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Suggested Citation:"Appendix B: Acronyms and Glossary." National Research Council. 2012. Continuing Kepler's Quest: Assessing Air Force Space Command's Astrodynamics Standards. Washington, DC: The National Academies Press. doi: 10.17226/13456.
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B

Acronyms and Glossary

AFSPC Air Force Space Command
AIAA American Institute of Aeronautics and Astronautics
AOF Area Overflight—computes when overhead satellites can see a particular location on Earth; uses both SGP4 and SP for generation of ephemerides
ASW astrodynamics support workstation
BATCHDC Batch Differential Correction—performs a least-squares batch differential correction of orbital elements using tracking data and both the SGP4 and the SP propagator
C2 Command and Control
CA conjunction assessment
CAVENet Command, Analysis, Verification and Ephemeris Network
CDD Capability Development Document
CMAFS Cheyenne Mountain Air Force Station
COMBO Computation of Miss Between Orbits—computes close approaches between satellites using both SGP4 and SP for generation of ephemerides
CRD Capstone Requirements Document
CSM conjunction summary message
CTIPe Coupled Thermosphere Ionosphere Plasmasphere Electrodynamics model
DMSP Defense Meteorological Satellite Program
DTM-2000 Drag Temperature Model, released in 2000; empirical model of thermospheric temperature, composition, and density
EKF extended Kalman filter
ephemeris a tabulation of computed positions and velocities (and/or various derived quantities such as right ascension and declination) of an orbiting body at specific times
ESA European Space Agency
Suggested Citation:"Appendix B: Acronyms and Glossary." National Research Council. 2012. Continuing Kepler's Quest: Assessing Air Force Space Command's Astrodynamics Standards. Washington, DC: The National Academies Press. doi: 10.17226/13456.
×
FOV field of view—determines times in which orbiting satellites fly through a ground-based observer’s conical field of view; can be defined by a constant azimuth and elevation, a constant right ascension and declination, or as a line of sight to another satellite; uses both SGP4 and SP for generation of ephemerides
FRD Functional Requirements Document
GEO geostationary orbit
GITM Global Ionosphere-Thermosphere Model
GP general perturbations
GSFC Goddard Space Flight Center
HASDM High Accuracy Satellite Drag Model
HEO highly elliptical orbit
ICD Initial Capabilities Document
IEEE Institute of Electrical and Electronics Engineers
IOMOD astrodynamics algorithm that computes an initial set of orbital elements from three observations
IR infrared
ITAR International Traffic in Arms Regulations
J70 Jacchia 1970 empirical model of thermospheric density
JB2008 Jacchia-Bowman 2008 empirical model of thermospheric density
JCD Joint Capabilities Document
JMS JSpOC Mission System
JSpOC Joint Space Operations Center
LAMOD astrodynamics algorithm that computes sensors’ (ground- or space-based) viewing opportunities (so-called look angles) for Earth-centered satellites; uses both SGP4 and SP for generation of ephemerides
MDA Missile Defense Agency
MHT multiple hypothesis tracking
MIT Massachusetts Institute of Technology
MSIS Mass Spectrometer Incoherent Scatter radar—series of models describing atmospheric temperature, composition, and density
NASA National Aeronautics and Space Administration
NOAA National Oceanic and Atmospheric Administration
NORAD North American Aerospace Defense Command
NRLMSISE-00 Naval Research Laboratory Mass Spectrometer Incoherent Scatter radar Extended—empirical model of atmospheric temperature, composition, and density, released in 2000
NRO National Reconnaissance Office
OCM orbital conjunction message
ROTAS Report/Observation Association—associates observations against satellite element sets
RSO resident space object
Suggested Citation:"Appendix B: Acronyms and Glossary." National Research Council. 2012. Continuing Kepler's Quest: Assessing Air Force Space Command's Astrodynamics Standards. Washington, DC: The National Academies Press. doi: 10.17226/13456.
×
SEQDC Sequential Differential Correction—performs a series of least-squares differential corrections that are computed in a sequential mode, which uses one or more observations or tracks while retrieving former covariance information from a prior differential correction; uses both SGP4 and SP for generation of ephemerides
SGP4 Simplified General Perturbations 4—an analytic method of generating ephemerides for satellites in Earth-centered orbits
SMC Space and Missile Systems Center
SOA service-oriented architecture
SP Special Perturbations—an algorithm that uses numerical integration to generate ephemerides for satellites in Earth-centered orbits
SPADOC Space Defense Operations Center
SPK a type of file that contains ephemeris (trajectory) data
SRP solar radiation pressure
SSA space situational awareness
SSN Space Surveillance Network
TIE-GCM Thermosphere Ionosphere Electrodynamics General Circulation Model
TIME-GCM Thermosphere Ionosphere Mesosphere Electrodynamics General Circulation Model
TLE two-line element
UCT uncorrrelated track
UKF unscented Kalman filter
USAF United States Air Force
WACCM-X Whole Atmosphere Community Climate Model, extended to the exobase
WAM Whole Atmosphere Model
WGS-72 World Geodetic Survey 1972 Earth gravity model
WGS-84 World Geodetic Survey 1984 Earth gravity model
Suggested Citation:"Appendix B: Acronyms and Glossary." National Research Council. 2012. Continuing Kepler's Quest: Assessing Air Force Space Command's Astrodynamics Standards. Washington, DC: The National Academies Press. doi: 10.17226/13456.
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Suggested Citation:"Appendix B: Acronyms and Glossary." National Research Council. 2012. Continuing Kepler's Quest: Assessing Air Force Space Command's Astrodynamics Standards. Washington, DC: The National Academies Press. doi: 10.17226/13456.
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Page 69
Suggested Citation:"Appendix B: Acronyms and Glossary." National Research Council. 2012. Continuing Kepler's Quest: Assessing Air Force Space Command's Astrodynamics Standards. Washington, DC: The National Academies Press. doi: 10.17226/13456.
×
Page 70
Suggested Citation:"Appendix B: Acronyms and Glossary." National Research Council. 2012. Continuing Kepler's Quest: Assessing Air Force Space Command's Astrodynamics Standards. Washington, DC: The National Academies Press. doi: 10.17226/13456.
×
Page 71
Suggested Citation:"Appendix B: Acronyms and Glossary." National Research Council. 2012. Continuing Kepler's Quest: Assessing Air Force Space Command's Astrodynamics Standards. Washington, DC: The National Academies Press. doi: 10.17226/13456.
×
Page 72
Continuing Kepler's Quest: Assessing Air Force Space Command's Astrodynamics Standards Get This Book
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In February 2009, the commercial communications satellite Iridium 33 collided with the Russian military communications satellite Cosmos 2251. The collision, which was not the first recorded between two satellites in orbit--but the most recent and alarming--produced thousands of pieces of debris, only a small percentage of which could be tracked by sensors located around the world. In early 2007, China tested a kinetic anti-satellite weapon against one of its own satellites, which also generated substantial amounts of space debris. These collisions highlighted the importance of maintaining accurate knowledge, and the associated uncertainty, of the orbit of each object in space. These data are needed to predict close approaches of space objects and to compute the probability of collision so that owners/operators can decide whether or not to make a collision avoidance maneuver by a spacecraft with such capability. The space object catalog currently contains more than 20,000 objects, and when the planned space fence radar becomes operational this number is expected to exceed 100,000.

A key task is to determine if objects might come closer to each other, an event known as "conjunction," and the probability that they might collide. The U.S. Air Force is the primary U.S. government organization tasked with maintaining the space object catalog and data on all space objects. This is a complicated task, involving collecting data from a multitude of different sensors-many of which were not specifically designed to track orbiting objects-and fusing the tracking data along with other data, such as data from atmospheric models, to provide predictions of where objects will be in the future.

The Committee for the Assessment of the U.S. Air Force's Astrodynamic Standards collected data and heard from numerous people involved in developing and maintaining the current astrodynamics standards for the Air Force Space Command (AFSPC), as well as representatives of the user community, such as NASA and commercial satellite owners and operators. Preventing collisions of space objects, regardless of their ownership, is in the national security interested of the United States. Continuing Kepler's Quest makes recommendations to the AFSPC in order for it to create and expand research programs, design and develop hardware and software, as well as determine which organizations to work with to achieve its goals.

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