That's the whole idea that they cannot sync. Otherwise Earth miners would take over the Mars Blockchain. They have a discussion on this on their Forum and FAQ.

That's the whole idea that they cannot sync. Otherwise Earth miners would take over the Mars Blockchain. They have a discussion on this on their Forum and FAQ. Someone suggested an "Interplanetary Coin" with several hour long confirmations that would work as an intermediary between the two networks. You change your BTC into MRS upon departure and when you arrive a few weeks later you have a few confirmations in the IPC. On Mars you then convert your IPC into MRS :-)