Some texture maps and 3d models come originally from NASA, but may have been modified since retrieval. Guidelines for NASA images and models are available at http://www.nasa.gov/audience/formedia/features/MP_Photo_Guidelines.html and at http://www.jpl.nasa.gov/imagepolicy/
Some texture maps come from the USGS astrogeology website, for more info see: http://astrogeology.usgs.gov
In general, attribution is given in a file in the same directory as the models.
Open Orbit is distributed under the GPLv3 or later licence. The full license text is available in the “licences” directory. Some files of the code may be available in other licenses as well, in such a case this will be mentioned in this file. For example, the modified BSD license has been applied on certain utility libraries (dynamic arrays, hashtables, linked lists et.c.) not relating directly to the actual simulation code.
You should assume that all source code is licensed according to the GPL unless otherwise explicitly stated otherwise. Exception are given on a file by file basis.
This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.
This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
You should have received a copy of the GNU General Public License along with this program. If not, see http://www.gnu.org/licenses/.