The Solar Wobble Or Gravity, Rosettes and Inertia [email protected] Http:Blackholeformulas.Com February 10, 2015
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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 -
Optimisation of Propellant Consumption for Power Limited Rockets
Delft University of Technology Faculty Electrical Engineering, Mathematics and Computer Science Delft Institute of Applied Mathematics Optimisation of Propellant Consumption for Power Limited Rockets. What Role do Power Limited Rockets have in Future Spaceflight Missions? (Dutch title: Optimaliseren van brandstofverbruik voor vermogen gelimiteerde raketten. De rol van deze raketten in toekomstige ruimtevlucht missies. ) A thesis submitted to the Delft Institute of Applied Mathematics as part to obtain the degree of BACHELOR OF SCIENCE in APPLIED MATHEMATICS by NATHALIE OUDHOF Delft, the Netherlands December 2017 Copyright c 2017 by Nathalie Oudhof. All rights reserved. BSc thesis APPLIED MATHEMATICS \ Optimisation of Propellant Consumption for Power Limited Rockets What Role do Power Limite Rockets have in Future Spaceflight Missions?" (Dutch title: \Optimaliseren van brandstofverbruik voor vermogen gelimiteerde raketten De rol van deze raketten in toekomstige ruimtevlucht missies.)" NATHALIE OUDHOF Delft University of Technology Supervisor Dr. P.M. Visser Other members of the committee Dr.ir. W.G.M. Groenevelt Drs. E.M. van Elderen 21 December, 2017 Delft Abstract In this thesis we look at the most cost-effective trajectory for power limited rockets, i.e. the trajectory which costs the least amount of propellant. First some background information as well as the differences between thrust limited and power limited rockets will be discussed. Then the optimal trajectory for thrust limited rockets, the Hohmann Transfer Orbit, will be explained. Using Optimal Control Theory, the optimal trajectory for power limited rockets can be found. Three trajectories will be discussed: Low Earth Orbit to Geostationary Earth Orbit, Earth to Mars and Earth to Saturn. After this we compare the propellant use of the thrust limited rockets for these trajectories with the power limited rockets. -
Flight and Orbital Mechanics
Flight and Orbital Mechanics Lecture slides Challenge the future 1 Flight and Orbital Mechanics AE2-104, lecture hours 21-24: Interplanetary flight Ron Noomen October 25, 2012 AE2104 Flight and Orbital Mechanics 1 | Example: Galileo VEEGA trajectory Questions: • what is the purpose of this mission? • what propulsion technique(s) are used? • why this Venus- Earth-Earth sequence? • …. [NASA, 2010] AE2104 Flight and Orbital Mechanics 2 | Overview • Solar System • Hohmann transfer orbits • Synodic period • Launch, arrival dates • Fast transfer orbits • Round trip travel times • Gravity Assists AE2104 Flight and Orbital Mechanics 3 | Learning goals The student should be able to: • describe and explain the concept of an interplanetary transfer, including that of patched conics; • compute the main parameters of a Hohmann transfer between arbitrary planets (including the required ΔV); • compute the main parameters of a fast transfer between arbitrary planets (including the required ΔV); • derive the equation for the synodic period of an arbitrary pair of planets, and compute its numerical value; • derive the equations for launch and arrival epochs, for a Hohmann transfer between arbitrary planets; • derive the equations for the length of the main mission phases of a round trip mission, using Hohmann transfers; and • describe the mechanics of a Gravity Assist, and compute the changes in velocity and energy. Lecture material: • these slides (incl. footnotes) AE2104 Flight and Orbital Mechanics 4 | Introduction The Solar System (not to scale): [Aerospace -
Spacecraft Trajectories in a Sun, Earth, and Moon Ephemeris Model
SPACECRAFT TRAJECTORIES IN A SUN, EARTH, AND MOON EPHEMERIS MODEL A Project Presented to The Faculty of the Department of Aerospace Engineering San José State University In Partial Fulfillment of the Requirements for the Degree Master of Science in Aerospace Engineering by Romalyn Mirador i ABSTRACT SPACECRAFT TRAJECTORIES IN A SUN, EARTH, AND MOON EPHEMERIS MODEL by Romalyn Mirador This project details the process of building, testing, and comparing a tool to simulate spacecraft trajectories using an ephemeris N-Body model. Different trajectory models and methods of solving are reviewed. Using the Ephemeris positions of the Earth, Moon and Sun, a code for higher-fidelity numerical modeling is built and tested using MATLAB. Resulting trajectories are compared to NASA’s GMAT for accuracy. Results reveal that the N-Body model can be used to find complex trajectories but would need to include other perturbations like gravity harmonics to model more accurate trajectories. i ACKNOWLEDGEMENTS I would like to thank my family and friends for their continuous encouragement and support throughout all these years. A special thank you to my advisor, Dr. Capdevila, and my friend, Dhathri, for mentoring me as I work on this project. The knowledge and guidance from the both of you has helped me tremendously and I appreciate everything you both have done to help me get here. ii Table of Contents List of Symbols ............................................................................................................................... v 1.0 INTRODUCTION -
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. -
GRAVITATION UNIT H.W. ANS KEY Question 1
GRAVITATION UNIT H.W. ANS KEY Question 1. Question 2. Question 3. Question 4. Two stars, each of mass M, form a binary system. The stars orbit about a point a distance R from the center of each star, as shown in the diagram above. The stars themselves each have radius r. Question 55.. What is the force each star exerts on the other? Answer D—In Newton's law of gravitation, the distance used is the distance between the centers of the planets; here that distance is 2R. But the denominator is squared, so (2R)2 = 4R2 in the denominator here. Two stars, each of mass M, form a binary system. The stars orbit about a point a distance R from the center of each star, as shown in the diagram above. The stars themselves each have radius r. Question 65.. In terms of each star's tangential speed v, what is the centripetal acceleration of each star? Answer E—In the centripetal acceleration equation the distance used is the radius of the circular motion. Here, because the planets orbit around a point right in between them, this distance is simply R. Question 76.. A Space Shuttle orbits Earth 300 km above the surface. Why can't the Shuttle orbit 10 km above Earth? (A) The Space Shuttle cannot go fast enough to maintain such an orbit. (B) Kepler's Laws forbid an orbit so close to the surface of the Earth. (C) Because r appears in the denominator of Newton's law of gravitation, the force of gravity is much larger closer to the Earth; this force is too strong to allow such an orbit. -
Effects of Planetesimals' Random Velocity on Tempo
42nd Lunar and Planetary Science Conference (2011) 1154.pdf EFFECTS OF PLANETESIMALS’ RANDOM VELOCITY ON TEMPO- RARY CAPTURE BY A PLANET Ryo Suetsugu1, Keiji Ohtsuki1;2;3, Takayuki Tanigawa2;4. 1Department of Earth and Planetary Sciences, Kobe University, Kobe 657-8501, Japan; 2Center for Planetary Science, Kobe University, Kobe 657-8501, Japan; 3Laboratory for Atmospheric and Space Physics, University of Colorado, Boulder, CO 80309-0392; 4Institute of Low Temperature Science, Hokkaido University, Sapporo 060-0819, Japan Introduction: When planetesimals encounter with a of large orbital eccentricities were not examined in detail. planet, the typical duration of close encounter during Moreover, the above calculations assumed that planetesi- which they pass within or near the planet’s Hill sphere is mals and a planet were initially in the same orbital plane, smaller than or comparable to the planet’s orbital period. and effects of orbital inclination were not studied. However, in some cases, planetesimals are captured by In the present work, we examine temporary capture the planet’s gravity and orbit about the planet for an ex- of planetesimals initially on eccentric and inclined orbits tended period of time, before they escape from the vicin- about the Sun. ity of the planet. This phenomenon is called temporary capture. Temporary capture may play an important role Numerical Method: We examine temporary capture us- in the origin and dynamical evolution of various kinds of ing three-body orbital integration (i.e. the Sun, a planet, a small bodies in the Solar System, such as short-period planetesimal). When the masses of planetesimals and the comets and irregular satellites. -
Session 6:Analytical Approximations for Low Thrust Maneuvers
Session 6: Analytical Approximations for Low Thrust Maneuvers As mentioned in the previous lecture, solving non-Keplerian problems in general requires the use of perturbation methods and many are only solvable through numerical integration. However, there are a few examples of low-thrust space propulsion maneuvers for which we can find approximate analytical expressions. In this lecture, we explore a couple of these maneuvers, both of which are useful because of their precision and practical value: i) climb or descent from a circular orbit with continuous thrust, and ii) in-orbit repositioning, or walking. Spiral Climb/Descent We start by writing the equations of motion in polar coordinates, 2 d2r �dθ � µ − r + = a (1) 2 2 r dt dt r 2 d θ 2 dr dθ aθ + = (2) 2 dt r dt dt r We assume continuous thrust in the angular direction, therefore ar = 0. If the acceleration force along θ is small, then we can safely assume the orbit will remain nearly circular and the semi-major axis will be just slightly different after one orbital period. Of course, small and slightly are vague words. To make the analysis rigorous, we need to be more precise. Let us say that for this approximation to be valid, the angular acceleration has to be much smaller than the corresponding centrifugal or gravitational forces (the last two terms in the LHS of Eq. (1)) and that the radial acceleration (the first term in the LHS in the same equation) is negligible. Given these assumptions, from Eq. (1), dθ r µ d2θ 3 r µ dr ≈ ! ≈ − (3) 3 2 5 dt r dt 2 r dt Substituting into Eq. -
Spacex Rocket Data Satisfies Elementary Hohmann Transfer Formula E-Mail: [email protected] and [email protected]
IOP Physics Education Phys. Educ. 55 P A P ER Phys. Educ. 55 (2020) 025011 (9pp) iopscience.org/ped 2020 SpaceX rocket data satisfies © 2020 IOP Publishing Ltd elementary Hohmann transfer PHEDA7 formula 025011 Michael J Ruiz and James Perkins M J Ruiz and J Perkins Department of Physics and Astronomy, University of North Carolina at Asheville, Asheville, NC 28804, United States of America SpaceX rocket data satisfies elementary Hohmann transfer formula E-mail: [email protected] and [email protected] Printed in the UK Abstract The private company SpaceX regularly launches satellites into geostationary PED orbits. SpaceX posts videos of these flights with telemetry data displaying the time from launch, altitude, and rocket speed in real time. In this paper 10.1088/1361-6552/ab5f4c this telemetry information is used to determine the velocity boost of the rocket as it leaves its circular parking orbit around the Earth to enter a Hohmann transfer orbit, an elliptical orbit on which the spacecraft reaches 1361-6552 a high altitude. A simple derivation is given for the Hohmann transfer velocity boost that introductory students can derive on their own with a little teacher guidance. They can then use the SpaceX telemetry data to verify the Published theoretical results, finding the discrepancy between observation and theory to be 3% or less. The students will love the rocket videos as the launches and 3 transfer burns are very exciting to watch. 2 Introduction Complex 39A at the NASA Kennedy Space Center in Cape Canaveral, Florida. This launch SpaceX is a company that ‘designs, manufactures and launches advanced rockets and spacecraft. -
The Equivalent Expressions Between Escape Velocity and Orbital Velocity
The equivalent expressions between escape velocity and orbital velocity Adrián G. Cornejo Electronics and Communications Engineering from Universidad Iberoamericana, Calle Santa Rosa 719, CP 76138, Col. Santa Mónica, Querétaro, Querétaro, Mexico. E-mail: [email protected] (Received 6 July 2010; accepted 19 September 2010) Abstract In this paper, we derived some equivalent expressions between both, escape velocity and orbital velocity of a body that orbits around of a central force, from which is possible to derive the Newtonian expression for the Kepler’s third law for both, elliptical or circular orbit. In addition, we found that the square of the escape velocity multiplied by the escape radius is equivalent to the square of the orbital velocity multiplied by the orbital diameter. Extending that equivalent expression to the escape velocity of a given black hole, we derive the corresponding analogous equivalent expression. We substituted in such an expression the respective data of each planet in the Solar System case considering the Schwarzschild radius for a central celestial body with a mass like that of the Sun, calculating the speed of light in all the cases, then confirming its applicability. Keywords: Escape velocity, Orbital velocity, Newtonian gravitation, Black hole, Schwarzschild radius. Resumen En este trabajo, derivamos algunas expresiones equivalentes entre la velocidad de escape y la velocidad orbital de un cuerpo que orbita alrededor de una fuerza central, de las cuales se puede derivar la expresión Newtoniana para la tercera ley de Kepler para un cuerpo en órbita elíptica o circular. Además, encontramos que el cuadrado de la velocidad de escape multiplicada por el radio de escape es equivalente al cuadrado de la velocidad orbital multiplicada por el diámetro orbital. -
Journal of Physics Special Topics an Undergraduate Physics Journal
View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by University of Leicester Open Journals Journal of Physics Special Topics An undergraduate physics journal P5 1 Conditions for Lunar-stationary Satellites Clear, H; Evan, D; McGilvray, G; Turner, E Department of Physics and Astronomy, University of Leicester, Leicester, LE1 7RH November 5, 2018 Abstract This paper will explore what size and mass of a Moon-like body would have to be to have a Hill Sphere that would allow for lunar-stationary satellites to exist in a stable orbit. The radius of this body would have to be at least 2500 km, and the mass would have to be at least 2:1 × 1023 kg. Introduction orbital period of 27 days. We can calculate the Geostationary satellites are commonplace orbital radius of the satellite using the following around the Earth. They are useful in provid- equation [3]: ing line of sight over the entire planet, excluding p 3 the polar regions [1]. Due to the Earth's gravi- T = 2π r =GMm; (1) tational influence, lunar-stationary satellites are In equation 1, r is the orbital radius, G is impossible, as the Moon's smaller size means it the gravitational constant, MM is the mass of has a small Hill Sphere [2]. This paper will ex- the Moon, and T is the orbital period. Solving plore how big the Moon would have to be to allow for r gives a radius of around 88000 km. When for lunar-stationary satellites to orbit it. -
SATELLITES ORBIT ELEMENTS : EPHEMERIS, Keplerian ELEMENTS, STATE VECTORS
www.myreaders.info www.myreaders.info Return to Website SATELLITES ORBIT ELEMENTS : EPHEMERIS, Keplerian ELEMENTS, STATE VECTORS RC Chakraborty (Retd), Former Director, DRDO, Delhi & Visiting Professor, JUET, Guna, www.myreaders.info, [email protected], www.myreaders.info/html/orbital_mechanics.html, Revised Dec. 16, 2015 (This is Sec. 5, pp 164 - 192, of Orbital Mechanics - Model & Simulation Software (OM-MSS), Sec 1 to 10, pp 1 - 402.) OM-MSS Page 164 OM-MSS Section - 5 -------------------------------------------------------------------------------------------------------43 www.myreaders.info SATELLITES ORBIT ELEMENTS : EPHEMERIS, Keplerian ELEMENTS, STATE VECTORS Satellite Ephemeris is Expressed either by 'Keplerian elements' or by 'State Vectors', that uniquely identify a specific orbit. A satellite is an object that moves around a larger object. Thousands of Satellites launched into orbit around Earth. First, look into the Preliminaries about 'Satellite Orbit', before moving to Satellite Ephemeris data and conversion utilities of the OM-MSS software. (a) Satellite : An artificial object, intentionally placed into orbit. Thousands of Satellites have been launched into orbit around Earth. A few Satellites called Space Probes have been placed into orbit around Moon, Mercury, Venus, Mars, Jupiter, Saturn, etc. The Motion of a Satellite is a direct consequence of the Gravity of a body (earth), around which the satellite travels without any propulsion. The Moon is the Earth's only natural Satellite, moves around Earth in the same kind of orbit. (b) Earth Gravity and Satellite Motion : As satellite move around Earth, it is pulled in by the gravitational force (centripetal) of the Earth. Contrary to this pull, the rotating motion of satellite around Earth has an associated force (centrifugal) which pushes it away from the Earth.