BSR/AIAA S-131-200X Draft American National Standard Astrodynamics – Propagation Specifications, Test Cases, and Recommended Practices Warning This document is not an approved AIAA Standard. It is distributed for review and comment. It is subject to change without notice. Recipients of this draft are invited to submit, with their comments, notification of any relevant patent rights of which they are aware and to provide supporting documentation. Sponsored by American Institute of Aeronautics and Astronautics Approved XX Month 200X American National Standards Institute Abstract This document provides the broad astrodynamics and space operations community with technical standards and lays out recommended approaches to ensure compatibility between organizations. Applicable existing standards and accepted documents are leveraged to make a complete—yet coherent—document. These standards are intended to be used as guidance and recommended practices for astrodynamics applications in Earth orbit where interoperability and consistency of results is a priority. For those users who are purely engaged in research activities, these standards can provide an accepted baseline for innovation. BSR/AIAA S-131-200X LIBRARY OF CONGRESS CATALOGING DATA WILL BE ADDED HERE BY AIAA STAFF Published by American Institute of Aeronautics and Astronautics 1801 Alexander Bell Drive, Reston, VA 20191 Copyright © 200X American Institute of Aeronautics and Astronautics All rights reserved No part of this publication may be reproduced in any form, in an electronic retrieval system or otherwise, without prior written permission of the publisher. Printed in the United States of America ii BSR/AIAA S-131-200X Contents Foreword ...................................................................................................................................................................... vii Introduction .................................................................................................................................................................... x 1 Scope ............................................................................................................................................................... 1 2 Tailoring ........................................................................................................................................................... 1 3 Applicable Documents ..................................................................................................................................... 1 4 Vocabulary ....................................................................................................................................................... 1 4.1 Acronyms and Abbreviated Terms ................................................................................................................... 1 4.2 Terms and Definitions ...................................................................................................................................... 5 5 Units, Precision, Time, Constants, Conversions, and Coordinates ................................................................ 18 5.1 Units............................................................................................................................................................... 18 5.1.1 Presentation of Units...................................................................................................................................... 18 5.1.2 Recommended Practice ................................................................................................................................. 19 5.2 Precision, Accuracy, and Uncertainty ............................................................................................................ 19 5.2.1 Expression of Uncertainty .............................................................................................................................. 19 5.2.2 Recommended Practice ................................................................................................................................. 20 5.3 Time Systems ................................................................................................................................................ 20 5.3.1 UTC Leap Seconds ....................................................................................................................................... 22 5.3.2 Presentation of Time ...................................................................................................................................... 23 5.3.3 Earth Orientation Parameter Data ................................................................................................................. 24 5.3.4 Data Sources ................................................................................................................................................. 24 5.3.5 Recommended Practice ................................................................................................................................. 25 5.4 Constants ....................................................................................................................................................... 25 5.4.1 Fundamental Defining Parameters ................................................................................................................ 25 5.4.2 Astronomical Parameters ............................................................................................................................... 25 5.4.3 Recommended Practice ................................................................................................................................. 26 5.5 Coordinate Systems....................................................................................................................................... 26 5.5.1 The International Terrestrial Reference Frame (ITRF) ................................................................................... 26 5.5.2 The International Celestial Reference Frame (ICRF) ..................................................................................... 27 5.5.3 Geocentric Celestial Reference System ........................................................................................................ 28 5.5.4 Implementation of the International Celestial Reference Frame .................................................................... 28 5.5.5 CIP, CIO, and TIO ......................................................................................................................................... 29 5.5.6 Celestial and Terrestrial Frame Transformations ........................................................................................... 29 5.5.7 Origins of Celestial Coordinate Frames ......................................................................................................... 32 5.5.8 Satellite Based Coordinate Frames ............................................................................................................... 33 5.5.9 Recommended Practice ................................................................................................................................. 35 iii BSR/AIAA S-131-200X 6 Force Models ................................................................................................................................................. 36 6.1 Overview ........................................................................................................................................................ 36 6.2 Central Body Gravitational Attraction ............................................................................................................. 38 6.2.1 Earth Gravitational Models ............................................................................................................................. 39 6.3 Atmospheric Drag .......................................................................................................................................... 44 6.3.1 Corrections to Atmospheric Models ............................................................................................................... 45 6.3.2 Specific Details of Atmospheric Drag ............................................................................................................. 46 6.3.3 US Standard 1976 (0–1,000 km) [Static] ....................................................................................................... 49 6.3.4 DTM (200–1,200 km) ..................................................................................................................................... 50 6.3.5 Jacchia Models .............................................................................................................................................. 50 6.3.6 Jacchia-Roberts 1971 .................................................................................................................................... 50 6.3.7 MSIS Models ................................................................................................................................................. 50 6.3.8 MET88/MET 99 .............................................................................................................................................. 51 6.3.9 GRAM 99 (0–2,500 km) ................................................................................................................................. 51 6.3.10 GOST