When you discard a unit/power up cards to activate the ability do you simply put them back on your piles (so you can play them another time) or do you actually remove them from the game?
Answer: You put them back on your pile so that you can play them again unless the card indicates something else.
Can the Astral Eagle ability be played when not being on the same tile and the enemy? So you can use it as a long distance missile?
Answer: It can be played anywhere on board.
When can you play butterfly effect and is it a onetime effect like the other cards?
Answer: You can play this card as a reaction when you draw a card. It is an one time effect
The advanced action cards have cards that give an extra slot for plains, do those stay in game? Or are they just for 1 round.
Answer: They stay in game.
When an event card that tells you to spawn 2 raiders....Do you spawn them on the same sector and do you choose which sector?
Answer: Unless specified otherwise you spawn them anywhere on board.
Can you built a Starbase on the Jumpgate?