When I played today, it was one asteroid per gravity which was not able to be used. I thought that I may be some new feature, such as the civilians having their own mining asteroid... however it is a bug and not a feature.
If such a type of thing were to be made into a feature, then possibly there should be a tax levied for civilian use of space objects, or something of the sort, so that there could be extra income if you needed it by leasing out an asteroid or a refinery or something of that kind. How would this sound?