Cluster Missiles - Attach (target lock) spend your target lock and discard this card to perform this attach twice.

Does that mean I perform the attach twice in the same combat phase?

Cluster Missiles - Attach (target lock) spend your target lock and discard this card to perform this attach twice.

Does that mean I perform the attach twice in the same combat phase?

Yes.

You attack once with the cluster missile and after you finish resolving that attack you immediately make the second cluster missile attack against the same target. They are two different attacks although they must target the same thing. This means one shot things that modify one attack aren't always there for the second attack.

Thanks Steven0 that clears things up

I guess I'll also point out that BOTH attacks need to miss to trigger Munitions Failsafe. Some have believed that if just one of the two Cluster Missile attacks misses you get to keep the upgrade card.

Although it almost never happens Cluster Missile also has some strange interactions with Gunner/Luke. If the first attack misses that will trigger Gunner/Luke which allows you to make a Primary Weapon attack. The strange/unusual thing is that taking that attack then means you can not make any more attacks (with that ship) that round which prevents the second Cluster Missile attack from happening. If not used on the first Cluster attack it is possible that Gunner/Luke could trigger on the second attack.