Most've already been answered, but I'll throw in my two cents anyhow.
Q3: If I'm recalling correctly, this also serves as a means by which to establish diplomatic contact. Note that contact is established in two directions: Them -> you and you -> them, if that makes sense. Activating the transponder will count as the former if they have a presence in the system. Having a recon vessel discover one of their colonies with an active sensor counts as the latter (Among various other possibilities).
Q4: I'm looking at going for a massive R1 sensor on my flagships with a smaller (1/3 to 1/4th the size of the R1) R60 for ship detection. Any ship with PD will also get a small R1 sensor as backup.
I'll be skipping over the anti-FAC sensor as I'd need to make it over a quarter of the size of the R1 to get any benefit out of it at all.
Q6: For a shipping line to start constructing ships you need the following: A place for them to ship colonists/trade goods to and have a set of commercial freighters/colony ships designed for their use. The easiest way to get civilian construction started is to simply drop a batch of infrastructure on Mars.
For the commercial mining colonies, you need a body with at least 15k+ duranium and/or sorium with 0.7+ accessibility that has not already been flagged as a colony. You can establish a colony there after the initial CMC development and it will not interfere with further CMC development. I might be wrong with some of the details here, but I'm pretty sure this is accurate.
Q9: There's a thread that I remember reading that went into extensive detail here, will spend some time looking for it and edit it in instead of typing out pages worth of material that already exists.
Edit 2 response: Shipyards are of two
types,
naval/military and
commercial. Commercial ships ignore maintenance but have many restrictions placed on potential designs, the largest being that no weapons capable of offensive attacks can be mounted (So only CIWS). I'm pretty sure, however, that commercial ships can be built in naval shipyards, just not vice versa.
Edit for Q9: The original post has some out of date info, but the quoted part applies currently. There might've also been some tweaks to the calculation (You will, for instance, inflict more casualties the higher your offensive combat ratio gets. That mechanic was introduced to prevent small garrisons from holding out for extended periods of time when faced with overwhelming opposition).
Combat
Any race with GCU on a planet can choose to attack ground units or PDCs of another race on the same planet. Note that attacking and defending are two different actions so the attacked race may decide to remain on the defensive and not counter-attack. If both sides attack each other, two separate combats are calculated. As the combat is potentially covering the entire planet, each combat round takes place during the five day increment. If time is advanced by more than five days, one combat round takes place for every 5 days in the increment.
Attacking ground forces will have the option to concentrate their efforts on a specific PDC (based on sensor contacts) or fight a general action against enemy ground forces outside PDCs (if there are any). This is accomplished by choosing which PDC or Population to attack on the Ground Units tab of the Economics window. If a PDC is under attack, only the defenders of that specific PDC are able to take part in the defensive battle. However, troops can emerge from other PDCs to fight an offensive action against the attackers in the field and try to destroy them. Obviously this won?t be a good idea if there are enemy spacecraft within weapon range. If the attackers are concentrating on a specific PDC, the defenders are able to move around between other PDCs but are not able to reinforce a PDC under attack. In addition, the PDC under attack may not reload its magazines from the planetary stockpile.
If a PDC is captured (i.e. all ground forces within it are eliminated), it becomes part of the attacking player?s forces. He can move troops in to garrison it and the defenders may try to recapture it. There may be a chance the defender will attempt to blow up the PDC or damage its systems before it is captured, depending on his racial characteristics.
Combat Ratio and Casualties
When an attack is carried out, the total attack strength of the attacker is compared to the total defence strength of the defender to create the Combat Ratio. For example, if Race A had an attack strength of 300 and Race B had a defence strength of 200, the Combat Ratio would be 300 / 200 = 1.5. Although defenders do have an advantage, this is already built into the attack and defence strengths of each unit type so the combat ratio is unaffected unless a PDC is involved. If the defenders are in a PDC, they gain a defensive multiplier equal to one third of the PDC?s armour. For example, defenders with a total defence strength of 50 within a PDC with 8 armour would have a modified defence strength of 50 x 8/3 = 133.33.
Each defending unit has a percentage chance of being destroyed equal to the Combat Ratio multiplied by 10. For example, if the Combat Ratio was 2.7, then every defending unit would have a 27% chance of being destroyed.
Each attacking unit has a percentage chance of being destroyed equal to 10 divided by the Combat Ratio. For example, if the Combat Ratio was 2.2 then each attacking unit would have a 10/2.2 = 4.5% chance of being destroyed. If the Combat Ratio was 0.4 then each attacking unit would have a 10/0.4 = 25% chance of being destroyed. Note that for a combat ratio of 1.0, both sides will have a ten percent chance of losing each unit.
HQ units have only half the normal chance to be destroyed as they will tend to be behind the lines. There are no damaged ground units in Aurora. They are either at full strength or they are destroyed.
Morale
Each GCU starts with a Morale of 100. As long as its morale stays at this level it has no effect on combat. If the morale is increased or decreased, it affects both the attack and defence strengths of the unit. The modifier is equal to Strength x (Morale/100). For example, a unit with 110 Morale would have attack and defence strengths 10 percent higher than normal. A unit with 80 Morale would have attack and defence strengths 20 percent less than normal. In addition, when the roll is made after combat to determine if a unit is lost, the chance of being destroyed is divided by the unit?s Morale/100. For example, if a unit with 120 Morale has a fifteen percent chance to be destroyed, the modified chance = 15% / (120/100) = 12.5%, so this unit has now only a 12.5% chance of being destroyed. This simulates that lower morale units are more likely to be destroyed than higher morale units.
Commanders
Officers may be assign to command a division or headquarters unit in the same way as they command a ship, a population or a fighter group. An officer?s Ground Combat Bonus improves the attack and defence strengths of any GCU to which he is assigned. In addition, the Ground Combat Bonus of the most senior HQ commander within a PDC will modify the combat strengths of all other units in that same PDC and the Ground Combat Bonus of the most senior HQ commander outside a PDC will modify the combat strengths of all other units outside of PDCs.
Supply
Ground Combat Units do not require any type of supply.
Occupation
If all PDCs and defending ground units are eliminated, the attacking player may be in a position to conquer and occupy the defending population. The required garrison strength is based on the defence strength of the occupying force. The garrison strength required to force a surrender is equal to:
Pop in millions * Racial Determination/100 * Racial Militancy/100
For example, if the defenders have a population of 400m, a Determination of 60 and a Militancy of 50, the required garrison strength will be: 400 * (60/100) * (50/100) = 120. Note that this is a minimum amount required to force a surrender. It may be desirable to station a larger force on the planet to avoid disruption to its production facilities.
When a population is conquered, there is a chance some tech will be recovered by the occupying forces. A check is made against every background tech known by the conquered race but not the conquering race. The percentage chance of learning each tech is equal to Pop in million/5. For example, conquering a pop of 200m will yield a 40% chance of learning each background tech known by the conquered race.
Steve