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Astrodynamic Standards Software

The following is a list of the Astrodynamic Standards software that can be requested. It includes a brief description of the software and information that allows you to discern which packages will fulfill your government project needs. It is important to correctly identify the software needed. For help determining the software algorithms you will need, please contact: Astrodynamic Standard Manager

Abbreviations used in this section:
ASTAT - Association STATus
JSpOC - Joint Space Operations Center
TLE - Two Line Element set
VCM - Vector Covariance Message


SGP4 - (Simplified General Perturbations #4) Is an analytic method based on a general perturbation theory for generating ephemerides for satellites in earth-centered orbits.  It is the proper means for correctly propagating a JSpOC TLE.  This algorithm is non-Export Controlled.  All other algorithms are Export Controlled.

SP and SPEPH - (Special Perturbations or Special Perturbations EPHemeris) Is a high accuracy special perturbations theory which uses numerical integration to calculate ephemerides for satellites in earth-centered orbits.  It is the proper means for correctly propagating a JSpOC VCM.

IDL (Interface Development Library) Non-Export Controlled Software

SP NuPro is a compiled library, which is not export controlled and does not give operationally useful results from the propagator inside.  However, it can be requested and used by developers to establish the SP library interface and does not require special permission to acquire.  Developers can test and develop applications using SP NuPro, then replace the NuPro library with SP’s whenever release of SP is granted.  That is, if NuPro works, then SP will.  This is especially useful for commercial vendors who want to provide application calls to the SP library, but don’t want to encounter the associated export control issues.  Instead, qualified application users can request the software directly from Headquarters, Air Force Space Command, and upon inclusion of the library, SP is used in the application.


AOF - (Area Over Flight) - AOF computes when overhead satellites have potential visibility to a geographic location or area on the surface of the earth.  Visibility is defined as a nominal FOV (user specified angle half-angle) around the satellite's subpoint intersecting the defined points or areas on the surface.  Supported geometries include either a point, a circular area about a point, or a regular trapezoidal area based on two geodetic coordinates.  The satellite's input orbit description may be either a SGP4 TLE or a SP VCM.

BAM – (Breakup Analysis Model) This program assists in determining the time and location of a satellite breakup. 

BATCHDC - (Batch Differential Correction) Performs a least squares batch differential correction of orbital elements using tracking data (sensor observations).  It will properly update either SGP4 keplerian elements (JSpOC TLE) or SP state vectors (JSpOC VCM) using the appropriate propagator theory.  

COCO -  (Computation of Coplaner Orbits) This program compares one elset against other elsets to find coplanar orbits.

COMBO - (Computation of Miss Between Orbits) Computes close approaches between satellite orbits based on user specified criteria. The input orbit descriptions may be either a SGP4 TLE, a SP VCM, or an externally generated ephemeris file.  In COMBO V7 probability of collision is calculated when SP VCMs are input.

ElComp – (Element Set Comparisons) This program compares specified primary element sets against a set of secondary element sets accounting for nodal-crossing time differences.

FOV - (Field-of-View) FOV determines times in which orbiting satellites fly through a ground based observer’s conical field of view.  The field of view can be defined by a constant azimuth and elevation boresight, a constant right ascension and declination boresight, or as a line-of-site to an orbiting satellite. The input orbit descriptions may be either a SGP4 TLE, a SP VCM, or an externally generated ephemeris file.        

GELCON – (Generalized Element Conversion) 

IOMOD - (Initial Orbit Generation) Computes an initial set of orbital elements (JSpOC TLE) from three sensor observations. 

LAMOD - (Look Angle Module) Computes sensor (ground based or space based) viewing opportunities (i.e., “look angles”) for earth centered satellites.  The input orbit description may be either a SGP4 TLE, a SP VCM, or an externally generated ephemeris file.

LAMOD SP Tasker has the following special features:

·         Treats observation types V and P as observation  type 9

·         Provides the ability to generate a customized format for observation types P and V (7 decimal digits)

This package includes a Windows 32bit executable, SGI 32bit executable and a LINUX 32/64 bit tar file. 

ROTAS - (Report/Observation Association) Associates sensor observations against satellite element sets using the same algorithms used by the JSpOC.  It correctly determines the appropriate ASTAT association status category (0, 1, 2, 3).  The input orbit description may be either a SGP4 TLE, a SP VCM, or an externally generated ephemeris file.

SAAS (Satellite Attack Assessment Program)  This program determines possible direct ascent windows. A zenith centered outreach cone is erected about a lat/lon point and geometries of satellite penetrations of the cone are examined. 

SEQDC - Sequential Differential Correction performs a series of least-squares differential corrections (DC). These differential corrections are computed in a sequential mode, which uses one or more observations or tracks while retrieving former covariance information from a prior DC. SEQDC uses either the SGP4 or SP theory for ephemeris calculation.

UTILITIES (Non-Export Controlled):

AS Utilities Package is made up of several DLLs/SOs that are Non-Export Controlled and can be obtained without authorization from AFSPC.  This package is required by the Export Control Software, so should be requested in conjunction with any request for Export Control software.  The package includes the following:

·         DllMain: Host DLL that allows all DLLs/SOs in the SAAL to communicate to each other.

·         EnvConst: Allows the users to set geopotential constants/FK models.

·         TimeFunc: Provides the users with methods to convert between different date time group strings to the internal days since 1950 UTC. It also allows the users to load timing constants data from a file so that the data can be used in other AS software.

·         AstroFunc: Provides the users with methods to convert between different types of orbital elements, coordinate frames, and many other Astrodynamic quantities.

·         TLE: Allows the users to load/delete/update/parse two-line element sets.

·         SPVEC: Allows the users to load/delete/update/parse SP osculating vectors.

·         VCM: Allows the users to load/delete/update/parse VCMs.

·         OBS: Allows the users to load/delete/update/parse observations.

·         Sensor: Allows the user to load/delete/update sensors.

·         ExtEphem: Allows the user to use their own ephemeris data as a substitute for data propagated by the  SGP4/SP propagators. It can load external ephemerides from many supported file formats (ASCII and/or BINARY). It uses its own interpolator to interpolate ephemeris to the desired time.

·         SatState: Returns satellite state by utilizing SGP4/SP/ExtEphem DLLs/SOs. This DLL/SO facilitates the use of the propagators and/or external ephemeris in the AS software.

·         ElOps:  Provides users with methods to calculate orbital parameters.


ISSA-AV -  Integrated Space Situation Awareness – Analyst Version is a government owned and government developed software product. It is based on the Space Common Operating Picture and Exploitation System (SCOPES), which was created in November 2003 by the Space Innovation and Development Center to support the Single Integrated Space Picture (SISP) initiative. 

ISSA can be used for creating specific scenarios and performing analyses, using either real world data or by importing exercise/wargame databases into the program. ISSA supports exercises, experiments, and wargames by using game-specific databases and associated space order of battle data files.

Tools in ISSA include Satellite Reconnaissance Advance Notice, satellite overflight, pass scheduling, navigation accuracy, and solar conjunction. Analysis functions include space and missile launch modeling, nodal analysis, and satellite filtering. Object editing can be performed in ISSA, including satellite and constellation creation, moving objects, and modification of space and ground sensors. Finally, ISSA can model offensive and defensive counter-space (OCS/DCS): including directed energy (DE) attacks, direct ascent anti-satellite (ASAT) attacks, satellite orbital attacks, conjunction analysis, exclusion zones, and co-planar orbit approaches. Blue, Gray, and Red systems are modeled in ISSA, including space and ground orders of battle. Futuristic systems and engagement scenarios can also be modeled. In particular, ISSA can quantify the impacts of actions taken on operational effectiveness.

ISSA 5.0 received DoDIIS certification to operate on JWICS on 18 Apr 2008.

SATRAK - (Satellite Trajectory and Attitude Kinetics) SATRAK V7 replaces the legacy DOS-based SATRAK V6 with a modern and richly interactive user interface suited for current Windows operating systems.  SATRAK allows analysts to generate SGP4 ephemeris, use LAMOD to determine satellite viewing opportunities, and analyze JSpOC TLE datasets.  The results may be displayed on 2D and 3D maps/views, as plain text listings, and/or as tabular data.  There is advanced sorting, filtering, and grouping capabilities for the tabular input and output data. Graphics options include the display of sensor coverage, color coding of various display elements, and various other enhancements/features that aid analysis.

In addition, some additional specialized functionality is also included:

·         SimOrb - Create a TLE from launch related data (launch time, launch location, azimuth or inclination, period or altitude).

·         Decay - Estimate when one or more satellites will decay using the King-Hele algorithm (TLE & solar flux inputs).

·         BLUE - Update a nominal launch folder TLE to a "on-orbit" TLE based on launch time.

·         MANAL - Given pre- and post- maneuver orbit descriptions (TLE), analyze a maneuver's parameters.

 SATRAK v7 received AF approval to operate on NIPRNet and SIPRNet on 29 April 2013.

SAINT - Space Analysis INtegration Tool is a toolkit that will integrate various DLLs/SOs in the SAAL and other analysis functions and algorithms into a single application.  SAINT provides the development environment and building blocks to put together quick turn space analysis tools. Visualization tools will be available for the analyst to display algorithm/function output into X-Y plots.  Data can be exported into standard formats such as XML and Excel.2D and 3D visualization tools have been added to view satellite propagation and sensor look angles. 

SAINT also provides a .Net API for working with the SAAL Fortran DLLs/SOs for integration with any other .Net application. 

Space Brawler - Space Brawler is a baseline, version control model of space operations that provides a standard point of departure, which can rapidly be modified or tailored for quick turn studies with a focus on space.   It is used in conjunction with the System Effectiveness Analysis Simulation (SEAS), V3.9 or higher.   Using SEAS alone without Space Brawler required doing extensive research, manually coding parameters for each satellite, and modeling the Command and Control (C2) structure from scratch.  Additional effort would be required to carefully construct the simulation to model space effects to the warfighter before one could investigate how the contribution of these space assets could be impaired by orbit degradation, maneuver, jamming, C2 constraints, Anti Satellites (ASATs) or a host of other threats to the orbital asset that the analyst may choose to investigate. The starting Space Brawler configuration contains a simple representation of normal peacetime operations. Satellite operations centers receive perception updates with rates and accuracies statistically matching that provided by the current Space Surveillance Network. By tracking the orbits of objects and monitoring the health of Space Vehicles, the Space Operations Centers (SOCs) decide how to command their satellites and how to request satellite control network resources to upload the commands. Operations that are currently automatically modeled in Space Brawler include Station Keeping (orbit maintenance), Collision Avoidance (COLA), and basic Defensive Counter Space (DCS) maneuvering which is designed to maintain a minimum separation distance between objects. All of the commands are scheduled for upload over the associated Satellite control network based on antenna status, visibility, and availability. 

Almost all functions in Space Brawler are based on these perceived states rather than truth.  Space Brawler represents four different and important states for a satellite:

1.       Its goal state (the orbit that it is trying maintain through station keeping)

2.       Its true state as a result of perturbations

3.       The state it is perceived to be in by the US (referred to as blue perception)

4.       The state foreign actors perceive the satellite to be in (red perception).

These values are calculated by one of two methods. The first method is to use the Space Brawler internal statistical perception engine, called SEAS SSA Modeling. The second method uses an external SSN modeling tool called the Maneuver Detection and Recovery Tool (MDR), MDR has separate representation of the Space Surveillance Network that is modeled to a high degree of fidelity outside of SEAS and Space Brawler. At this stage of development, the tools are loosely integrated, data is exchange between the tools via temporary text files. An analyst requiring high fidelity starting perception can use MDR to drive perception orbits in Space Brawler but currently performance limitations makes full catalog modeling with MDR prohibitive. MDR is most commonly used only for high interest objects.

Standardized Astrodynamic Standards Library - Program File Types

The following formats are provided:

The core library consists of Dynamic Link Library (DLL) files (MS Windows operating systems) or Shared Object (so) files (Linux/Unix operating systems). These programs cannot be run standalone. A separate driver program is required to access the algorithm. An example driver program (including source and build file) is included in all deliveries of this type.

Space Brawler V2.0.1, ISSA-AV and SATRAK 7.X are only available as standalone executable programs. Space Brawler requires you to request SEAS from SMC/XR. SATRAK V7 is available in an install package format. It relies on a .msi (Windows Install file) to install the software and modify the Windows registry.  It is approved to operate on Air Force Networks (see Air Force Enterprise Product List).