NX-2000
From Tardis Wiki, the free Doctor Who reference
The NX-2000 was an experimental spacecraft which underwent test flights during the 21st century. The tests were mentioned by The Department during their coverage of a "dissident attack" that later turned out to be nothing more than a publicity stunt on their part. (K9TV: The Bounty Hunter)
Behind the Scenes
The NX-2000 is a reference to the USS Excelsior of the Star Trek franchise which had a starship registry of NX-2000 in the third, fourth, and fifth Star Trek films.