TABLE 3.1 Summary of NASA MMOD Models and Their Interdependencies

Model Function/Usage Development Latest Version Models Used Used By
ORDEM (Orbital Debris Engineering Model) User-friendly, semi-empirical environment characterization, for current and short-term future (~30 years), of debris impact flux down to 10 Μm in Earth orbit (LEO and GEO) based on returned samples, remote observations, modeling, historical changes, and trends. Available to the public. Since 1970s, NASA has evolved through several codes; ORDEM96 was released in 1996. ORDEM2000; ORDEM3.0 due out in late 2011/early 2012 SBM Solar Flux GEOPROP PROP3D DAS/BUMPER
MEM (Meteoroid Environment Model) Semi-empirical meteoroid velocity and direction distribution for near-Earth and interplanetary (Mercury to asteroid belt) natural particulates down to 1 Μg to predict flux on spacecraft surfaces. Available to the public. Based on 2000-2004 work at University of Western Ontario. Version 2.0 Lunar MEM2/MEM CXP in 2008 Grün IFM BUMPER
DAS (Debris Assessment Software) Suite of tools (ORDEM, orbit propagators, and ballistic limit equations [BLE]) to assist NASA offices in verifying compliance with NASA STD 8719.14. Used widely inside and outside NASA. Available to the public. NASA developed to accompany NASA standard practices starting in 1995. DAS 2.0.1 2008 ORDEM “BLEs”/SBM None
BUMPER Semi-empirical model to determine the potential for debris and meteoroids to strike and penetrate spacecraft surfaces. Not available for public use. NASA developed and started to apply in mid-1990s. BUMPER II 2005 ORDEM/MEM None
ORSAT (Object Reentry Survival Analysis Tool) Simulates reentry of hardware to determine debris casualty area to calculate the reentry risk to people on Earth. Not available for public use. NASA evolved since 1993 but also used to analyze many non-NASA objects. ORSAT 6.0 2006 None None
LEGEND (LEO-to-GEO Environment Debris) Statistical, three-dimensional, debris evolutionary model for the study of the long-term debris environment for LEO, HEO, and GEO. Provides debris characteristics as functions of time, altitude, longitude, and latitude. Not available for public use. NASA EVOLVE leveraged to create LEGEND in 2003. 2005, but undergoing continual upgrades SBM GEOPROP PROP3D Solar Flux Launch Traffic None
SBM (Standard Breakup Model)a Semi-empirical model that determines the number, mass, velocity, and ballistic coefficient distributions of fragments produced down to 1 mm from a breakup event—collision and explosion. Not available for public use. NASA has been developing SBM since 1970s; used by IADC since 2008. 2001 None ORDEM DAS LEGEND SBRAM

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