The sound of crickets. Either folks are on vacation - or folks think the decision tree roughly outlined as v0.5 is perfect as it is - or folks think the whole thing is silly. A few comments will hopefully provoke some interest:
I) Existence [Adopt an international (or intergalactic) civil time standard?] A) yes B) no II) Multiplicity [How many standards?] A) one B) many
I suspect that we are all agreed that a single civil time standard should exist. The question of multiplicity is one of drawing narrow distinctions. Many people use devices and systems that rely on non- UTC time scales, for instance, GPS receivers. Is GPS a second civil time standard already?
III) Locale A) restricted to Earth [projects or users, not necessarily hardware] B) other than Earth [e.g., Martian rovers] B) Solar system scope C) truly Universal
Personally, I think each planet is likely to require a separate standard. Traveling between planets - or simply telecommuting like the MER project team - is likely to always require resolving incompatible clocks as per the "Martian jet lag" discussion.
IV) Synchronization [with underlying time standard(s)]
For the moment, I don't want to refocus on the too-familiar issues of Solar Time versus Atomic Time - we all know where we each stand. Rather perhaps we could examine the question of what distinguishes civil time from underlying time standards. I suspect that part of the friction is over who "owns" the definition of UTC. Astronomers are likely to regard this as a flavor of Universal Time and thus equivalent to its own fundamental time standard (over which they are perhaps understandably proprietary). Timekeepers perhaps regard UTC as simply an expedient way to reconcile Universal Time and Atomic Time and therefore as simply a synonym for civil time itself. The fundamental standards in this latter case would be UT1 and TAI. Ignoring issues for the moment of what the "best" standard would be, one might suggest that a possible way to identify a consensus position on a change to civil time would be to relayer it upon a completely different current standard (e.g., GPS) or on a newly defined fundamental standard (e.g., TI), either of which would be carefully chosen to avoid such baggage. UTC, and before it, GMT, have an extremely long history of usage. Removing them completely from the equation might provide both astronomers and timekeepers (only two of the many stakeholding communities, of course) enough common ground to build a new civil time infrastructure. In the absence of a consensus for change, the default decision should remain, of course, to retain the current standard. Rob Seaman National Optical Astronomy Observatory