As of August 2013, the download links for Pax Galaxia on the official Dio Games site have gone down.
Therefore, I have elected to host them on this server.
Please note that I am not affiliated in any way with Dio Games or Diodor Bitan. Diodor Bitan reserves all rights and ownership of Pax Galaxia. Furthermore, these links are for the free, "demo" version only. To purchase the full version, you should consult diogames.com.
You can download the Mac version here.
This version contains the interface mod which is detailed on the customization page. It also fixes a crash that occurs on later Mac OS versions when switching to fullscreen, by using an updated version of the SDL framework.
The Windows version is available here (hosted seperately by Sillysoft).