The DPDD currently lists times such as midpointTAI as simply "time" and "double", without specifying how that time is represented (e.g. MJD or nanoseconds-since-epoch, etc). A convention for representing times should be added to the DPDD.

RFC-648 is related but does not specifically address user-facing science tables.

If we also need to add barycentric times, this would be a good opportunity to do so.