Measurement Eccentricity the Moon's Orbit with Image Analysis
Total Page:16
File Type:pdf, Size:1020Kb
Load more
Recommended publications
-
The Utilization of Halo Orbit§ in Advanced Lunar Operation§
NASA TECHNICAL NOTE NASA TN 0-6365 VI *o M *o d a THE UTILIZATION OF HALO ORBIT§ IN ADVANCED LUNAR OPERATION§ by Robert W. Fmqcbar Godddrd Spctce Flight Center P Greenbelt, Md. 20771 NATIONAL AERONAUTICS AND SPACE ADMINISTRATION WASHINGTON, D. C. JULY 1971 1. Report No. 2. Government Accession No. 3. Recipient's Catalog No. NASA TN D-6365 5. Report Date Jul;v 1971. 6. Performing Organization Code 8. Performing Organization Report No, G-1025 10. Work Unit No. Goddard Space Flight Center 11. Contract or Grant No. Greenbelt, Maryland 20 771 13. Type of Report and Period Covered 2. Sponsoring Agency Name and Address Technical Note J National Aeronautics and Space Administration Washington, D. C. 20546 14. Sponsoring Agency Code 5. Supplementary Notes 6. Abstract Flight mechanics and control problems associated with the stationing of space- craft in halo orbits about the translunar libration point are discussed in some detail. Practical procedures for the implementation of the control techniques are described, and it is shown that these procedures can be carried out with very small AV costs. The possibility of using a relay satellite in.a halo orbit to obtain a continuous com- munications link between the earth and the far side of the moon is also discussed. Several advantages of this type of lunar far-side data link over more conventional relay-satellite systems are cited. It is shown that, with a halo relay satellite, it would be possible to continuously control an unmanned lunar roving vehicle on the moon's far side. Backside tracking of lunar orbiters could also be realized. -
Astrodynamics
Politecnico di Torino SEEDS SpacE Exploration and Development Systems Astrodynamics II Edition 2006 - 07 - Ver. 2.0.1 Author: Guido Colasurdo Dipartimento di Energetica Teacher: Giulio Avanzini Dipartimento di Ingegneria Aeronautica e Spaziale e-mail: [email protected] Contents 1 Two–Body Orbital Mechanics 1 1.1 BirthofAstrodynamics: Kepler’sLaws. ......... 1 1.2 Newton’sLawsofMotion ............................ ... 2 1.3 Newton’s Law of Universal Gravitation . ......... 3 1.4 The n–BodyProblem ................................. 4 1.5 Equation of Motion in the Two-Body Problem . ....... 5 1.6 PotentialEnergy ................................. ... 6 1.7 ConstantsoftheMotion . .. .. .. .. .. .. .. .. .... 7 1.8 TrajectoryEquation .............................. .... 8 1.9 ConicSections ................................... 8 1.10 Relating Energy and Semi-major Axis . ........ 9 2 Two-Dimensional Analysis of Motion 11 2.1 ReferenceFrames................................. 11 2.2 Velocity and acceleration components . ......... 12 2.3 First-Order Scalar Equations of Motion . ......... 12 2.4 PerifocalReferenceFrame . ...... 13 2.5 FlightPathAngle ................................. 14 2.6 EllipticalOrbits................................ ..... 15 2.6.1 Geometry of an Elliptical Orbit . ..... 15 2.6.2 Period of an Elliptical Orbit . ..... 16 2.7 Time–of–Flight on the Elliptical Orbit . .......... 16 2.8 Extensiontohyperbolaandparabola. ........ 18 2.9 Circular and Escape Velocity, Hyperbolic Excess Speed . .............. 18 2.10 CosmicVelocities -
Instructor's Guide for Virtual Astronomy Laboratories
Instructor’s Guide for Virtual Astronomy Laboratories Mike Guidry, University of Tennessee Kevin Lee, University of Nebraska The Brooks/Cole product Virtual Astronomy Laboratories consists of 20 virtual online astronomy laboratories (VLabs) representing a sampling of interactive exercises that illustrate some of the most important topics in introductory astronomy. The exercises are meant to be representative, not exhaustive, since introductory astronomy is too broad to be covered in only 20 laboratories. Material is approximately evenly divided between that commonly found in the Solar System part of an introductory course and that commonly associated with the stars, galaxies, and cosmology part of such a course. Intended Use This material was designed to serve two general functions: on the one hand it represents a set of virtual laboratories that can be used as part or all of an introductory astronomy laboratory sequence, either within a normal laboratory setting or in a distance learning environment. On the other hand, it is meant to serve as a tutorial supplement for standard textbooks. While this is an efficient use of the material, it presents some problems in organization since (as a rule of thumb) supplemental tutorial material is more concept oriented while astronomy laboratory material typically requires more hands-on problem-solving involving at least some basic mathematical manipulations. As a result, one will find material of varying levels of difficulty in these laboratories. Some sections are highly conceptual in nature, emphasizing more qualitative answers to questions that students may deduce without working through involved tasks. Other sections, even within the same virtual laboratory, may require students to carry out guided but non-trivial analysis in order to answer questions. -
Habitability of Planets on Eccentric Orbits: Limits of the Mean Flux Approximation
A&A 591, A106 (2016) Astronomy DOI: 10.1051/0004-6361/201628073 & c ESO 2016 Astrophysics Habitability of planets on eccentric orbits: Limits of the mean flux approximation Emeline Bolmont1, Anne-Sophie Libert1, Jeremy Leconte2; 3; 4, and Franck Selsis5; 6 1 NaXys, Department of Mathematics, University of Namur, 8 Rempart de la Vierge, 5000 Namur, Belgium e-mail: [email protected] 2 Canadian Institute for Theoretical Astrophysics, 60st St George Street, University of Toronto, Toronto, ON, M5S3H8, Canada 3 Banting Fellow 4 Center for Planetary Sciences, Department of Physical & Environmental Sciences, University of Toronto Scarborough, Toronto, ON, M1C 1A4, Canada 5 Univ. Bordeaux, LAB, UMR 5804, 33270 Floirac, France 6 CNRS, LAB, UMR 5804, 33270 Floirac, France Received 4 January 2016 / Accepted 28 April 2016 ABSTRACT Unlike the Earth, which has a small orbital eccentricity, some exoplanets discovered in the insolation habitable zone (HZ) have high orbital eccentricities (e.g., up to an eccentricity of ∼0.97 for HD 20782 b). This raises the question of whether these planets have surface conditions favorable to liquid water. In order to assess the habitability of an eccentric planet, the mean flux approximation is often used. It states that a planet on an eccentric orbit is called habitable if it receives on average a flux compatible with the presence of surface liquid water. However, because the planets experience important insolation variations over one orbit and even spend some time outside the HZ for high eccentricities, the question of their habitability might not be as straightforward. We performed a set of simulations using the global climate model LMDZ to explore the limits of the mean flux approximation when varying the luminosity of the host star and the eccentricity of the planet. -
The Search for Exomoons and the Characterization of Exoplanet Atmospheres
Corso di Laurea Specialistica in Astronomia e Astrofisica The search for exomoons and the characterization of exoplanet atmospheres Relatore interno : dott. Alessandro Melchiorri Relatore esterno : dott.ssa Giovanna Tinetti Candidato: Giammarco Campanella Anno Accademico 2008/2009 The search for exomoons and the characterization of exoplanet atmospheres Giammarco Campanella Dipartimento di Fisica Università degli studi di Roma “La Sapienza” Associate at Department of Physics & Astronomy University College London A thesis submitted for the MSc Degree in Astronomy and Astrophysics September 4th, 2009 Università degli Studi di Roma ―La Sapienza‖ Abstract THE SEARCH FOR EXOMOONS AND THE CHARACTERIZATION OF EXOPLANET ATMOSPHERES by Giammarco Campanella Since planets were first discovered outside our own Solar System in 1992 (around a pulsar) and in 1995 (around a main sequence star), extrasolar planet studies have become one of the most dynamic research fields in astronomy. Our knowledge of extrasolar planets has grown exponentially, from our understanding of their formation and evolution to the development of different methods to detect them. Now that more than 370 exoplanets have been discovered, focus has moved from finding planets to characterise these alien worlds. As well as detecting the atmospheres of these exoplanets, part of the characterisation process undoubtedly involves the search for extrasolar moons. The structure of the thesis is as follows. In Chapter 1 an historical background is provided and some general aspects about ongoing situation in the research field of extrasolar planets are shown. In Chapter 2, various detection techniques such as radial velocity, microlensing, astrometry, circumstellar disks, pulsar timing and magnetospheric emission are described. A special emphasis is given to the transit photometry technique and to the two already operational transit space missions, CoRoT and Kepler. -
TOPICS in CELESTIAL MECHANICS 1. the Newtonian N-Body Problem
TOPICS IN CELESTIAL MECHANICS RICHARD MOECKEL 1. The Newtonian n-body Problem Celestial mechanics can be defined as the study of the solution of Newton's differ- ential equations formulated by Isaac Newton in 1686 in his Philosophiae Naturalis Principia Mathematica. The setting for celestial mechanics is three-dimensional space: 3 R = fq = (x; y; z): x; y; z 2 Rg with the Euclidean norm: p jqj = x2 + y2 + z2: A point particle is characterized by a position q 2 R3 and a mass m 2 R+. A motion of such a particle is described by a curve q(t) where t runs over some interval in R; the mass is assumed to be constant. Some remarks will be made below about why it is reasonable to model a celestial body by a point particle. For every motion of a point particle one can define: velocity: v(t) =q _(t) momentum: p(t) = mv(t): Newton formulated the following laws of motion: Lex.I. Corpus omne perservare in statu suo quiescendi vel movendi uniformiter in directum, nisi quatenus a viribus impressis cogitur statum illum mutare 1 Lex.II. Mutationem motus proportionem esse vi motrici impressae et fieri secundem lineam qua vis illa imprimitur. 2 Lex.III Actioni contrarium semper et aequalem esse reactionem: sive corporum duorum actiones in se mutuo semper esse aequales et in partes contrarias dirigi. 3 The first law is statement of the principle of inertia. The second law asserts the existence of a force function F : R4 ! R3 such that: p_ = F (q; t) or mq¨ = F (q; t): In celestial mechanics, the dependence of F (q; t) on t is usually indirect; the force on one body depends on the positions of the other massive bodies which in turn depend on t. -
1961Apj. . .133. .6575 PHYSICAL and ORBITAL BEHAVIOR OF
.6575 PHYSICAL AND ORBITAL BEHAVIOR OF COMETS* .133. Roy E. Squires University of California, Davis, California, and the Aerojet-General Corporation, Sacramento, California 1961ApJ. AND DaVid B. Beard University of California, Davis, California Received August 11, I960; revised October 14, 1960 ABSTRACT As a comet approaches perihelion and the surface facing the sun is warmed, there is evaporation of the surface material in the solar direction The effect of this unidirectional rapid mass loss on the orbits of the parabolic comets has been investigated, and the resulting corrections to the observed aphelion distances, a, and eccentricities have been calculated. Comet surface temperature has been calculated as a function of solar distance, and estimates have been made of the masses and radii of cometary nuclei. It was found that parabolic comets with perihelia of 1 a u. may experience an apparent shift in 1/a of as much as +0.0005 au-1 and that the apparent shift in 1/a is positive for every comet, thereby increas- ing the apparent orbital eccentricity over the true eccentricity in all cases. For a comet with a perihelion of 1 a u , the correction to the observed eccentricity may be as much as —0.0005. The comet surface tem- perature at 1 a.u. is roughly 180° K, and representative values for the masses and radii of cometary nuclei are 6 X 10" gm and 300 meters. I. INTRODUCTION Since most comets are observed to move in nearly parabolic orbits, questions concern- ing their origin and whether or not they are permanent members of the solar system are not clearly resolved. -
Orbital Stability Zones About Asteroids
ICARUS 92, 118-131 (1991) Orbital Stability Zones about Asteroids DOUGLAS P. HAMILTON AND JOSEPH A. BURNS Cornell University, Ithaca, New York, 14853-6801 Received October 5, 1990; revised March 1, 1991 exploration program should be remedied when the Galileo We have numerically investigated a three-body problem con- spacecraft, launched in October 1989, encounters the as- sisting of the Sun, an asteroid, and an infinitesimal particle initially teroid 951 Gaspra on October 29, 1991. It is expected placed about the asteroid. We assume that the asteroid has the that the asteroid's surroundings will be almost devoid of following properties: a circular heliocentric orbit at R -- 2.55 AU, material and therefore benign since, in the analogous case an asteroid/Sun mass ratio of/~ -- 5 x 10-12, and a spherical of the satellites of the giant planets, significant debris has shape with radius R A -- 100 km; these values are close to those of never been detected. The analogy is imperfect, however, the minor planet 29 Amphitrite. In order to describe the zone in and so the possibility that interplanetary debris may be which circum-asteroidal debris could be stably trapped, we pay particular attention to the orbits of particles that are on the verge enhanced in the gravitational well of the asteroid must be of escape. We consider particles to be stable or trapped if they considered. If this is the case, the danger of collision with remain in the asteroid's vicinity for at least 5 asteroid orbits about orbiting debris may increase as the asteroid is approached. -
Orbital Inclination and Eccentricity Oscillations in Our Solar
Long term orbital inclination and eccentricity oscillations of the planets in our solar system Abstract The orbits of the planets in our solar system are not in the same plane, therefore natural torques stemming from Newton’s gravitational forces exist to pull them all back to the same plane. This causes the inclinations of the planet orbits to oscillate with potentially long periods and very small damping, because the friction in space is very small. Orbital inclination changes are known for some planets in terms of current rates of change, but the oscillation periods are not well published. They can however be predicted with proper dynamic simulations of the solar system. A three-dimensional dynamic simulation was developed for our solar system capable of handling 12 objects, where all objects affect all other objects. Each object was considered to be a point mass which proved to be an adequate approximation for this study. Initial orbital radii, eccentricities and speeds were set according to known values. The validity of the simulation was demonstrated in terms of short term characteristics such as sidereal periods of planets as well as long term characteristics such as the orbital inclination and eccentricity oscillation periods of Jupiter and Saturn. A significantly more accurate result, than given on approximate analytical grounds in a well-known solar system dynamics textbook, was found for the latter period. Empirical formulas were developed from the simulation results for both these periods for three-object solar type systems. They are very accurate for the Sun, Jupiter and Saturn as well as for some other comparable systems. -
Exoplanet Orbital Eccentricity: Multiplicity Relation and the Solar System
Exoplanet orbital eccentricity: Multiplicity relation and the Solar System Mary Anne Limbacha,b and Edwin L. Turnera,c,1 Departments of aAstrophysical Sciences and bMechanical and Aerospace Engineering, Princeton University, Princeton, NJ 08544; and cThe Kavli Institute for the Physics and Mathematics of the Universe, The University of Tokyo, Kashiwa 227-8568, Japan Edited by Neta A. Bahcall, Princeton University, Princeton, NJ, and approved November 11, 2014 (received for review April 10, 2014) The known population of exoplanets exhibits a much wider range of The dataset is discussed in the next section. We then show the orbital eccentricities than Solar System planets and has a much higher trend in eccentricity with multiplicity and comment on possible average eccentricity. These facts have been widely interpreted to sources of error and bias. Next we measure the mean, median, indicate that the Solar System is an atypical member of the overall and probability density distribution of eccentricities for various population of planetary systems. We report here on a strong anti- multiplicities and fit them to a simple power-law model for correlation of orbital eccentricity with multiplicity (number of planets multiplicities greater than two. This fit is used to make a rough in the system) among cataloged radial velocity (RV) systems. The estimate of the number of higher-multiplicity systems likely to be mean, median, and rough distribution of eccentricities of Solar System contaminating the one- and two-planet system samples due to as planets fits an extrapolation of this anticorrelation to the eight-planet yet undiscovered members under plausible, but far from certain, case rather precisely despite the fact that no more than two Solar assumptions. -
Orbital Mechanics of Gravitational Slingshots 1 Introduction 2 Approach
Orbital Mechanics of Gravitational Slingshots Final Paper 15-424: Foundations of Cyber-Physical Systems Adam Moran, [email protected] John Mann, [email protected] May 1, 2016 Abstract A gravitational slingshot is a maneuver to save fuel by using the gravity of a planet to accelerate or decelerate a spacecraft. Due to the large distances and high speeds involved, slingshots require precise accuracy to accomplish | the slightest mistake could cause the whole mission to fail. Therefore, we have developed a cyber-physical system to model the physics and prove the safety and efficiency of powered and unpowered gravitational slingshots. We present our findings and proof in this paper. 1 Introduction A gravitational slingshot is a maneuver performed to increase or decrease the speed of a spacecraft by simply approaching planetary bodies. A spacecraft's usefulness and maneuverability is basically tied to the amount of fuel it can carry, and the more fuel a spacecraft holds, the more fuel it needs to carry that fuel into orbit. Therefore, gravitational slingshots are a very appealing way to save mass, and therefore money, on deep-space missions since these maneuvers do not require any fuel. As missions conducted by national and private space programs become more frequent and ambitious, the need for these precise maneuvers will increase. Therefore, we have created a cyber-physical system that models the physics of a gravitational slingshot for a spacecraft approaching a planet. In the "Approach" section of this paper, we give a brief overview of the physics involved with orbits and gravitational slingshots. In the "Models and Properties" section of this paper, we describe what assumptions and simplifications we made to model these astrophysics in a way for us to prove our desired properties with KeYmaeraX. -
Kepler Press
National Aeronautics and Space Administration PRESS KIT/FEBRUARY 2009 Kepler: NASA’s First Mission Capable of Finding Earth-Size Planets www.nasa.gov Media Contacts J.D. Harrington Policy/Program Management 202-358-5241 NASA Headquarters [email protected] Washington 202-262-7048 (cell) Michael Mewhinney Science 650-604-3937 NASA Ames Research Center [email protected] Moffett Field, Calif. 650-207-1323 (cell) Whitney Clavin Spacecraft/Project Management 818-354-4673 Jet Propulsion Laboratory [email protected] Pasadena, Calif. 818-458-9008 (cell) George Diller Launch Operations 321-867-2468 Kennedy Space Center, Fla. [email protected] 321-431-4908 (cell) Roz Brown Spacecraft 303-533-6059. Ball Aerospace & Technologies Corp. [email protected] Boulder, Colo. 720-581-3135 (cell) Mike Rein Delta II Launch Vehicle 321-730-5646 United Launch Alliance [email protected] Cape Canaveral Air Force Station, Fla. 321-693-6250 (cell) Contents Media Services Information .......................................................................................................................... 5 Quick Facts ................................................................................................................................................... 7 NASA’s Search for Habitable Planets ............................................................................................................ 8 Scientific Goals and Objectives .................................................................................................................