This may be a silly question, but this came up last night in my first play through. On the card in question, Death Star Plans, I found the verbage a little vague. Can this card be played in any combat after a space fight, or does the Death Star have to be present to use the card?

It would be more than a little silly for a fighter in a battle at one system to destroy a Death Star in a different system. Most cards played during battle can only affect units in the system of that specific battle.

Last Bullet on page 6

"The “Death Star Plans” card cannot be played if a Death Star is not in the system."

It would be more than a little silly for a fighter in a battle at one system to destroy a Death Star in a different system.

I'm fairly sure he meant playing the card for 2 reputation without destroying any Death Stars at all - that's what the card wording suggests. : ) Not possible, of course, like already mentioned above.