DTN is the outer space version of TCP.  Transmission control with the ability to store an forward large amounts of data in the event of a solar storm or other disruption.  It takes 4 to twenty minutes using DTN to transmit data from Mars to Earth, which, at the speed of light, accounts for ‘space lag’.  The protocol was co-designed by Internet luminary Vint Cerf and NASA. Now when do I get my flying car? Pretty cool, check it out.