Comment by vageli
3 years ago
Real thought has indeed been given to interplanetary time (even by the subject of TFA). You may find this of interest:
https://webcache.googleusercontent.com/search?q=cache:pyKjMo... (forgive the cache but a postscript file is more easily viewed this way in the browser).
Few other relevant pointers: https://en.wikipedia.org/wiki/Deep_Space_Atomic_Clock and https://en.wikipedia.org/wiki/Barycentric_Coordinate_Time