Not sure if anyone figured this out, but if I have some attack value "A" and the enemy has def+att+invdef "D", then what is the % chance of invading ? I was looking at viewtopic.php?f=4&t=3449&start=0 , and thinking it might be similar,

CHANCE = (1 - (Total Defense / Your attack))

So, when they are equal, you have 0% chance (if anyone has invaded with attack less than the planet's defenses, this disproves this equation probably, let me know). Attack 2x the planet combined power is 50%. You must have 9.6x ratio or better to get the max of 90% chance, or if the planet has no defenses.

If anyone has their attack value and the planet's combined power, and the % chance when they fail, post it. Might give some clues.

Dan has stated that Attack, Defense, and Invasion Defense all play a part in the defense part of the equation.

Attack is used by the invading player, all the other stats by the defending. 6200 attack and 6000 defense = roughly a 41% chance. Per several battles over some planets last night. I have started an excel sheet in regards to several aspects including this one. More info will allow for better accuracy.

Thanks, that disproves my initial guess. You can invade with less attack than their power based on that (I'm just calling all three elements together "power" for lack of better term). I normally only invade inactives so I don't have to worry about counter invasion much, and so when I fail it's always 90% chance which tells me nothing.

Yes, I suggested the same thing you did, except with attack, defense, and invasion defense, and it was correct for the one case, but it seems that it doesn't go to zero so it can't be that.

EDIT: It wouldn't be 9.6x if that was true anyway, you would need 10x, that way invasion defense/attack = .1, 1 - .1 = .9, so 90% chance. But that equation's wrong anyway.

How do the chances change with an Aegis Shield on it?
I had a dude in my legion steal a planet I was going to invade and he put it on the planet. I'm going to be invading it when I'm able, but I want to know my chances. he has a Aegis shield and 5 structural shields on it. A friendly added a Ion Storm. What would my chances be?

The Aegis Shield just adds defense (five thousand?) so it affects it the same way that amount of defense does.

There is a minimum cap and a maximum cap to Invasion Probability. Outside the formula rules. 90% cap to invading when your attack is astronomical and 10% cap to invading when the defender's attack+defense is astronomical. The formula you mention ([CHANCE = (1 - (Total Defense / Your attack))] ) got shifted a bit to favour the attacker but not with much. 4-5%. Otherwise, as long as your attack as the invader is superior to the defender's total attack+defense the formula is pretty accurate. In the sense that the result of the fraction in the formula needs to be sub-unitary (i.e. smaller than 1).

Also bear in mind that 90%™ for Galaxy Legion isn't equivalent with the basic 90% used in RL. 90%™ is still slim _D

It's not like the cloak formula; when attack = def (as someone mention, "6200 attack and 6000 defense = roughly a 41% chance", might have been adjusted a bit). I think the minimum is not 10%, I have had ppl invade superior def and they got 3-6% as their rate. The max 90% is correct however afaik. It seems to be a log equation similar to attacking NPC, with regard to the att/def ratio. And yeah it was wierd 4 failures @ 90% the other day from people, that was pretty strange.

wait a minute, you guys are saying that the attack of a planet doesnt count to its invasion defense?
i thought that both attack and defense of the planet are used to defend against invasion? even in the game, if you hover over the "attack", it says it reduces the chance the planet will be invaded
so what's the truth?
thank you

Yes, it does count.