As Ground Combat turns are 6 hours long and Naval Combat turns can be as short as 5 seconds, this means that a weapon in general/naval unit bombardment with a 5 second reload can fire 4 320 times during a single ground combat turn.
It would hit the wrong target some 1 450 times in that time, which is really inconvenient when you are trying to hit ground units instead of just doing a planetary destruction bombardment, but it's a thing. It would seem to me that the ground combat timescale or the undirected naval bombardment timescale need to be reconsidered.
C# ground combat is every 3 hours, while in VB6 is it every 5 days. Naval combat is the same in both cases, so the difference has already been reduced quite a lot. However, just as in real life, there is a difference between providing fire as needed to support relatively slow ground advances and simply blasting a whole area. It is like artillery support vs carpet bombing. The difference in Aurora vs real life is that for energy weapons there is no ammunition so you can constantly carpet bomb. That is why I introduced the rules on weapon failure and the rules on dust creation for energy weapon fire.
For example, you could fire a 5-second weapon (lets assume a 10cm laser costing 20 BP) 2160 times in 3 hours, which will cause a dust level of 324 and suffer 43 weapon failures at a cost of 860 MSP. If you are firing at fully fortified infantry, you will kill about 24 of them. You will kill far fewer on a planet with rough terrain. That is also assuming the planet isn't defended with Surface-To-Orbit weapons, so you are free to carry out the bombardment.
If you do decide to go ahead, then you are going to be hitting the installations and population because that is where the infantry is likely to be. Blasting fortified defenders out of a city is not usually pleasant for the city - its meant to be inconvenient. To shift determined infantry, you will likely need to send in your own or use nuclear bombardment and accept the massive collateral damage (assuming the point defence STOs don't shoot down the missiles).
The simple fact is that ground combat and naval combat operate on different timescales. Even when naval units provide support to ground forces in real life, that is not a constant barrage but usually to eliminate particular strong points. That is what the Orbital Bombardment Support is intended to simulate. If you want to forget ground combat and try to smash the defenders from orbit, you can operate on naval timescales because you don't have to wait for the ground forces. However, you have to accept that digging out the defenders by applying massive firepower is going to cause equally massive collateral damage.
Note that if you do engage identified STO units (because they fired at you), the chance to hit will be much higher because you know exactly where they are. It will 100% base instead of 6.7%, although still subject to terrain and defender fortification. That will all take place on naval timescales (like ships attacking a shore battery). I will cover that situation in a different rules post. Plus, all of this is subject to play test and may change as a result.