This repository was imported from NASA's repository on bitbucket.
I've ported it to ROS Melodic (in the branch melodic; the master branch is still where the maintainers left it, other than this readme so it shows up in the default view on github). There were a number of changes in Gazebo which required fixing. A lot of them were related to replacing the Gazebo math library with Ignition Robotics' math library.