Radar Observations of Asteroid 2063 Bacchus
Total Page:16
File Type:pdf, Size:1020Kb

Load more
Recommended publications
-
Orbital Stability Assessments of Satellites Orbiting Small Solar System Bodies a Case Study of Eros
Delft University of Technology, Faculty of Aerospace Engineering Thesis report Orbital stability assessments of satellites orbiting Small Solar System Bodies A case study of Eros Author: Supervisor: Sjoerd Ruevekamp Jeroen Melman, MSc 1012150 August 17, 2009 Preface i Contents 1 Introduction 2 2 Small Solar System Bodies 4 2.1 Asteroids . .5 2.1.1 The Tholen classification . .5 2.1.2 Asteroid families and belts . .7 2.2 Comets . 11 3 Celestial Mechanics 12 3.1 Principles of astrodynamics . 12 3.2 Many-body problem . 13 3.3 Three-body problem . 13 3.3.1 Circular restricted three-body problem . 14 3.3.2 The equations of Hill . 16 3.4 Two-body problem . 17 3.4.1 Conic sections . 18 3.4.2 Elliptical orbits . 19 4 Asteroid shapes and gravity fields 21 4.1 Polyhedron Modelling . 21 4.1.1 Implementation . 23 4.2 Spherical Harmonics . 24 4.2.1 Implementation . 26 4.2.2 Implementation of the associated Legendre polynomials . 27 4.3 Triaxial Ellipsoids . 28 4.3.1 Implementation of method . 29 4.3.2 Validation . 30 5 Perturbing forces near asteroids 34 5.1 Third-body perturbations . 34 5.1.1 Implementation of the third-body perturbations . 36 5.2 Solar Radiation Pressure . 36 5.2.1 The effect of solar radiation pressure . 38 5.2.2 Implementation of the Solar Radiation Pressure . 40 6 About the stability disturbing effects near asteroids 42 ii CONTENTS 7 Integrators 44 7.1 Runge-Kutta Methods . 44 7.1.1 Runge-Kutta fourth-order integrator . 45 7.1.2 Runge-Kutta-Fehlberg Method . -
Asteroids Do Have Satellites 289
Merline et al.: Asteroids Do Have Satellites 289 Asteroids Do Have Satellites William J. Merline Southwest Research Institute Stuart J. Weidenschilling Planetary Science Institute Daniel D. Durda Southwest Research Institute Jean-Luc Margot California Institute of Technology Petr Pravec Astronomical Institute of the Academy of Sciences of the Czech Republic Alex D. Storrs Towson University After years of speculation, satellites of asteroids have now been shown definitively to exist. Asteroid satellites are important in at least two ways: (1) They are a natural laboratory in which to study collisions, a ubiquitous and critically important process in the formation and evolu- tion of the asteroids and in shaping much of the solar system, and (2) their presence allows to us to determine the density of the primary asteroid, something which otherwise (except for certain large asteroids that may have measurable gravitational influence on, e.g., Mars) would require a spacecraft flyby, orbital mission, or sample return. Binaries have now been detected in a variety of dynamical populations, including near-Earth, main-belt, outer main-belt, Tro- jan, and transneptunian regions. Detection of these new systems has been the result of improved observational techniques, including adaptive optics on large telescopes, radar, direct imaging, advanced lightcurve analysis, and spacecraft imaging. Systematics and differences among the observed systems give clues to the formation mechanisms. We describe several processes that may result in binary systems, all of which involve collisions of one type or another, either physi- cal or gravitational. Several mechanisms will likely be required to explain the observations. 1. INTRODUCTION sons between, for example, asteroid taxonomic types and our inventory of meteorites. -
Stable Orbits in the Small-Body Problem an Application to the Psyche Mission
Stable Orbits in the Small-Body Problem An Application to the Psyche Mission Stijn Mast Technische Universiteit Delft Stable Orbits in the Small-Body Problem Front cover: Artist illustration of the Psyche mission spacecraft orbiting asteroid (16) Psyche. Image courtesy NASA/JPL-Caltech. ii Stable Orbits in the Small-Body Problem An Application to the Psyche Mission by Stijn Mast to obtain the degree of Master of Science at Delft University of Technology, to be defended publicly on Friday August 31, 2018 at 10:00 AM. Student number: 4279425 Project duration: October 2, 2017 – August 31, 2018 Thesis committee: Ir. R. Noomen, TU Delft Dr. D.M. Stam, TU Delft Ir. J.A. Melkert, TU Delft Advisers: Ir. R. Noomen, TU Delft Dr. J.A. Sims, JPL Dr. S. Eggl, JPL Dr. G. Lantoine, JPL An electronic version of this thesis is available at http://repository.tudelft.nl/. Stable Orbits in the Small-Body Problem This page is intentionally left blank. iv Stable Orbits in the Small-Body Problem Preface Before you lies the thesis Stable Orbits in the Small-Body Problem: An Application to the Psyche Mission. This thesis has been written to obtain the degree of Master of Science in Aerospace Engineering at Delft University of Technology. Its contents are intended for anyone with an interest in the field of spacecraft trajectory dynamics and stability in the vicinity of small celestial bodies. The methods presented in this thesis have been applied extensively to the Psyche mission. Conse- quently, the work can be of interest to anyone involved in the Psyche mission. -
Radar Observations and a Physical Model of Asteroid 4660 Nereus, a Prime Space Mission Target ∗ Marina Brozovic A, ,Stevenj.Ostroa, Lance A.M
Icarus 201 (2009) 153–166 Contents lists available at ScienceDirect Icarus www.elsevier.com/locate/icarus Radar observations and a physical model of Asteroid 4660 Nereus, a prime space mission target ∗ Marina Brozovic a, ,StevenJ.Ostroa, Lance A.M. Benner a, Jon D. Giorgini a, Raymond F. Jurgens a,RandyRosea, Michael C. Nolan b,AliceA.Hineb, Christopher Magri c, Daniel J. Scheeres d, Jean-Luc Margot e a Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109-8099, USA b Arecibo Observatory, National Astronomy and Ionosphere Center, Box 995, Arecibo, PR 00613, USA c University of Maine at Farmington, Preble Hall, 173 High St., Farmington, ME 04938, USA d Aerospace Engineering Sciences, University of Colorado, Boulder, CO 80309-0429, USA e Department of Astronomy, Cornell University, 304 Space Sciences Bldg., Ithaca, NY 14853, USA article info abstract Article history: Near–Earth Asteroid 4660 Nereus has been identified as a potential spacecraft target since its 1982 Received 11 June 2008 discovery because of the low delta-V required for a spacecraft rendezvous. However, surprisingly little Revised 1 December 2008 is known about its physical characteristics. Here we report Arecibo (S-band, 2380-MHz, 13-cm) and Accepted 2 December 2008 Goldstone (X-band, 8560-MHz, 3.5-cm) radar observations of Nereus during its 2002 close approach. Available online 6 January 2009 Analysis of an extensive dataset of delay–Doppler images and continuous wave (CW) spectra yields a = ± = ± Keywords: model that resembles an ellipsoid with principal axis dimensions X 510 20 m, Y 330 20 m and +80 Radar observations Z = 241− m. -
Dynamics of Orbits Close to Asteroid 4179 Toutatis
ICARUS 132, 53±79 (1998) ARTICLE NO. IS975870 Dynamics of Orbits Close to Asteroid 4179 Toutatis D. J. Scheeres Department of Aerospace Engineering and Engineering Mechanics, Iowa State University, Ames, Iowa 50011-3231 E-mail: [email protected] S. J. Ostro Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California 91109-8099 R. S. Hudson School of Electrical Engineering and Computer Science, Washington State University, Pullman, Washington 99164-2752 E. M. DeJong Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California 91109-8099 and S. Suzuki Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California 91109-8099 Received June 19,1997; revised October 14, 1997 Toutatis' longest dimension. We identify families of periodic We use a radar-derived physical model of 4179 Toutatis orbits, which repeat in the Toutatis-®xed frame. Due to the (Hudson and Ostro 1995, Science 270, 84±86) to investigate time-periodic nature of the equations of motion, all periodic close-orbit dynamics around that irregularly shaped, non-prin- orbits about Toutatis in its body-®xed frame must be commen- cipal-axis rotator. The orbital dynamics about this body are surate with the 5.42-day period associated with those equations. Exact calculations of both stable and unstable periodic orbits markedly different than the dynamics about uniformly rotating are made. The sum of surface forces acting on a particle on asteroids. The results of this paper are generally applicable to Toutatis is time-varying, so particles on and in the asteroid are orbit dynamics about bodies in a non-principal-axis rotation being continually shaken with a period of 5.42 days, perhaps state. -
Jjmo News 06 19.Pdf
alactic Observer John J. McCarthy Observatory G Volume 12, No. 6 June 2019 GalacticGalactic MerMergggererers --s DancingDancing withwith thethe STSTARSARS AAAor PLANET Deadly Dos-I-Dos? IS BORN See page 18 inside http://www.mccarthyobservatory.org JJMO June 2019 • 1 The John J. McCarthy Observatory Galactic Observvvererer New Milford High School Editorial Committee 388 Danbury Road Managing Editor New Milford, CT 06776 Bill Cloutier Phone/Voice: (860) 210-4117 Phone/Fax: (860) 354-1595 Production & Design www.mccarthyobservatory.org Allan Ostergren Website Development JJMO Staff Marc Polansky It is through their efforts that the McCarthy Observatory has established itself as a significant educational and Technical Support recreational resource within the western Connecticut Bob Lambert community. Dr. Parker Moreland Steve Barone Peter Gagne Marc Polansky Colin Campbell Louise Gagnon Joe Privitera Dennis Cartolano John Gebauer Danielle Ragonnet Route Mike Chiarella Elaine Green Monty Robson Jeff Chodak Jim Johnstone Don Ross Bill Cloutier Carly KleinStern Gene Schilling Doug Delisle Bob Lambert Katie Shusdock Cecilia Detrich Roger Moore Jim Wood Dirk Feather Parker Moreland, PhD Paul Woodell Randy Fender Allan Ostergren Amy Ziffer In This Issue "OUT THE WINDOW ON YOUR LEFT .................................... 3 SUNRISE AND SUNSET ...................................................... 13 KIES PI LAVA DOME ....................................................... 4 SUMMER NIGHTS ........................................................... 13 -
Spacecraft Swarm Dynamics and Control About Asteroids
IWSCFF 19-1964 SPACECRAFT SWARM DYNAMICS AND CONTROL ABOUT ASTEROIDS Corinne Lippe∗ and Simone D’Amicoy This paper presents a novel methodology to control spacecraft swarms about single asteroids with arbitrary gravitational potential coefficients and spin characteristics. This approach enables the use of small, autonomous swarm spacecraft in conjunction with a mothership, reducing the need for the Deep Space Network and increasing safety in future asteroid mis- sions. The methodology is informed by a semi-analytical model for the spacecraft abso- lute and relative motion that includes relevant gravitational effects without assuming J2- dominance as well as solar radiation pressure. The dynamics model is exploited in an Ex- tended Kalman Filter (EKF) to produce an osculating-to-mean relative orbital element (ROE) conversion that is asteroid agnostic. The resulting real-time relative mean state estimate is utilized in the formation-keeping control algorithm. The control problem is cast in mean rel- ative orbital elements to leverage the geometric insight of secular and long-period effects in the definition of control windows for swarm maintenance. Analytical constraints that ensure collision avoidance and enforce swarm geometry are derived and enforced in ROE space. The proposed swarm-keeping algorithms are tested and validated in high-fidelity simulations for a reference asteroid mission. INTRODUCTION Missions to explore near-earth asteroids would provide valuable information about the solar system‘s for- mation and potential in-situ resources for interplanetary missions.1,2 As such, asteroid missions have become increasingly popular. However, information about the shape, gravity field, and rotational motion of the aster- oid is required to ensure safe and effective satellite operations. -
– Near-Earth Asteroid Mission Concept Study –
ASTEX – Near-Earth Asteroid Mission Concept Study – A. Nathues1, H. Boehnhardt1 , A. W. Harris2, W. Goetz1, C. Jentsch3, Z. Kachri4, S. Schaeff5, N. Schmitz2, F. Weischede6, and A. Wiegand5 1 MPI for Solar System Research, 37191 Katlenburg-Lindau, Germany 2 DLR, Institute for Planetary Research, 12489 Berlin, Germany 3 Astrium GmbH, 88039 Friedrichshafen, Germany 4 LSE Space AG, 82234 Oberpfaffenhofen, Germany 5 Astos Solutions, 78089 Unterkirnach, Germany 6 DLR GSOC, 82234 Weßling, Germany ASTEX Marco Polo Symposium, Paris 18.5.09, A. Nathues - 1 Primary Objectives of the ASTEX Study Identification of the required technologies for an in-situ mission to two near-Earth asteroids. ¾ Selection of realistic mission scenarios ¾ Definition of the strawman payload ¾ Analysis of the requirements and options for the spacecraft bus, the propulsion system, the lander system, and the launcher ASTEX ¾ Definition of the requirements for the mission’s operational ground segment Marco Polo Symposium, Paris 18.5.09, A. Nathues - 2 ASTEX Primary Mission Goals • The mission scenario foresees to visit two NEAs which have different mineralogical compositions: one “primitive'‘ object and one fragment of a differentiated asteroid. • The higher level goal is the provision of information and constraints on the formation and evolution history of our planetary system. • The immediate mission goals are the determination of: – Inner structure of the targets – Physical parameters (size, shape, mass, density, rotation period and spin vector orientation) – Geology, mineralogy, and chemistry ASTEX – Physical surface properties (thermal conductivity, roughness, strength) – Origin and collisional history of asteroids – Link between NEAs and meteorites Marco Polo Symposium, Paris 18.5.09, A. -
Constraints on Spin State and Hapke Parameters of Asteroid 4769 Castalia Using Lightcurves and a Radar-Derived Shape Model
ICARUS 130, 165±176 (1997) ARTICLE NO. IS975804 Constraints on Spin State and Hapke Parameters of Asteroid 4769 Castalia Using Lightcurves and a Radar-Derived Shape Model R. Scott Hudson School of Electrical Engineering and Computer Science, Washington State University, Pullman, Washington 99164-2752 E-mail: [email protected] Steven J. Ostro and Alan W. Harris Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California 91109-8099 Received October 21, 1996; revised April 18, 1997 1. INTRODUCTION A 167-parameter, 3-D shape model of the Earth-crossing asteroid Castalia, obtained from inversion of delay-Doppler It has long been clear that the asteroid population is images (Hudson and Ostro, 1994, Science 263, 940±943) con- immense, extremely diverse, and has a range of sizes that strained the object's pole to lie on a cone of half angle 55 6 virtually guarantees an abundance of irregular shapes and 108 centered on the radar line of sight (right ascension 0.3 hr, a wide range of pole directions under any conceivable declination 25.48) at the time of observations (Aug. 22, 1989) evolutionary scenario. Yet these objects are tantalizingly but could not constrain the pole's azimuthal orientation or the unresolvable to ground-based optical telescopes. Not sur- sense of rotation. Here we ®t lightcurves obtained at Table prisingly then, the relation between lightcurves and an Mountain Observatory on Aug. 23±25 with lightcurves calcu- asteroid's shape and spin state has been a subject of interest lated from Castalia's shape and Hapke's photometric model (Hapke 1981, J. -
Adaptive Filter for Osculating-To-Mean Relative Orbital Elements Conversion
AAS 20-496 ADAPTIVE FILTER FOR OSCULATING-TO-MEAN RELATIVE ORBITAL ELEMENTS CONVERSION Corinne Lippe∗ and Simone D’Amico y This paper addresses the osculating-to-mean conversion of relative orbital elements (ROE) for orbits about principal axis rotators. Current approaches assume the gravity potential is dominated by J2 or constrain the cental body’s rotation rate. To overcome limitations, an extended Kalman Filter (EKF) is presented that provides mean ROE estimates given osculat- ing ROE measurements in quasi-stable orbits. Additionally, covariance matching is applied to tune the measurement noise and account for uncertainties in gravity. The EKF is validated using a high-fidelity orbit propagator and a Monte Carlo simulation, where accurate conver- gence is achieved despite the execution of maneuvers and uncertainty in gravity parameters. INTRODUCTION Missions to asteroids have recently increased in popularity for both scientific and commercial purposes. Firstly, asteroids contain information about the formation of the universe. Secondly, asteroids contain valu- able materials such as platinum and gold, which can be mined for profit.1,2 Consequently, multiple corpo- rations are developing or have launched missions to near-earth asteroids, including Japanese Aerospace Ex- ploration Agency (JAXA),3,4 National Aeronautics and Space Administration (NASA),5,6 and the European Space Agency (ESA).7 While these missions typically rely on a single, monolithic spacecraft, autonomous spacecraft swarms provide multiple benefits. One, swarms have inherent redundancy through the use of multiple spacecraft. Therefore, if a spacecraft failure occurs, the workload can be redistributed among the remaining spacecraft without or with minimal loss of functionality. Two, autonomous spacecraft control reduces reliance on the over-subscribed Deep Space Network (DSN). -
Tidal Distortion and Disruption of Earth-Crossing Asteroids
ICARUS 134, 47±76 (1998) ARTICLE NO. IS985954 Tidal Distortion and Disruption of Earth-Crossing Asteroids Derek C. Richardson Department of Astronomy, University of Washington, Box 351580, Seattle, Washington 98195-1580 E-mail: [email protected] William F. Bottke, Jr. Center for Radiophysics and Space Research, 306 Space Sciences, Cornell University, Ithaca, New York 14853-6801 and Stanley G. Love1 Seismological Laboratory, California Institute of Technology, Mail Code 252-21, Pasadena, California 91125 Received December, 19, 1997; revised April 1, 1998 standing of doublet craters, crater chains, and asteroids with We present results of numerical simulations that show that peculiar shapes and spins. 1998 Academic Press Earth's tidal forces can both distort and disrupt Earth-crossing Key Words: asteroids, dynamics; asteroids, rotation; tides, asteroids that have weak ``rubble-pile'' structures. Building on solid body; cratering, terrestrial; computer techniques. previous studies, we consider more realistic asteroid shapes and trajectories, test a variety of spin rates and axis orientations, and employ a dissipation algorithm to treat more accurately 1. INTRODUCTION collisions between the particles that make up the model aster- oid. We explore a large parameter space, including the aster- 1.1. Evidence for ``Rubble-Pile'' Asteroids oid's periapse q, encounter velocity with the Earth v` , spin period P, initial spin axis orientation, and body orientation There is an increasing body of evidence to suggest that at periapse. most kilometer-sized asteroids and comets are ``rubble We parameterize the simulation outcomes by the amount of piles,'' collections of smaller fragments held together by mass stripped from the asteroid during a ¯yby. -
Detection of Semimajor Axis Drifts in 54 Near-Earth Asteroids: New Measurements of the Yarkovsky Effect
The Astronomical Journal, 144:60 (13pp), 2012 August doi:10.1088/0004-6256/144/2/60 C 2012. The American Astronomical Society. All rights reserved. Printed in the U.S.A. DETECTION OF SEMIMAJOR AXIS DRIFTS IN 54 NEAR-EARTH ASTEROIDS: NEW MEASUREMENTS OF THE YARKOVSKY EFFECT C. R. Nugent1, J. L. Margot1,2,S.R.Chesley3, and D. Vokrouhlicky´ 4 1 Department of Earth and Space Sciences, University of California, Los Angeles, CA 90095, USA 2 Department of Physics and Astronomy, University of California, Los Angeles, CA 90095, USA 3 Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109, USA 4 Institute of Astronomy, Charles University, V Holesovi˘ ck˘ ach´ 2, CZ-18000 Prague 8, Czech Republic Received 2012 April 16; accepted 2012 June 7; published 2012 July 12 ABSTRACT We have identified and quantified semimajor axis drifts in near-Earth asteroids (NEAs) by performing orbital fits to optical and radar astrometry of all numbered NEAs. We focus on a subset of 54 NEAs that exhibit some of the most reliable and strongest drift rates. Our selection criteria include a Yarkovsky sensitivity metric that quantifies the detectability of semimajor axis drift in any given data set, a signal-to-noise metric, and orbital coverage requirements. In 42 cases, the observed drifts (∼10−3 AU Myr−1) agree well with numerical estimates of Yarkovsky drifts. This agreement suggests that the Yarkovsky effect is the dominant non-gravitational process affecting these orbits, and allows us to derive constraints on asteroid physical properties. In 12 cases, the drifts exceed nominal Yarkovsky predictions, which could be due to inaccuracies in our knowledge of physical properties, faulty astrometry, or modeling errors.