near-Earth Orbit Research Articles

Aspects of information support in ensuring the survivability of spacecraft under electrophysical effects

In order to improve the operational efficiency of decision-making in the context of spacecraft (SC) endurance in operation, the task was set to increase the efficiency of adaptation of its control system to the environmental effects. The instruments installed on most Russian SCs in many cases do not provide for identification and timely elimination of accident sources due to delays in the identification of faults and failures. A technology is proposed that involves intellectualization of control systems. It is suggested to complement the SC control circuit with an expert system that includes a “prognostic decision support system”, a “control simulation and correction module”. Due to the ambiguity and common uncertainty of cosmic phenomena, it is suggested to predict the reaction of SC equipment to external effects rather than monitor such effects. The intelligence of the expert system is to be ensured through the analysis of the communication medium that defines the possibility to ensure SC survivability. The correction of control is suggested to be performed not on the basis of process parameters monitoring, but rather knowledge. This knowledge is held by experts who possess experience in SC flight mission performance. The results of the audit of external factors and development of SC functional units reactions represent the input data. After clearing, sorting and statistical analysis of data, it is suggested to regard it as information resources. The results of such resources analysis and design of messages based on expert conclusions transforms such resources into knowledge that is used in decision making and control correction. The diversity of architectures and processes of SC functional units design has defined the requirement to involve experts with diverse professional backgrounds. It was proposed to generate forecasts of SC equipment reactions development in the form of description of the dynamics of multifactor combination of the results of intersubject audit of functional units operations and subjective expert evaluations. In order to ensure agility of information analysis within the knowledge base, it was suggested to use the OLAP comprehensive multidimensional analysis technology. In particular, that regards fast analysis of shared multidimensional information that includes requirements for multidimensional analysis applications. The proposed model of systematic accumulation and processing of knowledge will enable flight control officers to timely identify inadequacies in the control inputs. The logical and statistical analysis capabilities ensured by this application will enable the delivery of analysis results to the experts within a time period sufficient for elimination of the causes of faults and failures in SC equipment operation. Multidimensional conceptual representation of data including the support of multiple hierarchies will define the capability to refer to any required information regardless of its size and place of storage. The proposed method of information support of SC equipment reactions forecasting is addressed in the light of the analysis of electrophysical effects that affect SC in near-Earth orbits. Combining the methods of computer data processing and intersubject analysis of functional units operation must insure efficient decision-making based on increased accuracy and agility of data processing and, consequently, selection of SC operation adaptation scenario subject to flight control officer’s preferences.

Comparative analysis of redirection methods for asteroid resource exploitation

An in-depth analysis and systematic comparison of asteroid redirection methods are performed within a resource exploitation framework using different assessment mechanisms. Through this framework, mission objectives and constraints are specified for the redirection of an asteroid from a near-Earth orbit to a stable orbit in the Earth–Moon system. The paper provides a detailed investigation of five redirection methods, i.e., ion beam, tugboat, gravity tractor, laser sublimation, and mass ejector, with respect to their capabilities for a redirection mission. A set of mission level criteria are utilized to assess the performance of each redirection method, and the means of assigning attributes to each criterion is discussed in detail. In addition, the uncertainty in physical characteristics of the asteroid population is quantified through the use of Monte Carlo analysis. The Monte Carlo simulation provides insight into the performance robustness of the redirection methods with respect to the targeted asteroid range. Lastly, the attributes for each redirection method are aggregated using three different multicriteria assessment approaches, i.e., the Analytical Hierarchy Process, a utility-based approach, and a fuzzy aggregation mechanism. The results of each assessment approach as well as recommendations for further studies are discussed in detail.

Moon/Sun interference analysis, identification and suppression on Dual Cone Earth Sensor

Focused on the problem of the Sun and Moon interference to Dual Cone scanning infrared Earth Sensor (DCES) which is installed on the near-Earth satellite, this paper puts forward the corresponding solutions. First of all, according to the working principle of the sensor, the paper analyzed the interference mechanism of the Sun and Moon in detail and carried out a simulation. By detecting and discriminating the pulse produced by the Sun, the Moon and the Earth, a novel method was presented and new software was developed to suppress the interference. The method was realized without additional sensors or other devices, and without remote control on the ground, resulted in low-cost and high autonomy of the satellite. Furthermore, the method was verified through an electrical signal testing as well as an optical signal source testing. Results showed that the Moon and Sun interference was identified and suppressed without corrupting the horizon crossing.

Evalution of technical means capabilities for minimisation of technogenic pollution of a near space

The conducted researches are directed on the solution of one of the most important problems of the space use – a problem connected with existence and inadmissibility of growth the quantity of a technogenic origin space debris on low near-earth and geostationary orbits because its further increase will overlap to mankind an exit in space and will terminate space activity. In the basis of a technique of researches the analysis of an existing ecological condition of the surrounding space environment on which base determined the major factors of pollution of the space and considered ways of struggle against space debris on near-earth orbits is put. It is established that the major factors of pollution of the near-earth space are spent stages of launch vehicles and accelerating units, the space crafts which have terminated its existence, fragments of destroyed artificial space objects, operational elements etc. Space debris basically is concentrated on low orbits and around a geostationary orbit which on the basis of the analysis of statistical data on space crafts starts are in most common use. Here groupings of space crafts of the various particular mission, including space crafts of communication, relay, TV, the early prevention of a rocket attack are concentrated. It is shown that the main ways of struggle against space debris are prevention of occurrence new and removal of the already existing debris. Notable decrease in level of the pollution can achieve at cumulative use of such measures, as an exception of explosions of the space objects, limitation of quantity of the started space crafts, reduction of number of the accompanying fragments injected into orbits at starts. Methods and means of withdrawal from working orbits of space crafts upon termination of term of their active existence and known ways and systems of active removal of already existing fragments of the space debris, such as: application of an ionic bunch, the space ship-towing vehicle, the polyurethane foam, the pulsing laser, harpoon system, electrodynamic cord system are considered. Scientific novelty of the presented results consists in the description of conceptual actions for reduction of pollution of the space. The activities executed in the given direction, have huge practical value as the outer space exploration gives huge advantage and significant progress to mankind, but the further operation at near-earth space by existing methods without acceptance of the measures indicated in the article, its further safe development already will not allow in the near future.

When comets get old: A synthesis of comet and meteor observations of the low activity comet 209P/LINEAR

It is speculated that some weakly active comets may be transitional objects between active and dormant comets. These objects are at a unique stage of the evolution of cometary nuclei, as they are still identifiable as active comets, in contrast to inactive comets that are observationally indistinguishable from low albedo asteroids. In this paper, we present a synthesis of comet and meteor observations of Jupiter-family Comet 209P/LINEAR, one of the most weakly active comets recorded to-date. Images taken by the Xingming 0.35-m telescope and the Gemini Flamingo-2 camera are modeled by a Monte Carlo dust model, which yields a low dust ejection speed (1/10 of that of moderately active comets), dominance of large dust grains, and a low dust production of 0.4kgs-1 at 19d after the 2014 perihelion passage. We also find a reddish nucleus of 209P/LINEAR that is similar to D-type asteroids and most Trojan asteroids. Meteor observations with the Canadian Meteor Orbit Radar (CMOR), coupled with meteoroid stream modeling, suggest a low dust production of the parent over the past few hundred orbits, although there are hints of a some temporary increase in activity in the 18th century. Dynamical simulations indicate 209P/LINEAR may have resided in a stable near-Earth orbit for ∼104yr, which is significantly longer than typical JFCs. All these lines of evidence imply that 209P/LINEAR as an aging comet quietly exhausting its remaining near surface volatiles. We also compare 209P/LINEAR to other low activity comets, where evidence for a diversity of the origin of low activity is seen.

How many asteroids are out there, exactly?

The effort to find objects that might threaten Earth is far from complete, and NASA admits it won’t meet a 2020 congressional deadline to find the bigger ones.

THE EUPHROSYNE FAMILY’S CONTRIBUTION TO THE LOW ALBEDO NEAR-EARTH ASTEROIDS

The Euphrosyne asteroid family is uniquely situated at high inclination in the outer Main Belt, bisected by the nu_6 secular resonance. This large, low albedo family may thus be an important contributor to specific subpopulations of the near-Earth objects. We present simulations of the orbital evolution of Euphrosyne family members from the time of breakup to the present day, focusing on those members that move into near-Earth orbits. We find that family members typically evolve into a specific region of orbital element-space, with semimajor axes near ~3 AU, high inclinations, very large eccentricities, and Tisserand parameters similar to Jupiter family comets. Filtering all known NEOs with our derived orbital element limits, we find that the population of candidate objects is significantly lower in albedo than the overall NEO population, although many of our candidates are also darker than the Euphrosyne family, and may have properties more similar to comet nuclei. Followup characterization of these candidates will enable us to compare them to known family properties, and confirm which ones originated with the breakup of (31) Euphrosyne.

Improving photovoltaic performance through radiative cooling in both terrestrial and extraterrestrial environments.

The method of detailed balance, introduced by Shockley and Queisser, is often used to find an upper theoretical limit for the efficiency of semiconductor pn-junction based photovoltaics. Typically the solar cell is assumed to be at an ambient temperature of 300 K. In this paper, we describe and analyze the use of radiative cooling techniques to lower the solar cell temperature below the ambient to surpass the detailed balance limit for a cell in contact with an ideal heat sink. We show that by combining specifically designed radiative cooling structures with solar cells, efficiencies higher than the limiting efficiency achievable at 300 K can be obtained for solar cells in both terrestrial and extraterrestrial environments. We show that our proposed structure yields an efficiency 0.87% higher than a typical PV module at operating temperatures in a terrestrial application. We also demonstrate an efficiency advantage of 0.4-2.6% for solar cells in an extraterrestrial environment in near-earth orbit.

Jupiter family comets in near-Earth orbits: Are some of them interlopers from the asteroid belt?

We analyze a sample of 58 Jupiter family comets (JFCs) in near-Earth orbits, defined as those whose perihelion distances at the time of discovery were qdisc<1.3au. In our definition JFCs have Tisserand parameters 2<T<3 and orbital periods P<20yr. We integrated the orbits of these objects, plus 50 clones for each one of them, for 104yr in the past and in the future. We find that most of them move on highly unstable orbits, having fallen in their current near-Earth orbits in the recent past, going from less than one hundred years to a few thousands years. They experience frequent close encounters with Jupiter down to distances ≲0.1au. This is the expected behavior for comets whose limited physical lifetimes in the near-Earth region make them unlikely to survive there for more than about a few hundred revolutions. In this sense the orbits of most JFCs are typically “cometary”, and they should be regarded as newcomers in the near-Earth region. Yet, a minor fraction of JFCs (less than about one third) are found to move on stable orbits for the past ∼104yr, and in some cases are found to continue to be stable at 5×104yr in the past. They also avoid very close encounters with Jupiter. Their orbital behavior is very similar to that of NEAs in cometary orbits. While “typical” JFCs in unstable orbits probably come from the trans-Neptunian region, the minor group of JFCs in asteroidal orbits may come from the main asteroid belt, like the NEAs. The asteroidal JFCs may have a more consolidated structure and a higher mineral content than that of comets coming from the trans-Neptunian belt or the Oort cloud, which could explain their much longer physical lifetimes in the near-Earth region. In particular, we mention comets 66P/du Toit, 162P/Siding Spring, 169P/NEAT, 182P/LONEOS, 189P/NEAT, 249P/LINEAR, 300P/Catalina, and P/2003 T12 (SOHO) as the most likely candidates to have an origin in the main asteroid belt. Another interesting case is 207P/NEAT, which stays near the 3:2 inner mean motion resonance with Jupiter, possibly evolving from the Hilda asteroid zone.

The IMPACTON Project: Pole and Shape of Eight Near-Earth Asteroids

AbstractThe formation and evolution of Solar System small bodies, in particular those in near-Earth orbits, is a complex problem which solution strongly depends on a better knowledge of their physical properties. To contribute to the international efforts in this direction the IMPACTON project (www.on.br/IMPACTON) set up a dedicated facility denominated Observatório Astronômico do Sertão de Itaparica (OASI). Using the 1-m telescope several dozens of NEAs were observed between March 2012 and October 2014. Here we will present the results obtained for 8 objects. Relative magnitudes were used to obtain lightcurves and derive rotational periods. Applying the inversion method developed by Kaasalainen and Torppa (2001) and Kaasalainen et al. (2001), along with lightcurves from literature, allowed to refine the rotational period of these asteroids as well as to derive their pole direction and shape. The obtained results confirm a lack of poles toward the ecliptic and with a majority of retrograde rotators. A more representative sample, however, is needed in order to drive robust conclusions.

Electrodynamic attitude stabilization of a satellite in the Konig frame

This paper deals with a satellite in a circular near-Earth orbit. The satellite is equipped with an electrodynamic attitude control system based on Lorentz and magnetic torque properties. The gravitational disturbing torque acting on the satellite attitude dynamics is taken into account since it is the largest disturbing torque. The possibility of using electrodynamic attitude control system for satellite three-axis stabilization in the Konig frame is analyzed. By the use of the Lyapunov direct method, conditions under which electrodynamic control solves the problem for a dynamically symmetric satellite are obtained. The procedure for the successive constructing of Lyapunov functions is suggested. On the basis of the analysis of nonlinear differential equations system, the domain of the control parameter values is found for which one can guarantee the asymptotic stability of the programmed satellite motion. The results of a numerical simulation are presented to demonstrate the effectiveness of the proposed approach.

Modeling of the Temperature and Stressed-Strained States of the Reflector of a Mirror Space Antenna

Results of modeling of the temperature and stressed-strained states of the reflector of a mirror space antenna installed on a spacecraft that conducts a flight on geostationary and low near-earth orbits have been presented.

Simulation of Supersonic Flow in a Channel with a Step on Nonstructured Meshes with the Use of the Weno Scheme

Results of modeling of the temperature and stressed-strained states of the reflector of a mirror space antenna installed on a spacecraft that conducts a flight on geostationary and low near-earth orbits have been presented.

High order transfer maps for perturbed Keplerian motion

The paper presents a new semi-analytical technique for the propagation of near-Earth satellite motion. The approach uses differential algebra techniques to compute the high order expansion of the solution of the system’s ordinary differential equation for one orbital revolution, referred to as the transfer map. Once computed, a single high order transfer map (HOTM) can be reused to map an initial condition, or a set of initial conditions, forward in time for many revolutions. The only limiting factor is that the mapped objects must stay close to the reference orbit such that they remain within the region of validity of the HOTM. The performance of the method is assessed through a set of test cases in which both autonomous and non-autonomous perturbations are considered, including the case of continuously propelled trajectories.

Modeling and analysis of dynamics for spacecraft relative motion actuated by inter-satellite non-contacting force

With the recent flurry of research on spacecraft relative motion actuated by inter-satellite non-contacting force, i.e., electrostatic force, electromagnetic force and magnetic flux-pinned force, the need has become apparent for dynamic modeling and dynamics analysis that capture the characteristics of this generic force. Based on the basic derivation of electrostatic force model and some theorems, the actuations of electrostatic force, electromagnetic force/torque and magnetic flux-pinned force/torque are unified and the corresponding mathematic models are derived. And then, with a general notation of this inter-satellite non-contacting force, the dynamic models are developed with respect to several assumptions of circular orbit, elliptical orbit and general Keplerian orbit pertaining to the motion of center of mass of the spacecraft cluster. A detailed dynamics analysis based on these derived models are carried out, including constraints of the relative motion dynamics, the special characteristics of applications to the near-Earth relative orbit motion and the deep space relative motion, and then a case with co-rotating pair of satellites subject to the previously mentioned inter-satellite non-contacting forces was simulated to validate the dynamic modeling and dynamics analysis. At last, some useful conclusions follow.

Giant comets and mass extinctions of life

I find evidence for clustering in age of well-dated impact craters over the last 500 Myr. At least nine impact episodes are identified, with durations whose upper limits are set by the dating accuracy of the craters. Their amplitudes and frequency are inconsistent with an origin in asteroid breakups or Oort cloud disturbances, but are consistent with the arrival and disintegration in near-Earth orbits of rare, giant comets, mainly in transit from the Centaur population into the Jupiter family and Encke regions. About 1 in 10 Centaurs in Chiron-like orbits enter Earth-crossing epochs, usually repeatedly, each such epoch being generally of a few thousand years duration. On time-scales of geological interest, debris from their breakup may increase the mass of the near-Earth interplanetary environment by two or three orders of magnitude, yielding repeated episodes of bombardment and stratospheric dusting. I find a strong correlation between these bombardment episodes and major biostratigraphic and geological boundaries, and propose that episodes of extinction are most effectively driven by prolonged encounters with meteoroid streams during bombardment episodes. Possible mechanisms are discussed.

Photoluminescence spectra of 1 MeV electron beam irradiated In0.53Ga0.47As/InP quantum well and bulk materials

Minimizing the impact of radiation-induced degradation on optoelectronic devices is important in several applications. Satellites and other spacecraft that fly in near-earth orbits (below 3.8 earth radius) are extremely susceptible to radiation damage caused by the high flux of electrons trapped in the earth’s magnetosphere. Optoelectronic devices are particularly vulnerable to displacement damage caused by electrons and protons. Effects of 1 MeV electron beam irradiation on the photoluminescence properties of In0.53Ga0.47As/InP quantum well (QW) and bulk structures, which are grown by metal-organic vapor phase epitaxy, are investigated. Samples are irradiated at room temperature using an ELV-8II accelerator with 1 MeV electron at doses ranging from 5×1012 to 9×1014 cm-2, and a dose rate of 1.075×1010 cm-2·s-1. Photoluminescence measurements are made using a 532 nm laser for excitation and a cooled Ge detector with lock-in techniques for signal detection. Photoluminescence intensity of all the structures is degraded after irradiation, and its reduction increases with increasing total dose of irradiation. Electron beam irradiation causes a larger reduction in the photoluminescence intensity and carrier lifetime of the bulk than that of quantum well. Photoluminescence intensity of five-layer quantum wells degenerates to 9% that before irradiation as the fluence reaches 6×1014 cm-2. As the electron beams bombard into the sample, the destruction of the lattice integrity will cause the decrease in the number of excitons and intensity of photoluminescence. Electron beam irradiation introduces defects in the samples, increases the density of the nonradiative recombination centers, and results in the decrease of carrier mobility. In a quantum well structure, due to the two-dimensional confinement, the probability of carrier nonradiative recombination at radiation-induced defect centers will be reduced. The reduction of photoluminescence intensity in the bulk is severer than in the quantum well while the cross-sectional area which is sensitive to radiation is kept the same. The number of interface defects which are produced by electron irradiation will increase with the number of layers in quantum well and the heterojunction interface of quantum wells, so is the degration of photoluminescence intensity. The degration is mainly due to the increase of non-radiative centers in the samples. By comparing the different structures, the quantum well structure shows a better radiation resistance.

Variation in the statistical properties of IMF direction fluctuations during the 22-year solar magnetic cycle

The variation in the IMF direction distribution during the 22-year solar magnetic cycle has been studied. Data obtained in near-Earth orbits and measurements in the heliospheric regions located far from the Earth, performed with the Helios and Ulysses spacecraft devices, have been analyzed. It has been found that the correlation between the azimuth and magnetic field fluctuations is statistically significant in the low-latitude heliospheric region at heliocentric distances of 0.3–5.4 AU, and the sign of this correlation reverses at a change in the polar solar magnetic field orientation. In the polar zones of the heliosphere outside the latitudinal extension of the heliospheric current sheet, the angle correlation coefficient rapidly decreases with increasing heliographic latitude. The angle correlation sign reversal during the 22-year cycle is accompanied by a change of the asymmetry sign of the magnetic field inclination distribution.

Mineralogy of V-type asteroids as a constraining tool of their past history

In the past few years, the genetic relationship between (4) Vesta, Vestoids and HED meteorites was reinforced (Drake, 2001, Meteorit. Planet. Sci. 36 (4), 501–513). It is believed that Vestoids and HED meteorites were originated from a collision suffered by (4) Vesta, during the early stages of the Solar System. Due to the effects of dynamical resonances, several fragments of this collision were ejected into near-Earth orbits and some of them have originated the so-called HED meteorites. We aim to infer about the hypothetical collision suffered by (4) Vesta and its connection to the genetic relationship between V-type asteroids and HED meteorites. For this purpose, reflectance spectra of a set of 11 V-type asteroids and 55 HED meteorites were obtained, respectively, from the publically available MIT-UH-IRTF Joint Campaign for NEO Reconaissance and RELAB database.Initially, for each of the selected V-type asteroids, we attempted to identify its meteoritic analogue. Afterwards, we have performed a numerical spectral analysis based on the Hapke radiative transfer model. We report the inferred surface composition and mineralogy of the V-type asteroids, for which we have identified a meteoritic analogue.Our results strength the relationship between HED meteorites and V-type asteroids, as also suggested by the results from the Dawn mission (de Sanctis et al., 2012, Science, 336 (6082), 697–690; 2013 Meteorit. Planet. Sci. 48 (11) 2166–2184; McSween et al., 2011, Space Sci. Rev. 163 (1–4), 141–174; 2013, Meteorit. Planet. Sci. 48 (11) 2090–2104). The latter is contradicting the results from Schiller et al. (2011, Astrophys. J. 740 L22) and Wasson (2013, Earth Planet. Sci. Lett. 381 138–146), which questioned this linkage. We also report the best meteoritic kind for the studied V-type asteroids, by comparing their spectra and mineralogies. We also report the pyroxenes mineralogical distributions of the HED meteorites, inferred through the Hapke radiative transfer model, which can be suitable for comparison with future mineralogical studies of these objects.

The effect of secular resonances on the long-term orbital evolution of uncontrolled near-Earth objects

AbstractA set of 29 low order secular resonance relations in the near-Earth satellite dynamics has been obtained and their influence on dynamic evolution of objects has been investigated on time intervals of 100 years. The analysis of the results shows that secular resonances are very common phenomena in the near-Earth orbital space. Sharp resonances are concentrated in the orbital space areas where the semi-major axes a ⩾ 20000 km and the inclinations i ⩾ 50○. In some areas objects have several secular resonances. The superposition of several secular resonances or orbital and secular resonances are the source of randomness in the motion of objects.