Satellite Orbits
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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 -
Up, Up, and Away by James J
www.astrosociety.org/uitc No. 34 - Spring 1996 © 1996, Astronomical Society of the Pacific, 390 Ashton Avenue, San Francisco, CA 94112. Up, Up, and Away by James J. Secosky, Bloomfield Central School and George Musser, Astronomical Society of the Pacific Want to take a tour of space? Then just flip around the channels on cable TV. Weather Channel forecasts, CNN newscasts, ESPN sportscasts: They all depend on satellites in Earth orbit. Or call your friends on Mauritius, Madagascar, or Maui: A satellite will relay your voice. Worried about the ozone hole over Antarctica or mass graves in Bosnia? Orbital outposts are keeping watch. The challenge these days is finding something that doesn't involve satellites in one way or other. And satellites are just one perk of the Space Age. Farther afield, robotic space probes have examined all the planets except Pluto, leading to a revolution in the Earth sciences -- from studies of plate tectonics to models of global warming -- now that scientists can compare our world to its planetary siblings. Over 300 people from 26 countries have gone into space, including the 24 astronauts who went on or near the Moon. Who knows how many will go in the next hundred years? In short, space travel has become a part of our lives. But what goes on behind the scenes? It turns out that satellites and spaceships depend on some of the most basic concepts of physics. So space travel isn't just fun to think about; it is a firm grounding in many of the principles that govern our world and our universe. -
Positioning: Drift Orbit and Station Acquisition
Orbits Supplement GEOSTATIONARY ORBIT PERTURBATIONS INFLUENCE OF ASPHERICITY OF THE EARTH: The gravitational potential of the Earth is no longer µ/r, but varies with longitude. A tangential acceleration is created, depending on the longitudinal location of the satellite, with four points of stable equilibrium: two stable equilibrium points (L 75° E, 105° W) two unstable equilibrium points ( 15° W, 162° E) This tangential acceleration causes a drift of the satellite longitude. Longitudinal drift d'/dt in terms of the longitude about a point of stable equilibrium expresses as: (d/dt)2 - k cos 2 = constant Orbits Supplement GEO PERTURBATIONS (CONT'D) INFLUENCE OF EARTH ASPHERICITY VARIATION IN THE LONGITUDINAL ACCELERATION OF A GEOSTATIONARY SATELLITE: Orbits Supplement GEO PERTURBATIONS (CONT'D) INFLUENCE OF SUN & MOON ATTRACTION Gravitational attraction by the sun and moon causes the satellite orbital inclination to change with time. The evolution of the inclination vector is mainly a combination of variations: period 13.66 days with 0.0035° amplitude period 182.65 days with 0.023° amplitude long term drift The long term drift is given by: -4 dix/dt = H = (-3.6 sin M) 10 ° /day -4 diy/dt = K = (23.4 +.2.7 cos M) 10 °/day where M is the moon ascending node longitude: M = 12.111 -0.052954 T (T: days from 1/1/1950) 2 2 2 2 cos d = H / (H + K ); i/t = (H + K ) Depending on time within the 18 year period of M d varies from 81.1° to 98.9° i/t varies from 0.75°/year to 0.95°/year Orbits Supplement GEO PERTURBATIONS (CONT'D) INFLUENCE OF SUN RADIATION PRESSURE Due to sun radiation pressure, eccentricity arises: EFFECT OF NON-ZERO ECCENTRICITY L = difference between longitude of geostationary satellite and geosynchronous satellite (24 hour period orbit with e0) With non-zero eccentricity the satellite track undergoes a periodic motion about the subsatellite point at perigee. -
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. -
A Decade of Growth
A publication of The Orbital Debris Program Office NASA Johnson Space Center Houston, Texas 77058 October 2000 Volume 5, Issue 4. NEWS A Decade of Growth P. Anz-Meador and Globalstar commercial communication of the population. For example, consider the This article will examine changes in the spacecraft constellations, respectively. Given peak between 840-850 km (Figure 1’s peak low Earth orbit (LEO) environment over the the uncertain future of the Iridium constellation, “B”). This volume is populated by the period 1990-2000. Two US Space Surveillance the spike between 770 and 780 km may change Commonwealth of Independent State’s Tselina- Network (SSN) catalogs form the basis of our drastically or even disappear over the next 2 spacecraft constellation, several US Defense comparison. Included are all unclassified several years. Less prominent is the Orbcomm Meteorological Support Program (DMSP) cataloged and uncataloged objects in both data commercial constellation, with a primary spacecraft, and their associated rocket bodies sets, but objects whose epoch times are “older” concentration between 810 and 820 km altitude and debris. While the region is traversed by than 30 days were excluded from further (peak “A” in Figure 1). Smaller series of many other space objects, including debris, consideration. Moreover, the components of satellites may also result in local enhancements these satellites and rocket boosters are in near the Mir orbital station are 3.0E-08 circular orbits. Thus, any “collectivized” into one group of spacecraft whose object so as not to depict a orbits are tightly January 1990 plethora of independently- 2.5E-08 maintained are capable of orbiting objects at Mir’s A January 2000 producing a spike similar altitude; the International B to that observed with the Space Station (ISS) is 2.0E-08 commercial constellations. -
Sun-Synchronous Satellites
Topic: Sun-synchronous Satellites Course: Remote Sensing and GIS (CC-11) M.A. Geography (Sem.-3) By Dr. Md. Nazim Professor, Department of Geography Patna College, Patna University Lecture-3 Concept: Orbits and their Types: Any object that moves around the Earth has an orbit. An orbit is the path that a satellite follows as it revolves round the Earth. The plane in which a satellite always moves is called the orbital plane and the time taken for completing one orbit is called orbital period. Orbit is defined by the following three factors: 1. Shape of the orbit, which can be either circular or elliptical depending upon the eccentricity that gives the shape of the orbit, 2. Altitude of the orbit which remains constant for a circular orbit but changes continuously for an elliptical orbit, and 3. Angle that an orbital plane makes with the equator. Depending upon the angle between the orbital plane and equator, orbits can be categorised into three types - equatorial, inclined and polar orbits. Different orbits serve different purposes. Each has its own advantages and disadvantages. There are several types of orbits: 1. Polar 2. Sunsynchronous and 3. Geosynchronous Field of View (FOV) is the total view angle of the camera, which defines the swath. When a satellite revolves around the Earth, the sensor observes a certain portion of the Earth’s surface. Swath or swath width is the area (strip of land of Earth surface) which a sensor observes during its orbital motion. Swaths vary from one sensor to another but are generally higher for space borne sensors (ranging between tens and hundreds of kilometers wide) in comparison to airborne sensors. -
Analysis of Space Elevator Technology
Analysis of Space Elevator Technology SPRING 2014, ASEN 5053 FINAL PROJECT TYSON SPARKS Contents Figures .......................................................................................................................................................................... 1 Tables ............................................................................................................................................................................ 1 Analysis of Space Elevator Technology ........................................................................................................................ 2 Nomenclature ................................................................................................................................................................ 2 I. Introduction and Theory ....................................................................................................................................... 2 A. Modern Elevator Concept ................................................................................................................................. 2 B. Climber Concept ............................................................................................................................................... 3 C. Base Station Concept ........................................................................................................................................ 4 D. Space Elevator Astrodynamics ........................................................................................................................ -
A Delta-V Map of the Known Main Belt Asteroids
Acta Astronautica 146 (2018) 73–82 Contents lists available at ScienceDirect Acta Astronautica journal homepage: www.elsevier.com/locate/actaastro A Delta-V map of the known Main Belt Asteroids Anthony Taylor *, Jonathan C. McDowell, Martin Elvis Harvard-Smithsonian Center for Astrophysics, 60 Garden St., Cambridge, MA, USA ARTICLE INFO ABSTRACT Keywords: With the lowered costs of rocket technology and the commercialization of the space industry, asteroid mining is Asteroid mining becoming both feasible and potentially profitable. Although the first targets for mining will be the most accessible Main belt near Earth objects (NEOs), the Main Belt contains 106 times more material by mass. The large scale expansion of NEO this new asteroid mining industry is contingent on being able to rendezvous with Main Belt asteroids (MBAs), and Delta-v so on the velocity change required of mining spacecraft (delta-v). This paper develops two different flight burn Shoemaker-Helin schemes, both starting from Low Earth Orbit (LEO) and ending with a successful MBA rendezvous. These methods are then applied to the 700,000 asteroids in the Minor Planet Center (MPC) database with well-determined orbits to find low delta-v mining targets among the MBAs. There are 3986 potential MBA targets with a delta- v < 8kmsÀ1, but the distribution is steep and reduces to just 4 with delta-v < 7kms-1. The two burn methods are compared and the orbital parameters of low delta-v MBAs are explored. 1. Introduction [2]. A running tabulation of the accessibility of NEOs is maintained on- line by Lance Benner3 and identifies 65 NEOs with delta-v< 4:5kms-1.A For decades, asteroid mining and exploration has been largely dis- separate database based on intensive numerical trajectory calculations is missed as infeasible and unprofitable. -
Orbital Mechanics Joe Spier, K6WAO – AMSAT Director for Education ARRL 100Th Centennial Educational Forum 1 History
Orbital Mechanics Joe Spier, K6WAO – AMSAT Director for Education ARRL 100th Centennial Educational Forum 1 History Astrology » Pseudoscience based on several systems of divination based on the premise that there is a relationship between astronomical phenomena and events in the human world. » Many cultures have attached importance to astronomical events, and the Indians, Chinese, and Mayans developed elaborate systems for predicting terrestrial events from celestial observations. » In the West, astrology most often consists of a system of horoscopes purporting to explain aspects of a person's personality and predict future events in their life based on the positions of the sun, moon, and other celestial objects at the time of their birth. » The majority of professional astrologers rely on such systems. 2 History Astronomy » Astronomy is a natural science which is the study of celestial objects (such as stars, galaxies, planets, moons, and nebulae), the physics, chemistry, and evolution of such objects, and phenomena that originate outside the atmosphere of Earth, including supernovae explosions, gamma ray bursts, and cosmic microwave background radiation. » Astronomy is one of the oldest sciences. » Prehistoric cultures have left astronomical artifacts such as the Egyptian monuments and Nubian monuments, and early civilizations such as the Babylonians, Greeks, Chinese, Indians, Iranians and Maya performed methodical observations of the night sky. » The invention of the telescope was required before astronomy was able to develop into a modern science. » Historically, astronomy has included disciplines as diverse as astrometry, celestial navigation, observational astronomy and the making of calendars, but professional astronomy is nowadays often considered to be synonymous with astrophysics. -
Arxiv:2004.00037V2 [Astro-Ph.EP] 26 May 2020
Draft version May 27, 2020 Typeset using LATEX twocolumn style in AASTeX62 Giant Planet Influence on the Collective Gravity of a Primordial Scattered Disk Alexander Zderic1 and Ann-Marie Madigan1 1JILA and Department of Astrophysical and Planetary Sciences, CU Boulder, Boulder, CO 80309, USA ABSTRACT Axisymmetric disks of high eccentricity, low mass bodies on near-Keplerian orbits are unstable to an out-of-plane buckling. This \inclination instability" exponentially grows the orbital inclinations, raises perihelion distances and clusters in argument of perihelion. Here we examine the instability in a massive primordial scattered disk including the orbit-averaged gravitational influence of the giant planets. We show that differential apsidal precession induced by the giant planets will suppress the inclination instability unless the primordial mass is & 20 Earth masses. We also show that the instability should produce a \perihelion gap" at semi-major axes of hundreds of AU, as the orbits of the remnant population are more likely to have extremely large perihelion distances (O(100 AU)) than intermediate values. Keywords: celestial mechanics { Outer Solar System: secular dynamics 1. INTRODUCTION In Madigan et al.(2018) we explained the mechanism Structures formed by the collective gravity of numer- behind the instability: secular torques acting between ous low-mass bodies are well-studied on many astrophys- the high eccentricity orbits. We also showed how the ical scales, for example, stellar bar formation in galaxies instability timescale scaled as a function of disk param- (Sellwood & Wilkinson 1993) and apsidally-aligned disks eters. One important result is that the growth timescale of stars orbiting supermassive black holes (Kazandjian & is sensitive to the number of bodies used in N-body Touma 2013; Madigan et al. -
Evolution of the Eccentricity and Orbital Inclination Caused by Planet-Disc Interactions Jean Teyssandier
Evolution of the eccentricity and orbital inclination caused by planet-disc interactions Jean Teyssandier To cite this version: Jean Teyssandier. Evolution of the eccentricity and orbital inclination caused by planet-disc interac- tions. Galactic Astrophysics [astro-ph.GA]. Université Pierre et Marie Curie - Paris VI, 2014. English. NNT : 2014PA066205. tel-01081966 HAL Id: tel-01081966 https://tel.archives-ouvertes.fr/tel-01081966 Submitted on 12 Nov 2014 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. THÈSE DE DOCTORAT DE L’UNIVERSITÉ PIERRE ET MARIE CURIE Spécialité : Physique École doctorale : ASTRONOMIE ET ASTROPHYSIQUE D’ÎLE-DE-FRANCE réalisée à l’Institut d’Astrophysique de Paris présentée par Jean TEYSSANDIER pour obtenir le grade de : DOCTEUR DE L’UNIVERSITÉ PIERRE ET MARIE CURIE Sujet de la thèse : Évolution de l’excentricité et de l’inclinaison orbitale due aux interactions planètes-disque soutenue le 16 Septembre 2014 devant le jury composé de : Bruno Sicardy Président Carl Murray Rapporteur Sean Raymond Rapporteur Alessandro Morbidelli Examinateur Clément Baruteau Examinateur Caroline Terquem Directrice de thèse Une mathématique bleue Dans cette mer jamais étale D’où nous remonte peu à peu Cette mémoire des étoiles Léo Ferré, La mémoire et la mer 2 Remerciements Mes remerciements vont tout d’abord à Caroline, pour avoir accepté de diriger cette thèse. -
Chapter 11 Satellite Orbits
CHAPTER 11 SATELLITE ORBITS 11.1 Orbital Mechanics Newton's laws of motion provide the basis for the orbital mechanics. Newton's three laws are briefly (a) the law of inertia which states that a body at rest remains at rest and a body in motion remains in motion unless acted upon by a force, (b) force equals the rate of change of momentum for a body, and (c) the law of equal but opposite forces. For a two body system comprising of the earth and a much smaller object such as a satellite, the motion of the body in the central gravitational field can be written → → dv / dt = -GM r / r3 → where v is the velocity of the body in its orbit, G is the universal gravitational constant (6.67 x 10**11 N m**2/kg**2), M is the mass of the earth, and r is position vector from the centre of mass of the system (assumed to be at the centre of the earth). The radial part of this equation has the more explicit form m d2r/dt2 - mrω2 = -GMm/r2 where ω is the angular velocity and m is the satellite mass. The second term on the left side of the equation is often referred to as the centrifugal force The total energy of the body in its orbit is a constant and is given by the sum of the kinetic and potential energies E = 1/2 m [(dr/dt)2 + r2ω2] - mMG/r . The angular momentum is also conserved so that L = mωr2 , which allows us to rewrite the energy E = 1/2 m (dr/dt)2 + L2/(2mr2) - mMG/r .