"lookback" Options

[MiniTES]

So, now that the shouting and the explosions are over, let's look back and examine:
What exactly have we learned about comets or cometary interiors that we did not know before Deep Impact, other than at least one of them is mantled in thick dust?

And just why did Deep Impact have its event on July 4? It sounds to me like something that Dan the man Goldin would have directed the mission to be built around, just for better PR.

[edstrick]

The hour of day of the encounter was timed for optimum visibility from two deep space network stations, to prevent non-zero probability simultaneous loss of a DSN station and loss of the flyby spacecraft due to a dust clump impact from causing loss-of-mission.

Regarding why July 4, it's primarily because of the requirement that the intercept be essentially in the ecliptic. I have *NEVER* seen a statement in the general PR and briefing materials of the exact range of arrival date/times that was in fact available to the mission once they had a nominal launch. It may have been July 3 to July 5 but not much more, and maybe only part of those days, especially Jul 3.