The move comes weeks after Scotland topped the shortlist for potential spaceport hubs, with six of the eight preferred UK bases located north of the Border.
Prestwick, Campbeltown and Stornoway airports were listed as possible locations for Europe's first spaceport, with RAF Leuchars, RAF Lossiemouth and Kinloss Barracks also under consideration.
The UK Government wants to establish a commercial spaceport by 2018.
Now a Memorandum of Cooperation agreed by government agencies either side of the Atlantic has expressed their desire to "encourage commercial transatlantic space travel" between the two nations.
The document has been signed by representatives of the Department for Transport, the Civil Aviation Authority and the UK Space Agency and, in the US, by the Office of Commercial Space Transportation, part of the Federal Aviation Administration.
The memorandum states: "The Participants intend for for enhanced cooperation to encourage free movement and operation of space transport vehicles between the US and UK.