Near Earth Asteroids

The recently announced quasi-moon 2025 PN7 orbits the Sun in near-synchrony with Earth, making it appear as though Earth has a "second moon." In fact, PN7 is not gravitationally bound to Earth, but instead follows a resonance-driven orbit. Within Fractal Theory (FT), this is read as a case of Unity illusion and recursive memory: PN7 temporarily echoes Earth's orbital shell, even though it does not belong to it. Quasimoons such as PN7 demonstrate how coherence, memory, and misfit can coexist in celestial structures, expanding the scope of the Memory Comets framework from interstellar archives to near-Earth wanderers.

Planetary Defense is a complex problem, not well understood by policy makers and the general public. The recent Chelyabinsk incident in Russia created temporary international attention but has failed to effectively stimulate public action. The lack of long-term attention to cosmic hazards has resulted in limited funding to defend our planet. Hence, it is hard to realistically address this challenge and achieve the high test and operational readiness needed for an effective Planetary Defense strategy. To address this problem, we have created a set of recommendations for the development of a Planetary Defense Program, for the purpose of contributing to the protection of Earth from asteroids and comets. The SSP15 READI Project focused on threats for which there is only a short-term warning, specifically a warning of two years or less from detection of the object to impact. We have provided recommendations in five areas of Planetary Defense including detection and tracking, deflection t...

Several broad search strategies were considered. These were coupled with three guiding philosophies. First, the one relied on most heavily, was the creation of ‘long-chain backbones,’ that is, long sequences of asteroid rendezvous by one probe. The Mothership and other probe trajectories were then built up, in that order, based on the long-chain backbone. The second and lesser used approach was to design first Mothership trajectories, a ‘Mothership backbone,’ wherein the mother would drop-off probes at a series of asteroids, followed by probe trajectories starting at these asteroids and returning to the mother at a final asteroid. The third philosophy was that all of these chains would be initially designed assuming the Mothership would rendezvous with asteroids for probe pick-up and drop-off. Once good candidates were found, this assumption was lifted and separation and rejoining of mother and probes was permitted to occur away from asteroids in order to boost the mass performance ...

Non-contact electromagnetic methods offer promising alternatives to conventional kinetic or explosive techniques for planetary defense. Simulations targeting asteroid 99942 Apophis and the smaller 2025 HX demonstrate that gravity tractors and ion-beam shepherds deliver the greatest cumulative velocity change over three years, respectively. Hybrid schemes offer marginal gains over their primary modality. At the same time, multi-spacecraft analyses reveal that even a ten-vehicle fleet struggles to achieve the 0.14 m/s deflection threshold within mission timelines for Apophis. Despite lower Technology Readiness Levels (TRL), the continuous, reusable operation and low fragmentation risk of electromagnetic strategies make them compelling complements to existing planetary defense techniques.

The Outer Space Treaty (OST) was established to ensure the peaceful use of outer space for the benefit of all humanity. However, it overlooked the existential risks posed by natural celestial threatssuch as asteroids and comets-during its formulation. With the increasing recognition of near-Earth objects (NEOs) as credible threats to planetary safety, the need for a globally coordinated response mechanism has become urgent and essential. This paper examines the legal and governance challenges in planetary defense, emphasizing absence of explicit international frameworks to guide deflection missions, assign liability, and govern the use of potentially dual-use technologies like nuclear deflection systems. The paper identifies key legal gaps based on existing treaties, such as the OST, the Liability Convention, and the Rescue Agreement. It proposes the formation of a Planetary Defense Council (PDC) under the auspices of the United Nations. The proposed framework addresses decisionmaking authority, funding, liability sharing, and ethical considerations, including public communication and global inclusivity. This study frames planetary defense as a collective action problem and underscores the necessity of multilateral cooperation, transparent governance, and equitable participation in protecting life on Earth.

This paper presents the design of a multi-spacecraft system for the deflection of asteroids. Each spacecraft is equipped with a fibre laser and a solar concentrator. The laser induces the sublimation of a portion of the surface of the asteroid, and the resultant jet of gas and debris thrusts the asteroid off its natural course. The main idea is to have a formation of spacecraft flying in the proximity of the asteroid with all the spacecraft beaming to the same location to achieve the required deflection thrust. The paper presents the design of the formation orbits and the multi-objective optimisation of the formation in order to minimise the total mass in space and maximise the deflection of the asteroid. The paper demonstrates how significant deflections can be obtained with relatively small sized, easy-to-control spacecraft.

This paper presents an autonomous guidance, navigation and control system for the deflection and attitude control of a small asteroid via laser ablation. Laser ablation consists of irradiating the surface of the asteroid with a laser beam with sufficient intensity to sublimate the irradiated material. The resulting jet of gas and debris induces a force and a torque thrusting the asteroid off its natural course and changing its tumbling motion. In this paper it is proposed to use the laser to first de-tumble the asteroid. A reduction of the rotational speed of the asteroid increases the yield of the laser ablation process. An autonomous proximity control system is then implemented to keep the spacecraft flying in formation with the asteroid under the effect of the thrust acting on the asteroid, plume impingement, laser recoil and solar radiation pressure. The spacecraft employs and processes the measurements coming from its own on board measurements, given by a laser range finder, high resolution cameras, and an impact sensor. The latter is combined with the attitude information and, thus, used to estimate the plume impingement force, which acts in the same direction of the exerted thrust due the laser ablation. In this way the spacecraft is able to estimate on-board the imparted acceleration and the effectiveness of the laser ablation procedure. An unscented Kalman filter is used to estimate spacecraft position and velocity together with the perturbative accelerations. A second filter is implemented to estimate the asteroid's rotation by extracting and tracking the motion of asteroid's features, using either optical flow or spectral methods. These variables are used to implement spacecraft trajectory control in order to permit the laser to work at his optimal focussing distance. Two trajectory control strategies are considered: in the first one, a series of impulse bits maintains the spacecraft within a 0.5 m box from the reference trajectory; the second strategy is based on a continuous low-thrust control. It is shown that both techniques are viable and accurate. The discrete impulsive control does not downgrade the laser performance given the small oscillations with respect to the nominal conditions. Nonetheless low thrust allows the spacecraft to impart a higher momentum onto the asteroid. .

In this paper some potentially interesting transfer options for missions to Near Earth Objects have been studied. Due to the high number of potential targets and to the large variety of possible missions that can be considered, especially if resorting to low-thrust propulsion, an extensive analysis of transfer options requires a preliminary approach oriented toward an effective global search, and an appropriately simplified trajectory transcription. Low-thrust options have been modeled through a novel shape-based approach and a global optimization method has been used to look for globally optimal transfers. Different targets have been identified and various mission scenarios have been considered: rendezvous, sample return missions both with and without Earth gravity assist and impact missions.

It has been recently argued that there is a strong component of the diffuse far-ultraviolet (FUV) background which is hard to explain by conventional physics in terms of the dust-scattered starlight. We propose that this excess in FUV radiation might be result of the dark matter annihilation events within the so-called axion quark nugget (AQN) dark matter model, which was originally invented for completely different purpose to explain the observed similarity between the dark and the visible components in the Universe, i.e. ΩDM ∼ Ω visible . We support this proposal by demonstrating that intensity and the spectral features of the AQN induced emissions are consistent with the corresponding characteristics of the observed excess of the FUV radiation.

We study a testable dark matter (DM) model outside of the standard WIMP paradigm in which the observed ratio Ω dark Ω visible for visible and dark matter densities finds its natural explanation as a result of their common QCD origin when both types of matter (DM and visible) are formed at the QCD phase transition and both are proportional to Λ QCD . Instead of the conventional "baryogenesis" mechanism we advocate a paradigm when the "baryogenesis" is actually a charge separation process which occur in the presence of the CP odd axion field a(x). In this scenario the global baryon number of the Universe remains zero, while the unobserved antibaryon charge is hidden in form of heavy nuggets, similar to Witten's strangelets and compromise the DM of the Universe. In the present work we study in great detail a possible formation mechanism of such macroscopically large heavy objects. We argue that the nuggets will be inevitably produced during the QCD phase transition as a result of Kibble-Zurek mechanism on formation of the topological defects during a phase transition. Relevant topological defects in our scenario are the closed bubbles made of the N DW = 1 axion domain walls. These bubbles, in general, accrete the baryon (or antibaryon) charge, which eventually result in formation of the nuggets and anti-nuggets carrying a huge baryon (antibaryon) charge. A typical size and the baryon charge of these macroscopically large objects is mainly determined by the axion mass m a . However, the main consequence of the model, Ω dark ≈ Ω visible is insensitive to the axion mass which may assume any value within the observationally allowed window 10 -6 eV m a 10 -3 eV. We also estimate the baryon to entropy ratio η ≡ n B /n γ ∼ 10 -10 within this scenario. Finally, we comment on implications of these results to the axion search experiments, including microwave cavity and the Orpheus experiments. The results of this thesis has been published on arXiv as Xunyu Liang and Ariel Zhitnitsky, arXiv:1606.00435 [hep-ph]. Section 2.4 and appendices were my work, but also being improved by Ariel Zhitnitsky, especially Appendix A, into a more logical framework. Additionally, the inclusion of the viscosity term was suggested by me. The rest of new results, chapter 2, 3, and 5, presented in this thesis was done and written by Ariel Zhitnitsky. Also, the remaining review chapters were written by Ariel Zhitnitsky.

Dark Matter (DM) being the vital ingredient in the cosmos, still remains a mystery. Standard assumption is that the collisionless cold dark matter (CCDM) particles are represented by some weakly interacting fundamental fields which can not be associated with any standard quarks or leptons. However, recent analyses of structure on galactic and sub-galactic scales have suggested discrepancies and stimulated numerous alternative proposals including, e.g. Self-Interacting dark matter, Self-Annihilating dark matter, Decaying dark matter, to name just a few. We propose the alternative to the standard assumption about the nature of DM particles (which are typically assumed to be weakly interacting fundamental point -like particles, yet to be discovered). Our proposal is based on the idea that DM particles are strongly interacting composite macroscopically large objects which made of well known light quarks (or even antiquarks). The required weakness of the DM particle interactions is guaranteed by a small geometrical factor ǫ ∼ area volume ∼ B -1/3 ≪ 1 of the composite objects with a large baryon charge B ≫ 1, rather than by a weak coupling constant of a new field. We argue that the interaction between hadronic matter and composite dark objects does not spoil the desired properties of the latter as cold matter. We also argue that such a scenario does not contradict to the current observational data. Rather, it has natural explanations of many observed data, such as ΩDM /ΩB ∼ 1 or 511 KeV line from the bulge of our galaxy. We also suggest that composite dark matter may modify the dynamics of structure formation in the central overdense regions of galaxies. We also present a number of other cosmological/astrophysical observations which indirectly support the novel concept of DM nature.

This data paper presents lightcurves of 101 near Earth asteroids (NEAs) observed mostly between 2014 and 2017 as part of the EURONEAR photometric survey using 11 telescopes with diameters between 0.4 and 4.2 m located in Spain, Chile, Slovakia and Romania. Most targets had no published data at the time of observing, but some objects were observed in the same period mainly by B. Warner, allowing us to confirm or improve the existing results. To plan the runs and select the targets, we developed the public Long Planning tool in PHP. For preliminary data reduction and rapid follow-up planning we developed the LiDAS pipeline in Python and IRAF. For final data reduction, flux calibration, night linkage and Fourier fitting, we used mainly MPO Canopus.

The study of minor planets is motivated both by fundamental science of Solar system origins (some of these bodies contain the most pristine materials from the early ages of the planetary nebula) and by practical reasons concerning space exploration and impact frequency with Earth. Among minor bodies, near-Earth asteroids are a particularly important group: these objects are nearby the Earth's orbit and they represent both resources and hazards to humans. This is the case of 2014 JO 25 . The encounter of this potentially hazardous asteroid with the Earth at 0.011 75 au on 2017 April 19 was a good opportunity to study its properties through photometric and spectral analyses. The work we present here has been carried out thanks to a worldwide observational campaign that included time-series photometry and spectroscopy in the visible and near-infrared wavelengths. The optical images for photometric analysis were collected at different phase angles using small telescopes (<0.5 m) and medium telescopes (from 0.6 to 1.5 m). Spectral analysis was performed by 2-4 m telescopes. The light curve of 2014 JO 25 indicates a synodic rotational period of 4.5286 ± 0.0004 h. Although rotational period had been previously obtained by other authors, this work confirms it with a better accuracy. The obtained reflectance spectrum of this asteroid indicates that it belongs to the S-complex and its surface is most likely composed of a mixture of pyroxenes and olivine. From the comparison of its spectrum to those of meteorite samples, as well as from the wavelength position of the first absorption band (close to 0.9 μm), we suggest that this asteroid might contain a large fraction of low-calcium pyroxene and, tentatively, some amounts of metal.

HAL is a multi-disciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

HAL is a multi-disciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

refueling station in space, then using the computed ∆ʋ for determining the mass propellant consumed , at different specific impulse of the propellants, help us to carefully plane a mission to minimize the propellant mass carried on the rocket.

Introduction: There are an estimated 10 5 Near Earth Objects (NEOs) larger than 100m in diameter. At the present there are only 2190 known NEOs, many of which are smaller than 100m in diameter [1]. Over the past few decades there has been convincing evidence that impacts of asteroids and comets have played a significant role in the evolution of life on Earth [2]. The threat that NEOs pose to civilization and the fact that NEOs might represent economically attractive mineral resources for the future emphasize the importance of locating and cataloguing these objects. Despite these facts, there are few observers to perform follow-up observations on NEO discoveries made at one of the major asteroid detection programs such as LINEAR, LONEOS, NEAT and Spacewatch. Objective: The majority of the asteroid tracking and search projects are located in the northern hemisphere [3]. The recently completed Evelyn L. Egan Observatory on the campus of Florida Gulf Coast University is located at 26.5° North latitude, ideally situated to observe a large portion of the southern celestial sphere. This location can provide valuable observations of low declination NEOs that can't be reached by more northerly observers. Approximately 80% of the minor planets have inclinations less than 20° to the ecliptic plane, the main objective of the LISAA project will be to observe the area of sky within 20° south of the ecliptic plane. Contrary to popular belief, born from the fact that South Florida is only a few feet above sea level, South Florida offers many clear and steady nights in an observing season that spans roughly October through May. This eight-month span would be the typical main observing interval of the LISAA project each year. Method: The Egan Observatory's automated 16" Ritchey-Chretien telescope equipped with an Apogee AP7ap CCD camera will be employed to take stereopaired images covering 0.1deg 2 of sky in an effort to detect previously unknown NEOs and to recover recent NEO discoveries from other search programs for follow-up astrometric observations. Furthermore, photometric studies using BVRI filters will provide valuable information about the rotational and compositional properties of some of the brighter Near Earth Objects. Due to the immense number of asteroid discoveries these are areas where observations are lacking.

 An IDP (a fragile-looking one)  Brownleeite TEM photo  Comet 26P/Grigg-Skjellerup (pretty sky photo; can do any comet if this specific one is too hard)  Comparison of some small world surfaces at same scales? Itokawa, 67P, Eros?  JSC sample curation facility (ideally, Keiko in her lab)  Hayabusa2 and OSIRIS-REx art [caption] Some IDPs are fragile, have primitive properties, and do not appear to be related to any meteorite. IDPs probably come from collisions among asteroids and from comet jets, but where any specific particle came from is unknown.

The Earth is nearing depletion of its natural resources at a time when human beings are rapidly expanding the frontiers of space. The resources which may exist on asteroids could have enormous potential for aiding and enhancing human space exploration as well as life on Earth. With the possibly limitless opportunities that exist, it is clear that asteroids are the next step for human existence in space. This report comprises the efforts of NEW WORLDS, Inc. to develop a comprehensive design for an asteroid exploration/sample return mission. This mission is a precursor to proof-of-concept missions that will investigate the validity of mining and materials processing on an asteroid. Project STONER (Systematic Transfer of Near Earth Resources) is based on two utilization scenarios: (1) moving an asteroid to an advantageous location for use by Earth; and (2) mining an asteroids and transporting raw materials back to Earth. The asteroid explorer/sample return mission is designed in the co...

We have used Minor Planet Center (MPC) data and tools to explore the discovery circumstances and properties of the currently known population of over 10,000 NEAs, and to quantify the challenges for follow-up from ground-based optical telescopes. The increasing rate of discovery has grown to ∼1,000/year as surveys have become more sensitive, by 1 mag every ∼7.5 years. However, discoveries of large (H ≤ 22) NEAs have remained stable at ∼365/year over the past decade, at which rate the 2005 Congressional mandate to find 90% of 140 m NEAs will not be met before 2030 (at least a decade late). Meanwhile, characterization is falling farther behind: Fewer than 10% of NEAs are well characterized in terms of size, rotation periods, and spectral composition, and at the current rates of follow-up it will take about a century to determine them even for the known population. Over 60% of NEAs have an orbital uncertainty parameter, U ≥ 4, making reacquisition more than a year following discovery difficult; for H > 22 this fraction is over 90%. We argue that rapid follow-up will be essential to characterize newly-discovered NEAs. Most new NEAs are found within 0.5 mag of their peak brightness and fade quickly, typically by 0.5/3.5/5 mag after 1/4/6 weeks. About 80% have synodic periods of <3 years that would bring them close to Earth several times per decade. However follow-up observations on subsequent apparitions will be difficult or impossible for the bulk of new discoveries, as these will be smaller (H > 22) NEAs that tend to return 100× fainter. We show that for characterization to keep pace with discovery would require: Quick (within days) visible spectroscopy with a dedicated ≥2 m telescope; long-arc (months) astrometry, to be used also for phase curves, with a ≥4 m telescope; and fast-cadence (<min) light curves obtained rapidly (within days) with a ≥4 m telescope. For the already-known large (H ≤ 22) NEAs, that tend to return to similar brightness, subsequent-apparition spectroscopy, astrometry, and photometry could be done with 1-2 m telescopes.

The Measurement and Analysis of Apophis Trajectory (MAAT) concept study investigated a low-cost characterization mission to the asteroid 99942 Apophis that leverage small spacecraft architectures and technologies. The mission goals were to perform physical characterization and improve the orbital model. The MAAT mission uses a small spacecraft free flyer and a bi-propellant transfer stage that can be incorporated as a secondary payload on Evolved Expendable Launch Vehicles (EELVs), Atlas V or Delta IV launches. Using the innovative secondary architecture allows the system to be launched on numerous GTO or LTO opportunities such as NASA science missions or commercial communication satellites. The trajectory takes advantage of the reduced Delta-V requirement during the 20122015 time frame, with a large flexible launch opportunity, from January to November 2012 and heliocentric injection occurs in April 2013. Primary communications use the traditional Deep Space Network (DSN) with a se...

Planetary Defense is a complex problem, not well understood by policy makers and the general public. The recent Chelyabinsk incident in Russia created temporary international attention but has failed to effectively stimulate public action. The lack of long-term attention to cosmic hazards has resulted in limited funding to defend our planet. Hence, it is hard to realistically address this challenge and achieve the high test and operational readiness needed for an effective Planetary Defense strategy. To address this problem, we have created a set of recommendations for the development of a Planetary Defense Program, for the purpose of contributing to the protection of Earth from asteroids and comets. The SSP15 READI Project focused on threats for which there is only a short-term warning, specifically a warning of two years or less from detection of the object to impact. We have provided recommendations in five areas of Planetary Defense including detection and tracking, deflection t...

The goal of the SINPLEX project is to develop an innovative solution to significantly reduce the mass of the navigation subsystem for exploration missions which include landing and/or rendezvous and capture phases. The system mass is reduced while still maintaining good navigation performance as compared to a conventional modular system. This is done by functionally integrating the navigation sensors, using microand nanotechnology to miniaturize electronics and fusing the sensor data within a navigation filter to improve navigation performance. A breadboard system was build including a navigation computer, IMU, laser altimeter/range finder, star tracker and navigation camera and has space for the redundant counterparts. Testing using the TRON hardware-in-the-loop testbench is ongoing. This

In response to the current interest in CubeSats and potential applications for planetary exploration, this work studies the feasibility of using autonomous CubeSats to flyby near-Earth asteroids. Considering the limited performance of current propulsion systems for CubeSats, low-energy (impulsive and low-thrust) trajectories are designed to encounter near-Earth asteroids in the medium-fidelity Circular Restricted Three-Body Problem, and their existence in a high-fidelity ephemeris model is also verified. The use of large ground antennas for deep-space communications might represent a major portion of CubeSat mission budgets, and thus the feasibility of performing optical navigation to autonomously estimate and correct the trajectory of the CubeSat is also evaluated through Monte Carlo simulations. Preliminary results show that approximately 4 asteroids per year could be reached by a 3U CubeSat if deployed around the first or second Sun-Earth Lagrange points. According to the limited...

Fast development of CubeSat technology now enables the first interplanetary missions. The potential application of CubeSats to flyby near-Earth asteroids is explored in this paper in consideration of CubeSats' limited propulsive capabilities and systems constraints. Low-energy asteroid flyby trajectories are designed assuming a CubeSat is initially parked around to the Sun-Earth Lagrange points. High-impulse and low-thrust trajectories with realistic thrusting models are computed first in the Circular Restricted Three-Body Problem (CR3BP), and then in a high-fidelity ephemeris model. Analysis in the ephemeris model is used to confirm that trajectories computed in the CR3BP model also exist in a more realistic dynamical model, and to verify the validity of the results obtained in CR3BP analysis. A catalogue of asteroid flyby opportunities between years 2019 and 2030 is provided, with 80 m/s of available ΔV and departure from halo orbits around the first and second Sun-Earth Lagrange points (of similar size to those typically used by scientific missions). Results show that the CR3BP model can serve as an effective tool to identify reachable asteroids and can provide an initial estimation of the ΔV cost in the ephemeris model (with ±15 m/s accuracy). An impulsive maneuver model can also provide an accurate estimation of the ΔV requirement for a CubeSat equipped with a high-impulse thruster (with 4 m/s accuracy), even if its thrust magnitude is small and requires duty cycling; low-thrust ΔV requirements, however, may differ significantly from the impulsive results (±15 m/s).

To deeply explore the solar system, it will be necessary to become less reliant on the resupply tether to Earth. An approach explored in this study is to convert hydrocarbons in asteroids to human edible food. After comparing the experimental pyrolysis breakdown products, which were able to be converted to biomass using a consortia, it was hypothesized that equivalent chemicals found on asteroids could also be converted to biomass with the same nutritional content as the pyrolyzed products. This study is a mathematical exercise that explores the potential food yield that could be produced from these methodologies. This study uses the abundance of aliphatic hydrocarbons in the Murchison meteorite (>35 ppm) as a baseline for the calculations, representing the minimum amount of organic matter that could theoretically be attributed to biomass production. Calculations for the total carbon in solvent-insoluble organic matter (IOM) represent the maximum amount of organic matter that could theoretically be attributed to food production. These two values will provide a range of realistic yields to determine how much food could theoretically be extractable from an asteroid. The results of this study found that if only the aliphatic hydrocarbons can be converted into biomass (minimum scenario) the resulting mass of edible biomass extractable from asteroid Bennu ranges from 5.070 × 10 7 g to 2.390 × 10 8 g. If the biomass extraction process, however, is more efficient, and all IOM is converted into edible biomass (maximum scenario), then the mass of edible biomass extractable from asteroid Bennu ranges from 1.391 × 10 9 g to 6.556 × 10 9 g. This would provide between 5.762 × 10 8 and 1.581 × 10 10 calories that is enough to support between 600 and 17 000 astronaut life years. The asteroid mass needed to support one astronaut for one year is between 160 000 metric tons and 5000 metric tons. Based on these results, this approach of using carbon in asteroids to provide a distributed food source for humans appears promising, but there are substantial areas of future work. Contents

Используя механическую трактовку производной и анализируя функцию y = x^n, можно вывести общую форму уравнения для закона всемирного тяготения Ньютона. Из общей и более точной формулировки закона тяготения следует, что гравитационная постоянная G (если уравнение записать в традиционной форме) уже не является постоянной и будет возрастать с увеличением расстояния между взаимодействующими телами.

P.S. This is the Russian version of the work: The Pioneer effect, Fermat's last theorem and the gravitational constant G.

In this paper, we investigate thermophysical characteristics of near-Earth asteroid (341843) 2008 EV5, based on our improved advanced thermal physical model by considering the contribution of sunlight reflection for rough surfaces, along with four waveband observations from the Wide-field Infrared Survey Explorer and the radarderived shape model. Here we derive that 2008 EV5 has a relatively low thermal inertia of G = eff 33 6 , respectively. The low thermal inertia indicates that 2008 EV5 may have undergone sufficient space weathering over secular evolution. The high roughness may have resemblance to the appearances of Bennu and Ryugu recently observed by spacecraft, where a great number of boulders are widely distributed on the asteroid's surface. Moreover, we numerically perform 1000 backward simulations of 2008 EV5ʼs cloned orbits within 1 Myr to explore its origin, and present a probability of ∼6.1% that the asteroid originates from the main belt. Finally, we estimate that the mean grain size of the surface ranges from 0.58 to 1.3 mm, and infer that it is unlikely to find water ice on most of the area of 2008 EV5, but there may exist water ice on high latitudes near the polar region.

Ao professor Amilton Sinatora pela oportunidade para vir ao Brasil e ter uma inesquecível experiência além do doutorado, pela amizade, apoio, conança e motivação para realizar este trabalho. À FAPESP pela bolsa de doutorado (processo 2005/59131-0) que permitiu o desenvolvimento deste projeto, a participação nos congressos e a minha manutenção. Aos professores César Chaves, Juan Manuel Vélez e Alejandro Toro que contribuíram bastante para seguir este caminho. À minha amiga Diana López pelo recebimento no Brasil, que fez mais suportável deixar longe a namorada, a família e os amigos. À minha sogra Candida Castillo e às famílias Arango Gómez e Viáfara Quintana pelo carinho e ajuda. Aos amigos de Medellín e outros lugares pela maravilhosa amizade. Aos amigos e doutores Mario Vitor Leite, Abel Recco, Vanderlei Ferreira e María Cristina Moré Farias pela amizade e experiência compartilhada.

In order for humans to explore beyond Low Earth Orbit both safely and economically, it will be essential to learn how to make use of in situ materials and energy in an environment much different than on earth. Precursor robotic missions will be necessary to determine what resources will be available and to demonstrate the capabilities for their use. To that end, we have recently been studying acidic Ionic Liquid (IL) systems for use in a low temperature (&lt; 200 C) process to solubilize regolith, and to extract, as water, the oxygen available in metal oxides. Using this method, we have solubilized lunar regolith simulant (JSC-1A), as well as extraterrestrial materials in the form of meteorites, and have extracted up to 80% of the available oxygen. Moreover, by using a hydrogen gas electrode, we have shown that the IL can be regenerated at the anode and metals (e.g. iron) can be plated onto the cathode. These results indicate that IL processing is an excellent candidate for extracti...

The European component of the joint ESA-NASA Asteroid Impact & Deflection Assessment (AIDA) mission has been redesigned from the original version called Asteroid Impact Mission (AIM), and is now called Hera. The main objectives of AIDA are twofold: (1) to perform an asteroid deflection test by means of a kinetic impactor under detailed study at NASA (called DART, for Double Asteroid Redirection Test); and (2) to investigate with Hera the changes in geophysical and dynamical properties of the target binary asteroid after the DART impact. This joint mission will allow extrapolating the results of the kinetic impact to other asteroids and therefore fully validate such asteroid deflection techniques. Hera leverages technology and payload pre-developments of the previous AIM, and focuses on key measurements to validate impact models such as the detailed characterisation of the impact crater. As such, AIDA will be the first documented deflection experiment and binary asteroid investigation. In particular, it will be the first mission to investigate a binary asteroid, and return new scientific knowledge with important implications for our understanding of asteroid formation and solar system history. Hera will investigate the smallest asteroid visited so far therefore providing a unique opportunity to shed light on the role cohesion and Van der Waals forces may play in the formation and resulting internal structure of such small bodies.

The Asteroid Impact & Deflection Assessment (AIDA) mission is a joint cooperation between European and US space agencies that consists of two separate and independent spacecraft that will be launched to a binary asteroid system, the near-Earth asteroid Didymos, to test the kinetic impactor technique to deflect an asteroid. The European Asteroid Impact Mission (AIM) is set to rendezvous with the asteroid system to fully characterise the smaller of the two binary components a few months prior to the impact by the US Double Asteroid Redirection Test (DART) spacecraft. AIM is a unique mission as it will be the first time that a spacecraft will investigate the surface, subsurface, and internal properties of a small binary near-Earth asteroid. In addition it will perform various important technology demonstrations that can serve other space missions. The knowledge obtained by this mission will have great implications for our understanding of the history of the Solar System. Having direct information on the surface and internal properties of small asteroids will allow us to understand how the vaious processes they undergo work and transform these small bodies as well as, for this particular case, how a binary system forms. Making these measurements from up close and comparing them with ground-based data from telescopes will also allow us to calibrate remote observations and improve our data interpretation of other systems. With DART, thanks to the characterization of the target by AIM, the mission will be the first fully documented impact experiment at asteroid scale, which will include the characterization of the target's properties and the outcome of the impact. AIDA will thus offer a great opportunity to test and refine our understanding and models at the actual scale of an asteroid, and to check whether the current extrapolations of material strength from laboratory-scale targets to the scale of AIDA's target are valid. Moreover, it will offer a first check of the validity of the kinetic impactor concept to deflect a small body and lead to improved efficiency for future kinetic impactor designs. This paper focuses on the science return of AIM, the current knowledge of its target from ground-based observations, and the instrumentation planned to get the necessary data.

In this paper we provide the calculated orbit for the meteoroid of the meteorite-producting fireball that exploded over Romania on 7 January 2015. Based on a large number of records on cameras, a trajectory, speed, and orbital elements are computed. Then, the backward numerical integration of the Solar System’s ordinary differential equations of motion is used to reconstruct the pre-atmospheric meteoroid’s orbit.

In response to the current interest in CubeSats and potential applications for planetary exploration, this work studies the feasibility of using autonomous CubeSats to flyby near-Earth asteroids. Considering the limited performance of current propulsion systems for CubeSats, low-energy (impulsive and low-thrust) trajectories are designed to encounter near-Earth asteroids in the medium-fidelity Circular Restricted Three-Body Problem, and their existence in a high-fidelity ephemeris model is also verified. The use of large ground antennas for deep-space communications might represent a major portion of CubeSat mission budgets, and thus the feasibility of performing optical navigation to autonomously estimate and correct the trajectory of the CubeSat is also evaluated through Monte Carlo simulations. Preliminary results show that approximately 4 asteroids per year could be reached by a 3U CubeSat if deployed around the first or second Sun-Earth Lagrange points. According to the limited...

Due to the complexity of obtaining the coefficients resulting from the spherical harmonics
expansion of any geometry and the great potential of neural networks, this project will study
the combination of both themes. Specifically, the analysis of asteroid geometries will be
addressed with the aim of taking advantage of the fast response capacity of neural networks
to perform such spherical harmonic expansion in space missions.

In order to carry out this study, an introduction to spherical harmonics and neural networks
will be made. Next, the types of structure with the best compatibility for the project’s
purpose will be chosen. Subsequently, a detailed explanation of the developed code will be
given, which, in a broad sense, will be in charge for: generating the randomly shaped asteroids
to be used in the project, standardizing and processing the data, creating and training the
neural networks, and calculating the metrics of these networks.

Following this, several parametric analyses of the chosen neural networks will be performed
in order to find relationships and dependencies among these parameters. Additionally, this
approach will yield parameter combinations that produce better metrics.

Finally, a comparison will be made between the studied neural networks, determining
whether the use of neural networks to expand asteroid geometries into spherical harmonics
is viable or not. Furthermore, some possible future works and practical applications of the
project carried out are established.

Hayabusa2 arrived at the asteroid Ryugu in June 2018, and as of April 2019, the mission succeeded in conducting two rovers landing, one lander landing, one spacecraft touchdown/sample collection and one kinetic impact operation. This paper describes the initial nine months of the asteroid proximity operation activity of the Hayabusa2 mission, and gives an overview of the achievements thus far. Some important engineering and scientific activities conducted synchronously with spacecraft operations in order to complete all planned operations in time against unexpectedly harsh environment of Ryugu are also described.

Hayabusa2 mission has started as the follow-on mission of Hayabusa. The target asteroid is 1999 JU3, which is a C-type asteroid. The scientific purpose is to study the formation and evolution of the solar system, especially to study the organic matter and water, which existed in the early stage of the solar system formation. The engineering is also important and the spacecraft will be much more robust and reliable with some new technological challenges. The launch of Hayabusa2 is planned at the end of 2014, arriving at the asteroid in the middle of 2018, and it comes back to the earth at the end of 2020. At present, the flight model is under manufacturing.

The near-Earth object population, composed mostly of asteroids rather than comets, poses an impact hazard to Earth. Space technology is reaching a sufficient level of capability and maturity where the deflection of an Earth impactor may be possible within the next decades. The paper focuses on assessing the maximum deflection capability (minimum response time) that could be achieved with a rendezvous/landed spacecraft, using electric propulsion and nuclear/solar power technologies likely to be available in the near-term, within the constraints of a single heavy launch into low Earth orbit. Preliminary design concepts are presented for large, high-power nuclear and solar electric spacecraft, based on a trade-off analysis of power/propulsion technology options and an optimisation of the complete mission design to the minimise the total response time for a representative impactor/deflection scenario. High specific impulse gridded-ion engines show significantly improved mission performance over Hall effect thrusters due to the high delta-V requirements for Earth spiral out, rendezvous, spin axis reorientation and deflection. Amorphous silicon thin film solar arrays perform substantially better than conventional high cell efficiency alternatives. It was found that solar electric spacecraft could achieve lower total response times for the deflection than a nuclear electric spacecraft of the same initial mass, if the asteroid perihelion is much lower than the Earth. The comparison is expected to be much closer if the asteroid perihelion is near the Earth. Both systems were found to provide effective deflection capabilities for small/moderate-size impactors.

During its approach to asteroid (101955) Bennu, NASA’s Origins, Spectral Interpretation, Resource Identification, and Security-Regolith Explorer (OSIRIS-REx) spacecraft surveyed Bennu’s immediate environment, photometric properties, and rotation state. Discovery of a dusty environment, a natural satellite, or unexpected asteroid characteristics would have had consequences for the mission’s safety and observation strategy. Here we show that spacecraft observations during this period were highly sensitive to satellites (sub-meter scale) but reveal none, although later navigational images indicate that further investigation is needed. We constrain average dust production in September 2018 from Bennu’s surface to an upper limit of 150 g s–1 averaged over 34 min. Bennu’s disk-integrated photometric phase function validates measurements from the pre-encounter astronomical campaign. We demonstrate that Bennu’s rotation rate is accelerating continuously at 3.63 ± 0.52 × 10–6 degrees day–2, ...

Hayabusa2 arrived at the asteroid Ryugu in June 2018, and as of April 2019, the mission succeeded in conducting two rovers landing, one lander landing, one spacecraft touchdown/sample collection and one kinetic impact operation. This paper describes the initial nine months of the asteroid proximity operation activity of the Hayabusa2 mission, and gives an overview of the achievements thus far. Some important engineering and scientific activities conducted synchronously with spacecraft operations in order to complete all planned operations in time against unexpectedly harsh environment of Ryugu are also described.

We consider synchronized trains of sub-picosecond pulses generated by mode-locked lasers applied to deflection of near Earth objects (NEO) on collision course with Earth. Our method is designed to avoid a predicted collision of the NEO with Earth by at least the diameter of Earth. We estimate deflecting a 10,000 MT NEO, such as the asteroid which struck Earth near Chelyabinsk, Russia to be feasible within several months using average power in the ten kilowatt range. We see this deflection method as scalable to larger NEO to a degree not possible using continuous laser systems.

Near Earth Asteroids (NEAs) are discovered daily, mainly by few major surveys, nevertheless many of them remain unobserved for years, even decades. Even so, there is room for new discoveries, including those submitted by smaller projects and amateur astronomers. Besides the well-known surveys that have their own automated system of asteroid detection, there are only a few software solutions designed to help amateurs and minisurveys in NEAs discovery. Some of these obtain their results based on the blink method in which a set of reduced images are shown one after another and the astronomer has to visually detect real moving objects in a series of images. This technique becomes harder with the increase in size of the CCD cameras. Aiming to replace manual detection we propose an automated pipeline prototype for asteroids detection, written in Python under Linux, which calls some 3rd party astrophysics libraries.