Tortuga as an open source project under the Lesser General Public License, version 2.1 (LGPLv2.1).
Tortuga meets the licensing requirements by providing all source code and binary executables available for download at the primary website listed in the "external links" section below.
As part of its support for simulation, Tortuga employs tools from aspect-oriented programming, or AOP.
This allows the developer to focus on simulation specifics without littering event handler code all over the place.
Tortuga was developed by Fred Kuhl and Richard Weatherly of The MITRE Corporation in 2004-2006 and they continue to maintain it.