Blank disks are used to store missions and spacecraft designs. They can be made out of metal or plastic. A spacecraft design is first saved at a design studio, then burned to a disk (which makes the design read-only, and allows it to be used for actual construction), and the disk is either taken straight to the spacecraft factory or sold back to the studio to add it to an empire's libraries.A CD-R (Compact Disc-Recordable) is a variation of the Compact Disc invented by Philips and Sony. CD-R is a Write Once Read Many (WORM) optical medium, although the whole disk does not have to be entirely written in the same session.DVD is an optical disc storage format, invented and developed by Philips, Sony, Toshiba, and Panasonic in 1995. DVDs offer higher storage capacity than Compact Discs while having the same dimensions.