Data engineering for archive evolution

From the moment astronomical observations are made the resulting data products begin to grow stale. Even if perfect binary copies are preserved through repeated timely migration to more robust storage media, data standards evolve and new tools are created that require different kinds of data or metadata. The expectations of the astronomical community change even if the data do not. We discuss data engineering to mitigate the ensuing risks with examples from a recent project to refactor seven million archival images to new standards of nomenclature, metadata, format, and compression.