“Maybe someday all of NASA’s tweets will be safely stored on magnetic tape, and SpaceX’s first reusable rocket landing video will be preserved in HD.”

First of all, magnetic tape does not exactly “safely” store things; it degrades over time. And it’s very naïve to think that even without the near-certainty of data degradation, digital media will preserve things as well as the typewriter and film did. Digital formats as well as the physical media they’re written on tend to become obsolete rather quickly. A huge amount of information and history from the early digital age has already been lost this way.

And we can be sure that things are worse today than when the NY Times 1990 article “Lost on Earth: Wealth of Data Found in Space” was written:

Even tapes in good condition may be missing the documents needed to decode them. Others are so old that computer experts no longer understand how they were programmed. Still others can be processed only on machinery so outdated that little of the necessary hardware remains.

Two years ago, for example, Eric Eliason of the United States Geological Survey learned that more than 3,000 images from the Viking mission to Mars, obtained in the late 1970’s, had never been processed from the master data record, the unprocessed data transmitted from the spacecraft.

After tracking down the data, Mr. Eliason looked up the NASA documents that described how theywere entered. ”It was written in technical jargon,” he said. ”Maybe it was clear to the person who wrote it but it was not clear to me 20 years later.”

There were copies of some old computer programs used to turn the raw data into pictures, he said, but the source codes the computer needed to run the programs could not be found and the computers themselves no longer existed.

http://www.nytimes.com/1990/03/20/science/lost-on-earth-wealth-of-data-found-in-space.html