Hm, you can sell the items that give minerals from the Items room in the left of the secret base room.
The minerals you have in your mothership you will have to convert (manufacture) in a mining facility.
In order to do this, you will need a space station, then build the mining facility.
Then load the minerals in the mining facility, you may want to load every category of mineral so it makes more credits.
Then wait and every day drop by your mining facility and pick up the credits.
There is a guide here to help you setup your station and mining facility:
http://wiki.spaceo.net/index.php/Guide:Galaxy:EmpireThank you.
OMG !!
The reason I decide to NOT having a planet because I do not have quadrillions and quadrillions of cr.
Just check the cost of building a space station and stuff ....
I have trouble keeping alive as it is, where in the universe I can get enough CP and cr to get things done?