[douglas]

Ship ID cannot be changed by any means, including retrofitting. If you retrofit your opener and closer to switch each to the other design, they will keep the same ID's and a repeat of the simultaneous close/open exercise would then work.

I'm not completely sure, but I think this is how the timing of star destruction orders works: every time a ship gets to move (each day in the movement days chart in the FAQ for its speed), it will execute as many orders as possible, ending only when the next order requires spending a movement point and it's already spent one that day or it has executed a maximum number of orders already that day (21, I think). I don't think star destruction spends a movement point, so it will be executed as soon as it reaches the top of the list. If it is already the first order in the queue at the beginning of the turn, then it will be executed when the ship gets its first move, following the usual execution order by ship ID. Thus, if an enemy fleet moves on the same day as your star destroyer and includes a ship with a lower ID than the star destroyer's, that fleet will be able to warp back out before the star explodes (assuming it's already on a warp point). If your star destroyer has the lower ID, however, the fleet will just have to sit there and get blown to bits by the shockwave.