The Stellar Credit (SC) is a currency used in-game for claiming and maintaining Deeds for colonies and Outer Star Bases (OSB).
Stellar Credits are obtained by purchasing in-game premiums at a rate of $1 United States Dollars (USD) per month per premium (see Premium Access). Stellar Credits are assigned daily pro rata at 100 SC per premium per month. You can purchase additional Stellar Credits above your subscription if you want to own more colonies and Outer Star Bases. If you purchased all three premiums, you will receive 300 SC per month (roughly 10 SC per day). When you first purchase your premium subscriptions, you do not receive all your Stellar Credits immediately.
80 SC is required to claim a Deed and 80 SC per month is required to maintain the deed. If you construct an Outer Star Base with no link to a Deed, then the OSB costs 40 SC to set-up and 40 SC per month maintenance. The maintenance fee is automatic.