Onboard Spacecraft Research Articles

Увеличение объемов передаваемой по космическим радиолиниям информации за счет применения алгоритмов сжатия

With the development of Earth remote sensing systems, requirements for the data transfer rate, which has almost reached the Shannon limit, become more demanding. A promising solution is the use of transmitted data compression algorithms on board the spacecraft. Of greatest interest for research is the compression of optical images, since they occupy the largest volume of transmitted information and lend themselves well to compression, including lossless compression. Currently, the authors of the article are not aware of efficient algorithms for compressing optical images that would be used onboard domestic spacecraft. Such algorithms must account for the functional features of the optoelectronic equipment matrices, the structure of the obtained images and the issued data packets. The right combination of compression methods, which would take into account the data structure at each stage and ensure the required balance between the compression ratio, compression rate, consumed onboard resources and implementation complexity, must also be applied. Algorithms used in common media data formats do not meet these requirements. The algorithms employed in some foreign spacecraft either compress with loss or with a low compression ratio. Thus, an in-depth analysis is required of the peculiarities of optoelectronic equipment, the structures of transmitted data, as well as of the methods and algorithms for their compression.

Уточненная расчетная оценка сбое- и отказоустойчивости критичных изделий ЭКБ с учетом фактической массовой защищенности

Nowadays rocket and space industry enterprises use a simplified method to evaluate failure and fault tolerance of the onboard equipment to single event effects (SEEs), when the calculation is performed for the minimum mass protection thickness (g/cm2 ) of potentially sensitive electronic components determined, as a rule, by the minimum wall thickness of the device under consideration. In this case, all structural elements of the onboard equipment, spacecraft, and neighboring devices are not included, which, in many cases, leads to a significant overestimation of the calculated SEEs frequency especially for large scale integration ICs. Neglecting the actual mass protection may require redundant measures to ensure failure and fault tolerance. The work proposes an improved approach of calculating failure and fault tolerance of sensitive electronic components and onboard equipment to the impact of heavy charged particles and high-energy protons that causes SEEs, which consists in using programs for calculating absorbed doses by the sectorization method in three-dimensional models, which makes possible to determine the minimum, maximum, and average mass protection of electronic components with the complete design of the onboard equipment and spacecraft.

Adsorbed xenon propellant storage: are nanoporous materials worth the weight?

Nanoporous materials could be used to store xenon propellant onboard spacecraft.

Decision-making support system model for spacecraft onboard systems diagnosing based on Bayesian networks

Decision-making support system model for spacecraft onboard systems diagnosing based on Bayesian networks

A method for survivability indices evaluation of a small spacecraft onboard systems under conditions of operating modes changing and destructive impacts

A method for survivability indices evaluation of a small spacecraft onboard systems under conditions of operating modes changing and destructive impacts

Passive cooling system designing for a spacecraft onboard complex

Passive cooling system designing for a spacecraft onboard complex

Quality control of the spacecraft onboard equipment functioning under the impact of the propulsion system radiation

Quality control of the spacecraft onboard equipment functioning under the impact of the propulsion system radiation

Электронная компонентная база космического назначения

The electrical, electronic and electromechanical parts (EEE parts) used in spacecraft onboard equipment must fully provide the target technical characteristics of radio-electronic equipment in terms of functional and electrical characteristics, as well as resistance to external factors and reliability indicators. The authors of the article analyze the current situation with the EEE parts and consider the prospects for the development and creation of the necessary electronics products. Currently, the results of the work are confirmed by the active use of the created space components in space technology.

A simulation experiment on the GM estimation for Comet 133P/Elst-Pizarro

In China’s asteroid mission to be launched around 2025, (7968) 133P/Elst-Pizarro (hereafter 133P) will be the second target, after a visit to asteroid (469219) Kamo’oalewa. This paper describes a simulation of precise orbit determination for the spacecraft around comet 133P, as well as estimation of its gravitational parameter (GM) value and the solar radiation pressure coefficient Cr for the spacecraft. Different cometocentric distances of 200, 150 and 100 km orbits are considered, as well as two tracking modes: exclusive two-way range-rate mode (Earth station to spacecraft) and combinations of two-way range-rate and local spacecraft onboard ranging to the comet. Compared to exclusive two-way range-rate, the introduction of local ranging observables improves the final GM uncertainties by up to one order of magnitude. An ephemeris error in the orbit of 133P is also considered, and we show that, to obtain a reliable estimate of the GM for 133P, this error cannot exceed a one km range.

The very high-speed SpaceFibre multi-lane CoDec: Implementation and experimental performance evaluation

On-board data handling sub-systems shall provide robust communication on-board spacecraft and have strict requirements in terms of reliability, fault-tolerance and redundancy. In the next years, on-board data handling sub-systems will be required to sustain high-speed payloads since satellites will host new high-resolution instruments, requiring a multi-gigabit data rate. The European Space Agency promotes the usage of a standard for the implementation of a very high-speed link for satellite on-board data-handling, SpaceFibre, that supports multi-lane communication links. Indeed, due to the stringent requirements of future on-board data handling subsystems, it will be necessary to have links that include more lanes to enhance system reliability and bandwidth. SpaceFibre aims at becoming the state-of-the-art for future on-board data handling subsystem, combining high-speed with high reliability and fault tolerance capability. In this paper, we introduce and report the development of an innovative multi-lane SpaceFibre core, and compares it with other promising space-oriented standards regarding multi-lane features. We present the results of a test campaign that aims at measuring SpaceFibre multi-lane performances in terms of recovery time after a lane failure, observing that the communication process can be completely restored between 4.42 μs and 6.30 μs. Implementation results on state-of-the-art space-oriented FPGAs, such as the Microsemi RTG4 and the Xilinx UltraScale Virtex KU060 are also included. Finally, we carry out a detailed power consumption analysis, including results for different core configurations, measuring the SpFi dynamic power consumption contribution to be between 576.7 mW and 148.4 mW for target configurations on a Microsemi RTG4.

Advanced Pointing Imaging Camera (APIC) for planetary science and mission opportunities

The Advanced Pointing Imaging Camera (APIC) is designed to obtain high-resolution imaging data to measure a target’s geophysical and geodetic properties. The development of APIC originates from NASA’s Homesteader program of technology development for candidate New Frontiers missions. The unique science enabled by APIC derives from its ability to simultaneously take images of the target and star field, allowing high-precision camera pointing knowledge with each high-resolution target image. APIC is small (28 ​cm ​× ​18 ​cm ​× ​24 ​cm encompassing volume), light-weight (6 ​kg total), and moderate in power (13 ​W maximum) while being high performance and robust to long missions in deep space. APIC incorporates two imagers, one narrow-angle camera (NAC) and one wide-angle camera (WAC) that can operate simultaneously. Both cameras utilize the CMOS-based Mars 2020 Engineering Camera technology with an option of either clear or Red-Green-Blue colors and have wide apertures to enable short exposures and thus perform at a wide range of targets. The NAC has a pixel resolution of 18 ​μrad and 4° field of view and the WAC has a pixel resolution of 82 ​μrad and 18° field of view. APIC also has two gimbals, allowing rapid camera pointing updates without the need to change the spacecraft attitude; thus, not interfering with other onboard sensors or spacecraft operations. Both gimbals are capable of compensating for relative spacecraft-target motion (i.e., image motion compensation) with an angular speed of up to 30°/s (i.e., 0.5 ​rad/s). Many of APIC components are commercial-off-the-shelf (COTS), or adapted from other NASA flight programs, which makes APIC very competitive in cost and gives it a high technical maturity. APIC’s high-resolution images enable the determination of high-accuracy topography for geologic studies. This paper presents details of APIC’s characteristics and functionalities as well as specific science objectives that APIC data can address, such as measuring a geometric tidal flexing through estimating the tidal Love number, h2 and l2, and small rotational effects, such as libration and precession, of natural satellites and small bodies (i.e., asteroids and comets) that are key to exploring a planetary body’s interior. Improved knowledge of spacecraft orbit via landmark tracking using the APIC data would also improve the recovery of low-degree gravitational parameters such as k2. In this paper, the performance of APIC is presented by showing how well the tidal deformation and libration measurements can be recovered with realistic mission scenarios and configurations.

Моделирование и макетирование космического детектора молний

The problem of detecting lightning flashes from space is becoming more and more important as the remote sensing of Earth, climatology and atmospheric physics develop. Orbital lightning detectors are designed both in Russia and abroad. The paper considers the problem of mathematical and physical simulation of a high-speed camera designed to observe lightning flashes from onboard spacecraft in low Earth orbit. Our previous works substantiated the exterior design of the lightning detector, computed its properties and described the algorithms behind the software. In order to validate the design results, we need to prototype the instrument. We describe the main problems of detecting lightning flashes as observed from space. We show a computer simulation method producing snapshots that takes into account the interference generated by the background and the photodetector. We studied the problems of recreating the target environment during prototyping of the lightning detector, accounting for the properties of the phenomenon observed, that is, the flash spot dimensions and the ratio of the background brightness to that of the lightning. We describe the principle of comparing these two types of snapshots (taken by the prototype and synthesised by the software) and compared the results of processing the images obtained. The results matched, which allowed us to validate the snapshot processing algorithm and confirmed that the lightning detector simulation method developed is correct

Janus polyimide films with outstanding AO resistance, good optical transparency and high mechanical strength

Polyimide films are required onboard spacecrafts withstanding atomic oxygen (AO) erosion in low earth orbit environment. We report a janus polyimide composite film consisting of HBPSi enriched and scanty surfaces/sides. This unique structure ensures both outstanding AO resistance—with relative mass loss merely 8.34% that of standard Kapton H—and admirable mechanical performance with ultimate tensile strength as high as ca. 89 MPa and fracture toughness up to 5.22 MJ·m−3. Besides, janus polyimide composite films are good at maintaining its surface morphology and integrity upon AO attack, showing a higher transmittance after AO exposure (ca. 82% at 600 nm) and lower root mean square roughness (RMS) value (5.14 nm vs. 6.62 nm) in comparison to its monolayered counterpart. These janus polyimide films demonstrate exceptional performance and thus show great potential for making surface protective blanket for spacecrafts functioning in space environment.

Method of vibration power spectral density calculation for spacecraft attached large-size and small-mass equipment units

During the lift-off and the ascent phase, spacecraft (SC) large-size attached equipment is impacted by intensive vibrations, largely due to acoustic pressures. To ensure a reliable in-orbit operation of all SC systems the modes of vibration loads shall be assessed as much as reliable (using experimentally-confirmed mathematical models). Determination of the vibroacoustic response parameters of the equipment structure is a very important issue for such equipment units (elements) which have a large surface square with a relatively small mass. Among such structures are folded solar arrays (SA) and reflector type antennae dishes (ART). The purpose of this study is to validate the calculation methodology of vibration power spectral density (PSD) for low and medium frequency band (25-400 Hz), and apply it for the aforesaid structures in the lift-off and flight phases as part of the integrated launch vehicle in the area of maximum ram effects, when the acoustic pressure levels, and therefore their impact on the vibroacoustic response of these structures are maximum. The target goal has been implemented using the example of the solar array and reflector type antenna being used in the spacecraft power supply system and onboard radio system of one of RSC Energia-developed spacecraft. Key words: environment air, spacecraft, solar array, reflector type antennae dish, dynamic model, sound pressure level, acoustic pressure, structure vibroacoustic response.

Refining the Earth Orientation Parameters Onboard Spacecraft: Concept and Information Technologies

We consider the problem of refining the evolving Earth Orientation Parameters (EOP) used during the converting from the inertial coordinate system to the Earth’s coordinate system, including ephemerides computations onboard spacecraft (SC). We discuss the approaches and technologies used to refine these parameters. We propose a concept to refine EOP by ground stations and SC, based on processing the measurements of the distance between the ground station and SC by the least squares method (LSM). We provide mathematical models, refining algorithms, and the results of their application in experiments simulating refining processes for parameters of the EOP onboard SC.

Structurally topological algorithm for star recognition and near-Earth space’ object detection

When solving a variety of celestial navigation tasks there is a problem of determining parameters of spacecraft motion and onboard primary payload orientation based on the coordinates of registered star images. Furthermore, unwanted objects, like active satellites, natural and artificial space debris, that reduce the probability of correct recognition may get into the field of view of a satellite sensor. This prompts the necessity to filter out such interference from the star field images. However, if the objects under recognition are bodies located in near-Earth space, in this case, the star images themselves will act as interferences. In addition, since the detection and cataloging of these objects from the Earth’s surface is complicated by their small size, the atmospheric effects, as well as other technical difficulties, it is worthwhile to use the existing equipment onboard spacecrafts to solve this task. The existing recognition algorithms for star groups, as well as their classification, are presented in this paper. Moreover, a structurally topological approach for identifying groups of stars based on the properties of enveloping polygons used in constructing topological star patterns is proposed. Specific features in the construction of topological configurations on the analyzed set of points, as well as the principles of dynamic space object detection within their limits are described. Results of the numerical experiments performed using the developed algorithm on the star field maps and model scenes are presented.

Time suboptimal formation flying manoeuvres through improved magnetic charged system search

The development of fast and reliable optimization algorithms is required in order to obtain real-time optimal trajectory on-board spacecraft. In addition, the wide spread of small satellites, due to their low costs, is leading to a greater number of satellite formations in space. This paper presents an Improved version of the Magnetic Charged System Search (IMCSS) metaheuristic algorithm to compute time-suboptimal manoeuvres for satellite formation flying. The proposed algorithm exploits some strategies aimed at improving the convergence to the optimum, such as the chaotic local search and the boundary handling technique, and it is able to self-tune its internal parameters and coefficients. Moreover, the inverse dynamics technique and the differential flatness approach, through the B-splines curves, are used to approximate the trajectory. The optimization procedure is applied to the circular J2 relative model developed by Schweighart and Sedwick and to the elliptical relative motion model developed by Yamanaka and Ankersen. The results of this paper show that the convergence is better achieved by using the proposed tools, thus proving the efficiency and reliability of the algorithm in solving some space engineering problems.

Neural network optimal control in astrodynamics: Application to the missed thrust problem

While high-efficiency propulsion techniques are enabling new mission concepts in deep space exploration, their limited thrust capabilities necessitate long thrusting arcs and make spacecraft more susceptible to missed thrust events. To correct for such mishaps, most spacecraft require updated trajectories that are relayed from Earth. While this solution is viable for spacecraft near Earth, in deep space, where one-way communication time is measured in hours, a delay in transmission may prolong the time of flight or result in a complete loss of mission. Such problems can be alleviated by increasing the spacecraft's onboard autonomy in guidance. This paper demonstrates how a computationally lightweight neural network can map the spacecraft's state to a near-optimal control action, autonomously guiding a spacecraft within different astrodynamic regimes and optimality criteria. The neural network is trained using supervised learning and datasets comprised of optimal state-action pairs, as determined through traditional direct and indirect methods. Additionally, the neural network-designed solutions retain optimality and time of flight corresponding to traditional trajectories. Finally, the same neural networks can autonomously correct for most missed thrust events encountered on long-duration low-thrust trajectories. The presented results provide a path for mitigating risks associated with the use of high-efficiency low-thrust propulsion techniques.

Spacecraft onboard computers control automation

This paper concerns the task of onboard spacecraft’s computers functioning analysis problem. Existing approach is analyzed. Criteria of onboard computers normative functioning and source data for analysis implementation are defined. As a result, telemetry analysis algorithm for forming decisions about onboard computer normative functioning is offered. Program based on it is developed.

Crewmember microbiome may influence microbial composition of ISS habitable surfaces.

The International Space Station (ISS) is a complex built environment physically isolated from Earth. Assessing the interplay between the microbial community of the ISS and its crew is important for preventing biomedical and structural complications for long term human spaceflight missions. In this study, we describe one crewmember’s microbial profile from body swabs of mouth, nose, ear, skin and saliva that were collected at eight different time points pre-, during and post-flight. Additionally, environmental surface samples from eight different habitable locations in the ISS were collected from two flights. Environmental samples from one flight were collected by the crewmember and samples from the next flight were collected after the crewmember departed. The microbial composition in both environment and crewmember samples was measured using shotgun metagenomic sequencing and processed using the Livermore Metagenomics Analysis Toolkit. Ordination of sample to sample distances showed that of the eight crew body sites analyzed, skin, nostril, and ear samples are more similar in microbial composition to the ISS surfaces than mouth and saliva samples; and that the microbial composition of the crewmember’s skin samples are more closely related to the ISS surface samples collected by the crewmember on the same flight than ISS surface samples collected by other crewmembers on different flights. In these collections, species alpha diversity in saliva samples appears to decrease during flight and rebound after returning to Earth. This is the first study to compare the ISS microbiome to a crewmember’s microbiome via shotgun metagenomic sequencing. We observed that the microbiome of the surfaces inside the ISS resemble those of the crew’s skin. These data support future crew and ISS microbial surveillance efforts and the design of preventive measures to maintain crew habitat onboard spacecraft destined for long term space travel.