An Introduction to ORSA

An Introduction to ORSA Pasquale Tricarico

An Introduction to ORSA

Pasquale Tricarico

Physics Department, Washington State University

Second ESAWorkshop on “Astrodynamics tools and Techniques”, 13-15 September 2004. page 1

mailto:[email protected]


Overview

• ORSA by samples: the graphical application

• ORSA by samples: the numerical library

• ORSA main features

• What can I do with ORSA?

• Incoming features: where is ORSA going?




ORSA by samples: the graphical application

We start showing some pictures, representing the ORSA graphical

application in action. The ORSA graphical application is called xorsa

under Unix/Linux, macorsa under Mac OS X, and winorsa under

Windows.

With the graphical application it is possible to create a physical system,

edit bodies, perform and visualize the numerical integration, and use

other analysis tools.

The working session can be saved on a single file, and after can be

completely restored by just loading the file.




A Meteosat Image. . .




. . . and the ORSA Image (with some low-orbit satellites)




More Weather Satellites




The GPS Constellation




Jupiter Trojans




Sample ORSA session: simulation of a binary system




ORSA by samples: the numerical library

• The core of ORSA is the liborsa numerical library, written using

the C++ programming language; any external application can link to

this library;

• This library defines an API and all the fundamental objects: Units,

Vector, Body, Interaction, Orbit, Integrator, Evolution, Universe;

• This library can use other numerical libraries like GSL, FFTW and

GINAC for more numerical algorithms;

• Initial support for parallel computing, using the MPI interface.



http://sources.redhat.com/gsl/

http://www.fftw.org/

http://www.ginac.de/

http://www-unix.mcs.anl.gov/mpi/


Some ORSA numerical C++ classes and their hierarchy

File

ReadFile

ReadWriteFile

WriteFile

AsteroidDatabaseFile

LocationFile

Mercury5IntegrationFile

MPCObsFile

RadauModIntegrationFile

RWOFile

SWIFTFile

TLEFile

AstDySMatrixFile

AstorbFile

JPLDastcomCometFile

JPLDastcomNumFile

JPLDastcomUnnumFile

MPCCometFile

MPCOrbFile

NEODYSCAT

OrsaConfigFile

OrsaFile

Interaction

ArmonicOscillator

GalacticPotentialAllen

GalacticPotentialAllenPlusNewton

GravitationalTree

JPLPlanetsNewton

Newton

Relativistic

Integrator

FixedTimestepIntegrator

VariableTimestepIntegrator

DissipativeRungeKutta

MultistepIntegrator

RungeKutta

ModifiedMidpoint

Stoer

Radau15

Body

BodyWithEpoch

BodyWithParameter

JPLBody

Orbit OrbitWithEpoch OrbitWithCovarianceMatrixGSL PreliminaryOrbit



$classorsa_1_1File.html

$classorsa_1_1ReadFile.html

$classorsa_1_1ReadWriteFile.html

$classorsa_1_1WriteFile.html

$classorsa_1_1AsteroidDatabaseFile.html

$classorsa_1_1LocationFile.html

$classorsa_1_1Mercury5IntegrationFile.html

$classorsa_1_1MPCObsFile.html

$classorsa_1_1RadauModIntegrationFile.html

$classorsa_1_1RWOFile.html

$classorsa_1_1SWIFTFile.html

$classorsa_1_1TLEFile.html

$classorsa_1_1AstDySMatrixFile.html

$classorsa_1_1AstorbFile.html

$classorsa_1_1JPLDastcomCometFile.html

$classorsa_1_1JPLDastcomNumFile.html

$classorsa_1_1JPLDastcomUnnumFile.html

$classorsa_1_1MPCCometFile.html

$classorsa_1_1MPCOrbFile.html

$classorsa_1_1NEODYSCAT.html

$classorsa_1_1OrsaConfigFile.html

$classorsa_1_1OrsaFile.html

$classorsa_1_1Interaction.html

$classorsa_1_1ArmonicOscillator.html

$classorsa_1_1GalacticPotentialAllen.html

$classorsa_1_1GalacticPotentialAllenPlusNewton.html

$classorsa_1_1GravitationalTree.html

$classorsa_1_1JPLPlanetsNewton.html

$classorsa_1_1Newton.html

$classorsa_1_1Relativistic.html

$classorsa_1_1Integrator.html

$classorsa_1_1FixedTimestepIntegrator.html

$classorsa_1_1VariableTimestepIntegrator.html

$classorsa_1_1DissipativeRungeKutta.html

$classorsa_1_1MultistepIntegrator.html

$classorsa_1_1RungeKutta.html

$classorsa_1_1ModifiedMidpoint.html

$classorsa_1_1Stoer.html

$classorsa_1_1Radau15.html

$classorsa_1_1Body.html

$classorsa_1_1BodyWithEpoch.html

$classorsa_1_1BodyWithParameter.html

$classorsa_1_1JPLBody.html

$classorsa_1_1Orbit.html

$classorsa_1_1OrbitWithEpoch.html

$classorsa_1_1OrbitWithCovarianceMatrixGSL.html

$classorsa_1_1PreliminaryOrbit.html


Sample C++ code: a numerical integration

#include <orsa universe . h>

#include <o r s a f i l e . h>

using namespace orsa ;

int main ( ) {

// Universe constructor : units ( length , mass , time ) , type

new Universe (AU, MSUN, YEAR, Simulated ) ;

// Body constructor : name, mass , posi t ion , v e l o c i t y

Body star ("star", FromUnits ( 1 . 4 , MSUN) , Vector ( 0 , 0 , 0 ) , Vector ( 0 , 0 , 0 ) ) ;Body planet ("planet", FromUnits ( 0 . 8 , MEARTH) , Vector ( 1 , 0 , 0 ) , Vector ( 0 , 6 . 2 , 0 . 1 ) ) ;Frame f ( 0 . 0 ) ; f . push back ( star ) ; f . push back ( planet ) ; // the system at t =0.0

Interaction ∗ i t r = new Newton ;

Integrator ∗ i t g = new Radau15 ; i tg−>accuracy = 1.0e−9; i tg−>timestep = 0 .01 ;

Evolution ∗ evol = new Evolution ; evol−>integrator = i tg ; evol−>in teract ion = i t r ;

evol−>sample period = 0 . 1 ; evol−>push back ( f ) ; universe−>push back ( evol ) ;

evol−>Integrate ( 100 . 0 ) ; // perform numerical integration , 100.0 years

OrsaFile o f ; o f . SetFileName ("sample.of") ; o f . Write ( ) ; o f . Close ( ) ; // save on f i l ereturn 0 ;

}




ORSA Current Main Features

• ORSA can simulate either the Solar System, providing

automatically a coherent environment and all the needed physical

constants, or any other planetary system, i.e. an Extra-Solar

System;

• Numerical library: object-oriented accuracy-minded C++ library,

continuously improving API allows the development of ORSA-based

third party applications, General Relativistic corrections to the

Newton interaction, different numerical integrators;

• Graphical library: fully featured graphical application, based on the

Qt library, with 2D and 3D (OpenGL) rendering windows, object

editing tools in Cartesian and Keplerian coordinates, numerical

integration management, all-in-one-file save and restore of

simulations, export of simulations to ascii tables.



http://www.trolltech.com/products/qt/

http://www.opengl.org/


ORSA Current Main Features (continued)

• Objects import: Solar System planets position from JPL ephemeris

files; asteroids and comets from MPC, JPL, Lowell, AstDyS, and

NEODyS database files; artificial satellites from TLE files;

• Portability: library and applications available for Linux,

Mac OS X andWindows;

• Source code freely available, GPL license.



http://cfa-www.harvard.edu/iau/mpc.html

http://www.jpl.nasa.gov/

http://asteroid.lowell.edu/

http://hamilton.dm.unipi.it/astdys

http://newton.dm.unipi.it/neodys

http://www.gnu.org/copyleft/gpl.html


What can be done using ORSA?

• Solar System dynamics: any object in the Solar System can be

simulated dynamically, using accurate numerical algorithms and the

best available initial conditions for all the known bodies;

• Simulated systems: a generic system can be simulated, using any

units system or interaction, and without constraints on the number

of massive and massless objects;

• Education: ORSA is a scientific grade tool, but can be used for

demonstrations and also as a teaching tool to effectively experiment

the gravitational dynamics;

• 3rd-party applications can use the ORSA numerical library to

perform numerical integrations;

• ORSA is free software so can be freely modified and enhanced to fit

any needs, and the user’s enhancements can be contributed back to

the main ORSA distribution.



http://www.gnu.org/copyleft/gpl.html


ORSA Incoming Features

The list of features we are working on includes:

• orbit determination from astrometic observations, with

determination of the covariance matrix and impact probability;

• natural satellites: organize published data into a database;

• more numerical integration algorithms, some symplectic;

• space probes: thrust scheduling, mission analysis and optimization;

• planetary accretion, objects with variable mass, inelastic impacts

with possible fragmentation;

• Something is still missing? Let us know! Feature requests are

always very welcome, and drive the ORSA development.




Contact us!

We want to hear from you! Feature requests are particularly

important to shape the future releases of ORSA, matching the

developers’ work with the users needs.

ORSA website: http://orsa.sourceforge.net

ORSA author and maintainer: Pasquale Tricarico <[email protected]>

This introduction is based on the ORSA public version 0.6.1 and on the

development version 0.6.1.x, and is available for download on the ORSA

documents page: http://orsa.sourceforge.net/docs.html



http://orsa.sourceforge.net


http://orsa.sourceforge.net/docs.html

An Introduction to ORSA

Documents

Transcript of An Introduction to ORSA