I been looking around and aparently nasa is giving away free models too. this is what they say about using there models.
Still Images, Audio Recordings, Video, and Related Computer Files
NASA still images; audio files; video; and computer files used in the rendition of 3-dimensional models, such as texture maps and polygon data in any format, generally are not copyrighted. You may use NASA imagery, video, audio, and data files used for the rendition of 3-dimensional models for educational or informational purposes, including photo collections, textbooks, public exhibits, computer graphical simulations and Internet Web pages. This general permission extends to personal Web pages.
This general permission does not extend to use of the NASA insignia logo (the blue "meatball" insignia), the retired NASA logotype (the red "worm" logo) and the NASA seal. These images may not be used by persons who are not NASA employees or on products (including Web pages) that are not NASA-sponsored.
NASA should be acknowledged as the source of the material except in cases of advertising. See NASA Advertising Guidelines.
If the NASA material is to be used for commercial purposes, especially including advertisements, it must not explicitly or implicitly convey NASA's endorsement of commercial goods or services. If a NASA image includes an identifiable person, using the image for commercial purposes may infringe that person's right of privacy or publicity, and permission should be obtained from the person. Any questions regarding application of any NASA image or emblem should be directed to:
Photo Department
NASA Headquarters
Go through yourself at a wall.
