In November 2010, The Spaceship Company had announced that it planned to build at least three additional White Knight Two aircraft and an additional five Space Ship Two rocket planes, the aircraft to be built by Virgin after the initial prototypes of each craft are built by Scaled Composites.
, it is not clear how many SS2 and WK2 vehicles will actually be built.
Their cargo delivered, they head back up the ramp and the van drives off.
This is the vision behind a new collaboration between delivery robot start-up Starship Technologies based in Tallinn, Estonia, and German car maker Mercedes-Benz.
A van pulls up in a village street and a ramp extends to the pavement from a side door.
A swarm of wheeled robots trundle down the ramp and head off down local streets on missions of their own.
In the meantime, ground-based delivery robots are ready to go.
The first White Knight Two is named VMS Eve after Richard Branson's mother Eve Branson; it was officially unveiled on July 28, 2008, and flew for the first time on December 21, 2008.