From conda packages (recommended if possible)
The easiest and often best way to install the Orekit Python Wrapper module in Python is to use pre-made packages for the python distribution Anaconda.
Orekit packages is being continously built in the conda-forge system and can then be installed from the Anaconda python distribution:
conda install -c conda-forge orekit
This will install all dependencies (openjdk) and install scripts that sets the necessary path variables (JCC_JDK, PATH) at activation.
Activation of the environment in conda
Note that it is needed to active the conda environment to be used, this activation triggers a script that sets up the right environment variables (JCC_JDK and in some cases PATH). If accessing the python executable directly, for example through an IDE such as PyCharm, the tool conda-wrappers can be used to create executable that runs the activation automatically. The wrapped python executable is then located under Scrips/wrappers/conda/python.bat for windows. Point your IDE to this file as python interpreter:
Screenshot from PyCharm configured with conda-wrappers to automatically activate the environment
Note: In recent versions of anaconda on Windows it seems like there are some issues if the conda is not "init'ed" on the machine. To do this, run "conda init" in the command prompt.
The physical data is not included in the orekit library and needs to be provided. A starting package of data is available from https://gitlab.orekit.org/orekit/orekit-data and can be downloaded from https://www.orekit.org/download.html
The python helper function setup_orekit_curdir() loads such file, default "orekit-data.zip" and sets up orekit to use it (you need to remove the "-master" from the filename if the repo download is used).
Installation from source requires to build a jar of the Orekit library including the python wrapper classes. This jar is then fed to the JCC tool, which builds the actual python wrapper together with some helper files. The process is described in the INSTALL.txt file in the repository.
The git repository for orekit is located at:
The modified orekit source code with the python additions are available at: https://github.com/petrushy/Orekit
The orekit conda package is automatically built and can be of interest if needed to compile it manually: