scale), termed internal and external models respectively. Local soil samples (52), were collected in a smallholder area, 83 ha, located in southeastern Brazil. Spectral data in the visible (Vis), near-infrared (NIR), and shortwave infrared (SWIR) regions were acquired in the laboratory using FieldSpec 3 sensor, and the clay content was determined by sedimentation technique. Afterward, bare soil images from AISA-FENIX, Planetscope, Sentinel-2 MultiSpectral Instrument (MSI) and Landsat-8 Operational Land Imager (OLI) were obtained. The clay content determined in the laboratory was related to the soil spectra acquired by each of the sensors and was predicted using the Cubist regression tree algorithm. The results obtained from local spectral libraries showed good predictions using FieldSpec 3 and AISA-FENIX sensors. Landsat-8 OLI and Sentinel-2 MSI provided satisfactory results, while PlanetScope gave poor results. For the prediction using regional spectral libraries, only lab-based FieldSpec 3 sensor provided a fair prediction, while other sensors gave poor results. This study demonstrated that soil sensing is possible at any level taking into account its advantages and limitations. This approach paves the way for acquiring soil spectra for smallholder farms.

Design of FPGA-Implemented Reed–Solomon Erasure Code (RS-EC) Decoders With Fault Detection and Location on User Memory

Reed-Solomon erasure codes (RS-ECs) are widely used in packet communication and storage systems to recover erasures. When the RS-EC decoder is implemented on a field-programmable gate array (FPGA) in a space platform, it will suffer single-event upsets (SEUs) that can cause failures. In this article, the reliability of an RS-EC decoder implemented on an FPGA when there are errors in the user memory is first studied. Then, a fault detection and location scheme is proposed based on partial reencoding for the faults in the user memory of the RS-EC decoder. Furthermore, check bits are added in the generator matrix to improve the fault location performance. The theoretical analysis shows that the scheme could detect most faults with small missing and false detection probability. Experimental results on a case study show that more than 90% of the faults on user memory could be tolerated by the decoder, and all the other faults can be detected by the fault detection scheme when the number of erasures is smaller than the correction capability of the code. Although false alarms exist (with probability smaller than 4%), they can be used to avoid fault accumulation. Finally, the fault location scheme could accurately locate all the faults. The theoretical estimates are very close to the experiment results, which verifies the correctness of the analysis done.

Research of the ranges of effective application of unified space platforms for geostationary communication satellites

The topical problem of choosing the standard size of the unified space platform developed by the joint-stock company «Academician M. F. Reshetnev» Information Satellite Systems» for geostationary communication satellites has been formulated. Previously, the task of assessing the effectiveness of using the developed unified platforms for creating a new spacecraft was solved to a greater extent empirically, by generalizing the groundwork for existing developments and assessing the possibility and feasibility of using the existing groundwork in the future (development continuity). However, a methodological basis for solving this kind of problem has not yet been developed. As part of the study, a model for assessing the efficiency of a spacecraft based on a unified space platform was developed. A method for evaluating the effectiveness of the use of unified space platforms with an excess resource (in terms of mass and energy consumption) for the payload and a method for evaluating the effectiveness of using a modernized unified space platform, which makes it possible to meet increased resource requirements (in terms of weight and energy consumption) for the payload, have been developed. With the help of the developed methods, the assessment of the range of effective use of a unified space platform for geostationary communication satellites developed by JSC ISS was carried out, both without revision and with the necessary modernization for a specific project (payload).

Space-based Optical Target Determination Based on Gooding Algorithm

In this paper, optical target monitoring orbit determination using the Gooding algorithm based on the 400 km altitude space platform was researched. The measurement error was set to 3″ and 6″ respectively for 800 km, 1500 km altitude low Earth orbits and 36 000 km altitude geosynchronous orbit to determine the initial orbit and precise orbit. Simulation results show that the initial orbit determination accuracy of the 4~15 min arc is about 10 km, and the 1~2 min arc is about 100 km when the measurement data error is between 3″ and 6″. The error of 15 min initial determination arc is 100 m. As the arc is less than 10 min, the improved error accuracy of the orbit is in the order of km scale. As the measurement data error is 3″, the initial orbit determination accuracy of the 15~20 min arc is about tens of kilometers, and that of the 8~10 min arc is 100 km. The improved orbit has an error of km. When the measurement data error is 6″, the accuracy of the initial orbit determination of the 20 min arc is at the magnitude of 10 km, the accuracy of the initial orbit determination of the 8~15 min arc is at the magnitude of 100 km, and the error accuracy of the improved orbit is at the magnitude of 10 km.

The Wafer-Level Integration of Single-Crystal LiNbO3 on Silicon via Polyimide Material.

In situ measurements of sensing signals in space platforms requires that the micro-electro-mechanical system (MEMS) sensors be located directly at the point to be measured and in contact with the subject to be measured. Traditional radiation-tolerant silicon-based MEMS sensors cannot acquire spatial signals directly. Compared to silicon-based structures, LiNbO3 single crystalline has wide application prospects in the aerospace field owing to its excellent corrosion resistance, low-temperature resistance and radiation resistance. In our work, 4-inch LiNbO3 and LiNbO3/Cr/Au wafers are fabricated to silicon substrate by means of a polyimide bonding method, respectively. The low-temperature bonding process (100 °C) is also useful for heterostructure to avoid wafer fragmentation results from a coefficient of thermal expansion (CTE) mismatch. The hydrophilic polyimide surfaces result from the increasing of -OH groups were acquired based on contact angle and X-ray photoelectron spectroscopy characterizations. A tight and defect-free bonding interface was confirmed by scanning electron microscopy. More importantly, benefiting from low-temperature tolerance and radiation-hardened properties of polyimide material, the bonding strength of the heterostructure based on oxygen plasma activation achieved 6.582 MPa and 3.339 MPa corresponding to room temperature and ultra-low temperature ( −263.15 °C), which meets the bonding strength requirements of aerospace applications.

Active and passive laser detection technology in space platform

摘要: 以空间攻防为应用背景，深入研究了主被动天基激光探测技术，简述了国内外在天基平台进行激光雷达和激光告警研究的相关情况。在此基础上，开展了基于天基平台的主被动激光探测技术架构设计，论述了各组成部分及其作用，并对涉及的激光收发、光束扫描及激光告警等关键技术进行了深入分析。 关键词: 空间攻防 / 主被动 / 激光探测

Semantics of life models in the information field of social networks

In the context of the rapid development of the information environment, a person’s life path, identity, and the living space of an individual are not only presented in real life, but also in the virtual world, as well as in augmented reality. The mixing of virtual and real spaces cannot but affect the daily life of young people. This article attempts to describe and structure the elements of life models as fragments of a life scenario, broadcast through communities in social networks. The social network VKontakte has become a meaningful field for analysis as it is the most popular and frequently used online platform in the information space for the purpose of transmitting interesting and relevant information among Russian peers. The starting point of the study was the assumption that the content of social network posts describing the spheres of life can serve as a basis for building elements of life models broadcast on the Internet. The research consisted of several stages: preparatory (questioning young people about their preferred Internet content) and the main one (semantic and content analysis of the content of social networks). The sample of the preparatory stage was 110 respondents, the average age was 22 years (SD=2.8). The main sample consisted of over 200,000 posts from the top 20 social media communities (with an average of 4 million subscribers, with entertainment and non-themed content) over the past 2 years. With the help of special program codes and computer programs, the posts devoted to the most significant spheres of human activity were analyzed. It was found that the most popular marker words denoting areas of life in posts are work, relationships, and family. The data of automated semantic and content analysis showed that most often, through posts in communities, a model of an active and purposeful person is declared. This is an individual who is ready for action, flexible, mobile with respect to work and self-development, but conservative in regard to building family relationships. The results obtained confirm the assumption that the characteristics of the components of life models are presented most vividly in the posts of Internet communities, are actively broadcast and have their own characteristics. The results of the research data can contribute to the study of the main mechanisms of transmission between contemporaries of characteristics of behavior in real life, values and information through Internet content, as well as the work of practicing psychologists when referring to the profile on social networks or preferred client communities.

A New Bargaining Game-Based Unlicensed Spectrum Sharing Scheme for TVWS Platform

The rapid boosting in the Internet-of-Things (IoT) paradigm and the scarcity of available spectrum resources have hindered the improvement of capacity in 5G wireless network systems. Therefore, it is necessary to discover an appropriate spectrum sharing technology by exploiting unlicensed spectrum bands. In this study, we design a new unlicensed spectrum sharing algorithm in the television white space (TVWS) platform. According to the cooperative bargaining game theory, our proposed algorithm explores the mutual benefits to achieve a reciprocal consensus for different data application services. In a sequentially iterative manner, our game based approach adaptively makes control decisions for the TVWS spectrum sharing problem. Based on the novel bargaining solution and well-known rationing rules, we compromise the conflicting views of IoT devices while leveraging a cooperative agreement for their services. Finally, numerical simulation results show that our proposed algorithm provides a very effective tradeoff between the spectrum efficiency and service fairness compared with the existing TVWS spectrum sharing protocols.

Spatial-Resolution Independent Object Detection Framework for Aerial Imagery

Earth surveillance through aerial images allows more accurate identification and characterization of objects present on the surface from space and airborne platforms. The progression of deep learning and computer vision methods and the availability of heterogeneous multispectral remote sensing data make the field more fertile for research. With the evolution of optical sensors, aerial images are becoming more precise and larger, which leads to a new kind of problem for object detection algorithms. This paper proposes the “Sliding Region-based Convolutional Neural Network (SRCNN),” which is an extension of the Faster Region-based Convolutional Neural Network (RCNN) object detection framework to make it independent of the image’s spatial resolution and size. The sliding box strategy is used in the proposed model to segment the image while detecting. The proposed framework outperforms the state-of-the-art Faster RCNN model while processing images with significantly different spatial resolution values. The SRCNN is also capable of detecting objects in images of any size.

Experimental Study on Photodiode Array Sensor Aided MEMS Fine Steering Mirror Control for Laser Communication Platforms

Line-of-sight laser communication application scenarios are numerous including land, mobile, maritime, airborne and space platforms for conventional and tactical utilization. However, beam pointing and stabilization are complicated in dynamic systems such as orbiting satellite to ground receiver, drones, aircrafts and metropolitan free-space optical links vulnerable to natural and artificial disturbances. Small Satellite platforms such as CubeSats are even more challenging due to their limited size and on-board resources. This paper presents an experimental study on a feedback photodiode array sensor assisted control of a one-axis micro-electromechanical (MEMS) fine steering mirror stabilizing a laser communication link on an optical bench in the laboratory. Disturbance profiles similar to vibrations on dynamic platforms are induced into the setup using an electrodynamic vibration machine to test the efficacy of the MEMS fine steering control mechanism. The Photodiode Array (PDA) sensor collocated with an Avalanche Photodiode at the receiving section provides sustained information about the transmitter's movements and beam displacements while the received optical signal strength is continuously monitored. The feedback signals are transmitted to the FSM controller via a radio link. We demonstrate the capacity to stabilize a laser beam transmission in the presence of external disturbances and platform movements using a PDA sensor assisted control.

Retrospect and Perspective on Microgravity Science in China

The major objective of microgravity science is to study the movement laws of substances in microgravity, as well as to reveal the influence of gravity on the movement of materials in different gravity environments. Chinas microgravity research started in the 1960s and really rose in the middle and late 1980s. After years of efforts, it has begun to take shape, and has obvious characteristics and advantages in some important directions. In this paper, the early history of Chinas microgravity science is briefly reviewed. The emphases are put on the recent progress and the latest achievements of microgravity science and application researches in China carried out mainly by using the national space platforms, such as SJ-10 scientific experiment satellite, TG-2 space lab, and so on. Finally, the vision of Chinas microgravity science in the coming era of China Space Station (CSS) is prospected, so as to promote the rapid and sustainable development of microgravity science and application researches in China, for better serving the country and benefiting mankind.

ВАРІАНТ СТРУКТУРИ СИСТЕМИ АВТОМАТИЧНОЇ СТАБІЛІЗАЦІЇ ПЛАТФОРМИ АНТЕННОГО ПОЛЯ РУХОМОГО ОБ’ЄКТУ

The article proposes a variant of constructing a digital system for automatic stabilization of the antenna field platform located on an object (vehicle), and also considers the structural diagrams of control channels. The choice of executive devices to ensure the performance and accuracy of the system is substantiated. The conditions of use, restrictions and initial data necessary for the synthesis of the automatic stabilization system are determined, the principles of calculating by the system - the coordinates of the position of the antenna field platform in space - are highlighted.The prerequisites for the use of a platform with stabilization at the facility is the need to ensure the most efficient use of communication facilities (antenna systems) in a complex electromagnetic environment and to reduce the deployment (folding) time, adjust radio and satellite communications in the operational-tactical and tactical control levels.The system of automatic stabilization of the antenna field platform will provide optimal conditions for the interaction of antenna systems that are part of the antenna field of radio-electronic means of the compact constellation. Optimal conditions should be understood as vertical placement of omnidirectional antennas, the possibility of changing the position of directional antennas in the azimuthal plane and ensuring the electromagnetic compatibility of radio electronic means. The deviation of the platform from the required angular positions of the reference coordinate system can be determined by accelerometers or other devices that measure the linear acceleration of an object in a given plane.It is proposed to stabilize the platform through two channels for each of the axes. The angular position of the stabilized platform in space is specified in the reference coordinate system, which is not associated with a moving object (vehicle) that is moving, and in a moving coordinate system, it is rigidly connected with this object. It is proposed to use an inertial coordinate system as a reference coordinate system, that is, motionless relative to the horizon, which is oriented at a given point on the earth's surface. The proposed automatic system is universal, with the ability to adapt to the driving performance of a moving object. Adaptability is ensured by the presence in the control loop of an automatic stabilization system of circuits, the parameters of the transfer functions of which are pre-calculated for the tactical and technical characteristics of the moving object.

Science Goals and Mission Objectives for the Future Exploration of Ice Giants Systems: A Horizon 2061 Perspective

The comparative study of planetary systems is a unique source of new scientific insight: following the six “key science questions” of the “Planetary Exploration, Horizon 2061” long-term foresight exercise, it can reveal to us the diversity of their objects (Question 1) and of their architectures (Question 2), help us better understand their origins (Question 3) and how they work (Question 4), find and characterize habitable worlds (Question 5), and ultimately, search for alien life (Question 6). But a huge “knowledge gap” exists which limits the applicability of this approach in the solar system itself: two of its secondary planetary systems, the ice giant systems of Uranus and Neptune, remain poorly explored. Starting from an analysis of our current limited knowledge of solar system ice giants and their systems in the light of these six key science questions, we show that a long-term plan for the space exploration of ice giants and their systems will greatly contribute to answer these questions. To do so, we identify the key measurements needed to address each of these questions, the destinations to choose (Uranus, Neptune, Triton or a subset of them), the combinations of space platform(s) and the types of flight sequences needed. We then examine the different launch windows available until 2061, using a Jupiter fly-by, to send a mission to Uranus or Neptune, and find that: (1) an optimized choice of platforms and flight sequences makes it possible to address a broad range of the key science questions with one mission at one of the planets. Combining an atmospheric entry probe with an orbiter tour starting on a high-inclination, low periapse orbit, followed by a sequence of lower inclination orbits (or the other way around) appears to be an optimal choice. (2) a combination of two missions to each of the ice giant systems, to be flown in parallel or in sequence, will address five out of the six key questions and establish the prerequisites to address the sixth one: searching for life at one of the most promising Ice Giant moons. (3) The 2032 Jupiter fly-by window, which offers a unique opportunity to implement this plan, should be considered in priority; if this window cannot be met, using the 2036 Jupiter fly-by window to send a mission to Uranus first, and then the 2045 window for a mission to Neptune, will allow one to achieve the same objectives; as a back-up option, one should consider an orbiter + probe mission to one of the planets and a close fly-by of the other planet to deliver a probe into its atmosphere, using the opportunity of a future mission on its way to Kuiper Belt Objects or the interstellar medium; (4) based on the examination of the habitability of the different moons by the first two missions, a third one can be properly designed to search for life at the most promising moon, likely Triton, or one of the active moons of Uranus. Thus, by 2061 the first two missions of this plan can be implemented and a third mission focusing on the search for life can be designed. Given that such a plan may be out of reach of a single national agency, international collaboration is the most promising way to implement it.

No Effect of Microgravity and Simulated Mars Gravity on Final Bacterial Cell Concentrations on the International Space Station: Applications to Space Bioproduction.

Microorganisms perform countless tasks on Earth and they are expected to be essential for human space exploration. Despite the interest in the responses of bacteria to space conditions, the findings on the effects of microgravity have been contradictory, while the effects of Martian gravity are nearly unknown. We performed the ESA BioRock experiment on the International Space Station to study microbe-mineral interactions in microgravity, simulated Mars gravity and simulated Earth gravity, as well as in ground gravity controls, with three bacterial species: Sphingomonas desiccabilis, Bacillus subtilis, and Cupriavidus metallidurans. To our knowledge, this was the first experiment to study simulated Martian gravity on bacteria using a space platform. Here, we tested the hypothesis that different gravity regimens can influence the final cell concentrations achieved after a multi-week period in space. Despite the different sedimentation rates predicted, we found no significant differences in final cell counts and optical densities between the three gravity regimens on the ISS. This suggests that possible gravity-related effects on bacterial growth were overcome by the end of the experiment. The results indicate that microbial-supported bioproduction and life support systems can be effectively performed in space (e.g., Mars), as on Earth.

Towards dark space stabilization and manipulation in driven dissipative Majorana platforms

We propose driven dissipative Majorana platforms for the stabilization and manipulation of robust quantum states. For Majorana box setups, in the presence of environmental electromagnetic noise and with tunnel couplings to quantum dots, we show that the time evolution of the Majorana sector is governed by a Lindblad master equation over a wide parameter regime. For the single-box case, arbitrary pure states (`dark states') can be stabilized by adjusting suitable gate voltages. For devices with two tunnel-coupled boxes, we outline how to engineer dark spaces, i.e., manifolds of degenerate dark states, and how to stabilize fault-tolerant Bell states. The proposed Majorana-based dark space platforms rely on the constructive interplay of topological protection mechanisms and the autonomous quantum error correction capabilities of engineered driven dissipative systems. Once a working Majorana platform becomes available, only standard hardware requirements are needed to implement our ideas.

A state estimation scheme with minimal sensor configuration for three-body tethered satellite formations

Tethered satellite formations in space have attracted widespread attention in recent years, as they can provide an excellent large-scale, self-stabilized space platform. At present, most studies on tethered satellite formation systems focus on dynamics, control deployment and stability analysis, and they all assume that the state information of the system is given or easily measured. However, it is not trivial to obtain accurate state measurements of tethered satellite formations in space, especially without using high-cost sensors. In this paper, we present a filter-based state estimation scheme with minimum sensor configuration for three-body tethered satellite formation. The satellite-to-satellite ranges and absolute attitude angles of tethered formation can be accurately estimated by fusing only the measurements of three gyroscopes and three tether releasing mechanisms. Particularly, the absolute attitude angles are obtained even without using any sensors that can measure absolute information. The feasibility of the proposed scheme is theoretically proven via the observability analysis of nonlinear systems, and the performance of the scheme is demonstrated through extensive simulations. This method can be readily extended to the state estimation process of other tethered formations in space.

Thermal Regulation of Space Platform Panels by Using Electric Heaters

In orbital flight, the temperature state of spacecraft and their constituent space platforms complexly changes in time and space. The inhomogeneous temperature field of the space platform can cause shape distortion, which negatively affects the performance of targets. To equalize the temperature field of the space platform, it is proposed to use electric heaters with differentiated power distributions. The formulation of the boundary inverse heat conduction problem is presented and the specific power of the heaters necessary for uniform distribution of the temperature field of a panel of composite material is determined.