discs

These 100 mm (3.9 in) in diameter and 1 mm (0.039 in) thick discs are made of industrial sapphire. At 9.0 on the Mohs hardness scale, sapphire is one of the hardest known materials, (compare with diamonds, a 10 on the Mohs scale). Sapphire can withstand the extreme temperatures of the lunar surface and remain unaltered over time. The information is physically micro-engraved without coding. The legibility of the engraved data is therefore not dependent upon future technological innovations.

The difficulty with storing information on digital devices like hard drives, CDs, DVDs or USB keys is that the data must be deciphered by complex and fragile devices. The Sanctuary discs will contain minuscule pixels from 1 to 1.4 microns per pixel. The advantage of our method is that all of the information contained on the discs will be readable with the naked eye or by using a simple magnifying glass. Furthermore, the pixels aren't made of pigments, which can fade over time in extreme temperatures. Because they're physically etched into one of the hardest materials we know they will last for millions of years.

Each disc is a combination of two 0.5 mm thick discs. One is filled with a thin layer of titanium nitride and is then fine etched by laser. The parts of the discs are then chemically bond together. It takes weeks for each disc to be engraved, and the final result is then compared to the original design files for error matching.