ORSA is an interactive tool for scientific grade Celestial Mechanics
computations. Asteroids, comets, artificial satellites, Solar and extra-Solar
planetary systems can be accurately reproduced, simulated, and analyzed.

Features
    * use of JPL ephemeris files for accurate planets positions
    * Qt-based graphical user interface
    * advanced 2D plotting tool and 3D OpenGL viewer
    * import asteroids and comets from all the known databases (MPC, JPL,
      Lowell, AstDyS, and NEODyS)
    * integrated download tool to update databases
    * stand alone numerical library liborsa
    * save and restore session from a single file

WWW: http://orsa.sourceforge.net/