Nasa's policy of outsourcing its cargo and crew transport needs is intended to find savings that can be ploughed back into building a rocket and capsule system capable of taking humans to more challenging destinations.

BBC: SpaceX capsule returns with safe landing in Pacific

Nasa's policy of outsourcing its cargo and crew transport needs is intended to find savings that can be ploughed back into building a rocket and capsule system capable of taking humans beyond low-Earth to more challenging destinations.

BBC: SpaceX lifts off with ISS cargo

The policy covers vessels carrying out an act of trade, which is landing passengers or cargo, with crew members' own cargo being among the allowed exceptions.

BBC: Sark shipping consultation begins