yep that helped, thanks.
In the end I ended up winning the fight, but I'm very surprised.
At the beginning I had only an engineer brigade on that planet, roaming 150+ installations, looking for anything salvageable.
They ended up awakening some robots so I brought real troops (4 battalions).
Then, I think some troop transport dropped some reinforcements, total was probably about 10 marine battalions, and they were devastating the limited troops I had brought here
After a tactical retreat, I invaded back with 2 full regiments, and about 6 months later, I eliminate the last ennemies.
What's really a surprise (and may be a bug), is that a whole lot (21) of troop transports then surrender to me from everywhere in the galaxy !
6th April 2055 13:36:26,Rettig,As a result of the population surrender, the troop transport CA Combat Transport 019 has surrendered
6th April 2055 13:36:26,Rettig,As a result of the population surrender, the troop transport CA Combat Transport 017 has surrendered
6th April 2055 13:36:26,Hedwig,As a result of the population surrender, the troop transport CA Combat Transport 021 has surrendered
6th April 2055 13:36:26,Rettig,As a result of the population surrender, the troop transport CA Combat Transport 020 has surrendered
6th April 2055 13:36:26,Alfredhaar,As a result of the population surrender, the troop transport CA Combat Transport 007 has surrendered
6th April 2055 13:36:26,Yubangtaek,As a result of the population surrender, the troop transport CA Combat Transport 005 has surrendered
6th April 2055 13:36:26,Wasserman,As a result of the population surrender, the troop transport CA Combat Transport 003 has surrendered
6th April 2055 13:36:26,Camdenmille,As a result of the population surrender, the troop transport CA Combat Transport 016 has surrendered
6th April 2055 13:36:26,Kapteyns Star,As a result of the population surrender, the troop transport CA Combat Transport 002 has surrendered
6th April 2055 13:36:26,Gropius,As a result of the population surrender, the troop transport CA Combat Transport 015 has surrendered
6th April 2055 13:36:26,Fermat,As a result of the population surrender, the troop transport CA Combat Transport 013 has surrendered
6th April 2055 13:36:26,Alpha Centauri,As a result of the population surrender, the troop transport CA Combat Transport 001 has surrendered
6th April 2055 13:36:26,Sameergupta,As a result of the population surrender, the troop transport CA Combat Transport 012 has surrendered
6th April 2055 13:36:26,70 Ophiuchi,As a result of the population surrender, the troop transport CA Combat Transport 010 has surrendered
6th April 2055 13:36:26,Alfredhaar,As a result of the population surrender, the troop transport CA Combat Transport 008 has surrendered
Is that supposeed to happen ?
edit : actually all those transports are full of troops, so i'm now owning some 100 more troops, and most of those are in systems i'm not even aware of