All images converted and resized with http://www.aconvert.com/image/

sun.dds (https://www.solarsystemscope.com/Textures)
earth.dds (https://www.solarsystemscope.com/Textures)
moon.dds (https://www.solarsystemscope.com/Textures)
wood_texture.dds cropped (http://www.commentnation.com/backgrounds/pages/wood_page1.htm)
bricks_diffuse.dds
bricks_specular.dds generated with GIMP plugin InsaneBump from bricks_diffuse.dds (http://registry.gimp.org/node/28638)
metal_texture.dds converted (http://www.publicdomainpictures.net/view-image.php?image=60465&picture=&jazyk=DE)
skybox Yokohama converted (http://www.humus.name/index.php?page=Textures&start=0)