The international space community is rapidly approaching the day when human colonies will orbit the Earth. Eventually, such colonies with populate the Solar System with human frontiers on Mars and possibly on Europa, one of Jupiter's moons. The ultimate goal will be the establishment of human colonies beyond the Solar System. One side effect will be interstellar commerce.
Such commerce will require a financial system based on a method of payment. In the U.S. payments are based on the dollar. In Europe, the Euro is used for financial exchange. There are eight major currencies in the world today and the value of each is continuously changing relative to each other. On Earth, changing currency values are annoying but usually a major problem.
Transaction times are typically short and do not usually cause transactions to be difficult. However, in space inter-colony distances are extremely long and information transit times can be minutes to days, and even years. Currency exchanges may not be possible. Therefore, creating and using a single currency among these colonies may be very practical.
This is an ideal situation for a cryptocurrency that is purely digital. The units of this currency should be uniquely identifiable. For example, we might want to use the "Digital Universal Currency," otherwise known as the DUC Coin. The value of the DUC could be set to the value of one US dollar.
A blockchain type system could be at the core of the DUC system. This is a ledger that records the rightful owner of every balance of DUC in existence. When you make a DUC transaction, you effectively announce to the system that you would like to transfer a balance of DUC on the ledger from one owner to another.
These transactions are grouped into a block and members on the system then compete to be the first person to confirm that the transactions in the block are legitimate. Once a block is confirmed, the ledger, or blockchain, is updated to reflect the most recent transactions.
On Earth, such transactions are almost instantaneous. So, cryptocurrencies transactions are recorded immediately. In space, transaction times may be much longer, possibly allowing hacking to occur while notifications are in transit.
Thus, there may have to be some adjustments to the blockchain operations. There is still lots of room for ideas and innovation here and someone like Satoshi Nakamoto may already have some of the answers.
