19.1 Attitude Determination and Control Systems Scott R. Starin
Total Page:16
File Type:pdf, Size:1020Kb
Load more
Recommended publications
-
Juno Telecommunications
The cover The cover is an artist’s conception of Juno in orbit around Jupiter.1 The photovoltaic panels are extended and pointed within a few degrees of the Sun while the high-gain antenna is pointed at the Earth. 1 The picture is titled Juno Mission to Jupiter. See http://www.jpl.nasa.gov/spaceimages/details.php?id=PIA13087 for the cover art and an accompanying mission overview. DESCANSO Design and Performance Summary Series Article 16 Juno Telecommunications Ryan Mukai David Hansen Anthony Mittskus Jim Taylor Monika Danos Jet Propulsion Laboratory California Institute of Technology Pasadena, California National Aeronautics and Space Administration Jet Propulsion Laboratory California Institute of Technology Pasadena, California October 2012 This research was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise, does not constitute or imply endorsement by the United States Government or the Jet Propulsion Laboratory, California Institute of Technology. Copyright 2012 California Institute of Technology. Government sponsorship acknowledged. DESCANSO DESIGN AND PERFORMANCE SUMMARY SERIES Issued by the Deep Space Communications and Navigation Systems Center of Excellence Jet Propulsion Laboratory California Institute of Technology Joseph H. Yuen, Editor-in-Chief Published Articles in This Series Article 1—“Mars Global -
THE ATTITUDE CONTROL and DETERMINATION SYSTEMS of the SAS-A Satellite
THE ATTITUDE CONTROL and DETERMINATION SYSTEMS of the SAS-A SATElliTE F. F. Mobley, A high-speed wheel inside the satellite provides the basic attitude sta B. E. Tossman, bilization for SAS-A. Wobbling of the spin axis is removed by an G. H. Fountain ultra-sensitive nutation damper which uses a copper vane pendulum on a taut-band suspension to dissipate energy by eddy-currents. The spin axis can be oriented anywhere in space as required for the X-ray ex periment by a magnetic control system operated by commands from the ground station at Quito, Ecuador. Magnetic torquing is also used to maintain the satellite spin rate at 1/ 12 revolution per minute. These systems are outgrowths of APL developments for previous satellites, chosen for simplicity and maximum expectation of satisfactory performance in orbit. The in-orbit performance has been essentially flawless. Introduction HE ATTITUDE CONTROL SYSTEM is used to a simple and reliable open-loop system, using orient SAS-A so that the X-ray detectors can commands from the ground. This is very appealing Tscan the regions of the celestial sphere in an or since the weight and power limitations on the derly and efficient manner to detect and measure SAS-A satellite do not permit an elaborate closed new X-ray sources. The two X-ray collimators loop control system. are mounted perpendicular to the satellite spin In addition to detecting and analyzing new (Z) axis. As the satellite rotates slowly about its X-ray sources, the experimenter is interested in Z axis, the detectors scan a 5-degree-wide great correlating X-ray sources with known visible stars, circle path in the celestial sphere. -
Phys 140A Lecture 8–Elastic Strain, Compliance, and Stiffness
Lecture 8 Elastic strains, compliance, and stiffness Review for exam Stress: force applied to a unit area Strain: deformation resulting from stress Purpose of today’s derivations: Generalize Hooke’s law to a 3D body that may be subjected to any arbitrary force. We imagine 3 orthogonal vectors 풙̂, 풚̂, 풛̂ embedded in a solid before we have deformed it. After we have deformed the solid, these vectors might be of different length and they might be pointing in different directions. We describe these deformed vectors 풙′, 풚′, 풛′ in the following way: ′ 풙 = (1 + 휖푥푥)풙̂ + 휖푥푦풚̂ + 휖푥푧풛̂ ′ 풚 = 휖푦푥풙̂ + (1 + 휖푦푦)풚̂ + 휖푦푧풛̂ ′ 풛 = 휖푧푥풙̂ + 휖푧푦풚̂ + (1 + 휖푧푧)풛̂ The components 휖훼훽 define the deformation. They are dimensionless and have values much smaller than 1 in most instances in solid state physics. How one ‘reads’ these vectors is (for example) 휖푥푥force along x, deformation along x; 휖푥푦shear xy-plane along x or y direction (depending which unit vector it is next to) The new axes have new lengths given by (for example): ′ ′ 2 2 2 풙 ∙ 풙 = 1 + 2휖푥푥 + 휖푥푥 + 휖푥푦 + 휖푥푧 Usually we are dealing with tiny deformations so 2nd order terms are often dropped. Deformation also changes the volume of a solid. Considering our unit cube, originally it had a volume of 1. After distortion, it has volume 1 + 휖푥푥 휖푥푦 휖푥푧 ′ ′ ′ ′ 푉 = 풙 ∙ 풚 × 풛 = | 휖푦푥 1 + 휖푦푦 휖푦푧 | ≈ 1 + 휖푥푥 + 휖푦푦 + 휖푧푧 휖푧푥 휖푧푦 1 + 휖푧푧 Dilation (훿) is given by: 푉 − 푉′ 훿 ≡ ≅ 휖 + 휖 + 휖 푉 푥푥 푦푦 푧푧 (2nd order terms have been dropped because we are working in a regime of small distortion which is almost always the appropriate one for solid state physics. -
Juno Spacecraft Description
Juno Spacecraft Description By Bill Kurth 2012-06-01 Juno Spacecraft (ID=JNO) Description The majority of the text in this file was extracted from the Juno Mission Plan Document, S. Stephens, 29 March 2012. [JPL D-35556] Overview For most Juno experiments, data were collected by instruments on the spacecraft then relayed via the orbiter telemetry system to stations of the NASA Deep Space Network (DSN). Radio Science required the DSN for its data acquisition on the ground. The following sections provide an overview, first of the orbiter, then the science instruments, and finally the DSN ground system. Juno launched on 5 August 2011. The spacecraft uses a deltaV-EGA trajectory consisting of a two-part deep space maneuver on 30 August and 14 September 2012 followed by an Earth gravity assist on 9 October 2013 at an altitude of 559 km. Jupiter arrival is on 5 July 2016 using two 53.5-day capture orbits prior to commencing operations for a 1.3-(Earth) year-long prime mission comprising 32 high inclination, high eccentricity orbits of Jupiter. The orbit is polar (90 degree inclination) with a periapsis altitude of 4200-8000 km and a semi-major axis of 23.4 RJ (Jovian radius) giving an orbital period of 13.965 days. The primary science is acquired for approximately 6 hours centered on each periapsis although fields and particles data are acquired at low rates for the remaining apoapsis portion of each orbit. Juno is a spin-stabilized spacecraft equipped for 8 diverse science investigations plus a camera included for education and public outreach. -
Beam Element Stiffness Matrices
Beam Element Stiffness Matrices CEE 421L. Matrix Structural Analysis Department of Civil and Environmental Engineering Duke University Henri P. Gavin Fall, 2014 Truss elements carry only axial forces. Beam elements carry shear forces and bending moments. Frame elements carry shear forces, bending moments, and axial forces. This document presents the development of beam element stiffness matrices in local coordinates. 1 A simply supported beam carrying end-moments Consider a simply supported beam resisting moments M1 and M2 applied at its ends. The flexibility relates the end rotations {θ1, θ2} to the end moments {M1,M2}: θ1 F11 F12 M1 = . θ2 F21 F22 M2 The flexibility coefficients, Fij, may be obtained from Castigliano’s 2nd Theo- ∗ rem, θi = ∂U (Mi)/∂Mi. First Column Second Column 2 CEE 421L. Matrix Structural Analysis – Duke University – Fall 2014 – H.P. Gavin The applied moments M1 and M2 are in equilibrium with the reactions forces V1 and V2; V1 = (M1 + M2)/L and V2 = −(M1 + M2)/L M + M x ! x V (x) = 1 2 M(x) = M − 1 + M L 1 L 2 L The total potential energy of a beam with these forces and moments is: 1Z L M 2 1Z L V 2 U = dx + dx 2 0 EI 2 0 G(A/α) By Castigliano’s Theorem, ∂U θ1 = ∂M1 ∂M(x) ∂V (x) Z L M(x) Z L V (x) = ∂M1 dx + ∂M1 dx 0 EI 0 G(A/α) x 2 x x Z L Z L Z L Z L L − 1 dx αdx L L − 1 dx αdx = + M1 + + M2 0 EI 0 GAL2 0 EI 0 GAL2 and ∂U θ2 = ∂M2 ∂M(x) ∂V (x) Z L M(x) Z L V (x) = ∂M2 dx + ∂M2 dx 0 EI 0 G(A/α) x x x 2 Z L Z L Z L Z L L L − 1 dx αdx L dx αdx = + M1 + + M2 0 EI 0 GAL2 0 EI 0 GAL2 -
+ New Horizons
Media Contacts NASA Headquarters Policy/Program Management Dwayne Brown New Horizons Nuclear Safety (202) 358-1726 [email protected] The Johns Hopkins University Mission Management Applied Physics Laboratory Spacecraft Operations Michael Buckley (240) 228-7536 or (443) 778-7536 [email protected] Southwest Research Institute Principal Investigator Institution Maria Martinez (210) 522-3305 [email protected] NASA Kennedy Space Center Launch Operations George Diller (321) 867-2468 [email protected] Lockheed Martin Space Systems Launch Vehicle Julie Andrews (321) 853-1567 [email protected] International Launch Services Launch Vehicle Fran Slimmer (571) 633-7462 [email protected] NEW HORIZONS Table of Contents Media Services Information ................................................................................................ 2 Quick Facts .............................................................................................................................. 3 Pluto at a Glance ...................................................................................................................... 5 Why Pluto and the Kuiper Belt? The Science of New Horizons ............................... 7 NASA’s New Frontiers Program ........................................................................................14 The Spacecraft ........................................................................................................................15 Science Payload ...............................................................................................................16 -
Introduction to Stiffness Analysis Stiffness Analysis Procedure
Introduction to Stiffness Analysis displacements. The number of unknowns in the stiffness method of The stiffness method of analysis is analysis is known as the degree of the basis of all commercial kinematic indeterminacy, which structural analysis programs. refers to the number of node/joint Focus of this chapter will be displacements that are unknown development of stiffness equations and are needed to describe the that only take into account bending displaced shape of the structure. deformations, i.e., ignore axial One major advantage of the member, a.k.a. slope-deflection stiffness method of analysis is that method. the kinematic degrees of freedom In the stiffness method of analysis, are well-defined. we write equilibrium equations in 1 2 terms of unknown joint (node) Definitions and Terminology Stiffness Analysis Procedure Positive Sign Convention: Counterclockwise moments and The steps to be followed in rotations along with transverse forces and displacements in the performing a stiffness analysis can positive y-axis direction. be summarized as: 1. Determine the needed displace- Fixed-End Forces: Forces at the “fixed” supports of the kinema- ment unknowns at the nodes/ tically determinate structure. joints and label them d1, d2, …, d in sequence where n = the Member-End Forces: Calculated n forces at the end of each element/ number of displacement member resulting from the unknowns or degrees of applied loading and deformation freedom. of the structure. 3 4 1 2. Modify the structure such that it fixed-end forces are vectorially is kinematically determinate or added at the nodes/joints to restrained, i.e., the identified produce the equivalent fixed-end displacements in step 1 all structure forces, which are equal zero. -
Cubesat Attitude Control System Based on Embedded Magnetorquers in Photovoltaic Panels Mario Castro Santiago Junio De 2018
Trabajo Fin de Grado en F´ısica Cubesat Attitude Control System based on embedded magnetorquers in photovoltaic panels Mario Castro Santiago Junio de 2018 Tutor: Andres´ Mar´ıa Roldan´ Aranda Departamento de Electr´onicay Tecnolog´ıade Computadores Universidad de Granada Abstract The use of magnetic actuation in order to stabilize and control a small 1U Cubesat is studied and analyzed, as a required step for the devel- opment of the future university satellite GranaSAT-I. This thesis gather crucial theoretical contents concerning the attitude control of a satellite in an orbit below 500 km, where the International Space Station is able to deploy nano-satellites. Moreover, these contents have been imple- mented in a MATLAB simulator. One stabilizing control law has been succesfully tested with this tool, and two different control algorithms have shown partial success when a 3-axis control has been required. In parallel, an autonomous Cubesat prototype has been manufactured in the GranaSAT Laboratory. The stabilizing algorithm has been imple- mented on the onboard computer. Telemetry data during tests reflect an adequate performance of the prototype. Resumen Se estudia el uso de actuadores magneticos´ con el objetivo de estabi- lizar y controlar un pequeno˜ Cubesat 1U, como paso necesario para el desarrollo futuro satelite´ universitario GranaSAT-I. Esta tesis recaba contenidos teoricos´ fundamentales respecto al control de orientacion´ de un satelite´ en una orbita´ por debajo de 500 km, donde la Estacion´ Espacial Internacional es capaz de lanzar nano-satelites.´ Ademas,´ esta teor´ıa ha sido implementada en un simulador en MATLAB. Con esta herramienta, se ha probado con exito´ un algoritmo de estabilizacion,´ y dos algoritmos de control han mostrado un exito´ parcial cuando un control en los tres ejes ha sido necesario. -
Space Sector Brochure
SPACE SPACE REVOLUTIONIZING THE WAY TO SPACE SPACECRAFT TECHNOLOGIES PROPULSION Moog provides components and subsystems for cold gas, chemical, and electric Moog is a proven leader in components, subsystems, and systems propulsion and designs, develops, and manufactures complete chemical propulsion for spacecraft of all sizes, from smallsats to GEO spacecraft. systems, including tanks, to accelerate the spacecraft for orbit-insertion, station Moog has been successfully providing spacecraft controls, in- keeping, or attitude control. Moog makes thrusters from <1N to 500N to support the space propulsion, and major subsystems for science, military, propulsion requirements for small to large spacecraft. and commercial operations for more than 60 years. AVIONICS Moog is a proven provider of high performance and reliable space-rated avionics hardware and software for command and data handling, power distribution, payload processing, memory, GPS receivers, motor controllers, and onboard computing. POWER SYSTEMS Moog leverages its proven spacecraft avionics and high-power control systems to supply hardware for telemetry, as well as solar array and battery power management and switching. Applications include bus line power to valves, motors, torque rods, and other end effectors. Moog has developed products for Power Management and Distribution (PMAD) Systems, such as high power DC converters, switching, and power stabilization. MECHANISMS Moog has produced spacecraft motion control products for more than 50 years, dating back to the historic Apollo and Pioneer programs. Today, we offer rotary, linear, and specialized mechanisms for spacecraft motion control needs. Moog is a world-class manufacturer of solar array drives, propulsion positioning gimbals, electric propulsion gimbals, antenna positioner mechanisms, docking and release mechanisms, and specialty payload positioners. -
Skylab Attitude and Pointing Control System
I' NASA TECHNICAL NOTE SKYLAB ATTITUDE AND POINTING CONTROL SYSTEM by W. B. Chzlbb and S. M. Seltzer George C. Marshall Space Flight Center Marshall Space Flight Center, Ala. 35812 NATIONAL AERONAUTICS AND SPACE ADMINISTRATION WASHINGTON, 0. C. FEBRUARY 1971 I I TECH LIBRARY KAFB, NM .. -, - ___.. 0132813 I. REPORT NO. 2. GOVERNMNT ACCESSION NO. j. KtLIPlbNl'b LAIALOb NO. - NASA- __ TN D-6068 I I 1 1. TITLE AND SUBTITLE 5. REPORT DATE L February 1971 Skylab Attitude and Pointing Control System 6. PERFORMING ORGANIZATION CODE __- I 7. AUTHOR(S) 8. PERFORMlNG ORGANlZATlON REPORT # - W... -B. Chubb and S. M. Seltzer I 3. PERFORMING ORGANIZATION NAME AND ADDRESS 10. WORK UNIT NO. 908 52 10 0000 M211 965 21 00 0000 George C. Marshall Space Flight Center I' 1. CONTRACT OR GRANT NO. Marshall Space Flight Center, Alabama 35812 L 13. TYPE OF REPORY & PERIOD COVERED - _-- .. .- __ 2. SPONSORING AGENCY NAME AN0 ADORES5 National Aeronautics and Space Administration Technical Note Washington, D. C. 20546 14. SPONSORING AGENCY CODE -. - - I 5. SUPPLEMENTARY NOTES Prepared by: Astrionics Laboratory Science and Engineering Directorate ~- 6. ABSTRACT NASA's Marshall Space Flight Center is developing an earth-orbiting manned space station called Skylab. The purpose of Skylab is to perform scientific experiments in solar astronomy and earth resources and to study biophysical and physical properties in a zero gravity environment. The attitude and pointing control system requirements are dictated by onboard experiments. These requirements and the resulting attitude and pointing control system are presented. 18 .- 0 1 STR inUT I ONSmTEMeNT Space station Control moment gyro Unclassified - Unlimited Attitude control -~ 9. -
1 the New Horizons Spacecraft Glen H. Fountain, David Y
The New Horizons Spacecraft Glen H. Fountain, David Y. Kusnierkiewicz, Christopher B. Hersman, Timothy S. Herder, Thomas B Coughlin, William T. Gibson, Deborah A. Clancy, Christopher C. DeBoy, T. Adrian Hill, James D. Kinnison, Douglas S. Mehoke, Geffrey K. Ottman, Gabe D. Rogers, S. Alan Stern, James M. Stratton, Steven R. Vernon, Stephen P. Williams Abstract The New Horizons spacecraft was launched on January 19, 2006. The spacecraft was designed to provide a platform for the seven instruments designated by the science team to collect and return data from Pluto in 2015 that would meet the requirements established by the National Aeronautics and Space Administration (NASA) Announcement of Opportunity AO-OSS-01. The design drew on heritage from previous missions developed at The Johns Hopkins University Applied Physics Laboratory (APL) and other NASA missions such as Ulysses. The trajectory design imposed constraints on mass and structural strength to meet the high launch acceleration consistent with meeting the AO requirement of returning data prior to the year 2020. The spacecraft subsystems were designed to meet tight resource allocations (mass and power) yet provide the necessary control and data handling finesse to support data collection and return when the one way light time during the Pluto fly-by is 4.5 hours. Missions to the outer regions of the solar system (where the solar irradiance is 1/1000 of the level near the Earth) require a Radioisotope Thermoelectric Generator (RTG) to supply electrical power. One RTG was available for use by New Horizons. To accommodate this constraint, the spacecraft electronics were designed to operate on less than 200 W. -
The Non-Gravitational Accelerations of the Cassini Spacecraft
THE NON-GRAVITATIONAL ACCELERATIONS OF THE CASSINI SPACECRAFT Mauro Di Benedetto (1), Luciano Iess (1), Duane C. Roth(2), [email protected] [email protected] [email protected] (1) Dipartimento di Ingegneria Aerospaziale e Astronautica, Università di Roma “Sapienza”, Italy (2) Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA ABSTRACT Accurate orbit determination of interplanetary spacecraft requires good knowledge of non- gravitational accelerations. Unfortunately, design and ground tests do not provide enough information for accurate modeling. Indeed, effects such as solar torque induced thruster firings and variations of thermo-optical coefficients, controlling solar radiation pressure, cannot be predicted very accurately and require an in-flight estimation. The accuracy of such determination relies on good quality radio-metric data. Cassini, a large planetary mission devoted to the study of Saturn and its satellites, is endowed with a unique radio system, enabling highly stable, coherent radio links to ground in X- and Ka-band. The leading Cassini non-gravitational accelerations are due to solar pressure and anisotropic thermal emission from the three on-board radioisotope thermoelectric generators (RTGs). With an initial area-to-mass ratio of about 0.0023 m2 kg-1, the effect of the solar radiation pressure decreased below that of the RTGs at about 2.7 AU. At the distance of the first radio science cruise experiment (6.65 AU) it was about 5×10-13 km s-2, approximately 1/6 of the acceleration due to the RTGs. The separation of the two sources of non-gravitational accelerations is complicated by the use of thrusters to control the spacecraft attitude.