Earth Objects Research Articles

QCMOS Detectors and the Case of Hypothetical Primordial Black Holes in the Solar System, near Earth Objects, Transients, and Other High-cadence Observations

Abstract Recent progress with CMOS detector development has opened new parameter space for high cadence time resolved imaging of transients and fast proper motion solar system objects. Using computer simulations for a ground-based 1.23 m telescope, this research note illustrates the gain of a new generation of fast readout low noise qCMOS sensors over CCDs and makes the case for high precision monitoring of asteroid orbits that can potentially shed light on the hypothetical existence of low mass primordial black holes, as well as for other applications requiring high speed imaging.

Debiasing astro-photometric observations with corrections using statistics (DePhOCUS)

Photometric measurements allow the determination of an asteroid’s absolute magnitude, which often represents the sole means to infer its size. Photometric observations can be obtained in a variety of filters that can be unique to a specific observatory. Those observations are then calibrated into specific bands with respect to reference star catalogs. In order to combine all the different measurements for evaluation, photometric observations need to be converted to a common band, typically V-band. Current band-correction schemes in use by IAU’s Minor Planet Center (MPC), JPL’s Center for Near Earth Object Studies (CNEOS) and ESA’s NEO Coordination Centre (NEOCC) use average correction values for the apparent magnitude derived from photometry of asteroids as the corrections are dependent on the typically unknown spectrum of the object to be corrected. By statistically analyzing the photometric residuals of asteroids, we develop a new photometric correction scheme that does not only consider the band, but also accounts for reference catalog and observatory. We analyzed nearly 500000 observations submitted to the MPC from 468 asteroids with published and independently determined high confidence H and G values. We describe a new statistical photometry correction scheme for asteroid observations with debiased corrections. Testing this scheme on a reference group of asteroids, we see a 36% reduction in the photometric residuals. Moreover, the new scheme leads to a more accurate and debiased determination of the H-G magnitude system and, in turn, to more reliable inferred sizes. We discuss the significant shift in the corrections with this “DePhOCUS” debiasing system, its limitations, and the impact for photometric and physical properties of all asteroids, especially Near-Earth Objects.

No evidence for interstellar fireballs in the CNEOS database

Context. The detection of interstellar meteors, especially meteorite-dropping meteoroids, would be transformative, as this would enable direct sampling of material from other stellar systems on Earth. One candidate is the fireball observed by U.S. government sensors on January 8, 2014. It has been claimed that fragments of this meteoroid have been recovered from the ocean floor near Papua New Guinea and that they support an extrasolar origin. Based on its parameters reported in the Center for Near Earth Object Studies (CNEOS) catalog, the fireball exhibits a hyperbolic excess velocity that indicates an interstellar origin; however, the catalog does not report parameter uncertainties. Aims. To achieve a clear confirmation of the fireball’s interstellar origin, we assessed the underlying error distributions of the catalog data. Our aim was also to confirm whether the fragments of this meteoroid survived passage through the atmosphere and assess all conditions needed to unambiguously determine the fragments’ origin. Methods. We approached the investigation of the entire catalog using statistical analyses and modeling, and we provide a comprehensive analysis of the individual hyperbolic CNEOS cases. Results. We have developed several independent arguments indicating substantial uncertainties in the velocity and radiant position of the CNEOS events. We determined that all the hyperbolic fireballs exhibit significant deviations from the majority of the events in one of their velocity components, and we show that such mismeasurements can produce spurious parameters. According to our estimation of the speed measurement uncertainty for the catalog, we found that it is highly probable that such a catalog containing only Sun-bound meteors would show at least one event that appears highly unlikely to be Sun-bound. We also establish that it is unlikely that any fragments from a fireball traveling at the high inferred velocities could survive passage through the atmosphere. When assuming a much lower velocity, some fragments of this meteoroid could survive; however, they would be of a common Solar System origin and thus highly probable to be indistinguishable from the quantity of other local micrometeorites that have gradually accumulated on the sea floor. Conclusions. We conclude that there is no evidence in the CNEOS data to confirm or reject the interstellar origin of any of the nominally hyperbolic fireballs in the CNEOS catalog. Therefore, the claim of an interstellar origin for the fireball recorded over Papua New Guinea in 2014 remains unsubstantiated. We have also gathered arguments that refute the claim that the collected spherules from the sea floor originated in the body of this fireball.

Asteroids discovered in the Baldone Observatory between 2017 and 2022: The orbits of asteroid 428694 Saule and 330836 Orius

Abstract We discovered 83 asteroids at the Baldone Astrophysical Observatory (MPC code 069) in 2017–2022. We studied one of the dynamically interesting Apollo (Near Earth object) observed at the Baldone Astronomical Observatory, namely 428694 Saule (2008 OS9) and the Centaur-type asteroid 330836 Orius (2009 HW77). We studied the evolution of the asteroid Saule’s rotation period, obliquity, and spin axis together with its non-gravitational parameter d a ∕ d t {\rm{d}}a/{\rm{d}}t connected with the Yarkovsky effect. Additionally, we studied the orbit of the Amor-type asteroid 2017 UW42, which has the significant non-gravitational parameter A 2 A2 .

IAA-PDC-23-09-20 low-cost mission architectures to small bodies

The 30,000+ known Near Earth Objects (NEOs) are some of the closest objects to Earth. A few dedicated missions such as NEAR, Hayabusa-1 and -2, OSIRIS-Rex, and DART have revealed a lot about their nature, with more to come from ESA's Hera mission, and others. Dedicated space missions to individual NEOs are relatively costly, however, so we seek to find a way to reduce costs so that the composition and structure of more NEOs can be fully characterized, and we can continue to explore how to change the trajectory of selected objects, as was done with DART. Here we describe a low-cost approach to NEO missions for small body science and planetary defense that makes use of existing or planned space vehicles.

Ellipsoidal estimation of motion parameters of a non-cooperative space vehicle from visual information

The use of near-Earth space is currently complicated by presence of space debris objects in Earth’s orbit, which include spent stages of launch vehicles, inoperative satellites, and other large and small artificial objects. One approach to solving the problem of space debris involves docking and capturing a non-cooperative space object or spacecraft (target) with a so-called service spacecraft (chaser) for further actions to repair, refuel or change its orbit. Rendezvous and docking are complicated by the rotation of uncontrolled space objects caused by various factors. To perform this task, it is necessary to know the parameters of the orbital, rotational and relative motion of the target. The parameters of the orbital motion of such objects are usually known quite accurately from measurements from the Earth. This paper examines the case of a tumbling non-cooperative target located in an elliptical orbit. It is assumed that the target relative position and orientation are measured by the computer vision system (CVS) of the chaser. In this case, the position and orientation of the graphical reference frame (GRF) associated with the known 3-D graphical model of the target are determined relative to the reference frame associated with the chaser. The specific type of CVS is not considered. It is assumed that the chaser can carry out some maneuvers near the target and all parameters of the chaser angular motion are known. Thus, the attitude of the GRF relative to inertial reference frame (IRF) can be determined. The measured parameters are not enough to ensure safe rendezvous and docking with the target. To complete this task, it is necessary to determine all kinematic and dynamic parameters of the relative motion between the spacecraft. The rest of the required parameters are estimated. Orientation and rotation parameterization is done using quaternions. The angular motion equation of the target is considered in the GRF. This makes the angular velocity estimation faster and the inertia tensor estimation more stable. Stochastic characteristics of measurement errors are considered to be unknown and are not used. The only information about the errors is the bounds of their values. To determine the relative motion parameters, we use a new dynamic set-membership filter with ellipsoidal estimates. The filter can be successfully implemented on low-power on-board processors. The properties of the proposed algorithm are demonstrated using numerical simulation. The results obtained are expected to be used in the development of a navigation system for the rendezvous and docking, developed by a group of Ukrainian space industry enterprises under the leadership of the LLC “Kurs-orbital” (https://kursorbital.com/).

Transport of dust across the Solar System: Constraints on the spatial origin of individual micrometeorites from cosmic-ray exposure.

The origin of micrometeorites (MMs) from asteroids and comets is well-established, but the relative contribution from these two classes remains poorly resolved. Likewise, determining the precise origin of individual MMs is an open challenge. Here, cosmic-ray exposure ages are used to resolve the spatial origins of 12 MMs collected from urban areas and Antarctica. Their 26Al and 10Be concentration, produced during cosmic-ray irradiation in space, were measured by accelerator mass spectrometry. These data are compared to results from a model simulating the transport and irradiation of the MM precursors in space. This model, for the first time, considers a variety of orbits, precursor particle sizes, compositions and densities and incorporates non-isotropic solar and galactic cosmic-ray flux profiles, depth-dependent production rates, as well as spherical evaporation during atmospheric entry. While the origin for six MMs remains ambiguous, two MMs show a preferential tendency towards an origin in the Inner Solar System (Near Earth Objects to the Asteroid Belt) and four towards an origin in the Outer Solar System (Jupiter Family Comets to the Kuiper Belt). These findings challenge the notion that dust originating from the Outer Solar System is unlikely to survive long-term transport and delivery to the terrestrial planets. This article is part of the theme issue 'Dust in the Solar System and beyond'.

NEOMOD 3: The debiased size distribution of Near Earth Objects

Our previous model (NEOMOD2) for the orbital and absolute magnitude distribution of Near Earth Objects (NEOs) was calibrated on the Catalina Sky Survey observations between 2013 and 2022. Here we extend NEOMOD2 to include visible albedo information from the Wide-Field Infrared Survey Explorer. The debiased albedo distribution of NEOs can be approximated by the sum of two Rayleigh distributions with the scale parameters pV,dark≃0.03 and pV,bright≃0.17. We find evidence for smaller NEOs having (on average) higher albedos than larger NEOs; this is likely a consequence of the size-dependent sampling of different main belt sources. These inferences and the absolute magnitude distribution from NEOMOD2 are used to construct the debiased size distribution of NEOs. We estimate 830±60 NEOs with diameters D>1 km and 20,000±2,000 NEOs with D>140 m. The new model, NEOMOD3, is available via the NEOMOD Simulator — an easy-to-operate code that can be used to generate user-defined samples (orbits, sizes and albedos) from the model.

Multiband photometric observations of GEO objects through Sloan filters

With the precipitous growth of the population of objects in Earth's orbit, all major space agencies and companies have made space surveillance a priority to ensure the safety of space missions. With the application of the methods of space surveillance, this article aims to characterize the population of objects in the Geostationary Earth Orbit (GEO) using optical measurements across multiple spectral bands. The study takes place in a context in which the existence of space debris poses a continuous hazard to the operations of active satellites in GEO. Photometric observations of GEO objects using Sloan filters were obtained with SCUDO, a small-aperture telescope part of the Sapienza network. Observations are divided into categories, including 11 objects: rocket bodies (4), defunct satellites (3), and active satellites (4). The spectral response of these objects has been analyzed leading to the identification of a photometric signature which was repeated for two Eutelsat satellites observed under same conditions. All the observed targets resulted in a lower magnitude in the near-infrared. Color indexes also indicate that they are redder than the Sun. This is particularly evident for SL-12 rocket bodies, whose g’-z’ reaches 1.5.

Infrasound analysis of the 2018-Dec-18 49 kiloton Bering Sea bolide: Misassociations and celerity-range models

Automatic detections at the International Data Centre (IDC) of the Comprehensive Nuclear-Test-Ban Treaty Organisation (CTBTO) are often misassociated. This occasionally leads to single events being split into multiple events. Infrasound signals generated from a large bolide over the Bering Sea on 2018-Dec-18 were recorded on more than 15 of the CTBTO International Monitoring System (IMS) stations. The bolide was also reported by the Center for Near Earth Object Studies (http://cneos.jpl.nasa.gov/fireballs) with a calculated total impact energy value of 49 kt. Signals from this bolide were automatically detected and associated at the IDC, into two different events, with the origin time differing by approximately 7.5 minutes and location by ∼125 km. To investigate why detections from this bolide event were misassociated in the automatic bulletins, we analyze infrasound observations from the IMS infrasound arrays and compare our arrival time observations to the automatic detections from the IDC. We use the Bayesian Infrasonic Source Localisation method and employ different celerity-range models, to investigate signal association for this event. Through comparison with the associations based on IDC detections, we aim to improve our understanding of the causes of misassociations and identify potential improvements to future event association algorithms.

Aristotle’s Static World and Traditional Education – A Secondary Publication

The purpose of this study is to understand the characteristics of Aristotle’s view of nature that is, the staticview of the universe, and find implications for education. Plato sought to interpret the natural world using a rationalapproach rather than an incomplete observation. He thought that viewing the world from the perspective of geometry andmathematical regularity was the best way to understand the world. On the other hand, Aristotle believed that we couldunderstand the world through observations. His worldview portrayed a static reality, imbued with individual purpose anda sense of deliberate legitimacy. In addition, the natural motion of earthly objects and celestial bodies, which are naturalmovements towards the world of order, are the original actions. Aristotle thought that all natural things would carry outsome movement. Above all, Plato and Aristotle view the world as a static universe. It is possible to fully grasp the worldby approaching the objective nature that exists independently of human beings with human reason and observation.After all, for Aristotle, like Plato, their belief that the natural world was subject to regular and orderly laws of nature,despite the complexity and seemingly unceasing changes, became the basis of Western thought. The universe, rooted inthe metaphysical perspective of ancient Greece and carried forward in modern philosophy, has traditionally depended ondeveloping a dichotomy of comprehension, distinguishing between what is already accomplished or predetermined, theideal and the inevitable. This dichotomy forms the foundation of traditional teaching methods that often do not prioritizethe opinions of learners.

A Solar Thermal Steam Propulsion System Using Disassociated Steam for Interplanetary Exploration

Sustainable space exploration will require using off-world resources for propellant generation. Using off-world-generated propellants significantly increases future missions’ range and payload capacity. Near Earth Objects (NEOs) contain a range of available resources, most notably water-ice and hydrated minerals. However, water-bearing regolith needs to be excavated and the water extracted. Water is a compelling choice for fuel as it is readily available in interplanetary space and easily stored. In this paper, we propose using solar concentrators, which can efficiently convert incident sunlight into heat without the need for moving parts. When water is heated up to 4000 K, a value consistent with high-performance refractive materials, it experiences significant disassociation into H2, O2, OH, H, and O components, providing a path for adding considerable additional chemical energy per degree of temperature increase, and producing theoretical specific impulse (Isp) values in the range of 643 s to 659 s.

Comparison of artificial neural networks and multiple linear regression model in the prediction of near-earth objects minimum distance to the earth

Comparison of artificial neural networks and multiple linear regression model in the prediction of near-earth objects minimum distance to the earth

Legal considerations on a regional security organization for planetary defence

Under the UN-Charter system, the maintenance of international peace and security is traditionally the primary responsibility of the UN Security Council as set forth in Chapter VII. Since the Security Council's competence for dealing with matters of international peace and security is not exclusive, other international bodies may take a role in addressing threats emanating from outer space. A regional security organization for planetary defence can be established under Article 52 UN-Charter and may provide for an alternative forum to decide upon the necessary steps for Near Earth Object (NEO)-deflection missions. The international legal personality of an international organization for planetary defence leads to the capacity of entering into treaties, the international responsibility for acts and omissions attributed to it and the enjoyment of privileges and immunities. Such organization can also declare acceptance of the UN Space Treaties.

Optimal Sensor Planning for SSA Using System Identification Concepts

The rapid growth of man-made objects in Earth’s orbit has created a need for planning and prioritizing sensor measurements of these objects in order to keep track of their motion in orbit. In this paper, we adapt a concept from the field of system identification, namely application-oriented input design, to the sensor-planning problem. Previous methods have predominantly focused on the problem of planning the measurements of different objects such that they are as accurate as possible (in a broad sense) from a given set of possible observations. Here we view the problem differently; the objective is to find the least costly number of measurement such that the estimated orbital parameters are good enough for their intended application. To this end, we introduce the concept of an application set. The application set contains all orbital parameters that are considered of sufficient accuracy for the intended use. The objective of the optimization is hence not to find the most accurate set of parameters but find the cheapest combinations of observations such that the estimated parameters are guaranteed to be within the application set with a high probability. We show how to formulate the planning problem as a convex optimization problem that can be solved efficiently with modern algorithms, even for large-scale problems. We then demonstrate the feasibility of the method in a simulation example. Finally, the paper discusses some interesting topics for future research.

IMPROVING THE USE OF GEODETIC, GEOCENTRIC, AND TOPOCENTRIC COORDINATE SYSTEMS IN METEOR ASTRONOMY AND RELATED TASKS

The problem of using the geodetic, geocentric, and topocentric coordinate systems in video observations’ processing of meteors and other dynamical objects in Earth’s atmosphere is considered. For meteor heights in a range of 0…200 km and arbitrary Earth’s ellipsoid latitudes, the following values are calculated: the difference between geodetic and geocentric latitudes, the meridian arc length corresponding to this shift, and the difference between geocentric and geodetic altitudes above the Earth’s ellipsoid. The carried-out calculations allowed us to conclude that the geocentric coordinate system is optimal for the calcula- tion of kinematic parameters of meteors and trajectory measurements of ballistic objects at all-range altitudes and long distances between observation points without using horizontal coordinate systems as intermediate ones. This coordinate system is also used in the computation of heliocentric orbit elements of meteoroids. It is noted that the transition from the geocentric to the geodetic coordinate system is necessary for mapping the projections of the meteor trajectory to search for their remnants — meteorites. The reason is related to the difference between them, which can reach 11 arcmin for objects located at an altitude of 100 km above the level of the Earth’s ellipsoid, which corresponds to the shift of 21 km. The difference between geocentric and geodetic altitudes is inessential and amounts to half a meter at an altitude of 100 km and slightly more than one meter at 200 km and can be neglected in meteor calculations and most ballistic tasks. These considerations formed the basis for our proposed alternative vector method for the inverse transition from geocentric to geodetic coordinates and the numerical solution of the corresponding equation. In order to decrease the calculation time for mass processing, it is recommended to change the numerical processing of the inverse task by fitting it with elementary functions. An example of fitting is given. It brings to the maximal deviation in latitude near one arcmin, which corresponds to approximately 35 meters. It is noted that such precision is satisfactory for meteor measurements, but for ballistic problems, the accuracy of fitting must be improved.

Machine learning techniques for classifying dangerous asteroids

There is an infinite number of objects in outer space, and these objects and asteroids might be harmful. Hence, it is wise to know what is surrounding us and what can harm us amongst those.Therefore, in this article, with the hyperparameters tuning of Extra Tree, Random Forest, Light Gradient Boosting Machine, Gradient Boosting, and Ada Boost, the hazards of asteroids around the Earth were classified, and the results of ROC Curves for these algorithms were compared.•Reviewing the list of NASA-certified asteroids classified as the nearest Earth object•Investigating the risk of asteroids with the help of Extra Tree, Random Forest, Light Gradient Boosting Machine, Gradient Boosting, and Ada Boost•Comparing the performance of machine learning algorithms in the classification of high-risk asteroids

Kinetic impact of a space vehicle with asteroid on collision course with earth

NEO (Near Earth Objects) are near-Earth space objects (asteroids and comets), whose orbit approaches the planet at one third of the average Earth-Sun distance. NEO are potentially capable of hitting Earth in the next century, with the exception of comets that can do so by the gravitational effect of Jupiter, pushing them into the Solar System. Current estimates1 indicate about 940 near-Earth objects larger than 1 kilometer in diameter. The US Congress has set targets for NASA's search for NEO, with 90% of them with a diameter of up to 1 km or greater in 10 years. This was motivated by a recent discovery in 2009 of a NEO approximately 2 to 3 km in diameter. These objects could cause global devastation if they hit Earth. In this research the NEO-Earth collision dynamics is studied and a statistic of physical and technological parameters is established as a mitigation strategy.

Enabling Interplanetary Exploration for CubeSats with a Fully Chemical Propulsion System

Interplanetary CubeSat missions are currently becoming more popular, with a significant number of recently planned missions. The context of this paper is a Mars mission, starting from a parking orbit around Earth: the adoption of a chemical propulsion system for the Earth-Mars transfer phase is investigated, considering the recent technological developments for CubeSats. A trade-off of propulsion system type and propellant results in the choice of a mono-propellant system adopting the HAN-based propellant AF-M315E (ASCENT). The main challenge for the propulsion system is to fit inside a CubeSat standardised volume, which can range up to 24 U, for which the implementation of a suitable COTS micro-pump is considered. Finally, the complete architecture and design of the propulsion system is presented. This work demonstrates the feasibility of adopting full chemical propulsion for an interplanetary CubeSat mission, with consequent advantages in terms of transfer time and required power, at the cost of relatively small mass and volume left for the other subsystems. Even better results can be expected for interplanetary missions requiring slightly lower ΔV budgets, such as Near Earth Objects exploration or asteroid fly-by missions. Keywords: CubeSat, Chemical Propulsion, Green Mono-propellant, Interplanetary Mission, Mars Exploration

Rapidly evolving Galactic plane outbursts in NEOWISE: revisiting the Galactic nova rate with the first all-sky search in the mid-infrared

ABSTRACT The Galactic nova rate is intimately linked to our understanding of its chemical enrichment and progenitor channels of Type Ia supernovae. Yet past estimates have varied by more than an order of magnitude (≈10–300 yr−1), owing to limitations in both discovery methods as well as assumptions regarding the Galactic dust distribution and extragalactic stellar populations. Recent estimates utilizing synoptic near-infrared surveys have begun to provide a glimpse of a consensus (≈25–50 yr−1); however, a consistent estimate remains lacking. Here, we present the first all-sky search for Galactic novae using 8 yr of data from the Near Earth Object WISE (NEOWISE) mid-infrared (MIR) survey. Operating at 3.4 and 4.6 µm where interstellar extinction is negligible, the 6-month cadence NEOWISE data set offers unique sensitivity to discover slowly evolving novae across the entire Galaxy. Using a novel image subtraction pipeline together with systematic selection criteria, we identify a sample of 49 rapidly evolving MIR outbursts as candidate Galactic novae. While 27 of these sources are known novae, the remaining are previously missed nova candidates discovered in this work. The unknown events are spatially clustered along the densest and most heavily obscured regions of the Galaxy where previous novae are severely underrepresented. We use simulations of the NEOWISE survey strategy, the pipeline detection efficiency, and our criteria to derive a Galactic nova rate of $47.9^{+3.1}_{-8.3}$ yr−1. The discovery of these exceptionally bright (yet overlooked) nova candidates confirms emerging suggestions that optical surveys have been highly incomplete in searches for Galactic novae, highlighting the potential for MIR searches in revealing the demographics of Galactic stellar outbursts.