This is a special rule for Mission T4 of the Tantive IV campaign.

If a small or large Rebel ship overlaps an asteroid, reveal and remove the charge token assigned to it from the play area. If it is a dud charge token, there is no effect. If it is an active charge token, the asteroid is also removed and the Imperial player rolls three attack dice. The overlapping ship suffers all damage [*] and critical damage [o] rolled.

Couple of questions:

1) does this rule initiate when the rebel manoeuvre template overlaps the asteroid or only when the rebel ship overlaps the asteroid?

2) does this rule initiate in addition to, or instead of the 'Moving into and through Obstacles' rule.

i.e.

When a rebel ship overlaps the asteroid does it:

- initiate the 'Moving into and through Obstacles' rule

- execute the manoeuvre as normal, but skip the 'Perform Action' step

- the player rolls one attack die. The ship then suffers any damage or critical damage rolled

- then initiate the 'Probing the Field' rule

- If a small or large Rebel ship overlaps an asteroid, reveal and remove the charge token assigned to it from the play area. If it is a dud charge token, there is no effect. If it is an active charge token, the asteroid is also removed and the Imperial player rolls three attack dice. The overlapping ship suffers all damage [*] and critical damage [o] rolled.

Or,

- does it only risk suffering damage from the 'Probing the Field' rule

- the 'Moving into and through Obstacles' rule is ignored

Interesting question. I am going to give my personal interpretation since there is really no specific guidance. In essence this seems to be a way for Rebels to check out which asteroids pose a threat to the mission.

1) I'd say this rule would come into play even if it is only only the template that overlaps the asteroid. A cursory flyby should give you enough info to determine if it was a dud. Normal obstacle rules would apply here (no action, roll for damage).

2) I'm going to go with "in addition to". Landing on the rock is perilous in itself, so roll for damage and lose action as normal. If it's a dud, you're still stuck with no attack. But if the charge detonates and you survive, there will not be a combat restriction since the rock has been removed.

Again, this is only my opinion, but it seems to fit with the scenario rules.

1) An overlap occurs when the template or base final position overlaps an asteroid. Unless the mission rule says you get to change it, template and base would count for an overlap. It is really hard to line up a base landing on a rock so the template gives you some leeway when trying to examine the asteroid with a fly over.

2) In addition too, unless the rule tells you it is replacing or you can ignore another rule for the scenario.

P.S. I don't have the Tantive rules insert with the mission so I can't advise on it completely. I am only going by the overlap rules as they have been defined.

Sergovan's right on 1), I have changed my original answer.