Dynamique du vol


The CNES reference tool for numerical propagation!

PSIMU is a tool allowing to propagate trajectories around the Earth. These trajectories may be elliptical ones (all kind of orbits, from LEO to GEO passing through MEO or HEO), hyperbolic ones or atmospheric ones (in particular in case of debris reentries).

PSIMU is usable via three modes:

  • GUI : its utilization is made user-friendly thanks to a graphical user interface (developed using GENIUS and GENOPUS) facilitating context elaboration and results exploitation,
  • Batch using a context file (in XML format),
  • Library via its Java interface. This mode allows to use it inside higher level tools (orbit restitution, maneuvers computation …).

Its initialization is made by:

  • The initial orbital parameters definition (epoch, frame, coordinates) with a great number of available options.
  • The vehicle modelling:
    • Different vehicle shapes (sphere, cylinder and parallelepiped) with or without solar panels,
    • Dimensions or surfaces,
    • Aerodynamic characteristics and/or radiative pressure ones,
    • Propulsive characteristics (engines, tanks).
  • A maneuver sequence (optional) including impulsive maneuvers and/or continuous ones
  • A sequence of attitude laws (optional) ; indeed, if PSIMU does not manage 6 DOF motion, it owns as input data, attitude laws depending on orbital events, allowing to know at every moment the vehicle attitude and thus, to deduce from it the forces applied to the vehicle.
  • Numerical integrator parametrization (Runge Kutta or Dormand Price) with, for usual applications, by default settings.
  • Choice of force models within:
    • Potential with several models available as the possibility to manage degree and order of zonal and tesseral terms,
    • Other bodies attraction as Moon or Sun via analytical or numerical ephemeris,
    • Atmospheric forces using different atmospheric models and their associated settings,
    • Solar radiative pressure (direct or rediffused one)
    • Oceanic and terrestrial tides.

PSIMU also allows to set its output data within several tens of variables, the output frame and, of course, the output step. A graphical interface for plots is also integrated.

Versions available on this site only start at V11.4.1. To get older ones, do not hesitate to contact us.





Programming language

Java ≥ 1.8 since V11.4 (Java ≥ 1.7 else)

Operating system

Windows, Linux


Attached documents

Release note

Documentation Information

PSIMU has its own Wiki (including tutorials) at the following adress: http://psimu.cnes.fr

Click to choose software version
contact image

A question about PSIMU?

Do not hesitate to contact us! We are here to help you.


Stay connected

Receive the latest software news of PSIMU