Antique books in the Vatican Library are being digitized to make the contents more accessible and preserve them for future generations, using the Flexible Image Transport System (FITS) format developed by the European Space Agency (ESA).

Stemming from radio astronomy, the open-source FITS is now used to store data from many space missions. The format also lends itself to the fragile, ancient tomes in the Vatican’s collection. Pressed against a plate of glass, the old pages can be distorted, but scanner software developed for the project automatically calculates the different angles, resulting in an accurate, flat image.

The secret of the format is that the instructions needed to read and process the data are in a text header tacked on top of the data. In a century, when computers will presumably be very different, that means all the information needed to decode them is in the same files. FITS can always be read without the need for conversion to another format, which could lose information or be incompatible with future systems, ESA experts say.

Founded in 1475 and one of the world’s oldest libraries, the Vatican Library houses tens of thousands of manuscripts and codices from before the invention of the printing press — some are 1800 years old.